import sqlite3

# ============================================================================
# CONFIGURACIÓN
# ============================================================================

DB_NAME = "emails.db"

# ============================================================================
def init_db() -> None:
    """
    Inicializa la base de datos SQLite y crea la tabla de correos si no existe.
    """
    conn = sqlite3.connect(DB_NAME)
    try:
        cursor = conn.cursor()

        # Crear tabla con id como llave primaria para evitar duplicados
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS emails (
                id TEXT PRIMARY KEY,
                fecha TEXT,
                sender TEXT,
                subject TEXT,
                has_attach INTEGER,
                fecha_descarga TEXT
            )
        ''')

        conn.commit()
    finally:
        conn.close()

# ============================================================================
def save_emails(emails_list: list[dict]) -> int:
    """
    Guarda una lista de correos en la base de datos.
    Retorna la cantidad de registros nuevos insertados.
    """
    if not emails_list:
        return 0
        
    conn = sqlite3.connect(DB_NAME)
    try:
        cursor = conn.cursor()

        from datetime import datetime
        fecha_ahora = datetime.now().strftime("%Y-%m-%d %H:%M:%S")

        # Mapear lista de diccionarios a tuplas para executemany
        # has_attach se guarda como 1 (True) o 0 (False)
        data = [
            (
                e['id'],
                e['fecha'],
                e['sender'],
                e['subject'],
                1 if e['has_attach'] else 0,
                fecha_ahora
            )
            for e in emails_list
        ]

        # INSERT OR IGNORE evita errores si el ID ya existe
        cursor.executemany('''
            INSERT OR IGNORE INTO emails (id, fecha, sender, subject, has_attach, fecha_descarga)
            VALUES (?, ?, ?, ?, ?, ?)
        ''', data)

        conn.commit()
        return cursor.rowcount
    finally:
        conn.close()
    
# ============================================================================
def get_existing_ids(ids_list: list[str]) -> list[str]:
    """
    Recibe una lista de IDs y devuelve una lista con aquellos que ya existen en la BD.
    """
    if not ids_list:
        return []
        
    conn = sqlite3.connect(DB_NAME)
    try:
        cursor = conn.cursor()

        existing_ids = []
        # Procesar por lotes para evitar límites de parámetros en SQLite
        for i in range(0, len(ids_list), 900):
            chunk = ids_list[i:i + 900]
            placeholders = ','.join(['?'] * len(chunk))
            query = f"SELECT id FROM emails WHERE id IN ({placeholders})"
            cursor.execute(query, chunk)
            existing_ids.extend([row[0] for row in cursor.fetchall()])

        return existing_ids
    finally:
        conn.close()

# ============================================================================
def delete_email_by_id(email_id: str) -> bool:
    """
    Elimina un correo de la base de datos por su ID.
    Retorna True si se eliminó el registro, False si no se encontró.
    """
    if not email_id:
        return False
        
    conn = sqlite3.connect(DB_NAME)
    try:
        cursor = conn.cursor()
        cursor.execute("DELETE FROM emails WHERE id = ?", (email_id,))
        conn.commit()
        return cursor.rowcount > 0
    finally:
        conn.close()
# ============================================================================