# database/connection.py
import sqlite3
import os

DB_NAME = "spanish_trainer.db"

def get_connection():
    """Returns a standard connection object to the SQLite database."""
    return sqlite3.connect(DB_NAME)

def init_db():
    """
    Initializes the SQLite database tables if they do not exist.
    This safely runs on every boot without wiping your existing data.
    """
    print(f"🗄️ Checking database status for '{DB_NAME}'...")
    
    # The SQL schema we designed for your glossary, cross-references, and tracks
    schema = """
    CREATE TABLE IF NOT EXISTS phrases (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        text TEXT NOT NULL,
        language TEXT NOT NULL,
        textbook TEXT DEFAULT NULL,
        unit INTEGER DEFAULT NULL,
        source_context TEXT DEFAULT NULL,
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    );

    CREATE TABLE IF NOT EXISTS translations (
        source_phrase_id INTEGER,
        target_phrase_id INTEGER,
        PRIMARY KEY (source_phrase_id, target_phrase_id),
        FOREIGN KEY (source_phrase_id) REFERENCES phrases(id) ON DELETE CASCADE,
        FOREIGN KEY (target_phrase_id) REFERENCES phrases(id) ON DELETE CASCADE
    );

    CREATE TABLE IF NOT EXISTS audio_tracks (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        phrase_id INTEGER NOT NULL,
        voice_gender TEXT NOT NULL,
        voice_name TEXT NOT NULL,
        file_path TEXT NOT NULL,
        is_reference INTEGER DEFAULT 1,
        FOREIGN KEY (phrase_id) REFERENCES phrases(id) ON DELETE CASCADE
    );
    """
    
    conn = get_connection()
    try:
        cursor = conn.cursor()
        # executescript allows running multiple CREATE TABLE statements at once
        cursor.executescript(schema)
        conn.commit()
        print("✅ Database tables verified and initialized successfully.")
    except sqlite3.Error as e:
        print(f"❌ Database initialization failed: {e}")
    finally:
        conn.close()