<?php
/**
 * Settings page for API key and defaults.
 *
 * @package 45Squared_AI_Image_Generator
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class Nano_Banana_Settings {

	const MODELS = array(
		'gemini-2.5-flash-image'         => 'Nano Banana (Fast)',
		'gemini-3-pro-image-preview'     => 'Nano Banana Pro (High Quality)',
		'gemini-3.1-flash-image-preview' => 'Nano Banana 2 (Balanced)',
	);

	const ASPECT_RATIOS = array(
		'1:1'  => '1:1 (Square)',
		'16:9' => '16:9 (Landscape)',
		'9:16' => '9:16 (Portrait)',
		'4:3'  => '4:3 (Standard)',
		'3:2'  => '3:2 (Photo)',
	);

	const IMAGE_SIZES = array(
		'512' => '512px',
		'1K'  => '1K (1024px)',
		'2K'  => '2K (2048px)',
		'4K'  => '4K (4096px)',
	);

	/**
	 * Hook into WordPress.
	 */
	public function init() {
		add_action( 'admin_menu', array( $this, 'add_menu_page' ) );
		add_action( 'admin_init', array( $this, 'register_settings' ) );
		add_action( 'wp_ajax_nano_banana_test_connection', array( $this, 'ajax_test_connection' ) );
	}

	/**
	 * Register the settings page under Settings.
	 */
	public function add_menu_page() {
		add_options_page(
			__( 'Nano Banana Settings', '45squared-ai-powered-image-generator' ),
			__( 'Nano Banana', '45squared-ai-powered-image-generator' ),
			'manage_options',
			'nano-banana',
			array( $this, 'render_settings_page' )
		);
	}

	/**
	 * Register settings fields.
	 */
	public function register_settings() {
		register_setting( 'nano_banana_settings', 'nano_banana_api_key', array(
			'type'              => 'string',
			'sanitize_callback' => array( $this, 'sanitize_api_key' ),
		) );

		register_setting( 'nano_banana_settings', 'nano_banana_model', array(
			'type'              => 'string',
			'default'           => 'gemini-3.1-flash-image-preview',
			'sanitize_callback' => array( $this, 'sanitize_model' ),
		) );

		register_setting( 'nano_banana_settings', 'nano_banana_default_aspect_ratio', array(
			'type'              => 'string',
			'default'           => '1:1',
			'sanitize_callback' => array( $this, 'sanitize_aspect_ratio' ),
		) );

		add_settings_section(
			'nano_banana_main',
			__( 'API Configuration', '45squared-ai-powered-image-generator' ),
			array( $this, 'render_section_description' ),
			'nano-banana'
		);

		add_settings_field(
			'nano_banana_api_key',
			__( 'Google AI API Key', '45squared-ai-powered-image-generator' ),
			array( $this, 'render_api_key_field' ),
			'nano-banana',
			'nano_banana_main'
		);

		add_settings_field(
			'nano_banana_model',
			__( 'Default Model', '45squared-ai-powered-image-generator' ),
			array( $this, 'render_model_field' ),
			'nano-banana',
			'nano_banana_main'
		);

		add_settings_field(
			'nano_banana_default_aspect_ratio',
			__( 'Default Aspect Ratio', '45squared-ai-powered-image-generator' ),
			array( $this, 'render_aspect_ratio_field' ),
			'nano-banana',
			'nano_banana_main'
		);

		register_setting( 'nano_banana_settings', 'nano_banana_default_image_size', array(
			'type'              => 'string',
			'default'           => '1K',
			'sanitize_callback' => array( $this, 'sanitize_image_size' ),
		) );

		add_settings_field(
			'nano_banana_default_image_size',
			__( 'Default Image Size', '45squared-ai-powered-image-generator' ),
			array( $this, 'render_image_size_field' ),
			'nano-banana',
			'nano_banana_main'
		);
	}

	/**
	 * Encrypt the API key before storage.
	 *
	 * @param string $value Raw API key.
	 * @return string Encrypted key.
	 */
	public function sanitize_api_key( $value ) {
		$value = sanitize_text_field( $value );
		if ( empty( $value ) ) {
			return '';
		}
		// Don't re-encrypt the masked placeholder — keep existing key.
		if ( str_repeat( "\u{2022}", 16 ) === $value ) {
			return get_option( 'nano_banana_api_key', '' );
		}
		// Guard against double encryption: on first save, update_option()
		// sanitizes the value and then falls through to add_option() which
		// sanitizes again. If the value already decrypts successfully, it
		// was already encrypted by a prior pass — return it as-is.
		$decrypted = self::decrypt( $value );
		if ( false !== $decrypted ) {
			return $value;
		}
		return self::encrypt( $value );
	}

	/**
	 * Validate model selection.
	 *
	 * @param string $value Model ID.
	 * @return string
	 */
	public function sanitize_model( $value ) {
		return array_key_exists( $value, self::MODELS ) ? $value : 'gemini-3.1-flash-image-preview';
	}

	/**
	 * Validate aspect ratio selection.
	 *
	 * @param string $value Aspect ratio.
	 * @return string
	 */
	public function sanitize_aspect_ratio( $value ) {
		return array_key_exists( $value, self::ASPECT_RATIOS ) ? $value : '1:1';
	}

	/**
	 * Validate image size selection.
	 *
	 * @param string $value Image size.
	 * @return string
	 */
	public function sanitize_image_size( $value ) {
		return array_key_exists( $value, self::IMAGE_SIZES ) ? $value : '1K';
	}

	/**
	 * Render the settings page.
	 */
	public function render_settings_page() {
		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}
		?>
		<div class="wrap">
			<h1><?php echo esc_html( get_admin_page_title() ); ?></h1>
			<form action="options.php" method="post">
				<?php
				settings_fields( 'nano_banana_settings' );
				do_settings_sections( 'nano-banana' );
				submit_button();
				?>
			</form>
			<hr>
			<h2><?php esc_html_e( 'Connection Test', '45squared-ai-powered-image-generator' ); ?></h2>
			<p>
				<button type="button" id="nano-banana-test-connection" class="button button-secondary">
					<?php esc_html_e( 'Test Connection', '45squared-ai-powered-image-generator' ); ?>
				</button>
				<span id="nano-banana-test-result"></span>
			</p>
		</div>
		<?php
	}

	/**
	 * Section description.
	 */
	public function render_section_description() {
		?>
		<div class="nano-banana-setup-instructions" style="background:#fff;border:1px solid #c3c4c7;border-left:4px solid #2271b1;padding:12px 16px;margin:12px 0 20px;max-width:700px;">
			<h3 style="margin-top:0;"><?php esc_html_e( 'How to get your Google AI API Key', '45squared-ai-powered-image-generator' ); ?></h3>
			<ol style="margin-bottom:0;">
				<li>
					<?php
					printf(
						/* translators: %s: Google AI Studio link */
						esc_html__( 'Go to %s and sign in with your Google account.', '45squared-ai-powered-image-generator' ),
						'<a href="https://aistudio.google.com/" target="_blank" rel="noopener">Google AI Studio</a>'
					);
					?>
				</li>
				<li><?php esc_html_e( 'In the top navigation, hover over "Solutions" and choose "Gemini API".', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Accept the Terms of Service when prompted.', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'In the left sidebar, navigate to "API Keys".', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Click "Create API Key" or view an existing Gemini API key. Accept the terms and conditions — a key will be created by default.', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Copy your API key.', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Paste it into the field below and click "Save Changes".', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Use the "Test Connection" button at the bottom to verify everything works.', '45squared-ai-powered-image-generator' ); ?></li>
			</ol>
			<h3><?php esc_html_e( 'Enable Billing (Required)', '45squared-ai-powered-image-generator' ); ?></h3>
			<p>
				<?php esc_html_e( 'Image generation requires billing to be enabled on your Google Cloud project. Without billing, API requests will be rejected with a quota error.', '45squared-ai-powered-image-generator' ); ?>
			</p>
			<ol>
				<li>
					<?php
					printf(
						/* translators: %s: Google Cloud Console billing link */
						esc_html__( 'Go to the %s.', '45squared-ai-powered-image-generator' ),
						'<a href="https://console.cloud.google.com/billing" target="_blank" rel="noopener">Google Cloud Console Billing page</a>'
					);
					?>
				</li>
				<li><?php esc_html_e( 'Create a billing account if you don\'t have one, or select an existing one.', '45squared-ai-powered-image-generator' ); ?></li>
				<li><?php esc_html_e( 'Link the billing account to the Google Cloud project associated with your API key.', '45squared-ai-powered-image-generator' ); ?></li>
			</ol>
			<p style="margin-bottom:0;">
				<strong><?php esc_html_e( 'Pricing:', '45squared-ai-powered-image-generator' ); ?></strong>
				<?php esc_html_e( 'The plugin is free. Image generation is billed by Google per API call.', '45squared-ai-powered-image-generator' ); ?>
				<?php
				printf(
					/* translators: %s: pricing page link */
					esc_html__( 'See %s for current rates.', '45squared-ai-powered-image-generator' ),
					'<a href="https://ai.google.dev/pricing" target="_blank" rel="noopener">' . esc_html__( 'Google AI pricing', '45squared-ai-powered-image-generator' ) . '</a>'
				);
				?>
			</p>
		</div>
		<?php
	}

	/**
	 * Render the API key field.
	 */
	public function render_api_key_field() {
		$encrypted = get_option( 'nano_banana_api_key', '' );
		$has_key   = ! empty( $encrypted );
		?>
		<input
			type="password"
			id="nano_banana_api_key"
			name="nano_banana_api_key"
			value="<?php echo $has_key ? esc_attr( '••••••••••••••••') : ''; ?>"
			class="regular-text"
			autocomplete="off"
		>
		<p class="description">
			<?php if ( $has_key ) : ?>
				<?php esc_html_e( 'A key is saved. Enter a new value to replace it, or leave as-is.', '45squared-ai-powered-image-generator' ); ?>
			<?php else : ?>
				<?php esc_html_e( 'Paste your Google AI API key here. It will be encrypted before storage.', '45squared-ai-powered-image-generator' ); ?>
			<?php endif; ?>
		</p>
		<?php
	}

	/**
	 * Render model selector.
	 */
	public function render_model_field() {
		$current = get_option( 'nano_banana_model', 'gemini-3.1-flash-image-preview' );
		?>
		<select id="nano_banana_model" name="nano_banana_model">
			<?php foreach ( self::MODELS as $id => $label ) : ?>
				<option value="<?php echo esc_attr( $id ); ?>" <?php selected( $current, $id ); ?>>
					<?php echo esc_html( $label ); ?>
				</option>
			<?php endforeach; ?>
		</select>
		<?php
	}

	/**
	 * Render aspect ratio selector.
	 */
	public function render_aspect_ratio_field() {
		$current = get_option( 'nano_banana_default_aspect_ratio', '1:1' );
		?>
		<select id="nano_banana_default_aspect_ratio" name="nano_banana_default_aspect_ratio">
			<?php foreach ( self::ASPECT_RATIOS as $ratio => $label ) : ?>
				<option value="<?php echo esc_attr( $ratio ); ?>" <?php selected( $current, $ratio ); ?>>
					<?php echo esc_html( $label ); ?>
				</option>
			<?php endforeach; ?>
		</select>
		<?php
	}

	/**
	 * Render image size selector.
	 */
	public function render_image_size_field() {
		$current = get_option( 'nano_banana_default_image_size', '1K' );
		?>
		<select id="nano_banana_default_image_size" name="nano_banana_default_image_size">
			<?php foreach ( self::IMAGE_SIZES as $size => $label ) : ?>
				<option value="<?php echo esc_attr( $size ); ?>" <?php selected( $current, $size ); ?>>
					<?php echo esc_html( $label ); ?>
				</option>
			<?php endforeach; ?>
		</select>
		<?php
	}

	/**
	 * AJAX handler for connection test.
	 */
	public function ajax_test_connection() {
		check_ajax_referer( 'nano_banana_nonce', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( __( 'Unauthorized.', '45squared-ai-powered-image-generator' ) );
		}

		$api    = new Nano_Banana_API();
		$result = $api->test_connection();

		if ( is_wp_error( $result ) ) {
			wp_send_json_error( $result->get_error_message() );
		}

		set_transient( 'nano_banana_connection_test', 'ok', HOUR_IN_SECONDS );
		wp_send_json_success( __( 'Connection successful!', '45squared-ai-powered-image-generator' ) );
	}

	/**
	 * Get the decrypted API key.
	 *
	 * @return string|false Decrypted key or false if not set.
	 */
	public static function get_api_key() {
		$encrypted = get_option( 'nano_banana_api_key', '' );
		if ( empty( $encrypted ) ) {
			return false;
		}
		return self::decrypt( $encrypted );
	}

	/**
	 * Encrypt a value using OpenSSL.
	 *
	 * @param string $value Plain text value.
	 * @return string Base64-encoded encrypted value.
	 */
	private static function encrypt( $value ) {
		$key    = self::get_encryption_key();
		$iv     = openssl_random_pseudo_bytes( 16 );
		$cipher = openssl_encrypt( $value, 'aes-256-cbc', $key, 0, $iv );
		return base64_encode( $iv . '::' . $cipher ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
	}

	/**
	 * Decrypt a value.
	 *
	 * @param string $value Base64-encoded encrypted value.
	 * @return string|false Decrypted value or false on failure.
	 */
	private static function decrypt( $value ) {
		$key  = self::get_encryption_key();
		$data = base64_decode( $value ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode
		if ( false === $data || false === strpos( $data, '::' ) ) {
			return false;
		}
		list( $iv, $cipher ) = explode( '::', $data, 2 );
		return openssl_decrypt( $cipher, 'aes-256-cbc', $key, 0, $iv );
	}

	/**
	 * Get or generate the encryption key.
	 *
	 * @return string
	 */
	private static function get_encryption_key() {
		if ( defined( 'NANO_BANANA_ENCRYPTION_KEY' ) ) {
			return NANO_BANANA_ENCRYPTION_KEY;
		}

		$key = get_option( 'nano_banana_encryption_key' );
		if ( ! $key ) {
			$key = wp_generate_password( 64, true, true );
			add_option( 'nano_banana_encryption_key', $key );
		}
		return $key;
	}
}