{# FE2-4: knowledge-graph fragment — lazy-loaded into #corpus-graph.

   Context:
     doi       — the seed paper's DOI.
     snapshot  — get_paper_snapshot() shape, or None when the graph isn't built:
                   {metadata, entities_by_type, relationships_in,
                    relationships_out}.
                 entities_by_type   : {type: [{canonical_id, type, surface, ...}]}
                 relationships_out  : [{predicate, target_kind, target_id,
                                        evidence, ...}]
                 relationships_in   : [{predicate, source_doi, evidence, ...}]
     error     — True when the snapshot raised (generic notice, no detail leaked).

   All content is rendered through Jinja autoescape ONLY — never |safe, never
   striptags (scientific text legitimately contains < and >).
#}
<div class="card" id="corpus-graph-card">
  <h2>Knowledge graph</h2>

  {% if error %}
  <p class="field-note">Could not load the knowledge graph — check the server logs.</p>
  {% elif snapshot is none %}
  <p class="field-note">
    No knowledge graph is built yet. Run
    <code>lit-monitor graph backfill --all</code> to build the graph for this
    paper.
  </p>
  {% else %}

  {# --- Entities grouped by type ------------------------------------------- #}
  <h3>Entities</h3>
  {% set _entities = snapshot.entities_by_type or {} %}
  {% if _entities %}
  {% for type_, items in _entities.items() %}
  <p class="paper-meta">
    <span class="badge">{{ type_ }}</span>
    {% for e in items %}
    {# Show the surface form (human-readable) plus the canonical_id so the
       normalized identity is visible too; fall back to either if one is blank. #}
    <span class="pill" title="{{ e.canonical_id }}">{{ e.surface or e.canonical_id }}
      {% if e.surface and e.canonical_id and e.surface != e.canonical_id %}
      <span class="muted">({{ e.canonical_id }})</span>
      {% endif %}
    </span>
    {% endfor %}
  </p>
  {% endfor %}
  {% else %}
  <p class="field-note">No entities linked to this paper in the graph.</p>
  {% endif %}

  {# --- Relationships (outgoing + incoming) -------------------------------- #}
  <h3>Relationships</h3>
  {% set _out = snapshot.relationships_out or [] %}
  {% set _in = snapshot.relationships_in or [] %}
  {% if _out or _in %}
  <table class="papers-table">
    <thead>
      <tr><th>Direction</th><th>Predicate</th><th>Other paper / entity</th><th>Evidence</th></tr>
    </thead>
    <tbody>
      {% for r in _out %}
      <tr>
        <td><span class="badge">out</span></td>
        <td>{{ r.predicate }}</td>
        <td>
          {% if r.target_kind == "Paper" and r.target_id %}
          <a href="/corpus/{{ r.target_id }}">{{ r.target_id }}</a>
          {% else %}
          {{ r.target_id }}
          {% endif %}
        </td>
        <td class="field-note">{{ r.evidence or "" }}</td>
      </tr>
      {% endfor %}
      {% for r in _in %}
      <tr>
        <td><span class="badge">in</span></td>
        <td>{{ r.predicate }}</td>
        <td>
          {% if r.source_doi %}
          <a href="/corpus/{{ r.source_doi }}">{{ r.source_doi }}</a>
          {% else %}
          <span class="muted">&mdash;</span>
          {% endif %}
        </td>
        <td class="field-note">{{ r.evidence or "" }}</td>
      </tr>
      {% endfor %}
    </tbody>
  </table>
  {% else %}
  <p class="field-note">No relationships recorded for this paper in the graph.</p>
  {% endif %}

  {% endif %}
</div>