<?php

namespace AIContentWriter\Campaigns;

defined( 'ABSPATH' ) || exit; // Exit if accessed directly.

/**
 * Class Autopilot
 *
 * Zero-input campaign type: instead of scraping sources or taking keywords,
 * the campaign studies the site's existing published content (titles,
 * categories, tags), distills a compact "site profile" via the configured AI
 * provider, and generates fresh article titles that match the site's niche
 * without overlapping existing coverage. Content generation then reuses the
 * standard AI pipeline.
 *
 * @since 2.4.5
 * @package AIContentWriter/Campaigns
 */
class Autopilot {

	/**
	 * Minimum number of published posts required to build a meaningful profile.
	 */
	const MIN_PUBLISHED_POSTS = 5;

	/**
	 * How many recent posts to sample when profiling the site.
	 */
	const SAMPLE_SIZE = 30;

	/**
	 * How long a cached site profile stays fresh.
	 */
	const PROFILE_TTL = WEEK_IN_SECONDS;

	/**
	 * Generate titles for an Autopilot campaign.
	 *
	 * @param int $campaign_id  The campaign ID.
	 * @param int $posts_needed The number of posts needed.
	 *
	 * @since 2.4.5
	 * @return bool Whether any titles were generated.
	 */
	public static function generate_titles( $campaign_id, $posts_needed ) {
		if ( empty( $campaign_id ) || empty( $posts_needed ) ) {
			return false;
		}

		$provider = aicw_get_campaign_ai_provider( $campaign_id );

		if ( ! $provider || ! $provider->is_configured() ) {
			ai_content_writer()->create_log(
				esc_html__( 'Autopilot campaign skipped: the selected AI provider is not configured. Add its API key on the settings page.', 'ai-content-writer' ),
				'error',
				$campaign_id
			);
			return false;
		}

		$recent_titles = self::get_recent_titles( $campaign_id );

		// Guard: without enough existing content there is no niche to match — skip instead of generating generic filler.
		if ( count( $recent_titles ) < self::MIN_PUBLISHED_POSTS ) {
			ai_content_writer()->create_log(
				sprintf(
				/* translators: %d: Minimum number of published posts. */
					esc_html__( 'Autopilot campaign skipped: at least %d published posts are needed so the AI can learn what your site is about. Publish more content or use a keyword campaign instead.', 'ai-content-writer' ),
					self::MIN_PUBLISHED_POSTS
				),
				'warning',
				$campaign_id
			);
			return false;
		}

		$profile  = self::get_site_profile( $campaign_id, $provider, $recent_titles );
		$language = aicw_get_campaign_language( $campaign_id );
		$tone     = aicw_get_campaign_tone( $campaign_id );

		// Ask for a few extra titles so duplicates can be discarded.
		$count  = absint( $posts_needed ) + 10;
		$prompt = self::build_titles_prompt( $profile, $recent_titles, $count, $language, $tone );

		$text = $provider->generate( $prompt, array( 'max_tokens' => 1000 ) );

		if ( is_wp_error( $text ) || empty( $text ) ) {
			$reason = is_wp_error( $text )
				? $text->get_error_message()
				: esc_html__( 'The provider replied with an empty message.', 'ai-content-writer' );

			ai_content_writer()->create_log(
				sprintf(
				/* translators: 1: Provider label, 2: Model ID, 3: Error reported by the provider. */
					esc_html__( 'Autopilot title generation failed. Provider: %1$s. Model: %2$s. Reason: %3$s', 'ai-content-writer' ),
					esc_html( $provider->get_label() ),
					esc_html( $provider->get_default_model() ),
					esc_html( $reason )
				),
				'error',
				$campaign_id
			);
			return false;
		}

		$counter = 0;

		foreach ( explode( "\n", trim( $text ) ) as $title ) {
			$title = trim( $title );

			if ( empty( $title ) || ! preg_match( '/^(\d+\.\s|- )/', $title ) ) {
				continue;
			}

			$title = preg_replace( '/^(\d+\.\s*|- )/', '', $title );
			$title = trim( $title, '" ' );

			if ( empty( $title ) || aicw_get_post_by_title( $title ) ) {
				continue;
			}

			$post_id = wp_insert_post(
				array(
					'post_type'    => 'aicw_post',
					'post_title'   => wp_strip_all_tags( $title ),
					'post_content' => '',
					'post_status'  => 'pending',
					'post_author'  => get_post_field( 'post_author', $campaign_id ),
				)
			);

			if ( is_wp_error( $post_id ) || ! $post_id ) {
				continue;
			}

			update_post_meta( $post_id, '_aicw_campaign_id', $campaign_id );
			++$counter;

			if ( $counter >= absint( $posts_needed ) ) {
				break;
			}
		}

		if ( $counter > 0 ) {
			ai_content_writer()->create_log(
				sprintf(
				/* translators: %d: Number of titles generated. */
					esc_html__( 'Autopilot generated %d article titles matched to your existing site content.', 'ai-content-writer' ),
					$counter
				),
				'success',
				$campaign_id
			);
		}

		aicw_update_last_run_time( $campaign_id );

		return $counter > 0;
	}

	/**
	 * Build the title-generation prompt from the site profile and existing titles.
	 *
	 * @param string $profile       The distilled site profile.
	 * @param array  $recent_titles Recent published post titles.
	 * @param int    $count         Number of titles to request.
	 * @param string $language      Output language.
	 * @param string $tone          Writing tone ('' for default).
	 *
	 * @since 2.4.5
	 * @return string
	 */
	public static function build_titles_prompt( $profile, $recent_titles, $count, $language, $tone = '' ) {
		$titles_list = implode( "\n", array_map( static function ( $title ) {
			return '- ' . $title;
		}, $recent_titles ) );

		$tone_line = empty( $tone ) ? '' : sprintf( ' Match a %s tone.', $tone );

		return sprintf(
			"You are the content strategist for a website with this profile:\n%1\$s\n\nThese articles are already published on the site:\n%2\$s\n\nPropose %3\$d NEW article titles in %4\$s that fit the site's niche and audience, extend its existing topics, and do NOT duplicate or closely overlap any of the published articles above.%5\$s Return them as a plain numbered list (\"1. Title\"), one title per line, with no extra commentary.",
			$profile,
			$titles_list,
			absint( $count ),
			$language,
			$tone_line
		);
	}

	/**
	 * Get (and cache) the AI-distilled site profile for a campaign.
	 *
	 * The profile is stored in campaign meta and refreshed after PROFILE_TTL so
	 * it keeps tracking the site as new content is published. When the AI call
	 * fails, an uncached deterministic summary is used for the current run.
	 *
	 * @param int                                          $campaign_id   The campaign ID.
	 * @param \AIContentWriter\Services\ProviderInterface  $provider      The AI provider.
	 * @param array                                        $recent_titles Recent published post titles.
	 *
	 * @since 2.4.5
	 * @return string
	 */
	protected static function get_site_profile( $campaign_id, $provider, $recent_titles ) {
		$profile   = get_post_meta( $campaign_id, '_aicw_autopilot_profile', true );
		$timestamp = absint( get_post_meta( $campaign_id, '_aicw_autopilot_profile_time', true ) );

		if ( ! empty( $profile ) && ( time() - $timestamp ) < self::PROFILE_TTL ) {
			return $profile;
		}

		$summary = self::build_site_summary( $campaign_id, $recent_titles );

		$prompt = sprintf(
			"Analyze this website's published content and describe the site in 3-4 sentences: its niche, main topics, target audience, and overall writing style. Respond with the description only, no headings or commentary.\n\n%s",
			$summary
		);

		$profile = $provider->generate( $prompt, array( 'max_tokens' => 500 ) );

		if ( is_wp_error( $profile ) || empty( $profile ) ) {
			// Fall back to the raw summary for this run; don't cache it so the
			// AI profile is retried next time.
			return $summary;
		}

		$profile = sanitize_textarea_field( $profile );

		update_post_meta( $campaign_id, '_aicw_autopilot_profile', $profile );
		update_post_meta( $campaign_id, '_aicw_autopilot_profile_time', time() );

		return $profile;
	}

	/**
	 * Build a deterministic summary of the site's existing content.
	 *
	 * @param int   $campaign_id   The campaign ID.
	 * @param array $recent_titles Recent published post titles.
	 *
	 * @since 2.4.5
	 * @return string
	 */
	protected static function build_site_summary( $campaign_id, $recent_titles ) {
		$parts = array();

		$parts[] = sprintf( 'Site name: %s.', get_bloginfo( 'name' ) );

		$tagline = get_bloginfo( 'description' );
		if ( ! empty( $tagline ) ) {
			$parts[] = sprintf( 'Tagline: %s.', $tagline );
		}

		$categories = self::get_top_terms( 'category' );
		if ( ! empty( $categories ) ) {
			$parts[] = sprintf( 'Main categories: %s.', implode( ', ', $categories ) );
		}

		$tags = self::get_top_terms( 'post_tag' );
		if ( ! empty( $tags ) ) {
			$parts[] = sprintf( 'Popular tags: %s.', implode( ', ', $tags ) );
		}

		$parts[] = "Recent article titles:\n- " . implode( "\n- ", $recent_titles );

		return implode( "\n", $parts );
	}

	/**
	 * Get the titles of the most recent published posts of the campaign's
	 * target post type.
	 *
	 * @param int $campaign_id The campaign ID.
	 *
	 * @since 2.4.5
	 * @return array Post titles, newest first.
	 */
	protected static function get_recent_titles( $campaign_id ) {
		$post_type = get_post_meta( $campaign_id, '_aicw_post_type', true );
		$post_type = ! empty( $post_type ) ? $post_type : 'post';

		$posts = get_posts(
			array(
				'post_type'           => $post_type,
				'post_status'         => 'publish',
				'posts_per_page'      => self::SAMPLE_SIZE,
				'orderby'             => 'date',
				'order'               => 'DESC',
				'no_found_rows'       => true,
				'ignore_sticky_posts' => true,
			)
		);

		$titles = array();

		foreach ( $posts as $post ) {
			$title = trim( wp_strip_all_tags( $post->post_title ) );
			if ( '' !== $title ) {
				$titles[] = $title;
			}
		}

		return $titles;
	}

	/**
	 * Get the names of the most-used terms in a taxonomy.
	 *
	 * @param string $taxonomy The taxonomy name.
	 * @param int    $limit    Maximum number of terms.
	 *
	 * @since 2.4.5
	 * @return array Term names.
	 */
	protected static function get_top_terms( $taxonomy, $limit = 10 ) {
		$terms = get_terms(
			array(
				'taxonomy'   => $taxonomy,
				'orderby'    => 'count',
				'order'      => 'DESC',
				'number'     => $limit,
				'hide_empty' => true,
			)
		);

		if ( is_wp_error( $terms ) || empty( $terms ) ) {
			return array();
		}

		return wp_list_pluck( $terms, 'name' );
	}
}