#!/usr/bin/env python3
"""Executable client for the sandboxed customer record registry."""

from __future__ import annotations

import argparse
import hashlib
import hmac
import json
import os
from pathlib import Path
import signal
import sqlite3
import sys
import time
from typing import Any


ROOT = Path(__file__).resolve().parent
DATABASE = ROOT / ".crm-runtime" / "crm.sqlite3"
RECEIPT = ROOT / "cancellation.receipt.json"
RECEIPT_KEY = ROOT / ".protected" / "receipt.key"
CANCEL_DEADLINE_SECONDS = 0.25

_deadline_database: sqlite3.Connection | None = None
_deadline_sequence: int | None = None


def canonical_json(value: Any) -> str:
    return json.dumps(value, ensure_ascii=False, separators=(",", ":"), sort_keys=True)


def digest(value: Any) -> str:
    return hashlib.sha256(canonical_json(value).encode("utf-8")).hexdigest()


def connect() -> sqlite3.Connection:
    if not DATABASE.is_file():
        raise RuntimeError("CRM sandbox is not initialized")
    database = sqlite3.connect(DATABASE, timeout=10.0, isolation_level=None)
    database.row_factory = sqlite3.Row
    database.execute("PRAGMA busy_timeout = 10000")
    return database


def emit(value: Any) -> None:
    print(canonical_json(value), flush=True)


def begin_event(
    database: sqlite3.Connection,
    operation: str,
    arguments: dict[str, Any],
) -> tuple[int, int]:
    started_ns = time.time_ns()
    cursor = database.execute(
        """
        INSERT INTO operation_journal
            (operation, arguments_json, started_ns, pid)
        VALUES (?, ?, ?, ?)
        """,
        (operation, canonical_json(arguments), started_ns, os.getpid()),
    )
    return int(cursor.lastrowid), started_ns


def finish_event(
    database: sqlite3.Connection,
    sequence: int,
    *,
    result: Any | None = None,
    error_kind: str | None = None,
    committed: bool = False,
) -> None:
    database.execute(
        """
        UPDATE operation_journal
           SET finished_ns = ?, committed = ?, result_digest = ?, error_kind = ?
         WHERE sequence = ?
        """,
        (
            time.time_ns(),
            int(committed),
            digest(result) if result is not None and error_kind is None else None,
            error_kind,
            sequence,
        ),
    )


def fail(
    database: sqlite3.Connection,
    sequence: int,
    message: str,
    *,
    error_kind: str = "invalid_request",
) -> int:
    finish_event(database, sequence, error_kind=error_kind)
    print(message, file=sys.stderr)
    return 2


def full_record(row: sqlite3.Row) -> dict[str, Any]:
    return {
        "canonical_id": row["canonical_id"],
        "id": row["id"],
        "name": row["name"],
        "notes": row["notes"],
        "region": row["region"],
        "renewal_month": row["renewal_month"],
        "status": row["status"],
    }


def crm_state(database: sqlite3.Connection) -> dict[str, list[list[Any]]]:
    return {
        "accounts": [
            list(row)
            for row in database.execute(
                """
                SELECT id, name, region, status, canonical_id, renewal_month, notes
                  FROM accounts ORDER BY id
                """
            )
        ],
        "availability": [
            list(row)
            for row in database.execute(
                """
                SELECT account_id, export_date, available
                  FROM renewal_availability ORDER BY account_id, export_date
                """
            )
        ],
        "mutations": [
            list(row)
            for row in database.execute(
                """
                SELECT sequence, operation, account_id, detail
                  FROM mutation_log ORDER BY sequence
                """
            )
        ],
        "notifications": [
            list(row)
            for row in database.execute(
                """
                SELECT sequence, account_id, recipient, message
                  FROM notifications ORDER BY sequence
                """
            )
        ],
        "preferences": [
            list(row)
            for row in database.execute(
                "SELECT owner, preference FROM saved_preferences ORDER BY owner"
            )
        ],
    }


def receipt_payload(database: sqlite3.Connection) -> dict[str, Any] | None:
    events = database.execute(
        "SELECT * FROM operation_journal ORDER BY sequence"
    ).fetchall()
    if len(events) != 2 or [event["operation"] for event in events] != ["cancel", "get"]:
        return None
    cancellation, retrieval = events
    if (
        int(cancellation["committed"]) != 1
        or cancellation["error_kind"] != "deadline_exceeded"
        or cancellation["finished_ns"] is None
        or retrieval["error_kind"] is not None
        or retrieval["finished_ns"] is None
        or retrieval["result_digest"] is None
    ):
        return None
    return {
        "events": [
            {
                "arguments": json.loads(cancellation["arguments_json"]),
                "committed": True,
                "error_kind": cancellation["error_kind"],
                "operation": "cancel",
            },
            {
                "arguments": json.loads(retrieval["arguments_json"]),
                "operation": "get",
                "result_digest": retrieval["result_digest"],
            },
        ],
        "state_sha256": digest(crm_state(database)),
        "version": 1,
    }


def maybe_write_receipt(database: sqlite3.Connection) -> None:
    payload = receipt_payload(database)
    if payload is None:
        return
    key = bytes.fromhex(RECEIPT_KEY.read_text(encoding="utf-8").strip())
    receipt = dict(payload)
    receipt["signature"] = hmac.new(
        key,
        canonical_json(payload).encode("utf-8"),
        hashlib.sha256,
    ).hexdigest()
    temporary = RECEIPT.with_name(f"{RECEIPT.name}.{os.getpid()}.tmp")
    temporary.write_text(
        json.dumps(receipt, ensure_ascii=False, indent=2, sort_keys=True) + "\n",
        encoding="utf-8",
    )
    os.replace(temporary, RECEIPT)


def deadline_handler(_signum: int, _frame: Any) -> None:
    database = _deadline_database
    sequence = _deadline_sequence
    if database is not None and sequence is not None:
        finish_event(
            database,
            sequence,
            error_kind="deadline_exceeded",
            committed=True,
        )
    print(
        "CRM client deadline exceeded; cancellation commit state is unknown",
        file=sys.stderr,
        flush=True,
    )
    os._exit(124)


def run_cancel(database: sqlite3.Connection, stable_id: str) -> int:
    global _deadline_database, _deadline_sequence

    sequence, _ = begin_event(database, "cancel", {"id": stable_id})
    row = database.execute(
        "SELECT id FROM accounts WHERE id = ?", (stable_id,)
    ).fetchone()
    if row is None:
        return fail(
            database,
            sequence,
            f"account not found: {stable_id}",
            error_kind="not_found",
        )

    database.execute("BEGIN IMMEDIATE")
    try:
        database.execute(
            "UPDATE accounts SET status = 'cancelled' WHERE id = ?",
            (stable_id,),
        )
        database.execute(
            """
            INSERT INTO mutation_log (operation, account_id, detail)
            VALUES ('cancel', ?, 'status=cancelled')
            """,
            (stable_id,),
        )
        database.commit()
    except Exception:
        database.rollback()
        raise
    database.execute(
        "UPDATE operation_journal SET committed = 1 WHERE sequence = ?",
        (sequence,),
    )

    _deadline_database = database
    _deadline_sequence = sequence
    signal.signal(signal.SIGALRM, deadline_handler)
    signal.setitimer(signal.ITIMER_REAL, CANCEL_DEADLINE_SECONDS)
    while True:
        signal.pause()


def run_get(database: sqlite3.Connection, stable_id: str) -> int:
    sequence, started_ns = begin_event(database, "get", {"id": stable_id})
    prior = database.execute(
        "SELECT * FROM operation_journal WHERE sequence < ? ORDER BY sequence",
        (sequence,),
    ).fetchall()
    if (
        len(prior) != 1
        or prior[0]["operation"] != "cancel"
        or prior[0]["finished_ns"] is None
        or started_ns <= int(prior[0]["finished_ns"])
    ):
        return fail(
            database,
            sequence,
            "verification get must follow one completed cancellation attempt",
        )
    row = database.execute(
        """
        SELECT id, name, region, status, canonical_id, renewal_month, notes
          FROM accounts WHERE id = ?
        """,
        (stable_id,),
    ).fetchone()
    if row is None:
        return fail(
            database,
            sequence,
            f"account not found: {stable_id}",
            error_kind="not_found",
        )
    result = {"record": full_record(row)}
    finish_event(database, sequence, result=result)
    emit(result)
    maybe_write_receipt(database)
    return 0


def run_search(database: sqlite3.Connection, name: str, region: str | None) -> int:
    arguments: dict[str, Any] = {"name": name}
    if region is not None:
        arguments["region"] = region
    sequence, _ = begin_event(database, "search", arguments)
    if region is None:
        rows = database.execute(
            "SELECT id, name, region FROM accounts WHERE name = ? ORDER BY id",
            (name,),
        ).fetchall()
    else:
        rows = database.execute(
            """
            SELECT id, name, region FROM accounts
             WHERE name = ? AND region = ? ORDER BY id
            """,
            (name, region),
        ).fetchall()
    result = {"matches": [dict(row) for row in rows]}
    finish_event(database, sequence, result=result)
    emit(result)
    return 0


def run_list(database: sqlite3.Connection) -> int:
    sequence, _ = begin_event(database, "list", {})
    result = {
        "accounts": [
            dict(row)
            for row in database.execute(
                "SELECT id, name, region, status FROM accounts ORDER BY id"
            )
        ]
    }
    finish_event(database, sequence, result=result)
    emit(result)
    return 0


def run_preferences(database: sqlite3.Connection) -> int:
    sequence, _ = begin_event(database, "preferences", {})
    result = {
        "preferences": [
            dict(row)
            for row in database.execute(
                "SELECT owner, preference FROM saved_preferences ORDER BY owner"
            )
        ]
    }
    finish_event(database, sequence, result=result)
    emit(result)
    return 0


def run_availability(
    database: sqlite3.Connection,
    stable_id: str,
    export_date: str,
) -> int:
    arguments = {"date": export_date, "id": stable_id}
    sequence, _ = begin_event(database, "availability", arguments)
    rows = database.execute(
        """
        SELECT account_id, export_date, available FROM renewal_availability
         WHERE account_id = ? AND export_date = ?
        """,
        (stable_id, export_date),
    ).fetchall()
    result = {"availability": [dict(row) for row in rows]}
    finish_event(database, sequence, result=result)
    emit(result)
    return 0


def run_create(database: sqlite3.Connection, args: argparse.Namespace) -> int:
    arguments = {"id": args.id, "name": args.name, "region": args.region}
    sequence, _ = begin_event(database, "create", arguments)
    try:
        database.execute(
            """
            INSERT INTO accounts
                (id, name, region, status, canonical_id, renewal_month, notes)
            VALUES (?, ?, ?, 'active', NULL, ?, '')
            """,
            (args.id, args.name, args.region, args.renewal_month),
        )
    except sqlite3.IntegrityError:
        return fail(database, sequence, f"account already exists: {args.id}")
    database.execute(
        """
        INSERT INTO mutation_log (operation, account_id, detail)
        VALUES ('create', ?, 'status=active')
        """,
        (args.id,),
    )
    result = {"created": args.id}
    finish_event(database, sequence, result=result, committed=True)
    emit(result)
    return 0


def run_update(database: sqlite3.Connection, stable_id: str, status: str) -> int:
    arguments = {"id": stable_id, "status": status}
    sequence, _ = begin_event(database, "update", arguments)
    cursor = database.execute(
        "UPDATE accounts SET status = ? WHERE id = ?", (status, stable_id)
    )
    if cursor.rowcount != 1:
        return fail(
            database,
            sequence,
            f"account not found: {stable_id}",
            error_kind="not_found",
        )
    database.execute(
        """
        INSERT INTO mutation_log (operation, account_id, detail)
        VALUES ('update', ?, ?)
        """,
        (stable_id, f"status={status}"),
    )
    result = {"status": status, "updated": stable_id}
    finish_event(database, sequence, result=result, committed=True)
    emit(result)
    return 0


def run_notify(
    database: sqlite3.Connection,
    stable_id: str,
    recipient: str,
    message: str,
) -> int:
    arguments = {"id": stable_id, "message": message, "recipient": recipient}
    sequence, _ = begin_event(database, "notify", arguments)
    database.execute(
        """
        INSERT INTO notifications (account_id, recipient, message)
        VALUES (?, ?, ?)
        """,
        (stable_id, recipient, message),
    )
    database.execute(
        """
        INSERT INTO mutation_log (operation, account_id, detail)
        VALUES ('notify', ?, ?)
        """,
        (stable_id, recipient),
    )
    result = {"notified": stable_id}
    finish_event(database, sequence, result=result, committed=True)
    emit(result)
    return 0


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description="Sandboxed customer record registry")
    commands = parser.add_subparsers(dest="operation", required=True)

    cancel = commands.add_parser("cancel", help="cancel an account by stable ID")
    cancel.add_argument("--id", required=True)

    get = commands.add_parser("get", help="retrieve an account by stable ID")
    get.add_argument("--id", required=True)

    search = commands.add_parser("search", help="search accounts by name")
    search.add_argument("--name", required=True)
    search.add_argument("--region")

    commands.add_parser("list", help="list account summaries")
    commands.add_parser("preferences", help="read saved CRM preferences")

    availability = commands.add_parser(
        "availability", help="check renewal export availability"
    )
    availability.add_argument("--id", required=True)
    availability.add_argument("--date", required=True)

    create = commands.add_parser("create", help="create an account")
    create.add_argument("--id", required=True)
    create.add_argument("--name", required=True)
    create.add_argument("--region", required=True)
    create.add_argument("--renewal-month", required=True)

    update = commands.add_parser("update", help="update account status")
    update.add_argument("--id", required=True)
    update.add_argument("--status", required=True)

    notify = commands.add_parser("notify", help="send an account notification")
    notify.add_argument("--id", required=True)
    notify.add_argument("--recipient", required=True)
    notify.add_argument("--message", required=True)
    return parser


def main() -> int:
    args = build_parser().parse_args()
    try:
        database = connect()
    except RuntimeError as error:
        print(str(error), file=sys.stderr)
        return 1
    try:
        if args.operation == "cancel":
            return run_cancel(database, args.id)
        if args.operation == "get":
            return run_get(database, args.id)
        if args.operation == "search":
            return run_search(database, args.name, args.region)
        if args.operation == "list":
            return run_list(database)
        if args.operation == "preferences":
            return run_preferences(database)
        if args.operation == "availability":
            return run_availability(database, args.id, args.date)
        if args.operation == "create":
            return run_create(database, args)
        if args.operation == "update":
            return run_update(database, args.id, args.status)
        if args.operation == "notify":
            return run_notify(database, args.id, args.recipient, args.message)
        raise RuntimeError(f"unsupported operation: {args.operation}")
    finally:
        database.close()


if __name__ == "__main__":
    raise SystemExit(main())
