"""T93 (Phase 4): cross-chat FTS5 search across all owners and chats.

Verifies that ``chat.services.cross_chat_search.search_all_memories``:
* surfaces matches across multiple owner_ids (the per-owner restriction
  used by ``state.memory.search_memories`` is intentionally absent),
* applies no witness filter (admin/power-user surface),
* orders results by FTS5 BM25 rank (lower = stronger match, surfaced
  first), and
* honours the ``k`` LIMIT and the empty-query fast-path.
"""

from __future__ import annotations

from chat.db.connection import open_db
from chat.db.migrate import apply_migrations
from chat.eventlog.log import append_event
from chat.eventlog.projector import project
from chat.services.cross_chat_search import search_all_memories
import chat.state.memory  # noqa: F401  (registers memory_written handler)


def _seed(db, *, memory_specs):
    """Apply migrations + project a list of memory_written events."""
    apply_migrations(db)
    with open_db(db) as conn:
        for spec in memory_specs:
            payload = {
                "owner_id": spec.get("owner_id", "bot_a"),
                "chat_id": spec.get("chat_id", "chat_bot_a"),
                "pov_summary": spec["pov_summary"],
                "witness_you": spec.get("witness_you", 1),
                "witness_host": spec.get("witness_host", 1),
                "witness_guest": spec.get("witness_guest", 0),
                "source": "direct",
                "reliability": 1.0,
                "significance": spec.get("significance", 1),
                "pinned": 0,
                "auto_pinned": 0,
            }
            append_event(conn, kind="memory_written", payload=payload)
        project(conn)


def test_search_all_memories_returns_matches_across_owners(tmp_path):
    """Cross-owner: a single query must surface memories from every owner.

    The per-owner ``owner_id = ?`` predicate that ``search_memories`` uses
    is intentionally absent here, so a "rabbit" memory under ``bot_a`` and
    one under ``bot_b`` should both come back from a single call.
    """
    db = tmp_path / "t.db"
    _seed(
        db,
        memory_specs=[
            {
                "owner_id": "bot_a",
                "chat_id": "chat_bot_a",
                "pov_summary": "the rabbit darted into the brambles",
            },
            {
                "owner_id": "bot_b",
                "chat_id": "chat_bot_b",
                "pov_summary": "a white rabbit watched from the hedge",
            },
            # Distractor: must not appear for "rabbit".
            {
                "owner_id": "bot_a",
                "chat_id": "chat_bot_a",
                "pov_summary": "the kettle whistled",
            },
        ],
    )
    with open_db(db) as conn:
        out = search_all_memories(conn, query="rabbit")
        owners = {row["owner_id"] for row in out}
        assert owners == {"bot_a", "bot_b"}
        assert len(out) == 2
        # Returned shape contract.
        for row in out:
            assert set(row.keys()) >= {
                "memory_id",
                "owner_id",
                "chat_id",
                "scene_id",
                "pov_summary",
                "significance",
                "ts",
                "fts_rank",
            }


def test_search_all_memories_orders_by_fts_rank(tmp_path):
    """Stronger BM25 match must come first (rank ASC = lower is better)."""
    db = tmp_path / "t.db"
    _seed(
        db,
        memory_specs=[
            # Single occurrence -> weaker BM25 score.
            {
                "owner_id": "bot_a",
                "chat_id": "chat_bot_a",
                "pov_summary": "a rabbit appeared",
            },
            # Triple occurrence in a short row -> stronger BM25 score.
            {
                "owner_id": "bot_b",
                "chat_id": "chat_bot_b",
                "pov_summary": "rabbit rabbit rabbit",
            },
        ],
    )
    with open_db(db) as conn:
        out = search_all_memories(conn, query="rabbit", k=5)
        assert len(out) == 2
        # Stronger match first; fts_rank monotonically non-decreasing
        # (lower-is-better, so ASC).
        assert out[0]["pov_summary"] == "rabbit rabbit rabbit"
        assert out[0]["fts_rank"] <= out[1]["fts_rank"]


def test_search_all_memories_respects_k_limit(tmp_path):
    """LIMIT ? must cap result count even when more matches exist."""
    db = tmp_path / "t.db"
    _seed(
        db,
        memory_specs=[
            {
                "owner_id": f"bot_{i}",
                "chat_id": f"chat_{i}",
                "pov_summary": f"rabbit sighting number {i}",
            }
            for i in range(10)
        ],
    )
    with open_db(db) as conn:
        out = search_all_memories(conn, query="rabbit", k=3)
        assert len(out) == 3


def test_search_all_memories_empty_query_returns_empty(tmp_path):
    """Empty / whitespace-only query must short-circuit to []."""
    db = tmp_path / "t.db"
    _seed(
        db,
        memory_specs=[
            {
                "owner_id": "bot_a",
                "chat_id": "chat_bot_a",
                "pov_summary": "the rabbit darted into the brambles",
            },
        ],
    )
    with open_db(db) as conn:
        assert search_all_memories(conn, query="") == []
        assert search_all_memories(conn, query="   ") == []