Coverage for little_loops / cli / loop / layout.py: 3%
1155 statements
« prev ^ index » next coverage.py v7.12.0, created at 2026-06-08 15:34 -0500
1"""FSM diagram layout engine.
3Implements adaptive layout for FSM diagrams using a Sugiyama-inspired
4layered graph drawing approach. Supports topology detection, vertical
5linear chains, side-by-side branching, and margin back-edge rendering.
7Extracted from info.py and extended with adaptive layout capabilities.
8"""
10from __future__ import annotations
12import re
13from collections import deque
15from wcwidth import wcswidth as _wcswidth
16from wcwidth import wcwidth as _wcwidth
18from little_loops.cli.output import colorize, strip_ansi, terminal_width
19from little_loops.fsm.schema import FSMLoop, StateConfig
21# ---------------------------------------------------------------------------
22# Edge label colorization
23# ---------------------------------------------------------------------------
25_EDGE_LABEL_COLORS: dict[str, str] = {
26 "yes": "32",
27 "no": "38;5;208",
28 "error": "31",
29 "partial": "33",
30 "next": "2",
31 "_": "2",
32 "blocked": "31",
33 "retry_exhausted": "38;5;208",
34 "rate_limit_exhausted": "38;5;214",
35 "throttle_hard": "38;5;196",
36}
39def _colorize_label(label: str) -> str:
40 """Colorize a (possibly compound) edge label like 'no/error'."""
41 parts = label.split("/")
42 code = ""
43 for part in parts:
44 if part in ("no", "error"):
45 code = _EDGE_LABEL_COLORS["no"]
46 break
47 if part == "partial" and not code:
48 code = _EDGE_LABEL_COLORS["partial"]
49 elif part == "yes" and not code:
50 code = _EDGE_LABEL_COLORS["yes"]
51 elif part in ("next", "_") and not code:
52 code = _EDGE_LABEL_COLORS["next"]
53 return colorize(label, code) if code else label
56def _edge_line_color(label: str) -> str:
57 """Return the ANSI SGR code to use for connector characters of an edge.
59 Applies the same priority cascade as ``_colorize_label`` so that line
60 characters (│, ─, ▼, ▶, corners) match the semantic color of their label.
61 Returns an empty string when no color applies (callers treat this as "no-op").
62 """
63 parts = label.split("/")
64 code = ""
65 for part in parts:
66 if part in (
67 "no",
68 "error",
69 "blocked",
70 "retry_exhausted",
71 "rate_limit_exhausted",
72 "throttle_hard",
73 ):
74 return _EDGE_LABEL_COLORS.get(part, "31")
75 if part == "partial" and not code:
76 code = _EDGE_LABEL_COLORS["partial"]
77 elif part == "yes" and not code:
78 code = _EDGE_LABEL_COLORS["yes"]
79 elif part in ("next", "_") and not code:
80 code = _EDGE_LABEL_COLORS["next"]
81 return code
84def _colorize_diagram_labels(diagram: str, colors: dict[str, str] | None = None) -> str:
85 """Apply ANSI color to known edge labels in a rendered diagram string.
87 Labels are colorized only when bounded by box-drawing or whitespace chars
88 to avoid coloring partial matches inside state names.
90 Args:
91 colors: Optional label→SGR-code mapping; falls back to _EDGE_LABEL_COLORS if None.
92 """
93 label_colors = colors if colors is not None else _EDGE_LABEL_COLORS
94 for label, code in label_colors.items():
95 colored = colorize(label, code)
96 diagram = re.sub(
97 r"(?<=[─ │▶\n])" + re.escape(label) + r"(?=[─ │▶\n])",
98 colored,
99 diagram,
100 )
101 return diagram
104# ---------------------------------------------------------------------------
105# State box badge definitions
106# ---------------------------------------------------------------------------
108_ACTION_TYPE_BADGES: dict[str, str] = {
109 "prompt": "\u2726", # ✦
110 "slash_command": "/\u2501\u25ba", # /━►
111 "shell": "\u276f_", # ❯_
112 "mcp_tool": "\u26a1", # ⚡
113}
115_SUB_LOOP_BADGE = "\u21b3\u27f3" # ↳⟳
116_ROUTE_BADGE = "\u2443" # ⑃
119def _badge_display_width(badge: str) -> int:
120 """Compute terminal display width of a badge string using wcwidth."""
121 w = _wcswidth(badge)
122 return w if w >= 0 else len(badge)
125def _get_state_badge(state: StateConfig | None, badges: dict[str, str] | None = None) -> str:
126 """Return the unicode badge string for a state, or '' if none."""
127 if state is None:
128 return ""
129 effective = {**_ACTION_TYPE_BADGES, **(badges or {})}
130 sub_loop_badge = (badges or {}).get("sub_loop", _SUB_LOOP_BADGE)
131 route_badge = (badges or {}).get("route", _ROUTE_BADGE)
132 if state.loop is not None:
133 return sub_loop_badge
134 if state.action_type:
135 return effective.get(state.action_type, f"[{state.action_type}]")
136 if state.action:
137 return effective["shell"]
138 if state.route is not None:
139 return route_badge
140 return ""
143# ---------------------------------------------------------------------------
144# Box content helpers for multi-row diagram boxes
145# ---------------------------------------------------------------------------
148def _box_inner_lines(
149 state: StateConfig | None,
150 display_label: str,
151 verbose: bool,
152 inner_width: int,
153 title_only: bool = False,
154) -> list[str]:
155 """Return interior lines for a state box (between top and bottom borders).
157 The first line is always ``display_label`` + type badge (if any).
158 Subsequent lines are action content lines. All lines fit within
159 ``inner_width`` characters (content is truncated or wrapped accordingly).
161 When ``title_only`` is True, only the name row is returned (used by
162 ``--show-diagrams=mini`` for skeleton rendering).
163 """
164 # Badge is now rendered in the top-right corner by _draw_box; name row is label only
165 name_line = display_label[:inner_width]
167 lines: list[str] = [name_line]
169 if title_only:
170 return lines
172 # Action lines
173 if state and state.action:
174 action_src = [ln.rstrip() for ln in state.action.strip().splitlines()]
175 if verbose:
176 for src in action_src:
177 if not src:
178 continue
179 # Wrap long lines to inner_width
180 while len(src) > inner_width:
181 lines.append(src[:inner_width])
182 src = src[inner_width:]
183 if src:
184 lines.append(src)
185 else:
186 # Show first non-empty line, truncated
187 first = next((ln for ln in action_src if ln), "")
188 if len(first) > inner_width:
189 first = first[: inner_width - 1] + "\u2026"
190 if first:
191 lines.append(first)
193 return lines
196# ---------------------------------------------------------------------------
197# Topology detection
198# ---------------------------------------------------------------------------
201def _collect_edges(fsm: FSMLoop) -> list[tuple[str, str, str]]:
202 """Collect all (source, target, label) edges from an FSM."""
203 edges: list[tuple[str, str, str]] = []
204 for name, state in fsm.states.items():
205 if state.on_yes:
206 edges.append((name, state.on_yes, "yes"))
207 if state.on_no:
208 edges.append((name, state.on_no, "no"))
209 if state.on_error:
210 edges.append((name, state.on_error, "error"))
211 if state.on_partial:
212 edges.append((name, state.on_partial, "partial"))
213 if state.on_blocked:
214 edges.append((name, state.on_blocked, "blocked"))
215 if state.on_retry_exhausted:
216 edges.append((name, state.on_retry_exhausted, "retry_exhausted"))
217 if state.on_rate_limit_exhausted:
218 edges.append((name, state.on_rate_limit_exhausted, "rate_limit_exhausted"))
219 if state.on_throttle_hard:
220 edges.append((name, state.on_throttle_hard, "throttle_hard"))
221 if state.next:
222 edges.append((name, state.next, "next"))
223 if state.route:
224 for verdict, target in state.route.routes.items():
225 edges.append((name, target, verdict))
226 if state.route.default:
227 edges.append((name, state.route.default, "_"))
228 for verdict, target in state.extra_routes.items():
229 edges.append((name, target, verdict))
230 return edges
233def _bfs_order(initial: str, edges: list[tuple[str, str, str]]) -> tuple[list[str], dict[str, int]]:
234 """BFS from initial state. Returns (order, depth_map)."""
235 order: list[str] = []
236 depth: dict[str, int] = {initial: 0}
237 queue: deque[str] = deque([initial])
238 while queue:
239 node = queue.popleft()
240 order.append(node)
241 for src, dst, _ in edges:
242 if src == node and dst not in depth:
243 depth[dst] = depth[node] + 1
244 queue.append(dst)
245 return order, depth
248def _trace_main_path(
249 fsm: FSMLoop, edges: list[tuple[str, str, str]]
250) -> tuple[list[str], set[tuple[str, str]]]:
251 """Trace the main (happy) path through the FSM."""
252 visited: set[str] = set()
253 main_path: list[str] = []
254 main_edge_set: set[tuple[str, str]] = set()
255 current = fsm.initial
256 while current and current not in visited:
257 visited.add(current)
258 main_path.append(current)
259 st = fsm.states.get(current)
260 if not st or st.terminal:
261 break
262 nxt: str = st.on_yes or st.next or ""
263 if not nxt and st.route:
264 nxt = next(iter(st.route.routes.values()), "") or st.route.default or ""
265 if nxt:
266 main_edge_set.add((current, nxt))
267 current = nxt
268 else:
269 break
270 return main_path, main_edge_set
273def _classify_edges(
274 edges: list[tuple[str, str, str]],
275 main_edge_set: set[tuple[str, str]],
276 bfs_order: list[str],
277) -> tuple[list[tuple[str, str, str]], list[tuple[str, str, str]]]:
278 """Split non-main edges into branches and back_edges."""
279 main_consumed: set[int] = set()
280 for src, dst in main_edge_set:
281 for i, (s, d, _) in enumerate(edges):
282 if s == src and d == dst and i not in main_consumed:
283 main_consumed.add(i)
284 break
286 branches: list[tuple[str, str, str]] = []
287 back_edges: list[tuple[str, str, str]] = []
288 for i, (src, dst, label) in enumerate(edges):
289 if i in main_consumed:
290 continue
291 src_pos = bfs_order.index(src) if src in bfs_order else len(bfs_order)
292 dst_pos = bfs_order.index(dst) if dst in bfs_order else len(bfs_order)
293 if dst == src or dst_pos < src_pos:
294 back_edges.append((src, dst, label))
295 else:
296 branches.append((src, dst, label))
297 return branches, back_edges
300class TopologyDetector:
301 """Classify FSM graph topology for layout strategy selection."""
303 def __init__(
304 self,
305 edges: list[tuple[str, str, str]],
306 main_path: list[str],
307 branches: list[tuple[str, str, str]],
308 back_edges: list[tuple[str, str, str]],
309 ) -> None:
310 self._edges = edges
311 self._main_path = main_path
312 self._branches = branches
313 self._back_edges = back_edges
315 def classify(self) -> str:
316 """Return 'linear', 'tree', or 'general'.
318 Linear: main path only, no non-self branches, only self-loop back-edges.
319 Tree: branches exist but no fan-in (every non-initial state has ≤1 incoming).
320 General: everything else (full Sugiyama needed).
321 """
322 non_self_branches = [b for b in self._branches if b[0] != b[1]]
323 non_self_back = [b for b in self._back_edges if b[0] != b[1]]
325 if not non_self_branches and not non_self_back:
326 return "linear"
328 # Check for fan-in: any state with >1 incoming forward edge
329 in_count: dict[str, int] = {}
330 for _, dst, _ in self._edges:
331 # Only count forward edges (not back-edges)
332 in_count[dst] = in_count.get(dst, 0) + 1
334 if not non_self_back and all(v <= 1 for v in in_count.values()):
335 return "tree"
337 return "general"
340# ---------------------------------------------------------------------------
341# Sugiyama layout pipeline
342# ---------------------------------------------------------------------------
345class LayerAssigner:
346 """Assign nodes to layers using longest-path + width constraint."""
348 def __init__(
349 self,
350 all_states: list[str],
351 edges: list[tuple[str, str, str]],
352 back_edge_set: set[tuple[str, str]],
353 initial: str,
354 max_width: int = 4,
355 ) -> None:
356 self._all_states = all_states
357 self._edges = edges
358 self._back_edge_set = back_edge_set
359 self._initial = initial
360 self._max_width = max_width
362 def assign(self) -> list[list[str]]:
363 """Return list of layers, each a list of state names (top to bottom)."""
364 # Build adjacency (forward edges only)
365 forward: dict[str, list[str]] = {s: [] for s in self._all_states}
366 reverse: dict[str, list[str]] = {s: [] for s in self._all_states}
367 seen_edges: set[tuple[str, str]] = set()
368 for src, dst, _ in self._edges:
369 if (src, dst) in self._back_edge_set or src == dst:
370 continue
371 if src in forward and dst in forward and (src, dst) not in seen_edges:
372 forward[src].append(dst)
373 reverse[dst].append(src)
374 seen_edges.add((src, dst))
376 # Longest-path layer assignment (topological order)
377 layer_of: dict[str, int] = {}
379 # Kahn's algorithm for topological order
380 in_degree = {s: len(reverse[s]) for s in self._all_states}
381 queue: deque[str] = deque()
382 for s in self._all_states:
383 if in_degree[s] == 0:
384 queue.append(s)
386 topo_order: list[str] = []
387 while queue:
388 node = queue.popleft()
389 topo_order.append(node)
390 for dst in forward[node]:
391 in_degree[dst] -= 1
392 if in_degree[dst] == 0:
393 queue.append(dst)
395 # Handle nodes not reached by topo sort (cycles in forward graph)
396 for s in self._all_states:
397 if s not in set(topo_order):
398 topo_order.append(s)
400 # Assign layers: longest path from root
401 for node in topo_order:
402 if not reverse[node]:
403 layer_of[node] = 0
404 else:
405 layer_of[node] = max(
406 (layer_of.get(p, 0) + 1 for p in reverse[node]),
407 default=0,
408 )
410 # Ensure initial state is at layer 0
411 if self._initial in layer_of and layer_of[self._initial] != 0:
412 offset = layer_of[self._initial]
413 for s in layer_of:
414 layer_of[s] -= offset
416 # Build layers list
417 max_layer = max(layer_of.values(), default=0)
418 layers: list[list[str]] = [[] for _ in range(max_layer + 1)]
419 for s in self._all_states:
420 layer = layer_of.get(s, 0)
421 layers[layer].append(s)
423 # Width constraint: if any layer exceeds max_width, split
424 if self._max_width > 0:
425 new_layers: list[list[str]] = []
426 for grp in layers:
427 remaining = list(grp)
428 while len(remaining) > self._max_width:
429 new_layers.append(remaining[: self._max_width])
430 remaining = remaining[self._max_width :]
431 if remaining:
432 new_layers.append(remaining)
433 layers = new_layers
435 return layers
438class CrossingMinimizer:
439 """Minimize edge crossings using barycenter heuristic."""
441 def __init__(
442 self,
443 layers: list[list[str]],
444 edges: list[tuple[str, str, str]],
445 back_edge_set: set[tuple[str, str]],
446 ) -> None:
447 self._layers = layers
448 self._edges = edges
449 self._back_edge_set = back_edge_set
451 def minimize(self) -> list[list[str]]:
452 """Return reordered layers with reduced crossings."""
453 # Build position lookup
454 layer_of: dict[str, int] = {}
455 for i, layer in enumerate(self._layers):
456 for s in layer:
457 layer_of[s] = i
459 # Forward adjacency (non-back, non-self)
460 adj_down: dict[str, list[str]] = {}
461 adj_up: dict[str, list[str]] = {}
462 for src, dst, _ in self._edges:
463 if (src, dst) in self._back_edge_set or src == dst:
464 continue
465 if src in layer_of and dst in layer_of:
466 adj_down.setdefault(src, []).append(dst)
467 adj_up.setdefault(dst, []).append(src)
469 layers = [list(layer) for layer in self._layers]
471 # 3 sweeps: down, up, down
472 for sweep in range(3):
473 if sweep % 2 == 0:
474 # Top-down sweep
475 for i in range(1, len(layers)):
476 pos_above = {s: j for j, s in enumerate(layers[i - 1])}
477 bary: dict[str, float] = {}
478 for s in layers[i]:
479 parents = [p for p in adj_up.get(s, []) if p in pos_above]
480 if parents:
481 bary[s] = sum(pos_above[p] for p in parents) / len(parents)
482 else:
483 bary[s] = float(layers[i].index(s))
484 layers[i].sort(key=lambda s: bary.get(s, 0))
485 else:
486 # Bottom-up sweep
487 for i in range(len(layers) - 2, -1, -1):
488 pos_below = {s: j for j, s in enumerate(layers[i + 1])}
489 bary_up: dict[str, float] = {}
490 for s in layers[i]:
491 children = [c for c in adj_down.get(s, []) if c in pos_below]
492 if children:
493 bary_up[s] = sum(pos_below[c] for c in children) / len(children)
494 else:
495 bary_up[s] = float(layers[i].index(s))
496 layers[i].sort(key=lambda s: bary_up.get(s, 0))
498 return layers
501# ---------------------------------------------------------------------------
502# Rendering helpers
503# ---------------------------------------------------------------------------
506def _compute_display_labels(
507 all_states: list[str],
508 initial: str,
509 terminal_states: set[str],
510) -> dict[str, str]:
511 """Compute display labels with → prefix and ◉ suffix."""
512 display_label: dict[str, str] = {}
513 for s in all_states:
514 label = s
515 if s == initial:
516 label = "\u2192 " + label
517 if s in terminal_states:
518 label = label + " \u25c9"
519 display_label[s] = label
520 return display_label
523def _compute_box_sizes(
524 all_states: list[str],
525 display_label: dict[str, str],
526 fsm_states: dict[str, StateConfig] | None,
527 verbose: bool,
528 max_box_inner: int,
529 badges: dict[str, str] | None = None,
530 title_only: bool = False,
531) -> tuple[dict[str, list[str]], dict[str, int], dict[str, int], dict[str, str]]:
532 """Compute box content, widths, and heights for all states.
534 Returns (box_inner, box_width, box_height, box_badge).
536 When ``title_only`` is True, action body lines are suppressed (used by
537 ``--show-diagrams=mini`` for skeleton rendering); box widths are computed
538 from the name label / badge only.
539 """
540 box_inner: dict[str, list[str]] = {}
541 box_width: dict[str, int] = {}
542 box_badge: dict[str, str] = {}
544 for s in all_states:
545 state_obj = fsm_states.get(s) if fsm_states else None
547 badge = _get_state_badge(state_obj, badges)
548 badge_w = _badge_display_width(badge) if badge else 0
549 box_badge[s] = badge
551 # Width must fit: name label on content row, badge on top border (with one space
552 # of padding on each side: " badge ")
553 base_w = max(len(display_label[s]), badge_w + 2 if badge_w else 0)
555 inner_w = base_w
556 if not title_only and state_obj and state_obj.action and max_box_inner > 0:
557 action_lines = state_obj.action.strip().splitlines()
558 if verbose:
559 max_action_w = max(
560 (len(ln.rstrip()) for ln in action_lines if ln.rstrip()), default=0
561 )
562 inner_w = max(base_w, min(max_action_w, max_box_inner))
563 else:
564 first_action = next((ln.rstrip() for ln in action_lines if ln.rstrip()), "")
565 inner_w = max(base_w, min(len(first_action), max_box_inner))
567 content = _box_inner_lines(
568 state_obj, display_label[s], verbose, inner_w, title_only=title_only
569 )
570 actual_w = max(len(ln) for ln in content)
571 inner_w = max(inner_w, actual_w)
572 box_inner[s] = content
573 box_width[s] = inner_w + 4 # "│ " + content + " │"
575 box_height: dict[str, int] = {s: len(box_inner[s]) + 2 for s in all_states}
576 return box_inner, box_width, box_height, box_badge
579def _draw_box(
580 grid: list[list[str]],
581 row: int,
582 col: int,
583 width: int,
584 height: int,
585 content: list[str],
586 is_highlighted: bool,
587 highlight_color: str,
588 badge: str = "",
589) -> None:
590 """Draw a state box onto a character grid at (row, col).
592 If *badge* is provided it is placed right-aligned in the top border row with
593 one space of padding on each side (``─ badge ┐``), colorized via ``_bc()``.
594 """
595 total_width = len(grid[0]) if grid else 0
596 try:
597 bg_code: str | None = str(int(highlight_color) + 10)
598 except (ValueError, TypeError):
599 bg_code = None
601 def _bc(ch: str) -> str:
602 if not is_highlighted:
603 return ch
604 if bg_code:
605 return colorize(ch, f"{highlight_color};{bg_code}")
606 return colorize(ch, highlight_color)
608 # Top border: ┌ ─ ─ … ─ ┐
609 if col < total_width:
610 grid[row][col] = _bc("\u250c")
611 for j in range(1, width - 1):
612 if col + j < total_width:
613 grid[row][col + j] = _bc("\u2500")
614 if col + width - 1 < total_width:
615 grid[row][col + width - 1] = _bc("\u2510")
617 # Overlay badge in top-right corner with one space of padding on each side: " badge ┐"
618 if badge:
619 badge_w = _badge_display_width(badge)
620 # Trailing space between badge end and ┐
621 trail_pos = col + width - 2
622 if col + 1 <= trail_pos < col + width - 1 and trail_pos < total_width:
623 grid[row][trail_pos] = _bc(" ")
624 # Leading space before badge
625 lead_pos = col + width - badge_w - 3
626 if col + 1 <= lead_pos < col + width - 1 and lead_pos < total_width:
627 grid[row][lead_pos] = _bc(" ")
628 # Badge characters (shifted left by 1 compared to no-padding placement)
629 pos = col + width - 1 - badge_w - 1
630 for ch in badge:
631 ch_w = _wcwidth(ch)
632 if ch_w < 1:
633 ch_w = 1
634 if col + 1 <= pos < col + width - 1 and pos < total_width:
635 grid[row][pos] = _bc(ch)
636 if ch_w == 2 and pos + 1 < col + width - 1 and pos + 1 < total_width:
637 grid[row][pos + 1] = ""
638 pos += ch_w
640 # Pre-fill all interior cells with bg color so padding rows and gaps are filled
641 if is_highlighted and bg_code:
642 for ri in range(row + 1, row + height - 1):
643 if ri >= len(grid):
644 break
645 for ci in range(col + 1, col + width - 1):
646 if ci < total_width:
647 grid[ri][ci] = colorize(" ", bg_code)
649 # Content rows
650 for i, line in enumerate(content):
651 r = row + i + 1
652 if r >= len(grid):
653 break
654 if col < total_width:
655 grid[r][col] = _bc("\u2502")
656 if col + width - 1 < total_width:
657 grid[r][col + width - 1] = _bc("\u2502")
658 if is_highlighted and i == 0:
659 name_code = f"97;{bg_code};1" if bg_code else f"{highlight_color};1"
660 colored_line = colorize(line, name_code)
661 if col + 2 < total_width:
662 grid[r][col + 2] = colored_line
663 for j in range(1, len(line)):
664 if col + 2 + j < col + width - 1:
665 grid[r][col + 2 + j] = ""
666 elif i == 0:
667 bold_line = colorize(line, "1")
668 if col + 2 < total_width:
669 grid[r][col + 2] = bold_line
670 for j in range(1, len(line)):
671 if col + 2 + j < col + width - 1:
672 grid[r][col + 2 + j] = ""
673 else:
674 for j, ch in enumerate(line):
675 if col + 2 + j < col + width - 1:
676 if is_highlighted and bg_code:
677 grid[r][col + 2 + j] = colorize(ch, f"97;{bg_code}")
678 else:
679 grid[r][col + 2 + j] = ch
681 # Padding rows between content and bottom border
682 for i in range(len(content) + 1, height - 1):
683 r = row + i
684 if r >= len(grid):
685 break
686 if col < total_width:
687 grid[r][col] = _bc("\u2502")
688 if col + width - 1 < total_width:
689 grid[r][col + width - 1] = _bc("\u2502")
691 # Bottom border
692 brow = row + height - 1
693 if brow < len(grid):
694 if col < total_width:
695 grid[brow][col] = _bc("\u2514")
696 for j in range(1, width - 1):
697 if col + j < total_width:
698 grid[brow][col + j] = _bc("\u2500")
699 if col + width - 1 < total_width:
700 grid[brow][col + width - 1] = _bc("\u2518")
703# ---------------------------------------------------------------------------
704# Layered (vertical) renderer
705# ---------------------------------------------------------------------------
708def _render_layered_diagram(
709 layers: list[list[str]],
710 edges: list[tuple[str, str, str]],
711 main_edge_set: set[tuple[str, str]],
712 branches: list[tuple[str, str, str]],
713 back_edges: list[tuple[str, str, str]],
714 initial: str,
715 terminal_states: set[str] | None,
716 fsm_states: dict[str, StateConfig] | None,
717 verbose: bool,
718 highlight_state: str | None,
719 highlight_color: str,
720 edge_label_colors: dict[str, str] | None = None,
721 badges: dict[str, str] | None = None,
722 title_only: bool = False,
723 suppress_labels: bool = False,
724) -> str:
725 """Render FSM using layered (Sugiyama-style) vertical layout.
727 When ``title_only`` is True, per-state body lines are suppressed.
728 When ``suppress_labels`` is True, inter-state edges render without labels.
729 """
730 terminal_states = terminal_states or set()
731 fsm_states = fsm_states or {}
732 tw = terminal_width()
734 # Flatten layers to get all states
735 all_states = [s for layer in layers for s in layer]
736 if not all_states:
737 return ""
739 display_label = _compute_display_labels(all_states, initial, terminal_states)
741 # Compute max_box_inner based on widest layer
742 max_layer_size = max(len(layer) for layer in layers)
743 if verbose:
744 max_box_inner = max(20, min(60, (tw - 4) // max(1, max_layer_size) - 6))
745 else:
746 max_box_inner = max(20, min(40, (tw - 4) // max(1, max_layer_size) - 6))
748 box_inner, box_width, box_height, box_badge = _compute_box_sizes(
749 all_states,
750 display_label,
751 fsm_states,
752 verbose,
753 max_box_inner,
754 badges,
755 title_only=title_only,
756 )
758 # Post-hoc layer merge: re-merge adjacent single-state layers that were
759 # over-split by the conservative max_width_per_layer estimate. Only merge
760 # when both layers receive an edge from the same source state (indicating
761 # they were originally one layer split by width constraint).
762 available_w = tw - 20 # conservative content-area estimate
763 gap_between = 6
764 # Build edge target sets: for each state, which earlier states point to it
765 _incoming: dict[str, set[str]] = {s: set() for layer in layers for s in layer}
766 for src, dst, _ in edges:
767 if src != dst and dst in _incoming:
768 _incoming[dst].add(src)
769 merged = True
770 while merged:
771 merged = False
772 i = 0
773 while i < len(layers) - 1:
774 la, lb = layers[i], layers[i + 1]
775 # Only merge single-state layers that share an incoming source
776 if len(la) == 1 and len(lb) == 1:
777 sources_a = _incoming.get(la[0], set())
778 sources_b = _incoming.get(lb[0], set())
779 shared_source = sources_a & sources_b
780 else:
781 shared_source = set()
782 combined_w = (
783 sum(box_width[s] for s in la)
784 + gap_between * (len(la) - 1)
785 + gap_between
786 + sum(box_width[s] for s in lb)
787 + gap_between * (len(lb) - 1)
788 )
789 if shared_source and combined_w <= available_w and len(la) + len(lb) <= 4:
790 layers[i] = la + lb
791 layers.pop(i + 1)
792 merged = True
793 else:
794 i += 1
796 # Collect ALL non-self-loop forward edge labels (main + branches + same-depth back-edges)
797 # Multiple edges between the same pair are combined as "label1/label2"
798 forward_edge_labels: dict[tuple[str, str], str] = {}
799 for src, dst, lbl in edges:
800 if src == dst:
801 continue
802 if (src, dst) in main_edge_set or (src, dst, lbl) in branches:
803 if (src, dst) in forward_edge_labels:
804 forward_edge_labels[(src, dst)] += "/" + lbl
805 else:
806 forward_edge_labels[(src, dst)] = lbl
808 # True back-edges: only those going to an earlier layer (computed after layer assignment)
809 # Will be finalized below after col positions are computed
810 # Combine same-pair back-edges into single entries with merged labels (e.g. "error/fail")
811 back_edge_labels_initial: dict[tuple[str, str], str] = {}
812 for s, d, lbl in back_edges:
813 if s != d:
814 if (s, d) in back_edge_labels_initial:
815 back_edge_labels_initial[(s, d)] += "/" + lbl
816 else:
817 back_edge_labels_initial[(s, d)] = lbl
819 # Pre-compute layer positions to detect main-path cycle edges early.
820 # This ensures back_edge_margin accounts for ALL backward-pointing edges
821 # (including main-path cycles like commit → initial_state) before column
822 # positions are computed.
823 prelim_layer_of: dict[str, int] = {}
824 for li, layer in enumerate(layers):
825 for s in layer:
826 prelim_layer_of[s] = li
828 # Include main-path/branch edges that point backward in margin estimate
829 all_back_labels: dict[tuple[str, str], str] = dict(back_edge_labels_initial)
830 for (src, dst), lbl in forward_edge_labels.items():
831 src_layer = prelim_layer_of.get(src, -1)
832 dst_layer = prelim_layer_of.get(dst, -1)
833 if dst_layer < src_layer:
834 if (src, dst) in all_back_labels:
835 all_back_labels[(src, dst)] += "/" + lbl
836 else:
837 all_back_labels[(src, dst)] = lbl
839 non_self_back_initial = [(s, d, lbl) for (s, d), lbl in all_back_labels.items()]
840 back_edge_margin = 0
841 if non_self_back_initial:
842 max_label_len = max(len(lbl) for _, _, lbl in non_self_back_initial)
843 n_back_initial = len(non_self_back_initial)
844 back_edge_margin = max_label_len + max(6, 2 * n_back_initial + 2)
846 content_left = 2 + back_edge_margin
848 # Self-loops per state
849 self_loops: dict[str, list[str]] = {}
850 for src, dst, lbl in back_edges:
851 if src == dst:
852 self_loops.setdefault(src, []).append(lbl)
854 # --- Compute a common center column for alignment ---
855 # For layers with single boxes, we want vertical alignment through a
856 # shared center column. Use the widest single-state layer's center.
857 max_single_w = max((box_width[layer[0]] for layer in layers if len(layer) == 1), default=0)
858 # The common center is at content_left + max_single_w // 2
859 common_center = content_left + max_single_w // 2
861 # Compute column positions per layer
862 col_start: dict[str, int] = {}
863 col_center: dict[str, int] = {}
864 layer_of: dict[str, int] = {}
866 for li, layer in enumerate(layers):
867 if len(layer) == 1:
868 # Single-state layer: center-align to common center
869 sname = layer[0]
870 col_start[sname] = common_center - box_width[sname] // 2
871 col_center[sname] = common_center
872 layer_of[sname] = li
873 else:
874 # Multi-state layer: place side-by-side, centered around common_center
875 gap_between = 6
876 total_layer_w = sum(box_width[s] for s in layer) + gap_between * (len(layer) - 1)
877 x = common_center - total_layer_w // 2
878 x = max(content_left, x)
879 for i, sname in enumerate(layer):
880 col_start[sname] = x
881 col_center[sname] = x + box_width[sname] // 2
882 layer_of[sname] = li
883 if i < len(layer) - 1:
884 next_s = layer[i + 1]
885 # Check for edge labels in both directions between adjacent states
886 label_fwd = forward_edge_labels.get((sname, next_s), "")
887 label_rev = forward_edge_labels.get((next_s, sname), "")
888 max_label = max(len(label_fwd), len(label_rev))
889 gap = max(gap_between, max_label + 6) if max_label > 0 else gap_between
890 x += box_width[sname] + gap
891 else:
892 x += box_width[sname]
894 # Reclassify back-edges based on actual layer positions
895 # Only edges going to an earlier layer are true margin back-edges
896 # Combine same-pair edges into merged labels (e.g. "error/fail")
897 back_edge_labels_reclass: dict[tuple[str, str], str] = {}
898 same_layer_edges: list[tuple[str, str, str]] = []
899 for src, dst, lbl in back_edges:
900 if src == dst:
901 continue
902 src_layer = layer_of.get(src, -1)
903 dst_layer = layer_of.get(dst, -1)
904 if dst_layer < src_layer:
905 if (src, dst) in back_edge_labels_reclass:
906 back_edge_labels_reclass[(src, dst)] += "/" + lbl
907 else:
908 back_edge_labels_reclass[(src, dst)] = lbl
909 elif dst_layer == src_layer:
910 same_layer_edges.append((src, dst, lbl))
911 else: # dst_layer > src_layer: actually forward edge
912 if (src, dst) in forward_edge_labels:
913 forward_edge_labels[(src, dst)] += "/" + lbl
914 else:
915 forward_edge_labels[(src, dst)] = lbl
917 # Also reclassify main/branch edges in forward_edge_labels that point backward
918 # after layer assignment (e.g. main-path cycle edges like commit → initial_state)
919 backward_in_fwd: list[tuple[str, str]] = []
920 for (src, dst), lbl in forward_edge_labels.items():
921 src_layer = layer_of.get(src, -1)
922 dst_layer = layer_of.get(dst, -1)
923 if dst_layer < src_layer:
924 backward_in_fwd.append((src, dst))
925 if (src, dst) in back_edge_labels_reclass:
926 back_edge_labels_reclass[(src, dst)] += "/" + lbl
927 else:
928 back_edge_labels_reclass[(src, dst)] = lbl
929 elif dst_layer == src_layer and src != dst:
930 backward_in_fwd.append((src, dst))
931 same_layer_edges.append((src, dst, lbl))
932 for key in backward_in_fwd:
933 del forward_edge_labels[key]
935 # Add same-layer back-edges to forward_edge_labels so gap calculation accounts for them
936 for src, dst, lbl in same_layer_edges:
937 if (src, dst) in forward_edge_labels:
938 forward_edge_labels[(src, dst)] += "/" + lbl
939 else:
940 forward_edge_labels[(src, dst)] = lbl
942 # Recalculate inter-box gaps for layers with newly discovered same-layer edges
943 affected_layers: set[int] = set()
944 for src, dst, _lbl in same_layer_edges:
945 sl = layer_of.get(src, -1)
946 dl = layer_of.get(dst, -1)
947 if sl >= 0:
948 affected_layers.add(sl)
949 if dl >= 0:
950 affected_layers.add(dl)
951 for li in affected_layers:
952 layer = layers[li]
953 if len(layer) < 2:
954 continue
955 gap_between = 6
956 total_layer_w = sum(box_width[s] for s in layer)
957 # For non-adjacent same-layer edges the label lands in the gap immediately
958 # adjacent to the source box (left of src for right-to-left, right of src
959 # for left-to-right). Collect those requirements so the gap is wide enough.
960 extra_gap_req: dict[tuple[str, str], int] = {}
961 for src, dst, lbl in same_layer_edges:
962 if layer_of.get(src) != li or layer_of.get(dst) != li:
963 continue
964 try:
965 si, di = layer.index(src), layer.index(dst)
966 except ValueError:
967 continue
968 if abs(si - di) <= 1:
969 continue # adjacent — already handled by forward_edge_labels
970 if si > di:
971 key = (layer[si - 1], src) # gap to the left of src
972 else:
973 key = (src, layer[si + 1]) # gap to the right of src
974 extra_gap_req[key] = max(extra_gap_req.get(key, 0), len(lbl))
975 # Recalculate gaps with label-aware spacing
976 gaps: list[int] = []
977 for i in range(len(layer) - 1):
978 sname, next_s = layer[i], layer[i + 1]
979 label_fwd = forward_edge_labels.get((sname, next_s), "")
980 label_rev = forward_edge_labels.get((next_s, sname), "")
981 max_label = max(len(label_fwd), len(label_rev), extra_gap_req.get((sname, next_s), 0))
982 gap = max(gap_between, max_label + 6) if max_label > 0 else gap_between
983 gaps.append(gap)
984 total_layer_w += sum(gaps)
985 x = common_center - total_layer_w // 2
986 x = max(content_left, x)
987 for i, sname in enumerate(layer):
988 col_start[sname] = x
989 col_center[sname] = x + box_width[sname] // 2
990 if i < len(layer) - 1:
991 x += box_width[sname] + gaps[i]
992 else:
993 x += box_width[sname]
995 non_self_back = [(s, d, lbl) for (s, d), lbl in back_edge_labels_reclass.items()]
997 # Recalculate back-edge margin if it changed
998 if non_self_back:
999 max_label_len = max(len(lbl) for _, _, lbl in non_self_back)
1000 n_back = len(non_self_back)
1001 actual_margin = max_label_len + max(6, 2 * n_back + 2)
1002 if actual_margin != back_edge_margin:
1003 # Need to recalculate positions (rare case - usually matches)
1004 back_edge_margin = actual_margin
1005 content_left = 2 + back_edge_margin
1007 # Identify forward skip-layer edges (span > 1 layer, not handled by consecutive renderer)
1008 skip_forward_edges: list[tuple[str, str, str]] = []
1009 for (src, dst), lbl in forward_edge_labels.items():
1010 src_layer = layer_of.get(src, -1)
1011 dst_layer = layer_of.get(dst, -1)
1012 if dst_layer > src_layer + 1:
1013 skip_forward_edges.append((src, dst, lbl))
1015 # Pre-compute right margin width for forward skip-layer edges
1016 right_edge_margin = 0
1017 if skip_forward_edges:
1018 max_fwd_label_len = max(len(lbl) for _, _, lbl in skip_forward_edges)
1019 right_edge_margin = max_fwd_label_len + 6
1021 # Compute total width needed
1022 total_content_w = 0
1023 for s in all_states:
1024 right = col_start[s] + box_width[s]
1025 total_content_w = max(total_content_w, right)
1026 total_width = max(total_content_w + right_edge_margin + 4, tw)
1028 # Compute vertical positions with space for self-loops and inter-layer arrows
1029 row_start: dict[str, int] = {}
1030 y = 0
1031 for li, layer in enumerate(layers):
1032 layer_h = max(box_height[s] for s in layer)
1033 for sname in layer:
1034 row_start[sname] = y
1035 y += layer_h
1037 # Add self-loop row if any state in this layer has self-loops
1038 has_self_loop = any(s in self_loops for s in layer)
1039 if has_self_loop:
1040 y += 1 # self-loop marker row
1042 if li < len(layers) - 1:
1043 y += 2 if suppress_labels else 3 # arrow gap: suppress_labels skips label row
1045 total_height = y
1047 # Build character grid
1048 grid: list[list[str]] = [[" "] * total_width for _ in range(total_height)]
1050 # Draw boxes
1051 for sname in all_states:
1052 is_highlighted = highlight_state is not None and sname == highlight_state
1053 _draw_box(
1054 grid,
1055 row_start[sname],
1056 col_start[sname],
1057 box_width[sname],
1058 box_height[sname],
1059 box_inner[sname],
1060 is_highlighted,
1061 highlight_color,
1062 badge=box_badge[sname],
1063 )
1065 # Precompute box-occupied (row, col) pairs so connector lines can avoid overwriting box cells
1066 _box_occ: dict[int, set[int]] = {}
1067 for _s in all_states:
1068 for _r in range(row_start[_s], row_start[_s] + box_height[_s]):
1069 _row_set = _box_occ.setdefault(_r, set())
1070 for _c in range(col_start[_s], col_start[_s] + box_width[_s]):
1071 _row_set.add(_c)
1073 # Draw self-loop markers immediately below their boxes
1074 for sname, labels in self_loops.items():
1075 marker = "\u21ba" if suppress_labels else "\u21ba " + ", ".join(labels)
1076 r = row_start[sname] + box_height[sname]
1077 if r < total_height:
1078 cx = col_center[sname]
1079 pos = max(0, cx - len(marker) // 2)
1080 for j, ch in enumerate(marker):
1081 if pos + j < total_width:
1082 grid[r][pos + j] = ch
1084 # Shared row tracker: prevents two labels (back-edge, skip-forward, or adjacent)
1085 # landing on the same grid row, which would clobber the first label written there.
1086 used_label_rows: set[int] = set()
1088 # Draw forward edges between layers (vertical arrows with labels)
1089 for li in range(len(layers) - 1):
1090 layer_h = max(box_height[s] for s in layers[li])
1091 has_self_loop = any(s in self_loops for s in layers[li])
1092 self_loop_offset = 1 if has_self_loop else 0
1094 # Arrow area starts after box bottom + self-loop row
1095 arrow_start_row = row_start[layers[li][0]] + layer_h + self_loop_offset
1096 arrow_end_row = row_start[layers[li + 1][0]] - 1
1098 # Collect all inter-layer edges from this layer to the next
1099 inter_edges: list[tuple[str, str, str]] = []
1100 for src in layers[li]:
1101 for dst in layers[li + 1]:
1102 label = forward_edge_labels.get((src, dst))
1103 if label is not None:
1104 inter_edges.append((src, dst, label))
1106 # Draw each edge with its own vertical pipe to the target's center
1107 for src, dst, label in inter_edges:
1108 dst_cc = col_center[dst]
1109 src_left = col_start[src]
1110 src_right = src_left + box_width[src]
1111 ec = _edge_line_color(label) # ANSI code for this edge's connector chars
1113 def _lc(ch: str, _ec: str = ec) -> str: # noqa: E306
1114 return colorize(ch, _ec) if _ec else ch
1116 # Horizontal connector when pipe is outside source box range
1117 if dst_cc >= src_right or dst_cc < src_left:
1118 conn_row = arrow_start_row
1119 if 0 <= conn_row < total_height:
1120 if dst_cc >= src_right:
1121 # Pipe right of source: └───┐
1122 src_cc = col_center[src]
1123 if 0 <= src_cc < total_width and grid[conn_row][src_cc] == " ":
1124 grid[conn_row][src_cc] = _lc("\u2514") # └
1125 start_c = src_cc + 1
1126 else:
1127 start_c = src_right
1128 for c in range(start_c, dst_cc):
1129 if 0 <= c < total_width:
1130 grid[conn_row][c] = _lc("\u2500")
1131 if 0 <= dst_cc < total_width:
1132 grid[conn_row][dst_cc] = _lc("\u2510") # ┐
1133 else:
1134 # Pipe left of source: ┌───┘
1135 src_cc = col_center[src]
1136 if 0 <= src_cc < total_width and grid[conn_row][src_cc] == " ":
1137 end_c = src_cc
1138 grid[conn_row][src_cc] = _lc("\u2518") # ┘
1139 else:
1140 end_c = src_left
1141 for c in range(dst_cc + 1, end_c):
1142 if 0 <= c < total_width:
1143 grid[conn_row][c] = _lc("\u2500")
1144 if 0 <= dst_cc < total_width:
1145 grid[conn_row][dst_cc] = _lc("\u250c") # ┌
1146 pipe_start = arrow_start_row + 1
1147 else:
1148 pipe_start = arrow_start_row
1150 # Draw vertical pipe at destination's center column
1151 for r in range(pipe_start, arrow_end_row):
1152 if 0 <= dst_cc < total_width and r < total_height:
1153 grid[r][dst_cc] = _lc("\u2502")
1155 # Arrow tip at destination center
1156 if arrow_end_row < total_height and 0 <= dst_cc < total_width:
1157 grid[arrow_end_row][dst_cc] = _lc("\u25bc")
1159 # Label to the right of the pipe. When skip-layer forward edges
1160 # exist their vertical pipes occupy columns starting at
1161 # total_content_w+2, so clamp to total_content_w to avoid
1162 # overwriting them (BUG-1500). Without skip-layer edges the right
1163 # margin is empty and the full total_width is available.
1164 label_row = arrow_start_row
1165 # Nudge if this row already has a label from another inter-layer edge
1166 # (e.g., two edges from the same source go to states in the same layer).
1167 # Try pipe rows (pipe_start..arrow_end_row) before giving up (BUG-1501).
1168 if label_row in used_label_rows:
1169 for _cand in range(pipe_start, arrow_end_row + 1):
1170 if _cand not in used_label_rows:
1171 label_row = _cand
1172 break
1173 if label_row < total_height and not suppress_labels:
1174 used_label_rows.add(label_row)
1175 label_start = dst_cc + 2
1176 max_col = total_content_w if skip_forward_edges else total_width
1177 max_label = max_col - label_start
1178 if 0 < max_label < len(label):
1179 label = label[: max_label - 1] + "…"
1180 for j, ch in enumerate(label):
1181 if label_start + j < max_col:
1182 grid[label_row][label_start + j] = ch
1184 # Post-pass: connect horizontal gaps for multi-branch sources
1185 if len(inter_edges) >= 2 and 0 <= arrow_start_row < total_height:
1186 src_targets: dict[str, list[int]] = {}
1187 for src, dst, _ in inter_edges:
1188 if dst in col_center:
1189 src_targets.setdefault(src, []).append(col_center[dst])
1190 for _src, centers in src_targets.items():
1191 if len(centers) < 2:
1192 continue
1193 left = min(centers)
1194 right = max(centers)
1195 for c in range(left + 1, right):
1196 if 0 <= c < total_width:
1197 cell = grid[arrow_start_row][c]
1198 if cell == " ":
1199 grid[arrow_start_row][c] = "\u2500" # ─
1200 elif cell == "\u2502": # │ → ┼
1201 grid[arrow_start_row][c] = "\u253c"
1202 elif cell == "\u2518": # ┘ → ┴
1203 grid[arrow_start_row][c] = "\u2534"
1204 elif cell == "\u2514": # └ → ┴
1205 grid[arrow_start_row][c] = "\u2534"
1206 elif cell == "\u2510": # ┐ → ┬
1207 grid[arrow_start_row][c] = "\u252c"
1208 elif cell == "\u250c": # ┌ → ┬
1209 grid[arrow_start_row][c] = "\u252c"
1210 # Update boundary junction chars where the horizontal bar meets a pipe
1211 if 0 <= left < total_width and grid[arrow_start_row][left] == "\u2502": # │ → ├
1212 grid[arrow_start_row][left] = "\u251c"
1213 if 0 <= right < total_width and grid[arrow_start_row][right] == "\u2502": # │ → ┤
1214 grid[arrow_start_row][right] = "\u2524"
1216 # Draw same-layer edges (horizontal arrows between states on same layer)
1217 # Includes both branches and reclassified back-edges within same layer
1218 all_same_layer: list[tuple[str, str, str]] = list(same_layer_edges)
1219 for _li, layer in enumerate(layers):
1220 for i, src in enumerate(layer):
1221 for j, dst in enumerate(layer):
1222 if i == j:
1223 continue
1224 label = forward_edge_labels.get((src, dst))
1225 if label is not None and (src, dst, label) not in all_same_layer:
1226 all_same_layer.append((src, dst, label))
1228 for src, dst, label in all_same_layer:
1229 if src not in col_start or dst not in col_start:
1230 continue
1231 if suppress_labels:
1232 label = ""
1233 name_row = row_start[src] + 1
1234 src_right = col_start[src] + box_width[src]
1235 dst_right = col_start[dst] + box_width[dst]
1236 dst_left = col_start[dst]
1237 src_left = col_start[src]
1238 _row_boxes = _box_occ.get(name_row, set())
1239 ec = _edge_line_color(label)
1241 def _lc(ch: str, _ec: str = ec) -> str: # noqa: E306
1242 return colorize(ch, _ec) if _ec else ch
1244 if dst_left >= src_right:
1245 # Left to right horizontal arrow: src ──label──▶ dst
1246 start = src_right
1247 end = dst_left
1248 edge_text = "\u2500" + label + "\u2500\u2500\u25b6"
1249 available = end - start
1250 if available < len(edge_text):
1251 edge_text = edge_text[: max(1, available)]
1252 left_dashes = max(0, available - len(edge_text))
1253 for k in range(left_dashes):
1254 pos = start + k
1255 if pos < total_width and name_row < total_height and pos not in _row_boxes:
1256 grid[name_row][pos] = _lc("\u2500")
1257 for k, ch in enumerate(edge_text):
1258 pos = start + left_dashes + k
1259 if (
1260 0 <= pos < end
1261 and pos < total_width
1262 and name_row < total_height
1263 and pos not in _row_boxes
1264 ):
1265 grid[name_row][pos] = _lc(ch)
1266 elif dst_right <= src_left:
1267 # Right to left: dst is left of src: src → dst drawn as dst ◀──label── src
1268 start = dst_right
1269 end = src_left
1270 edge_text = "\u25c4\u2500\u2500" + label + "\u2500"
1271 available = end - start
1272 if available < len(edge_text):
1273 edge_text = edge_text[: max(1, available)]
1274 for k, ch in enumerate(edge_text):
1275 pos = start + k
1276 if (
1277 0 <= pos < end
1278 and pos < total_width
1279 and name_row < total_height
1280 and pos not in _row_boxes
1281 ):
1282 grid[name_row][pos] = _lc(ch)
1283 for k in range(start + len(edge_text), end):
1284 if k < total_width and name_row < total_height and k not in _row_boxes:
1285 grid[name_row][k] = _lc("\u2500")
1287 # Back-edges: left-margin vertical arrows with labels
1288 if non_self_back:
1289 sorted_back = sorted(
1290 non_self_back,
1291 key=lambda e: abs(row_start.get(e[0], 0) - row_start.get(e[1], 0)),
1292 reverse=True,
1293 )
1294 used_cols: list[int] = []
1295 # Compute rightmost pipe column so labels go right of ALL pipes
1296 rightmost_pipe_col = 1 + (len(sorted_back) - 1) * 2
1298 for src, dst, label in sorted_back:
1299 # Source: name row of source box; target: name row of target box
1300 src_row = row_start.get(src, 0) + 1 # name row, not bottom border
1301 dst_row = row_start.get(dst, 0) + 1 # name row
1303 # Find a free column in the margin
1304 col = 1
1305 for uc in sorted(used_cols):
1306 if uc == col:
1307 col += 2
1308 used_cols.append(col)
1310 if col >= content_left - 1:
1311 continue
1313 top_row = min(src_row, dst_row)
1314 bot_row = max(src_row, dst_row)
1315 ec = _edge_line_color(label)
1317 def _lc(ch: str, _ec: str = ec) -> str: # noqa: E306
1318 return colorize(ch, _ec) if _ec else ch
1320 # Draw vertical line in margin (exclude corner rows handled below)
1321 for r in range(top_row + 1, bot_row):
1322 if 0 <= r < total_height and col < total_width:
1323 cell = grid[r][col]
1324 if cell == "\u2500": # ─ → ┼ (junction, leave uncolored)
1325 grid[r][col] = "\u253c"
1326 elif cell == " ":
1327 grid[r][col] = _lc("\u2502")
1329 # Horizontal connector from source box to margin
1330 # Draw right-to-left, crossing existing pipes with junction chars
1331 if 0 <= src_row < total_height:
1332 src_left = col_start.get(src, col + 1)
1333 _src_row_boxes = _box_occ.get(src_row, set())
1334 for c in range(col + 1, src_left):
1335 if c < total_width and c not in _src_row_boxes:
1336 cell = grid[src_row][c]
1337 if cell == " ":
1338 grid[src_row][c] = _lc("\u2500") # ─
1339 elif cell == "\u2502": # │ → ┼ (junction)
1340 grid[src_row][c] = "\u253c"
1341 elif cell == "\u2514": # └ → ┴ (junction)
1342 grid[src_row][c] = "\u2534"
1343 elif cell == "\u250c": # ┌ → ┬ (junction)
1344 grid[src_row][c] = "\u252c"
1345 elif cell == "\u251c": # ├ → ┼ (junction)
1346 grid[src_row][c] = "\u253c"
1347 # Leave ─, ▶, box chars unchanged
1349 # Horizontal connector from margin to target box
1350 # Draw right-to-left, crossing existing pipes with junction chars
1351 dst_left = col_start.get(dst, col + 1)
1352 if 0 <= dst_row < total_height:
1353 _dst_row_boxes = _box_occ.get(dst_row, set())
1354 for c in range(col + 1, dst_left):
1355 if c < total_width and c not in _dst_row_boxes:
1356 cell = grid[dst_row][c]
1357 if cell == " ":
1358 grid[dst_row][c] = _lc("\u2500") # ─
1359 elif cell == "\u2502": # │ → ┼ (junction)
1360 grid[dst_row][c] = "\u253c"
1361 elif cell == "\u2514": # └ → ┴ (junction)
1362 grid[dst_row][c] = "\u2534"
1363 elif cell == "\u250c": # ┌ → ┬ (junction)
1364 grid[dst_row][c] = "\u252c"
1365 elif cell == "\u251c": # ├ → ┼ (junction)
1366 grid[dst_row][c] = "\u253c"
1368 # Corner characters at pipe-to-horizontal turn points
1369 for row in (src_row, dst_row):
1370 if 0 <= row < total_height and col < total_width:
1371 existing = grid[row][col]
1372 if row == bot_row:
1373 # Pipe ends, turns right: └; if horizontal already crosses here: ┴
1374 grid[row][col] = "\u2534" if existing == "\u2500" else _lc("\u2514")
1375 else: # row == top_row
1376 # Pipe starts going down, turns right: ┌; if horizontal already crosses here: ┬
1377 grid[row][col] = "\u252c" if existing == "\u2500" else _lc("\u250c")
1379 # Arrow tip at target: place ▶ at end of horizontal connector (entering box from left)
1380 if 0 <= dst_row < total_height and dst_left - 1 > col and dst_left - 1 < total_width:
1381 grid[dst_row][dst_left - 1] = _lc("\u25b6")
1383 # Label on the margin line (right of ALL pipes, not just this one)
1384 label_row_pos = (top_row + bot_row) // 2
1385 # Nudge away from already-used rows to prevent clobbering earlier labels
1386 if label_row_pos in used_label_rows and top_row + 1 < bot_row:
1387 midpoint = label_row_pos
1388 found = False
1389 for _off in range(1, bot_row - top_row):
1390 for _cand in (midpoint - _off, midpoint + _off):
1391 if top_row < _cand < bot_row and _cand not in used_label_rows:
1392 label_row_pos = _cand
1393 found = True
1394 break
1395 if found:
1396 break
1397 if not found:
1398 label_row_pos = top_row + 1
1399 used_label_rows.add(label_row_pos)
1400 if 0 <= label_row_pos < total_height and not title_only:
1401 label_start = rightmost_pipe_col + 2
1402 for j, ch in enumerate(label):
1403 if label_start + j < content_left - 1 and label_start + j < total_width:
1404 grid[label_row_pos][label_start + j] = _lc(ch)
1406 # Forward skip-layer edges: right-margin vertical arrows with labels
1407 # Symmetric to the left-margin back-edge renderer above
1408 if skip_forward_edges:
1409 sorted_fwd_skip = sorted(
1410 skip_forward_edges,
1411 key=lambda e: abs(row_start.get(e[0], 0) - row_start.get(e[1], 0)),
1412 reverse=True,
1413 )
1414 used_fwd_cols: list[int] = []
1415 # Rightmost pipe column (furthest from content) for label placement
1416 rightmost_fwd_pipe_col = total_content_w + 2 + (len(sorted_fwd_skip) - 1) * 2
1418 for src, dst, label in sorted_fwd_skip:
1419 src_row = row_start.get(src, 0) + 1 # name row
1420 dst_row = row_start.get(dst, 0) + 1 # name row
1422 # Allocate column in right margin (starting from content edge, going right)
1423 col = total_content_w + 2
1424 for uc in sorted(used_fwd_cols):
1425 if uc == col:
1426 col += 2
1427 used_fwd_cols.append(col)
1429 if col >= total_width:
1430 continue
1432 top_row = min(src_row, dst_row)
1433 bot_row = max(src_row, dst_row)
1434 ec = _edge_line_color(label)
1436 def _lc(ch: str, _ec: str = ec) -> str: # noqa: E306
1437 return colorize(ch, _ec) if _ec else ch
1439 # Draw vertical line in right margin (exclude corner rows handled below)
1440 for r in range(top_row + 1, bot_row):
1441 if 0 <= r < total_height and col < total_width:
1442 cell = grid[r][col]
1443 if cell == "\u2500": # ─ → ┼ (junction)
1444 grid[r][col] = "\u253c"
1445 elif cell == " ":
1446 grid[r][col] = _lc("\u2502")
1448 # Horizontal connector from source box right side to margin
1449 # Draw left-to-right, crossing existing pipes with junction chars
1450 src_right = col_start.get(src, 0) + box_width.get(src, 0)
1451 _src_row_boxes = _box_occ.get(src_row, set())
1452 if 0 <= src_row < total_height:
1453 for c in range(src_right, col):
1454 if 0 <= c < total_width and c not in _src_row_boxes:
1455 cell = grid[src_row][c]
1456 if cell == " ":
1457 grid[src_row][c] = _lc("\u2500") # ─
1458 elif cell == "\u2502": # │ → ┼ (junction)
1459 grid[src_row][c] = "\u253c"
1460 elif cell == "\u2518": # ┘ → ┴ (junction)
1461 grid[src_row][c] = "\u2534"
1462 elif cell == "\u2510": # ┐ → ┬ (junction)
1463 grid[src_row][c] = "\u252c"
1464 elif cell == "\u2524": # ┤ → ┼ (junction)
1465 grid[src_row][c] = "\u253c"
1466 # Leave ─, ◀, box chars unchanged
1468 # Horizontal connector from margin to destination box right side
1469 dst_right = col_start.get(dst, 0) + box_width.get(dst, 0)
1470 _dst_row_boxes = _box_occ.get(dst_row, set())
1471 if 0 <= dst_row < total_height:
1472 for c in range(dst_right, col):
1473 if 0 <= c < total_width and c not in _dst_row_boxes:
1474 cell = grid[dst_row][c]
1475 if cell == " ":
1476 grid[dst_row][c] = _lc("\u2500") # ─
1477 elif cell == "\u2502": # │ → ┼ (junction)
1478 grid[dst_row][c] = "\u253c"
1479 elif cell == "\u2518": # ┘ → ┴ (junction)
1480 grid[dst_row][c] = "\u2534"
1481 elif cell == "\u2510": # ┐ → ┬ (junction)
1482 grid[dst_row][c] = "\u252c"
1483 elif cell == "\u2524": # ┤ → ┼ (junction)
1484 grid[dst_row][c] = "\u253c"
1486 # Corner characters at pipe-to-horizontal turn points
1487 for row in (src_row, dst_row):
1488 if 0 <= row < total_height and col < total_width:
1489 existing = grid[row][col]
1490 if row == bot_row:
1491 # Pipe ends, turns left: ┘; if horizontal crosses: ┤
1492 grid[row][col] = "\u2524" if existing == "\u2500" else _lc("\u2518")
1493 else: # row == top_row
1494 # Pipe starts going down, turns left: ┐; if horizontal crosses: ┤
1495 grid[row][col] = "\u2524" if existing == "\u2500" else _lc("\u2510")
1497 # Arrow tip at target: ◀ entering box from right side
1498 if 0 <= dst_row < total_height and dst_right < col and dst_right < total_width:
1499 grid[dst_row][dst_right] = _lc("\u25c0")
1501 # Label on the margin line (right of ALL pipes, mirroring left-margin
1502 # approach). Truncate with … when label would exceed total_width
1503 # to prevent extending diagram lines far past the content area (BUG-1500).
1504 label_row_pos = (top_row + bot_row) // 2
1505 # Nudge to avoid row collision with a previously-placed label (back- or fwd-edge)
1506 if label_row_pos in used_label_rows and top_row + 1 < bot_row:
1507 midpoint = label_row_pos
1508 found = False
1509 for _off in range(1, bot_row - top_row):
1510 for _cand in (midpoint - _off, midpoint + _off):
1511 if top_row < _cand < bot_row and _cand not in used_label_rows:
1512 label_row_pos = _cand
1513 found = True
1514 break
1515 if found:
1516 break
1517 if not found:
1518 label_row_pos = top_row + 1
1519 used_label_rows.add(label_row_pos)
1520 if 0 <= label_row_pos < total_height and not title_only:
1521 label_start = rightmost_fwd_pipe_col + 2
1522 max_label = total_width - label_start
1523 if 0 < max_label < len(label):
1524 label = label[: max_label - 1] + "…"
1525 for j, ch in enumerate(label):
1526 if label_start + j < total_width:
1527 grid[label_row_pos][label_start + j] = _lc(ch)
1529 # Convert grid to string
1530 lines = ["".join(row).rstrip() for row in grid]
1532 # Remove trailing empty lines
1533 while lines and not lines[-1].strip():
1534 lines.pop()
1536 # Center diagram
1537 max_line_len = max((len(strip_ansi(ln)) for ln in lines), default=0)
1538 diagram_indent = max(0, (tw - max_line_len) // 2)
1539 if diagram_indent > 0:
1540 lines = [" " * diagram_indent + ln if ln.strip() else ln for ln in lines]
1542 return _colorize_diagram_labels("\n".join(lines), edge_label_colors)
1545# ---------------------------------------------------------------------------
1546# FSM diagram renderer (main entry point)
1547# ---------------------------------------------------------------------------
1550_MAIN_PATH_EDGE_LABELS: frozenset[str] = frozenset({"yes", "no", "next", "_"})
1553def _filter_main_path_graph(
1554 fsm: FSMLoop, edges: list[tuple[str, str, str]]
1555) -> tuple[list[tuple[str, str, str]], set[str]]:
1556 """Filter edges to the main happy-path subgraph and the states reachable through it.
1558 Drops off-happy-path labels (anything not in ``_MAIN_PATH_EDGE_LABELS`` and not
1559 a ``route``-verdict label) plus any state unreachable from ``fsm.initial`` once
1560 those edges are gone. Route-verdict labels (everything emitted by ``state.route``
1561 other than the default ``_``) are kept since routes encode normal branching.
1562 """
1563 route_verdicts: set[str] = set()
1564 for _name, state in fsm.states.items():
1565 if state.route is not None:
1566 route_verdicts.update(state.route.routes.keys())
1567 route_verdicts.update(state.extra_routes.keys())
1569 def _is_main_label(label: str) -> bool:
1570 return label in _MAIN_PATH_EDGE_LABELS or label in route_verdicts
1572 filtered_edges = [(s, t, lbl) for (s, t, lbl) in edges if _is_main_label(lbl)]
1573 _bfs_visited_order, depth_map = _bfs_order(fsm.initial, filtered_edges)
1574 reachable: set[str] = set(depth_map.keys())
1575 filtered_edges = [
1576 (s, t, lbl) for (s, t, lbl) in filtered_edges if s in reachable and t in reachable
1577 ]
1578 return filtered_edges, reachable
1581def _render_fsm_diagram(
1582 fsm: FSMLoop,
1583 verbose: bool = False,
1584 highlight_state: str | None = None,
1585 highlight_color: str = "32",
1586 edge_label_colors: dict[str, str] | None = None,
1587 badges: dict[str, str] | None = None,
1588 mode: str = "full",
1589 *,
1590 suppress_labels: bool = False,
1591 title_only: bool = False,
1592) -> str:
1593 """Render an adaptive text diagram of the FSM graph.
1595 Detects FSM topology and selects appropriate layout:
1596 - Linear chains: vertical top-to-bottom
1597 - Branching/cyclic: layered Sugiyama-style
1599 Args:
1600 fsm: The FSM loop to render.
1601 verbose: If True, show expanded action content in boxes.
1602 highlight_state: If provided, render this state's box with the highlight color.
1603 highlight_color: ANSI SGR code for the highlighted state (default: green).
1604 edge_label_colors: Optional label→SGR-code mapping for transition labels.
1605 Falls back to hardcoded defaults when None.
1606 badges: Optional glyph-key→string mapping for state type badges.
1607 Falls back to hardcoded defaults when None.
1608 mode: Controls edge scope: "main" (default when filtering active) hides
1609 off-happy-path edges. "full" renders every edge and state. "mini" is
1610 an alias for main-scope; use ``suppress_labels=True, title_only=True``
1611 instead. Callers that need full-detail dumps (e.g. ``ll-loop info``)
1612 keep the default "full".
1613 suppress_labels: If True, edge labels are omitted from all rendered edges.
1614 title_only: If True, state boxes show only the state name (no action body).
1615 """
1616 edges = _collect_edges(fsm)
1617 if mode in ("main", "mini"):
1618 edges, _reachable = _filter_main_path_graph(fsm, edges)
1619 bfs_order_list, bfs_depth = _bfs_order(fsm.initial, edges)
1620 main_path, main_edge_set = _trace_main_path(fsm, edges)
1621 branches, back_edges = _classify_edges(edges, main_edge_set, bfs_order_list)
1623 terminal_states = {name for name, state in fsm.states.items() if state.terminal}
1625 # Collect all states
1626 all_states = list(main_path)
1627 for src, dst, _ in branches:
1628 for s in (src, dst):
1629 if s not in all_states:
1630 all_states.append(s)
1632 # Topology detection
1633 detector = TopologyDetector(edges, main_path, branches, back_edges)
1634 topology = detector.classify()
1636 # Build back-edge set for layout pipeline
1637 back_edge_set: set[tuple[str, str]] = set()
1638 for src, dst, _ in back_edges:
1639 if src != dst:
1640 back_edge_set.add((src, dst))
1642 tw = terminal_width()
1644 if topology == "linear" and len(all_states) <= 1:
1645 # Single state or empty — use simple horizontal
1646 return _render_horizontal_simple(
1647 main_path,
1648 edges,
1649 main_edge_set,
1650 branches,
1651 back_edges,
1652 bfs_order_list,
1653 fsm.initial,
1654 terminal_states,
1655 fsm.states,
1656 verbose,
1657 highlight_state,
1658 highlight_color,
1659 edge_label_colors,
1660 badges,
1661 title_only=title_only or (mode == "mini"),
1662 suppress_labels=suppress_labels or (mode == "mini"),
1663 )
1665 # Compute max node width to determine width constraint
1666 # Quick estimate: widest state name or badge + padding
1667 max_node_w = 30 # reasonable default
1668 for s in all_states:
1669 st = fsm.states.get(s)
1670 badge = _get_state_badge(st, badges)
1671 badge_w = _badge_display_width(badge) if badge else 0
1672 label = s
1673 if s == fsm.initial:
1674 label = "\u2192 " + label
1675 if s in terminal_states:
1676 label = label + " \u25c9"
1677 w = max(len(label), badge_w)
1678 max_node_w = max(max_node_w, w + 4 + 4) # inner + borders + padding
1680 max_width_per_layer = max(1, (tw - 10) // (max_node_w + 4))
1682 # Layer assignment
1683 assigner = LayerAssigner(all_states, edges, back_edge_set, fsm.initial, max_width_per_layer)
1684 layers = assigner.assign()
1686 # Crossing minimization
1687 minimizer = CrossingMinimizer(layers, edges, back_edge_set)
1688 layers = minimizer.minimize()
1690 return _render_layered_diagram(
1691 layers,
1692 edges,
1693 main_edge_set,
1694 branches,
1695 back_edges,
1696 fsm.initial,
1697 terminal_states,
1698 fsm.states,
1699 verbose,
1700 highlight_state,
1701 highlight_color,
1702 edge_label_colors,
1703 badges,
1704 title_only=title_only or (mode == "mini"),
1705 suppress_labels=suppress_labels or (mode == "mini"),
1706 )
1709_PREV_STATE_COLOR = "33" # ANSI orange/yellow border for the just-prior FSM state.
1712def _render_neighborhood_diagram(
1713 fsm: FSMLoop,
1714 active_state: str,
1715 *,
1716 edge_label_colors: dict[str, str] | None = None,
1717 badges: dict[str, str] | None = None,
1718 highlight_color: str = "32",
1719 mode: str = "full",
1720 prev_state: str | None = None,
1721) -> str:
1722 """Render a compact 1-hop neighborhood: predecessors → [active] → successors.
1724 Suitable as a fallback when the full FSM diagram does not fit the viewport.
1725 Bounded: ``max(len(preds), len(succs), 1) * 3`` rows (each state box is 3
1726 lines tall). Returns the empty string when ``active_state`` is not in
1727 ``fsm.states``.
1729 Self-loops are collapsed: a state that only points to itself contributes
1730 neither predecessors nor successors here.
1732 Args:
1733 mode: ``"full"`` (default) includes every edge. ``"main"`` filters edges
1734 through ``_filter_main_path_graph`` so off-happy-path predecessors
1735 (e.g. those connected only via ``on_error``) are hidden. Falls back
1736 to ``"full"`` if the active state would be filtered out.
1737 prev_state: Name of the predecessor the FSM most recently transitioned
1738 from. When that name appears in the rendered pred stack, its box is
1739 drawn with the orange ``_PREV_STATE_COLOR`` border. Silently
1740 skipped if the name is missing from the pred stack.
1741 """
1742 if active_state not in fsm.states:
1743 return ""
1745 edges = _collect_edges(fsm)
1746 if mode == "main":
1747 filtered_edges, reachable = _filter_main_path_graph(fsm, edges)
1748 if active_state in reachable:
1749 edges = filtered_edges
1750 preds = sorted({s for (s, t, _lbl) in edges if t == active_state and s != active_state})
1751 succs = sorted({t for (s, t, _lbl) in edges if s == active_state and t != active_state})
1753 terminal_states = {n for n, st in fsm.states.items() if st.terminal}
1755 def _label(name: str) -> str:
1756 label = name
1757 if name == fsm.initial:
1758 label = "→ " + label
1759 if name in terminal_states:
1760 label = label + " ◉"
1761 return label
1763 pred_labels = [_label(p) for p in preds]
1764 active_label = _label(active_state)
1765 succ_labels = [_label(s) for s in succs]
1767 inner_pred = max((len(lbl) for lbl in pred_labels), default=0)
1768 inner_active = len(active_label)
1769 inner_succ = max((len(lbl) for lbl in succ_labels), default=0)
1771 box_w_pred = inner_pred + 4 if pred_labels else 0
1772 box_w_active = inner_active + 4
1773 box_w_succ = inner_succ + 4 if succ_labels else 0
1775 n_rows = max(len(pred_labels), len(succ_labels), 1)
1776 try:
1777 nd_bg_code: str | None = str(int(highlight_color) + 10)
1778 except (ValueError, TypeError):
1779 nd_bg_code = None
1781 def _make_box(
1782 label: str,
1783 inner_w: int,
1784 highlighted: bool,
1785 *,
1786 border_color: str | None = None,
1787 ) -> list[str]:
1788 top = "┌" + "─" * (inner_w + 2) + "┐"
1789 bot = "└" + "─" * (inner_w + 2) + "┘"
1790 padded = label.ljust(inner_w)
1791 if highlighted:
1792 border_code = f"{highlight_color};{nd_bg_code}" if nd_bg_code else highlight_color
1793 top = colorize(top, border_code)
1794 bot = colorize(bot, border_code)
1795 if nd_bg_code:
1796 mid = (
1797 colorize("│", border_code)
1798 + colorize(" ", nd_bg_code)
1799 + colorize(padded, f"97;{nd_bg_code};1")
1800 + colorize(" ", nd_bg_code)
1801 + colorize("│", border_code)
1802 )
1803 else:
1804 mid = (
1805 colorize("│", border_code)
1806 + " "
1807 + colorize(padded, f"{highlight_color};1")
1808 + " "
1809 + colorize("│", border_code)
1810 )
1811 elif border_color is not None:
1812 top = colorize(top, border_color)
1813 bot = colorize(bot, border_color)
1814 mid = (
1815 colorize("│", border_color)
1816 + " "
1817 + colorize(padded, "1")
1818 + " "
1819 + colorize("│", border_color)
1820 )
1821 else:
1822 mid = "│ " + colorize(padded, "1") + " │"
1823 return [top, mid, bot]
1825 center_idx = (n_rows - 1) // 2
1827 def _build_stack(
1828 labels: list[str],
1829 box_w: int,
1830 *,
1831 color_for: dict[str, str] | None = None,
1832 ) -> list[str]:
1833 rows: list[str] = []
1834 # Align the stack to the arrow row (the active state's slot). Without
1835 # this, a shorter stack always sits at row 0 and the single ``──▶``
1836 # arrow drawn at ``active_line_offset`` points into empty space.
1837 # ``min(center_idx, n_rows - len(labels))`` caps the start so longer
1838 # but still-smaller stacks (e.g. 4 succs vs. 5 preds) don't overflow.
1839 start = max(0, min(center_idx, n_rows - len(labels)))
1840 color_map = color_for or {}
1841 for i in range(n_rows):
1842 j = i - start
1843 if 0 <= j < len(labels):
1844 border = color_map.get(labels[j])
1845 rows.extend(_make_box(labels[j], box_w - 4, False, border_color=border))
1846 else:
1847 rows.extend([" " * box_w] * 3)
1848 return rows
1850 pred_color_for: dict[str, str] = {}
1851 if prev_state is not None and prev_state in preds:
1852 pred_color_for[_label(prev_state)] = _PREV_STATE_COLOR
1854 pred_col = (
1855 _build_stack(pred_labels, box_w_pred, color_for=pred_color_for) if pred_labels else None
1856 )
1857 succ_col = _build_stack(succ_labels, box_w_succ) if succ_labels else None
1858 active_rows: list[str] = []
1859 for i in range(n_rows):
1860 if i == center_idx:
1861 active_rows.extend(_make_box(active_label, inner_active, True))
1862 else:
1863 active_rows.extend([" " * box_w_active] * 3)
1865 arrow = " ──▶ "
1866 arrow_blank = " " * len(arrow)
1867 active_line_offset = center_idx * 3 + 1
1869 total_lines = n_rows * 3
1870 out_lines: list[str] = []
1871 for i in range(total_lines):
1872 parts: list[str] = []
1873 if pred_col is not None:
1874 parts.append(pred_col[i])
1875 parts.append(arrow if i == active_line_offset else arrow_blank)
1876 parts.append(active_rows[i])
1877 if succ_col is not None:
1878 parts.append(arrow if i == active_line_offset else arrow_blank)
1879 parts.append(succ_col[i])
1880 out_lines.append("".join(parts).rstrip())
1882 return "\n".join(out_lines)
1885def _render_horizontal_simple(
1886 main_path: list[str],
1887 edges: list[tuple[str, str, str]],
1888 main_edge_set: set[tuple[str, str]],
1889 branches: list[tuple[str, str, str]],
1890 back_edges: list[tuple[str, str, str]],
1891 bfs_order: list[str],
1892 initial: str,
1893 terminal_states: set[str],
1894 fsm_states: dict[str, StateConfig],
1895 verbose: bool,
1896 highlight_state: str | None,
1897 highlight_color: str,
1898 edge_label_colors: dict[str, str] | None = None,
1899 badges: dict[str, str] | None = None,
1900 title_only: bool = False,
1901 suppress_labels: bool = False,
1902) -> str:
1903 """Simple horizontal rendering for single-state or very simple FSMs.
1905 When ``title_only`` is True, per-state body lines and self-loop labels are suppressed.
1906 When ``suppress_labels`` is True, self-loop markers omit label text.
1907 """
1908 if not main_path:
1909 return ""
1910 all_states = list(main_path)
1911 display_label = _compute_display_labels(all_states, initial, terminal_states)
1913 tw = terminal_width()
1914 num_main = max(1, len(main_path))
1915 if verbose and fsm_states and main_path:
1916 max_box_inner = max(20, min(60, (tw - 4) // num_main - 6))
1917 else:
1918 max_box_inner = max(20, min(40, (tw - 4) // num_main - 6))
1920 box_inner, box_width, box_height, box_badge = _compute_box_sizes(
1921 all_states,
1922 display_label,
1923 fsm_states,
1924 verbose,
1925 max_box_inner,
1926 badges,
1927 title_only=title_only,
1928 )
1930 main_height = max((box_height[s] for s in main_path), default=3)
1931 total_width = tw
1933 # Column positions
1934 col_start: dict[str, int] = {}
1935 col_center: dict[str, int] = {}
1936 x = 2
1937 for i, sname in enumerate(main_path):
1938 col_start[sname] = x
1939 col_center[sname] = x + box_width[sname] // 2
1940 x += box_width[sname]
1941 if i < len(main_path) - 1:
1942 x += 4
1944 rows: list[list[str]] = [[" "] * total_width for _ in range(main_height)]
1946 for sname in main_path:
1947 is_highlighted = highlight_state is not None and sname == highlight_state
1948 _draw_box(
1949 rows,
1950 0,
1951 col_start[sname],
1952 box_width[sname],
1953 main_height,
1954 box_inner[sname],
1955 is_highlighted,
1956 highlight_color,
1957 badge=box_badge[sname],
1958 )
1960 # Self-loops
1961 self_loops_list = [(s, d, lbl) for s, d, lbl in back_edges if s == d]
1962 lines = ["".join(row).rstrip() for row in rows]
1963 if self_loops_list:
1964 self_labels: dict[str, list[str]] = {}
1965 for src, _, label in self_loops_list:
1966 self_labels.setdefault(src, []).append(label)
1967 for sname, labels in self_labels.items():
1968 marker = "\u21ba" if suppress_labels else "\u21ba " + ", ".join(labels)
1969 self_row = [" "] * total_width
1970 cx = col_center.get(sname, 0)
1971 pos = max(0, cx - len(marker) // 2)
1972 for j, ch in enumerate(marker):
1973 if pos + j < total_width:
1974 self_row[pos + j] = ch
1975 lines.append("".join(self_row).rstrip())
1977 diagram_indent = max(0, (tw - (x + 4)) // 2)
1978 if diagram_indent > 0:
1979 lines = [" " * diagram_indent + ln if ln.strip() else ln for ln in lines]
1981 return _colorize_diagram_labels("\n".join(lines), edge_label_colors)