import sqlite3
import os
from werkzeug.security import generate_password_hash

DB_PATH = os.environ.get('DB_PATH', '/data/dyndns.db')


def get_db():
    db_dir = os.path.dirname(DB_PATH)
    if db_dir:
        os.makedirs(db_dir, exist_ok=True)
    conn = sqlite3.connect(DB_PATH)
    conn.row_factory = sqlite3.Row
    return conn


def _columns(db, table):
    return [r['name'] for r in db.execute(f'PRAGMA table_info({table})').fetchall()]


def init_db():
    db = get_db()

    db.executescript('''
        CREATE TABLE IF NOT EXISTS settings (
            key   TEXT PRIMARY KEY,
            value TEXT NOT NULL DEFAULT ''
        );

        CREATE TABLE IF NOT EXISTS admin_users (
            id            INTEGER PRIMARY KEY AUTOINCREMENT,
            username      TEXT UNIQUE NOT NULL,
            password_hash TEXT NOT NULL
        );

        CREATE TABLE IF NOT EXISTS dyndns_users (
            id            INTEGER PRIMARY KEY AUTOINCREMENT,
            username      TEXT UNIQUE NOT NULL,
            password_hash TEXT NOT NULL,
            active        INTEGER NOT NULL DEFAULT 1,
            created_at    TEXT NOT NULL DEFAULT (datetime('now'))
        );

        CREATE TABLE IF NOT EXISTS subdomains (
            id             INTEGER PRIMARY KEY AUTOINCREMENT,
            dyndns_user_id INTEGER NOT NULL,
            subdomain      TEXT UNIQUE NOT NULL,
            current_ip     TEXT,
            last_updated   TEXT,
            created_at     TEXT NOT NULL DEFAULT (datetime('now')),
            FOREIGN KEY (dyndns_user_id) REFERENCES dyndns_users(id)
        );

        CREATE TABLE IF NOT EXISTS update_log (
            id              INTEGER PRIMARY KEY AUTOINCREMENT,
            dyndns_user_id  INTEGER NOT NULL,
            subdomain_id    INTEGER,
            old_ip          TEXT,
            new_ip          TEXT NOT NULL,
            result          TEXT NOT NULL,
            timestamp       TEXT NOT NULL DEFAULT (datetime('now')),
            FOREIGN KEY (dyndns_user_id) REFERENCES dyndns_users(id)
        );
    ''')

    # --- Migration vom alten Schema (genau eine Subdomain pro Benutzer) ---
    # Früher trug dyndns_users die Spalten subdomain/current_ip/last_updated
    # direkt. Diese werden in die neue subdomains-Tabelle überführt.
    if 'subdomain' in _columns(db, 'dyndns_users'):
        db.execute('''
            INSERT OR IGNORE INTO subdomains (dyndns_user_id, subdomain, current_ip, last_updated)
            SELECT id, subdomain, current_ip, last_updated FROM dyndns_users
        ''')
        db.executescript('''
            CREATE TABLE dyndns_users_new (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                username      TEXT UNIQUE NOT NULL,
                password_hash TEXT NOT NULL,
                active        INTEGER NOT NULL DEFAULT 1,
                created_at    TEXT NOT NULL DEFAULT (datetime('now'))
            );
            INSERT INTO dyndns_users_new (id, username, password_hash, active, created_at)
                SELECT id, username, password_hash, active, created_at FROM dyndns_users;
            DROP TABLE dyndns_users;
            ALTER TABLE dyndns_users_new RENAME TO dyndns_users;
        ''')

    # update_log: subdomain_id nachrüsten, falls noch altes Schema
    if 'subdomain_id' not in _columns(db, 'update_log'):
        db.execute('ALTER TABLE update_log ADD COLUMN subdomain_id INTEGER')

    existing = db.execute('SELECT id FROM admin_users LIMIT 1').fetchone()
    if not existing:
        db.execute(
            'INSERT INTO admin_users (username, password_hash) VALUES (?, ?)',
            ('admin', generate_password_hash('admin'))
        )

    db.commit()
    db.close()


def get_setting(key, default=''):
    db = get_db()
    row = db.execute('SELECT value FROM settings WHERE key = ?', (key,)).fetchone()
    db.close()
    return row['value'] if row else default


def set_setting(key, value):
    db = get_db()
    db.execute('INSERT OR REPLACE INTO settings (key, value) VALUES (?, ?)', (key, value))
    db.commit()
    db.close()