from pathlib import Path

import pytest
from sqlalchemy import create_engine, text

from services.shared.schema_migrations import (
    ensure_schema_migrations_table,
    resolve_schema_management_mode,
    validate_schema_migrations_applied,
)


def test_resolve_schema_management_mode_defaults_by_backend():
    assert resolve_schema_management_mode(None, backend_name="sqlite") == "legacy"
    assert resolve_schema_management_mode(None, backend_name="postgresql") == "migrations"


def test_resolve_schema_management_mode_rejects_postgres_legacy():
    with pytest.raises(RuntimeError, match="SCHEMA_MANAGEMENT_MODE=legacy"):
        resolve_schema_management_mode("legacy", backend_name="postgresql")


def test_validate_schema_migrations_applied_reports_missing_migration_table(tmp_path: Path):
    migrations_dir = tmp_path / "migrations"
    migrations_dir.mkdir()
    (migrations_dir / "0001_dummy_sqlite.sql").write_text("SELECT 1;", encoding="utf-8")
    db_path = tmp_path / "schema_missing.sqlite"
    db_engine = create_engine(f"sqlite:///{db_path.as_posix()}")

    with pytest.raises(RuntimeError, match="python scripts/migrate_core_db.py"):
        validate_schema_migrations_applied(db_engine=db_engine, migrations_dir=migrations_dir)


def test_validate_schema_migrations_applied_accepts_up_to_date_schema(tmp_path: Path):
    migrations_dir = tmp_path / "migrations"
    migrations_dir.mkdir()
    migration_file = migrations_dir / "0001_dummy_sqlite.sql"
    migration_file.write_text("SELECT 1;", encoding="utf-8")
    db_path = tmp_path / "schema_ready.sqlite"
    db_engine = create_engine(f"sqlite:///{db_path.as_posix()}")

    ensure_schema_migrations_table(db_engine=db_engine)
    with db_engine.begin() as conn:
        conn.execute(
            text("INSERT INTO schema_migrations(version, applied_at) VALUES (:v, CURRENT_TIMESTAMP)"),
            {"v": migration_file.name},
        )

    validate_schema_migrations_applied(db_engine=db_engine, migrations_dir=migrations_dir)