<?php
namespace Akram;

defined( 'ABSPATH' ) || exit;

/**
 * Optional AI assistant, powered by the WordPress AI Client (WordPress 7.0+). The site owner picks and
 * configures the AI provider once in WordPress; this plugin stores no API keys and calls no AI service itself.
 */
final class Ai {

	/** Whether WordPress has an AI provider that can generate text (no network request). */
	public static function available() {
		if ( ! function_exists( 'wp_ai_client_prompt' ) ) {
			return false;
		}
		// The builder forwards its fluent methods through __call, so is_callable() (not method_exists()) is the check.
		$builder = wp_ai_client_prompt( 'test' );
		return is_object( $builder ) && is_callable( array( $builder, 'is_supported_for_text_generation' ) ) && (bool) $builder->is_supported_for_text_generation();
	}

	public static function rest( \WP_REST_Request $r ) {
		if ( ! self::available() ) {
			return new \WP_Error( 'akram_ai_off', __( 'Connect an AI provider to WordPress (WordPress 7.0 or later) to use the AI assistant.', 'akram' ), array( 'status' => 400 ) );
		}
		$p      = $r->get_json_params();
		$mode   = in_array( $p['mode'] ?? '', array( 'text', 'rewrite', 'section', 'alt' ), true ) ? $p['mode'] : 'text';
		$prompt = trim( wp_strip_all_tags( (string) ( $p['prompt'] ?? '' ) ) );
		$ctx    = trim( wp_strip_all_tags( (string) ( $p['context'] ?? '' ) ) );
		if ( '' === $prompt && 'alt' !== $mode ) {
			return new \WP_Error( 'akram_ai_empty', __( 'Describe what you want.', 'akram' ), array( 'status' => 400 ) );
		}
		$rkey = 'akram_ai_' . get_current_user_id();
		$hits = (int) get_transient( $rkey );
		if ( $hits > 30 ) {
			return new \WP_Error( 'akram_ai_rate', __( 'Too many AI requests. Try again in a few minutes.', 'akram' ), array( 'status' => 429 ) );
		}
		set_transient( $rkey, $hits + 1, 10 * MINUTE_IN_SECONDS );

		$site   = get_bloginfo( 'name' ) . ' — ' . get_bloginfo( 'description' );
		$system = "You write website copy inside a visual page builder for the site \"{$site}\". Write clear, specific, human copy. Never use lorem ipsum, placeholder brackets or emojis unless asked. Match the language of the request.";
		switch ( $mode ) {
			case 'rewrite':
				$message = "Rewrite the following text. Instruction: {$prompt}

Text:
{$ctx}

Return only the rewritten text, no preamble.";
				break;
			case 'alt':
				$message = "Write concise alt text (max 120 characters) for an image described by its file name and context: {$ctx}. Return only the alt text.";
				break;
			case 'section':
				$message = "Plan website sections for this request: {$prompt}
" . ( $ctx ? "Page context: {$ctx}
" : '' ) . 'Choose layouts that fit the content. Icons must be Lucide icon names (e.g. zap, shield-check, rocket, heart, globe, users, clock, star, sparkles, layers). Return JSON only.';
				break;
			default:
				$message = $prompt . ( $ctx ? "

Context:
{$ctx}" : '' ) . "

Return only the text to place on the page, no preamble or quotes.";
		}

		$builder = wp_ai_client_prompt( $message )->using_system_instruction( $system )->using_max_tokens( 'section' === $mode ? 8000 : 2000 );
		if ( 'section' === $mode ) {
			$builder = $builder->as_json_response( self::section_schema() );
		}
		$text = $builder->generate_text();
		if ( is_wp_error( $text ) ) {
			return new \WP_Error( 'akram_ai_api', $text->get_error_message(), array( 'status' => 502 ) );
		}
		$text = (string) $text;
		if ( 'section' === $mode ) {
			$json = json_decode( $text, true );
			if ( ! is_array( $json ) ) {
				return new \WP_Error( 'akram_ai_parse', __( 'The AI response could not be read. Please try again.', 'akram' ), array( 'status' => 502 ) );
			}
			return array( 'sections' => $json['sections'] ?? array() );
		}
		return array( 'text' => trim( $text ) );
	}

	private static function section_schema() {
		$str = array( 'type' => 'string' );
		return array(
			'type'                 => 'object',
			'additionalProperties' => false,
			'required'             => array( 'sections' ),
			'properties'           => array(
				'sections' => array(
					'type'  => 'array',
					'items' => array(
						'type'                 => 'object',
						'additionalProperties' => false,
						'required'             => array( 'layout', 'eyebrow', 'title', 'subtitle', 'buttons', 'items', 'dark' ),
						'properties'           => array(
							'layout'   => array(
								'type' => 'string',
								'enum' => array( 'hero', 'features', 'split', 'stats', 'testimonials', 'faq', 'cta', 'pricing', 'steps', 'logos' ),
							),
							'eyebrow'  => $str,
							'title'    => $str,
							'subtitle' => $str,
							'dark'     => array( 'type' => 'boolean' ),
							'buttons'  => array(
								'type'  => 'array',
								'items' => array(
									'type'                 => 'object',
									'additionalProperties' => false,
									'required'             => array( 'text', 'primary' ),
									'properties'           => array(
										'text'    => $str,
										'primary' => array( 'type' => 'boolean' ),
									),
								),
							),
							'items'    => array(
								'type'  => 'array',
								'items' => array(
									'type'                 => 'object',
									'additionalProperties' => false,
									'required'             => array( 'icon', 'title', 'text', 'value' ),
									'properties'           => array(
										'icon'  => $str,
										'title' => $str,
										'text'  => $str,
										'value' => $str,
									),
								),
							),
						),
					),
				),
			),
		);
	}
}