"""
Application séquentielle des migrations SQL du dossier `migrations/`
sur la base « bolsa ». À exécuter depuis la racine du projet :

    python migrations/apply_migrations.py

Lit la configuration MySQL depuis les variables d'environnement (.env).
N'applique que les fichiers non déjà enregistrés dans la table
`__migrations__` (créée automatiquement).
"""
import os
import sys
from pathlib import Path

import pymysql
from dotenv import load_dotenv

load_dotenv()

MIGRATIONS_DIR = Path(__file__).parent


def get_connection():
    return pymysql.connect(
        host=os.environ.get("MYSQL_HOST", "db"),
        port=int(os.environ.get("MYSQL_PORT", "3306")),
        user=os.environ.get("MYSQL_USER", "jfgiraud"),
        password=os.environ.get("MYSQL_PASSWORD", ""),
        database=os.environ.get("MYSQL_DATABASE", "bolsa"),
        charset="utf8mb4",
        autocommit=False,
    )


def main():
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                "CREATE TABLE IF NOT EXISTS `__migrations__` ("
                "  `id` int NOT NULL AUTO_INCREMENT,"
                "  `filename` varchar(255) NOT NULL,"
                "  `applied_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,"
                "  PRIMARY KEY (`id`),"
                "  UNIQUE KEY `idx_filename` (`filename`)"
                ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4"
            )
            conn.commit()

            cur.execute("SELECT filename FROM `__migrations__`")
            applied = {row[0] for row in cur.fetchall()}

            sql_files = sorted(
                f for f in MIGRATIONS_DIR.glob("*.sql")
                if f.name != "schema.sql"
            )

            if not sql_files:
                print("Aucune migration à appliquer.")
                return

            for sql_file in sql_files:
                if sql_file.name in applied:
                    print(f"[déjà appliquée] {sql_file.name}")
                    continue

                print(f"[application] {sql_file.name}")
                sql = sql_file.read_text(encoding="utf-8")
                # Découpage sur les ';' pour exécuter instruction par instruction
                statements = [s.strip() for s in sql.split(";") if s.strip()]
                for stmt in statements:
                    cur.execute(stmt)
                cur.execute(
                    "INSERT INTO `__migrations__` (filename) VALUES (%s)",
                    (sql_file.name,),
                )
                conn.commit()
                print(f"[OK] {sql_file.name}")

    except Exception as e:
        conn.rollback()
        print(f"[ERREUR] {e}", file=sys.stderr)
        sys.exit(1)
    finally:
        conn.close()


if __name__ == "__main__":
    main()