import os
import sqlite3 as sql
from pathlib import Path
from typing import List

from src import DATABASE_DIR, settings
from src.shared.logging import log

MIGRATIONS_DIR = Path(__file__).parent / "migrations"


def _ensure_migrations_table(conn: sql.Connection) -> None:
    cursor = conn.cursor()
    cursor.execute(
        """
        CREATE TABLE IF NOT EXISTS schema_migrations (
            id TEXT PRIMARY KEY,
            applied_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
        )
        """
    )
    conn.commit()


def _applied_migrations(conn: sql.Connection) -> List[str]:
    cursor = conn.cursor()
    cursor.execute("SELECT id FROM schema_migrations ORDER BY id")
    rows = cursor.fetchall()
    return [r[0] for r in rows]


def _apply_sql_file(conn: sql.Connection, path: Path) -> None:
    log.info(f"Applying migration {path.name}")
    sql_text = path.read_text(encoding="utf-8")
    cursor = conn.cursor()
    cursor.executescript(sql_text)
    cursor.execute(
        "INSERT OR REPLACE INTO schema_migrations (id) VALUES (?)", (path.name,)
    )
    conn.commit()


def run_migrations(db_path: Path) -> None:
    """Run all unapplied migrations from the migrations directory against the database at db_path."""
    if not MIGRATIONS_DIR.exists():
        log.debug("Migrations directory does not exist, skipping migrations")
        return

    # Ensure database directory exists
    db_dir = settings.database.path or Path(DATABASE_DIR)
    if not db_dir.exists():
        os.makedirs(db_dir, exist_ok=True)

    conn = sql.connect(db_path)
    try:
        _ensure_migrations_table(conn)
        applied = set(_applied_migrations(conn))

        migration_files = sorted(
            [p for p in MIGRATIONS_DIR.iterdir() if p.suffix in (".sql",)]
        )
        for m in migration_files:
            if m.name in applied:
                log.debug(f"Skipping already applied migration {m.name}")
                continue
            _apply_sql_file(conn, m)
    finally:
        conn.close()