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
import chat.state.branches  # registers handlers
from chat.state.branches import active_branch, get_branch, list_branches


def test_main_branch_bootstrapped_by_migration(tmp_path):
    db = tmp_path / "t.db"
    apply_migrations(db)
    with open_db(db) as conn:
        active = active_branch(conn)
        assert active is not None
        assert active["name"] == "main"
        assert active["is_active"] is True
        assert active["origin_event_id"] == 0
        assert active["head_event_id"] == 0


def test_branch_created_inserts_row(tmp_path):
    db = tmp_path / "t.db"
    apply_migrations(db)
    with open_db(db) as conn:
        append_event(
            conn,
            kind="branch_created",
            payload={
                "name": "experiment",
                "origin_event_id": 42,
                "chat_id": "chat_a",
            },
        )
        project(conn)

        b = get_branch(conn, "experiment")
        assert b is not None
        assert b["name"] == "experiment"
        assert b["origin_event_id"] == 42
        # head defaults to origin when not specified
        assert b["head_event_id"] == 42
        assert b["chat_id"] == "chat_a"
        assert b["is_active"] is False

        # main remains active
        active = active_branch(conn)
        assert active is not None
        assert active["name"] == "main"


def test_branch_switched_atomic(tmp_path):
    db = tmp_path / "t.db"
    apply_migrations(db)
    with open_db(db) as conn:
        append_event(
            conn,
            kind="branch_created",
            payload={
                "name": "experiment",
                "origin_event_id": 5,
                "chat_id": "chat_a",
            },
        )
        append_event(
            conn,
            kind="branch_switched",
            payload={"name": "experiment"},
        )
        project(conn)

        active = active_branch(conn)
        assert active is not None
        assert active["name"] == "experiment"

        main = get_branch(conn, "main")
        assert main is not None
        assert main["is_active"] is False

        # switch back
        append_event(
            conn,
            kind="branch_switched",
            payload={"name": "main"},
        )
        project(conn)

        active2 = active_branch(conn)
        assert active2 is not None
        assert active2["name"] == "main"

        experiment = get_branch(conn, "experiment")
        assert experiment is not None
        assert experiment["is_active"] is False


def test_branch_head_updated_changes_head(tmp_path):
    db = tmp_path / "t.db"
    apply_migrations(db)
    with open_db(db) as conn:
        append_event(
            conn,
            kind="branch_created",
            payload={
                "name": "experiment",
                "origin_event_id": 10,
                "head_event_id": 10,
                "chat_id": "chat_a",
            },
        )
        append_event(
            conn,
            kind="branch_head_updated",
            payload={"name": "experiment", "head_event_id": 20},
        )
        project(conn)

        b = get_branch(conn, "experiment")
        assert b is not None
        assert b["head_event_id"] == 20


def test_list_branches_returns_all(tmp_path):
    db = tmp_path / "t.db"
    apply_migrations(db)
    with open_db(db) as conn:
        append_event(
            conn,
            kind="branch_created",
            payload={
                "name": "experiment",
                "origin_event_id": 1,
                "chat_id": "chat_a",
            },
        )
        project(conn)

        names = [b["name"] for b in list_branches(conn)]
        assert "main" in names
        assert "experiment" in names