<?php
/**
 * Generator module — REST routes and asset enqueuing for the post-generation wizard.
 *
 * @package Plume
 */

declare( strict_types=1 );
namespace Plume\Modules\Generator;

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

use Plume\Providers\ProviderFactory;
use Plume\Settings\ProviderSettings;
use Plume\Tiers\TierManager;

/**
 * Registers the post-generator admin assets and REST route.
 */
class GeneratorModule {

	/**
	 * Register WordPress hooks for this module.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function register(): void {
		\add_action( 'admin_enqueue_scripts', [ self::class, 'enqueue_assets' ] );
		\add_action( 'rest_api_init', [ self::class, 'register_routes' ] );
	}

	/**
	 * Enqueue generator assets on the generator admin page only.
	 *
	 * @since 1.0.0
	 * @param string $hook Current admin page hook suffix (unused; page detection uses $_GET).
	 * @return void
	 */
	public static function enqueue_assets( string $hook ): void { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found -- Required by admin_enqueue_scripts hook signature.
		// Only load on the generator admin page.
		if ( ! isset( $_GET['page'] ) || 'plume-generator' !== $_GET['page'] ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			return;
		}

		$asset_file = PLUME_DIR . 'assets/generator/index.asset.php';
		$asset      = file_exists( $asset_file )
			? require $asset_file
			: [
				'dependencies' => [],
				'version'      => PLUME_VERSION,
			];

		\wp_enqueue_script(
			'plume-generator',
			PLUME_URL . 'assets/generator/index.js',
			array_merge( $asset['dependencies'], [ 'wp-element', 'wp-api-fetch', 'wp-i18n' ] ),
			$asset['version'],
			true
		);

		\wp_localize_script(
			'plume-generator',
			'plumeData',
			[
				'nonce'         => \wp_create_nonce( 'wp_rest' ),
				'restUrl'       => \esc_url_raw( \rest_url( 'plume/v1' ) ),
				'currentPostId' => 0,
				'isPaid'        => TierManager::is_paid(),
				'siteTitle'     => \get_bloginfo( 'name' ),
			]
		);
	}

	/**
	 * Register the /plume/v1/generate REST route.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function register_routes(): void {
		\register_rest_route(
			'plume/v1',
			'/generate',
			[
				'methods'             => \WP_REST_Server::CREATABLE,
				'callback'            => [ self::class, 'handle_generate' ],
				'permission_callback' => function () {
					return \current_user_can( 'edit_posts' );
				},
				'args'                => [
					'title'    => [
						'type'              => 'string',
						'required'          => true,
						'sanitize_callback' => 'sanitize_text_field',
					],
					'keywords' => [
						'type'              => 'string',
						'required'          => false,
						'sanitize_callback' => 'sanitize_text_field',
						'default'           => '',
					],
					'tone'     => [
						'type'              => 'string',
						'required'          => false,
						'sanitize_callback' => 'sanitize_text_field',
						'default'           => 'professional',
					],
					'length'   => [
						'type'              => 'string',
						'required'          => false,
						'sanitize_callback' => 'sanitize_text_field',
						'default'           => 'medium',
						'enum'              => [ 'short', 'medium', 'long' ],
					],
				],
			]
		);
	}

	/**
	 * Generate a draft post from the request parameters using the default AI provider.
	 *
	 * @since 1.0.0
	 * @param \WP_REST_Request $request Incoming REST request.
	 * @return \WP_REST_Response 201 on success with post_id, edit_url, content, credits_used; 500 on error.
	 */
	public static function handle_generate( \WP_REST_Request $request ): \WP_REST_Response {
		$title    = $request->get_param( 'title' );
		$keywords = $request->get_param( 'keywords' );
		$tone     = $request->get_param( 'tone' );
		$length   = $request->get_param( 'length' );

		$length_map = [
			'short'  => '300–500',
			'medium' => '600–900',
			'long'   => '1200–1800',
		];
		$word_count = $length_map[ $length ] ?? '600–900';

		$prompt = "Write a complete blog post with the following specifications:\n\n"
			. "Title: {$title}\n"
			. ( $keywords ? "Keywords to include: {$keywords}\n" : '' )
			. "Tone: {$tone}\n"
			. "Length: approximately {$word_count} words\n\n"
			. 'Write the post in Markdown. Use ## for main section headings and ### for sub-headings. '
			. 'Return only the post body — no title, no preamble, no code fence around the post.';

		try {
			$factory  = new ProviderFactory( new ProviderSettings() );
			$provider = $factory->make_default();
			$voice    = new \Plume\Voice\VoiceInjector();

			$req = new \Plume\Providers\CompletionRequest(
				messages:    [
					[
						'role'    => 'user',
						'content' => $prompt,
					],
				],
				system:      $voice->build_system_prompt( 'Post generation', \get_current_user_id() ),
				model:       $provider->get_default_model(),
				temperature: 0.7,
				max_tokens:  2000,
				metadata:    [
					'feature'    => 'generator',
					'post_title' => $title,
				]
			);

			$response = $provider->complete( $req );
			// Usage logged by the provider layer: proxy for pro_managed, AbstractProvider::maybe_log() for pro_byok.
			$content = ( new \Plume\Content\ContentNormaliser() )->normalise( $response->content );

			// Create a draft post.
			$post_id = \wp_insert_post(
				[
					'post_title'   => \sanitize_text_field( $title ),
					'post_content' => \wp_kses_post( $content ),
					'post_status'  => 'draft',
					'post_author'  => \get_current_user_id(),
					'post_type'    => 'post',
				],
				true
			);

			if ( \is_wp_error( $post_id ) ) {
				return new \WP_REST_Response( [ 'error' => $post_id->get_error_message() ], 500 );
			}

			return new \WP_REST_Response(
				[
					'post_id'      => $post_id,
					'edit_url'     => \get_edit_post_link( $post_id, 'raw' ),
					'content'      => $content,
					'credits_used' => $response->credits_charged,
				],
				201
			);

		} catch ( \Throwable $e ) {
			if ( defined( 'WP_DEBUG_LOG' ) && WP_DEBUG_LOG ) {
				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				\error_log( '[Plume][Generator] ' . get_class( $e ) . ': ' . $e->getMessage() . ' in ' . $e->getFile() . ':' . $e->getLine() );
			}
			return new \WP_REST_Response( [ 'error' => $e->getMessage() ], 500 );
		}
	}
}