const sqlite3 = require('sqlite3').verbose();
const path = require('path');
const bcrypt = require('bcryptjs');

const dbPath = process.env.DB_PATH || path.join(__dirname, '../data/database.sqlite');
const db = new sqlite3.Database(dbPath);

console.log('Using database at', dbPath);

function bootstrapInitialAdmin() {
    const username = process.env.INITIAL_ADMIN_USERNAME;
    const password = process.env.INITIAL_ADMIN_PASSWORD;
    const passwordHash = process.env.INITIAL_ADMIN_PASSWORD_HASH || (password ? bcrypt.hashSync(password, 10) : null);

    if (!username && !passwordHash) {
        return;
    }
    if (!username || !passwordHash) {
        console.warn('Set INITIAL_ADMIN_USERNAME together with INITIAL_ADMIN_PASSWORD_HASH to bootstrap an admin.');
        return;
    }

    db.get('SELECT id FROM users WHERE username = ?', [username], (err, row) => {
        if (err || row) return;

        db.run(
            'INSERT INTO users (username, password_hash, role) VALUES (?, ?, ?)',
            [username, passwordHash, 'admin'],
            (insertErr) => {
                if (insertErr) {
                    console.error('Failed to create initial admin:', insertErr.message);
                    return;
                }
                console.log(`Initial admin created: ${username}`);
            }
        );
    });

    db.get('SELECT id, role FROM users WHERE username = ?', [username], (err, row) => {
        if (err || !row || row.role === 'admin') return;

        db.run('UPDATE users SET role = ? WHERE id = ?', ['admin', row.id], (updateErr) => {
            if (updateErr) {
                console.error('Failed to promote initial admin:', updateErr.message);
                return;
            }
            console.log(`Initial admin promoted: ${username}`);
        });
    });
}

function runMigrations(migrations, index = 0) {
    if (index >= migrations.length) {
        bootstrapInitialAdmin();
        return;
    }

    migrations[index](() => runMigrations(migrations, index + 1));
}

db.serialize(() => {
    // Users: mit created_at fuer Client-Ablauf (30 Tage)
    db.run(`CREATE TABLE IF NOT EXISTS users (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        username TEXT UNIQUE NOT NULL,
        password_hash TEXT NOT NULL,
        role TEXT NOT NULL DEFAULT 'client',
        created_at DATETIME DEFAULT CURRENT_TIMESTAMP
    )`);

    // Migration: Spalten hinzufuegen falls Tabelle schon existiert (alte DB ohne role/created_at).
    // SQLite erlaubt CURRENT_TIMESTAMP nicht als DEFAULT bei ALTER TABLE, deshalb wird created_at
    // ohne Default angelegt und danach fuer bestehende Nutzer befuellt.
    db.all(`PRAGMA table_info(users)`, (err, columns) => {
        if (err) {
            console.error('User-Migration fehlgeschlagen:', err.message);
            return;
        }

        const columnNames = new Set(columns.map((column) => column.name));

        const migrations = [];

        if (!columnNames.has('role')) {
            migrations.push((done) => db.run(`ALTER TABLE users ADD COLUMN role TEXT NOT NULL DEFAULT 'client'`, (alterErr) => {
                if (alterErr) {
                    console.error('Migration role fehlgeschlagen:', alterErr.message);
                    done();
                    return;
                }

                // Alte Admins (die einzigen User vor dem Update) als admin markieren.
                db.run(`UPDATE users SET role = 'admin' WHERE id = 1`, () => {
                    console.log('Migration: role-Spalte hinzugefuegt, User ID 1 als admin gesetzt');
                    done();
                });
            }));
        }

        if (!columnNames.has('created_at')) {
            migrations.push((done) => db.run(`ALTER TABLE users ADD COLUMN created_at DATETIME`, (alterErr) => {
                if (alterErr) {
                    console.error('Migration created_at fehlgeschlagen:', alterErr.message);
                    done();
                    return;
                }

                db.run(`UPDATE users SET created_at = datetime('now') WHERE created_at IS NULL`, () => {
                    console.log('Migration: created_at-Spalte hinzugefuegt');
                    done();
                });
            }));
        } else {
            migrations.push((done) => db.run(`UPDATE users SET created_at = datetime('now') WHERE created_at IS NULL`, done));
        }

        runMigrations(migrations);
    });

    // Ordner-Zuweisung (neu)
    db.run(`CREATE TABLE IF NOT EXISTS user_folders (
        user_id INTEGER,
        folder_name TEXT,
        FOREIGN KEY(user_id) REFERENCES users(id),
        UNIQUE(user_id, folder_name)
    )`);

    // Alte Tabelle behalten fuer Kompatibilitaet, aber nicht mehr nutzen
    db.run(`CREATE TABLE IF NOT EXISTS user_images (
        user_id INTEGER,
        image_name TEXT,
        FOREIGN KEY(user_id) REFERENCES users(id),
        UNIQUE(user_id, image_name)
    )`);

});

module.exports = db;