# database.py
import sqlite3
import os

DB_NAME = "spanish_trainer.db"

def get_connection():
    """Returns a connection to the SQLite database with row factory enabled."""
    conn = sqlite3.connect(DB_NAME)
    conn.row_factory = sqlite3.Row
    return conn

def ensure_database_populated():
    """
    Creates empty tables using the unified schema if running 
    in a fresh environment without a database file.
    """
    conn = get_connection()
    cursor = conn.cursor()
    try:
        # 1. Simplified unified translations table
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS translations (
                translation_id INTEGER PRIMARY KEY AUTOINCREMENT,
                es_text TEXT NOT NULL,
                en_text TEXT NOT NULL,
                source_context TEXT,
                tags TEXT,
                notes TEXT
            );
        """)
        
        # 2. Key-value configuration table
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS settings (
                key TEXT PRIMARY KEY,
                value TEXT
            );
        """)
        conn.commit()
    finally:
        conn.close()

# ==========================================
# SETTINGS CRUD FUNCTIONS
# ==========================================

def load_all_settings():
    """Fetches all system configuration properties into a flat Python dictionary."""
    conn = get_connection()
    cursor = conn.cursor()
    settings_dict = {}
    try:
        cursor.execute("SELECT settings.key, settings.value FROM settings;")
        for row in cursor.fetchall():
            settings_dict[row["key"]] = row["value"]
    finally:
        conn.close()
    return settings_dict

def save_setting_to_db(key, value):
    """Inserts or replaces an application configuration entry."""
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            INSERT OR REPLACE INTO settings (key, value)
            VALUES (?, ?);
        """, (key, value))
        conn.commit()
    finally:
        conn.close()

# ==========================================
# TRANSLATIONS CRUD FUNCTIONS
# ==========================================

def get_all_translations_explicit():
    """
    Retrieves all 784+ records using completely explicit, 
    table-qualified column declarations for the engines.
    """
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            SELECT 
                translations.translation_id,
                translations.es_text,
                translations.en_text,
                translations.source_context,
                translations.tags,
                translations.notes
            FROM translations
            ORDER BY translations.translation_id ASC;
        """)
        return [dict(row) for row in cursor.fetchall()]
    finally:
        conn.close()

def get_translation_by_id(translation_id):
    """Loads a single unified record row for specific inspection or editing."""
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            SELECT 
                translations.translation_id,
                translations.es_text,
                translations.en_text,
                translations.source_context,
                translations.tags,
                translations.notes
            FROM translations
            WHERE translations.translation_id = ?;
        """, (translation_id,))
        row = cursor.fetchone()
        return dict(row) if row else None
    finally:
        conn.close()

def update_translation_record(translation_id, es_text, en_text, source_context, tags, notes):
    """Saves sandbox interface edits directly back down into the table."""
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            UPDATE translations
            SET 
                es_text = ?,
                en_text = ?,
                source_context = ?,
                tags = ?,
                notes = ?
            WHERE translation_id = ?;
        """, (es_text, en_text, source_context, tags, notes, translation_id))
        conn.commit()
    finally:
        conn.close()

def delete_translation_record(translation_id):
    """Permanently drops a phrase card row from the data index."""
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            DELETE FROM translations
            WHERE translations.translation_id = ?;
        """, (translation_id,))
        conn.commit()
    finally:
        conn.close()
        
def insert_translation_record(es_text, en_text, source_context, tags, notes):
    """Inserts a completely fresh record into the translations table."""
    conn = get_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("""
            INSERT INTO translations (es_text, en_text, source_context, tags, notes)
            VALUES (?, ?, ?, ?, ?);
        """, (es_text, en_text, source_context, tags, notes))
        conn.commit()
    finally:
        conn.close()