<?php
require_once 'config.php';

try {
    $pdo = db();
    
    // Create surveys table
    $pdo->exec("CREATE TABLE IF NOT EXISTS surveys (
        id INT AUTO_INCREMENT PRIMARY KEY,
        title VARCHAR(255) NOT NULL,
        description TEXT,
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    )");

    // Create questions table
    $pdo->exec("CREATE TABLE IF NOT EXISTS questions (
        id INT AUTO_INCREMENT PRIMARY KEY,
        survey_id INT NOT NULL,
        question_text VARCHAR(255) NOT NULL,
        question_type VARCHAR(50) NOT NULL,
        options TEXT, -- JSON encoded options for multiple_choice/checkboxes
        FOREIGN KEY (survey_id) REFERENCES surveys(id) ON DELETE CASCADE
    )");

    $pdo->exec("CREATE TABLE IF NOT EXISTS survey_responses (
        id INT AUTO_INCREMENT PRIMARY KEY,
        survey_id INT NOT NULL,
        submitted_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        FOREIGN KEY (survey_id) REFERENCES surveys(id) ON DELETE CASCADE
    )");

    $pdo->exec("CREATE TABLE IF NOT EXISTS survey_answers (
        id INT AUTO_INCREMENT PRIMARY KEY,
        response_id INT NOT NULL,
        question_id INT NOT NULL,
        answer_text TEXT,
        FOREIGN KEY (response_id) REFERENCES survey_responses(id) ON DELETE CASCADE,
        FOREIGN KEY (question_id) REFERENCES questions(id) ON DELETE CASCADE
    )");

    // Create users table
    $pdo->exec("CREATE TABLE IF NOT EXISTS users (
        id INT AUTO_INCREMENT PRIMARY KEY,
        username VARCHAR(50) NOT NULL UNIQUE,
        password VARCHAR(255) NOT NULL,
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    )");

    // Insert a default admin user if one doesn't exist
    $stmt = $pdo->prepare("SELECT id FROM users WHERE username = ?");
    $stmt->execute(['admin']);
    if ($stmt->rowCount() == 0) {
        $username = 'admin';
        $password = password_hash('password', PASSWORD_DEFAULT);
        $pdo->prepare("INSERT INTO users (username, password) VALUES (?, ?)")->execute([$username, $password]);
    }

    echo "Database tables created successfully!";

} catch (PDOException $e) {
    die("Database migration failed: " . $e->getMessage());
}