<?php
/**
 * Settings Validator.
 *
 * Handles validation of admin settings.
 *
 * @package Accessibility_Audio_TTS_Player
 * @subpackage Admin\Settings
 * @since 1.0.0
 */

namespace Accessibility_Audio_TTS\Admin;

if ( ! defined( 'ABSPATH' ) ) {
	\texit;
}

/**
 * Settings Validator class.
 *
 * @since 1.0.0
 */
class Settings_Validator {

	/**
     * Allowed processing modes.
	 *
	 * @since 1.0.0
	 * @var array
	 */
	private const ALLOWED_MODES = array(
		'instant',
		'wp_cron',
	);

	/**
     * Validate all settings.
	 *
	 * @since 1.0.0
     * @param array $settings Settings to validate.
     * @return array Validation result with errors if any.
	 */
	public function validate_settings( array $settings ): array {
		$errors = array();

        // Validate API key.
		$api_key_validation = $this->validate_api_key( $settings['api_key'] ?? '' );
		if ( ! $api_key_validation['valid'] ) {
			$errors['api_key'] = $api_key_validation['error'];
		}

        // Validate voice settings.
		$voice_validation = $this->validate_voice_settings( $settings );
		if ( ! $voice_validation['valid'] ) {
			$errors = array_merge( $errors, $voice_validation['errors'] );
		}

        // Validate model.
		$model_validation = $this->validate_model( $settings['model'] ?? '' );
		if ( ! $model_validation['valid'] ) {
			$errors['model'] = $model_validation['error'];
		}

        // Validate processing mode.
		$mode_validation = $this->validate_processing_mode( $settings['mode'] ?? '' );
		if ( ! $mode_validation['valid'] ) {
			$errors['mode'] = $mode_validation['error'];
		}

        // Validate post types.
		$post_types_validation = $this->validate_post_types( $settings['post_types'] ?? array() );
		if ( ! $post_types_validation['valid'] ) {
			$errors['post_types'] = $post_types_validation['error'];
		}

		return array(
			'valid'  => empty( $errors ),
			'errors' => $errors,
		);
	}

	/**
     * Validate API key.
	 *
	 * @since 1.0.0
     * @param string $api_key API key to validate.
     * @return array Validation result.
	 */
	public function validate_api_key( string $api_key ): array {
		if ( empty( $api_key ) ) {
			return array(
				'valid' => false,
				'error' => __( 'API key is required', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		if ( strlen( $api_key ) < 10 ) {
			return array(
				'valid' => false,
				'error' => __( 'API key appears to be too short', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		if ( ! preg_match( '/^[a-zA-Z0-9_-]+$/', $api_key ) ) {
			return array(
				'valid' => false,
				'error' => __( 'API key contains invalid characters', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		return array( 'valid' => true );
	}

	/**
     * Validate voice settings.
	 *
	 * @since 1.0.0
     * @param array $settings Settings containing voice data.
     * @return array Validation result.
	 */
	public function validate_voice_settings( array $settings ): array {
		$errors = array();

		$voice_id   = $settings['voice_id'] ?? '';
		$voice_name = $settings['voice_name'] ?? '';

        // Allow first-time save when voice cache is not yet populated.
		$voices       = get_option( 'accessibility_audio_tts_voices_list', array() );
		$voices_known = is_array( $voices ) && ! empty( $voices );

		if ( empty( $voice_id ) && $voices_known ) {
			$errors['voice_id'] = __( 'Voice selection is required', 'accessibility-audio-tts-text-to-speech-for-articles' );
		}

		if ( empty( $voice_name ) && $voices_known ) {
			$errors['voice_name'] = __( 'Voice name is required', 'accessibility-audio-tts-text-to-speech-for-articles' );
		}

        // Validate voice ID format (ElevenLabs format).
		if ( ! empty( $voice_id ) && ! preg_match( '/^[a-zA-Z0-9]{20,}$/', $voice_id ) ) {
			$errors['voice_id'] = __( 'Invalid voice ID format', 'accessibility-audio-tts-text-to-speech-for-articles' );
		}

		return array(
			'valid'  => empty( $errors ),
			'errors' => $errors,
		);
	}

	/**
     * Validate model selection.
	 *
	 * @since 1.0.0
     * @param string $model Model to validate.
     * @return array Validation result.
	 */
	public function validate_model( string $model ): array {
		if ( empty( $model ) ) {
			return array(
				'valid' => false,
				'error' => __( 'Model selection is required', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		if ( ! \Accessibility_Audio_TTS\Core\ElevenLabs_Models::is_supported( $model ) ) {
			return array(
				'valid' => false,
				'error' => __( 'Invalid model selected', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		return array( 'valid' => true );
	}

	/**
     * Validate processing mode.
	 *
	 * @since 1.0.0
     * @param string $mode Processing mode to validate.
     * @return array Validation result.
	 */
	public function validate_processing_mode( string $mode ): array {
		if ( empty( $mode ) ) {
			return array(
				'valid' => false,
				'error' => __( 'Processing mode is required', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		if ( ! in_array( $mode, self::ALLOWED_MODES, true ) ) {
			return array(
				'valid' => false,
				'error' => __( 'Invalid processing mode selected', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		return array( 'valid' => true );
	}

	/**
     * Validate post types selection.
	 *
	 * @since 1.0.0
     * @param array $post_types Post types to validate.
     * @return array Validation result.
	 */
	public function validate_post_types( array $post_types ): array {
		if ( empty( $post_types ) ) {
			return array(
				'valid' => false,
				'error' => __( 'At least one content type must be selected', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

		if ( ! is_array( $post_types ) ) {
			return array(
				'valid' => false,
				'error' => __( 'Invalid post types format', 'accessibility-audio-tts-text-to-speech-for-articles' ),
			);
		}

        // Get available post types.
		$available_post_types = get_post_types( array( 'public' => true ) );

        // Check if all selected post types are valid.
		foreach ( $post_types as $post_type ) {
			if ( ! in_array( $post_type, $available_post_types, true ) ) {
				return array(
					'valid' => false,
					'error' => sprintf(
						/* translators: %s: invalid post type */
						__( 'Invalid post type: %1$s', 'accessibility-audio-tts-text-to-speech-for-articles' ),
						esc_html( $post_type )
					),
				);
			}
		}

		return array( 'valid' => true );
	}

	/**
     * Validate ChatGPT settings.
	 *
	 * @since 1.0.0
     * @param array $settings ChatGPT settings.
     * @return array Validation result.
	 */
	public function validate_chatgpt_settings( array $settings ): array {
		$errors = array();

		$api_key = $settings['chatgpt_api_key'] ?? '';
		$prompt  = $settings['chatgpt_prompt'] ?? '';

		if ( ! empty( $api_key ) ) {
			if ( strlen( $api_key ) < 20 ) {
				$errors['chatgpt_api_key'] = __( 'ChatGPT API key appears to be too short', 'accessibility-audio-tts-text-to-speech-for-articles' );
			}

            if ( ! str_starts_with( $api_key, 'sk-' ) ) {
				$errors['chatgpt_api_key'] = __( 'ChatGPT API key should start with "sk-"', 'accessibility-audio-tts-text-to-speech-for-articles' );
			}
		}

		if ( ! empty( $prompt ) && strlen( $prompt ) > 2000 ) {
			$errors['chatgpt_prompt'] = __( 'ChatGPT prompt is too long (max 2000 characters)', 'accessibility-audio-tts-text-to-speech-for-articles' );
		}

		return array(
			'valid'  => empty( $errors ),
			'errors' => $errors,
		);
	}

	/**
     * Sanitize setting value based on setting type.
	 *
	 * @since 1.0.0
     * @param string $setting_key Setting key.
     * @param mixed  $value       Setting value.
     * @return mixed Sanitized value.
	 */
	public function sanitize_setting_value( string $setting_key, $value ) {
		switch ( $setting_key ) {
			case 'api_key':
			case 'voice_id':
			case 'voice_name':
			case 'chatgpt_api_key':
				return sanitize_text_field( $value );

			case 'model':
				return sanitize_text_field( $value );

			case 'mode':
				return in_array( $value, self::ALLOWED_MODES, true ) ? $value : 'wp_cron';

			case 'post_types':
				return is_array( $value ) ? array_map( 'sanitize_text_field', $value ) : array();

			case 'chatgpt_prompt':
				return sanitize_textarea_field( $value );

			default:
				return sanitize_text_field( $value );
		}
	}

	/**
     * Get allowed models.
	 *
	 * @since 1.0.0
     * @return array Allowed models.
	 */
	public function get_allowed_models(): array {
		return \Accessibility_Audio_TTS\Core\ElevenLabs_Models::ids();
	}

	/**
     * Get allowed processing modes.
	 *
	 * @since 1.0.0
     * @return array Allowed processing modes.
	 */
	public function get_allowed_modes(): array {
		return self::ALLOWED_MODES;
	}
}