"""
db/database.py
--------------
SQLite initialization, schema creation, and default game seeding.
All table definitions live here. Call init_db() once on app startup.
"""

import sqlite3
import logging
import os
import shutil
from datetime import datetime

from core.paths import user_data_dir

logger = logging.getLogger(__name__)

DB_PATH = os.path.join(user_data_dir(), "data", "lottosight.db")


def get_connection():
    """Return a sqlite3 connection with foreign keys enabled."""
    conn = sqlite3.connect(DB_PATH)
    conn.execute("PRAGMA foreign_keys = ON")
    conn.row_factory = sqlite3.Row
    return conn


def init_db():
    """
    Initialize the database — create all tables if they don't exist,
    then seed default game configs.
    Safe to call on every app launch (uses IF NOT EXISTS).
    """
    logger.info("[DB] Initializing database at %s", DB_PATH)

    # Ensure data/ directory exists
    os.makedirs(os.path.dirname(DB_PATH), exist_ok=True)

    conn = get_connection()
    try:
        cursor = conn.cursor()

        # ── games ──────────────────────────────────────────────────────────
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS games (
                id          INTEGER PRIMARY KEY AUTOINCREMENT,
                name        TEXT    NOT NULL UNIQUE,
                main_count  INTEGER NOT NULL,
                main_max    INTEGER NOT NULL,
                bonus_count INTEGER NOT NULL DEFAULT 0,
                bonus_max   INTEGER NOT NULL DEFAULT 0,
                active      INTEGER NOT NULL DEFAULT 1
            )
        """)

        # ── draws ──────────────────────────────────────────────────────────
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS draws (
                id          INTEGER PRIMARY KEY AUTOINCREMENT,
                game_id     INTEGER NOT NULL REFERENCES games(id),
                draw_date   TEXT    NOT NULL,
                numbers     TEXT    NOT NULL,
                bonus       TEXT,
                multiplier  TEXT,
                source      TEXT,
                created_at  TEXT    NOT NULL DEFAULT (datetime('now'))
            )
        """)

        # Unique constraint: one record per game per draw date
        cursor.execute("""
            CREATE UNIQUE INDEX IF NOT EXISTS idx_draws_game_date
            ON draws (game_id, draw_date)
        """)

        # Index for fast date-range queries
        cursor.execute("""
            CREATE INDEX IF NOT EXISTS idx_draws_date
            ON draws (draw_date)
        """)

        # ── predictions ────────────────────────────────────────────────────
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS predictions (
                id          INTEGER PRIMARY KEY AUTOINCREMENT,
                game_id     INTEGER NOT NULL REFERENCES games(id),
                strategy    TEXT    NOT NULL,
                numbers     TEXT    NOT NULL,
                bonus       TEXT,
                created_at  TEXT    NOT NULL DEFAULT (datetime('now'))
            )
        """)

        # ── fetch_log ──────────────────────────────────────────────────────
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS fetch_log (
                id          INTEGER PRIMARY KEY AUTOINCREMENT,
                source      TEXT    NOT NULL,
                fetched_at  TEXT    NOT NULL DEFAULT (datetime('now')),
                added       INTEGER NOT NULL DEFAULT 0,
                skipped     INTEGER NOT NULL DEFAULT 0,
                status      TEXT    NOT NULL DEFAULT 'success',
                message     TEXT
            )
        """)

        conn.commit()
        logger.info("[DB] Tables created/verified OK")

        _seed_games(cursor, conn)

    except Exception as e:
        conn.rollback()
        logger.error("[ERROR] DB init failed: %s", e, exc_info=True)
        raise
    finally:
        conn.close()


def _seed_games(cursor, conn):
    """
    Insert default game configs if they don't already exist.
    Uses INSERT OR IGNORE to be idempotent on every launch.
    """
    defaults = [
        # name                    main_count  main_max  bonus_count  bonus_max  active
        ("Powerball",             5,          69,        1,           26,        1),
        ("Mega Millions",         5,          70,        1,           25,        1),
        ("Cash 5",                5,          45,        0,            0,        1),
        ("Millionaire for Life",  5,          58,        1,            5,        1),
        ("Bank a Million",        6,          40,        1,           40,        1),
    ]

    for row in defaults:
        cursor.execute("""
            INSERT OR IGNORE INTO games
                (name, main_count, main_max, bonus_count, bonus_max, active)
            VALUES (?, ?, ?, ?, ?, ?)
        """, row)

    inserted = conn.total_changes
    conn.commit()

    if inserted > 0:
        logger.info("[DB] Seeded %d default game(s)", inserted)
    else:
        logger.info("[DB] Default games already seeded — skipped")


def backup_db(dest_dir: str | None = None) -> str:
    """Copy the live DB to dest_dir and return the backup file path."""
    if dest_dir is None:
        dest_dir = os.path.join(user_data_dir(), "exports")
    os.makedirs(dest_dir, exist_ok=True)
    ts   = datetime.now().strftime("%Y%m%d_%H%M%S")
    dest = os.path.join(dest_dir, f"lottosight_backup_{ts}.db")
    shutil.copy2(DB_PATH, dest)
    logger.info("[DB] Backup created: %s", dest)
    return dest


def restore_db(source_path: str) -> None:
    """Overwrite the live DB with a backup file."""
    if not os.path.isfile(source_path):
        raise FileNotFoundError(f"Backup file not found: {source_path}")
    os.makedirs(os.path.dirname(DB_PATH), exist_ok=True)
    shutil.copy2(source_path, DB_PATH)
    logger.info("[DB] Database restored from: %s", source_path)


def get_db_stats():
    """
    Return a dict of basic DB stats for display in Settings screen.
    {game_name: draw_count, ...}
    """
    conn = get_connection()
    try:
        cursor = conn.cursor()
        cursor.execute("""
            SELECT g.name, COUNT(d.id) as draw_count
            FROM games g
            LEFT JOIN draws d ON d.game_id = g.id
            GROUP BY g.id
            ORDER BY g.name
        """)
        rows = cursor.fetchall()
        return {row["name"]: row["draw_count"] for row in rows}
    finally:
        conn.close()