"""Tests for session handoff (CLI to gateway platform).

The handoff state machine lives on the ``sessions`` table:

    None  → "pending" → "running" → ("completed" | "failed")

CLI side calls ``request_handoff`` and poll-waits on ``get_handoff_state``.
Gateway side iterates ``list_pending_handoffs``, calls ``claim_handoff`` to
flip pending → running, and finishes with ``complete_handoff`` or
``fail_handoff``.
"""

from __future__ import annotations

import time

import pytest

from hermes_state import SessionDB


class TestHandoffStateDB:
    """Test the handoff schema + helper methods on SessionDB."""

    @pytest.fixture
    def db(self, tmp_path, monkeypatch):
        home = tmp_path / ".hermes"
        home.mkdir()
        monkeypatch.setenv("HERMES_HOME", str(home))
        return SessionDB(db_path=home / "state.db")

    def _make_session(self, db, session_id, source="cli", title=None):
        """Insert a session row directly for testing."""
        def _do(conn):
            conn.execute(
                "INSERT OR IGNORE INTO sessions (id, source, title, started_at) "
                "VALUES (?, ?, ?, ?)",
                (session_id, source, title, time.time()),
            )
        db._execute_write(_do)

    def test_columns_exist(self, db):
        db._conn.execute(
            "SELECT handoff_state, handoff_platform, handoff_error "
            "FROM sessions LIMIT 0"
        )

    def test_request_handoff_marks_pending(self, db):
        sid = "sess-1"
        self._make_session(db, sid)

        assert db.request_handoff(sid, "telegram") is True

        state = db.get_handoff_state(sid)
        assert state == {
            "state": "pending",
            "platform": "telegram",
            "error": None,
        }

    def test_request_handoff_rejects_in_flight(self, db):
        sid = "sess-2"
        self._make_session(db, sid)

        assert db.request_handoff(sid, "telegram") is True
        # Still pending → reject re-request
        assert db.request_handoff(sid, "discord") is False

        # And after gateway claims it (running) → still rejected
        assert db.claim_handoff(sid) is True
        assert db.request_handoff(sid, "discord") is False

    def test_request_handoff_after_terminal_state_resets_error(self, db):
        sid = "sess-3"
        self._make_session(db, sid)
        db.request_handoff(sid, "telegram")
        db.claim_handoff(sid)
        db.fail_handoff(sid, "earlier failure")

        # User retries — should be allowed and clear the prior error.
        assert db.request_handoff(sid, "discord") is True
        state = db.get_handoff_state(sid)
        assert state["state"] == "pending"
        assert state["platform"] == "discord"
        assert state["error"] is None

    def test_list_pending_handoffs_excludes_running_and_terminal(self, db):
        a, b, c, d = "sess-a", "sess-b", "sess-c", "sess-d"
        for sid in (a, b, c, d):
            self._make_session(db, sid)

        db.request_handoff(a, "telegram")
        db.request_handoff(b, "discord")
        db.request_handoff(c, "telegram")
        db.claim_handoff(c)  # c is now running, not pending
        db.request_handoff(d, "slack")
        db.claim_handoff(d)
        db.complete_handoff(d)  # d is terminal

        pending = db.list_pending_handoffs()
        ids = [r["id"] for r in pending]
        assert set(ids) == {a, b}

    def test_claim_handoff_is_atomic(self, db):
        sid = "sess-claim"
        self._make_session(db, sid)
        db.request_handoff(sid, "telegram")

        # First claim wins
        assert db.claim_handoff(sid) is True
        # Second claim is a no-op (state is now "running", not "pending")
        assert db.claim_handoff(sid) is False
        assert db.get_handoff_state(sid)["state"] == "running"

    def test_complete_handoff_clears_error(self, db):
        sid = "sess-complete"
        self._make_session(db, sid)
        db.request_handoff(sid, "telegram")
        db.claim_handoff(sid)
        db.fail_handoff(sid, "transient")
        # User retries; mock the watcher path
        db.request_handoff(sid, "telegram")
        db.claim_handoff(sid)
        db.complete_handoff(sid)

        state = db.get_handoff_state(sid)
        assert state["state"] == "completed"
        assert state["error"] is None

    def test_fail_handoff_records_reason(self, db):
        sid = "sess-fail"
        self._make_session(db, sid)
        db.request_handoff(sid, "telegram")
        db.claim_handoff(sid)
        db.fail_handoff(sid, "no home channel for telegram")

        state = db.get_handoff_state(sid)
        assert state["state"] == "failed"
        assert state["error"] == "no home channel for telegram"

    def test_fail_handoff_truncates_long_reasons(self, db):
        sid = "sess-fail-long"
        self._make_session(db, sid)
        db.request_handoff(sid, "telegram")
        db.claim_handoff(sid)

        # 1000-character error string
        big_err = "x" * 1000
        db.fail_handoff(sid, big_err)

        state = db.get_handoff_state(sid)
        assert len(state["error"]) <= 500

    def test_get_handoff_state_for_unknown_session(self, db):
        assert db.get_handoff_state("does-not-exist") is None

    def test_full_pending_to_completed_flow(self, db):
        """End-to-end sequence the CLI + gateway watcher follow."""
        sid = "sess-flow"
        self._make_session(db, sid, title="my session")
        db.append_message(sid, "user", "Hello")
        db.append_message(sid, "assistant", "Hi there!")

        # CLI: request handoff
        assert db.request_handoff(sid, "telegram") is True
        assert db.get_handoff_state(sid)["state"] == "pending"

        # Gateway watcher: discover + claim
        pending = db.list_pending_handoffs()
        assert len(pending) == 1
        assert pending[0]["id"] == sid
        assert db.claim_handoff(sid) is True
        assert db.get_handoff_state(sid)["state"] == "running"

        # Gateway uses get_messages to load the transcript (real flow uses
        # session_store.switch_session which reads the same table).
        messages = db.get_messages(sid)
        assert [m["role"] for m in messages] == ["user", "assistant"]

        # Gateway: mark completed
        db.complete_handoff(sid)
        assert db.get_handoff_state(sid)["state"] == "completed"
        assert db.list_pending_handoffs() == []


class TestHandoffCommandRegistration:
    """Slash-command surface checks."""

    def test_command_registered(self):
        from hermes_cli.commands import resolve_command
        cmd = resolve_command("handoff")
        assert cmd is not None
        assert cmd.name == "handoff"
        assert cmd.category == "Session"

    def test_command_is_cli_only(self):
        """`/handoff` is initiated from the CLI; gateway shouldn't expose it."""
        from hermes_cli.commands import resolve_command, GATEWAY_KNOWN_COMMANDS
        cmd = resolve_command("handoff")
        assert cmd is not None
        assert cmd.cli_only is True
        assert "handoff" not in GATEWAY_KNOWN_COMMANDS