<?php
namespace FPCA;

defined( 'ABSPATH' ) || exit;

/**
 * Tracks which posts are enrolled in Fresh Plugins Content Audit monitoring.
 *
 * @package FPCA
 */
class Post_Tracker {

	public function register(): void {
		add_action( 'save_post', [ $this, 'maybe_enroll_post' ], 10, 2 );
	}

	/**
	 * Auto-enrol a post on save if it is a published post of a tracked type.
	 *
	 * There is no cap to check: enrolment is unlimited on every tier.
	 */
	public function maybe_enroll_post( int $post_id, \WP_Post $post ): void {
		if ( wp_is_post_revision( $post_id ) || wp_is_post_autosave( $post_id ) ) {
			return;
		}

		$tracked_types = get_option( 'fpca_tracked_post_types', [ 'post', 'page' ] );
		if ( ! in_array( $post->post_type, $tracked_types, true ) ) {
			return;
		}

		if ( $post->post_status !== 'publish' ) {
			return;
		}

		if ( $this->is_enrolled( $post_id ) ) {
			return;
		}

		$this->enroll( $post_id );
	}

	public function enroll( int $post_id ): bool {
		global $wpdb;
		$result = $wpdb->insert(
			$wpdb->prefix . 'fpca_posts',
			[
				'post_id'    => $post_id,
				'status'     => 'unreviewed',
				'created_at' => current_time( 'mysql' ),
				'updated_at' => current_time( 'mysql' ),
			],
			[ '%d', '%s', '%s', '%s' ]
		);

		return $result !== false;
	}

	public function is_enrolled( int $post_id ): bool {
		global $wpdb;
		return (bool) $wpdb->get_var(
			$wpdb->prepare(
				'SELECT id FROM %i WHERE post_id = %d LIMIT 1',
				$wpdb->prefix . 'fpca_posts',
				$post_id
			)
		);
	}

	public function enrolled_count(): int {
		global $wpdb;
		return (int) $wpdb->get_var(
			$wpdb->prepare( 'SELECT COUNT(*) FROM %i', $wpdb->prefix . 'fpca_posts' )
		);
	}

	/**
	 * Returns all enrolled posts joined with WP post data — used by the dashboard.
	 */
	public function get_dashboard_data( array $args = [] ): array {
		global $wpdb;

		$defaults = [
			'orderby' => 'freshness_score',
			'order'   => 'ASC',
		];
		$args = wp_parse_args( $args, $defaults );

		// word_count is computed in PHP (after stripping HTML), so it's sorted post-fetch.
		$php_sort_cols   = [ 'word_count' ];
		$sql_orderby_map = [
			'freshness_score' => 'fs.freshness_score',
			'post_modified'   => 'p.post_modified',
			'status'          => 'fs.status',
			'post_title'      => 'p.post_title',
			'assigned_to'     => "COALESCE(fa.first_assignee_name, '')",
			'gsc_clicks'      => 'fs.gsc_clicks',
			'gsc_position'    => 'fs.gsc_position',
			'gsc_ctr'         => 'fs.gsc_ctr',
		];

		$sort_in_php = in_array( $args['orderby'], $php_sort_cols, true );
		$orderby_col = $sql_orderby_map[ $args['orderby'] ] ?? 'fs.freshness_score';
		$order       = strtoupper( $args['order'] ) === 'DESC' ? 'DESC' : 'ASC';

		// Push NULLs to the bottom for columns where NULL means "no data".
		$null_first = '';
		if ( $args['orderby'] === 'freshness_score' && $order === 'ASC' ) {
			$null_first = 'ISNULL(fs.freshness_score) ASC, ';
		} elseif ( in_array( $args['orderby'], [ 'gsc_clicks', 'gsc_position', 'gsc_ctr' ], true ) ) {
			$null_first = "ISNULL({$orderby_col}) ASC, ";
		}

		$tracked_types = array_values( array_filter( array_map(
			'sanitize_key',
			(array) get_option( 'fpca_tracked_post_types', [ 'post', 'page' ] )
		) ) );

		// An empty list would produce `IN ()` (a syntax error) and call prepare()
		// with no placeholders, which triggers _doing_it_wrong and returns null.
		if ( empty( $tracked_types ) ) {
			return [];
		}

		$placeholders = implode( ', ', array_fill( 0, count( $tracked_types ), '%s' ) );

		// Schema migrations run on admin_init, which fires before any admin page
		// renders, so every column selected below is guaranteed to exist here.
		// phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQLPlaceholders -- $placeholders is a generated run of %s, one per element of $tracked_types, and $null_first/$orderby_col/$order are literals picked from the allow-lists above. Every table name and every user-supplied value is bound.
		$rows = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT fs.id, fs.post_id, fs.freshness_score, fs.sub_scores, fs.scored_at,
				        fs.ai_reasoning, fs.status, fs.assigned_to,
				        p.post_title, p.post_modified, p.post_content, p.post_type
				 FROM %i fs
				 JOIN %i p ON fs.post_id = p.ID
				 LEFT JOIN (
				     SELECT a.post_id, MIN(u.display_name) AS first_assignee_name
				     FROM %i a
				     JOIN %i u ON a.user_id = u.ID
				     GROUP BY a.post_id
				 ) fa ON fa.post_id = fs.post_id
				 WHERE p.post_status = 'publish'
				   AND p.post_type IN ({$placeholders})
				 ORDER BY {$null_first}{$orderby_col} {$order}",
				$wpdb->prefix . 'fpca_posts',
				$wpdb->posts,
				$wpdb->prefix . 'fpca_assignments',
				$wpdb->users,
				...$tracked_types
			),
			ARRAY_A
		);
		// phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQLPlaceholders

		foreach ( $rows as &$row ) {
			$row['word_count'] = str_word_count( Freshness_Scorer::get_scoreable_content( (int) $row['post_id'], $row['post_content'] ) );
			$row['edit_url']   = get_edit_post_link( (int) $row['post_id'], 'raw' );
			$row['view_url']   = get_permalink( (int) $row['post_id'] );
			$row['ai_reasons'] = ! empty( $row['ai_reasoning'] )
				? json_decode( $row['ai_reasoning'], true )
				: [];
			// Safely decode sub_scores JSON, defaulting to empty array
			$decoded_sub_scores = null;
			if ( ! empty( $row['sub_scores'] ) ) {
				$decoded_sub_scores = json_decode( $row['sub_scores'], true );
			}
			$row['sub_scores'] = is_array( $decoded_sub_scores ) ? $decoded_sub_scores : [];
			unset( $row['post_content'], $row['ai_reasoning'] );
		}
		unset( $row );

		// Sort columns whose values are only available after PHP processing.
		if ( $sort_in_php && ! empty( $rows ) ) {
			$col = $args['orderby'];
			usort( $rows, function ( $a, $b ) use ( $col, $order ) {
				$va = $a[ $col ] ?? 0;
				$vb = $b[ $col ] ?? 0;
				$cmp = $va <=> $vb;
				return $order === 'DESC' ? -$cmp : $cmp;
			} );
		}

		return $rows;
	}

	/**
	 * Enrol every published post of the tracked types that isn't already tracked.
	 * Returns count of newly enrolled posts.
	 *
	 * Enrolment is deliberately uncapped on every tier: the only metered
	 * resource is scores per month, and that is enforced server-side at the
	 * proxy. Do not reintroduce a local cap here — one used to stop free sites
	 * at 25 enrolled posts and then report "0 post(s) enrolled." on every
	 * subsequent click.
	 */
	public function enroll_existing( array $post_types = [] ): int {
		if ( empty( $post_types ) ) {
			$post_types = (array) get_option( 'fpca_tracked_post_types', [ 'post', 'page' ] );
		}

		$posts = get_posts( [
			'post_type'      => $post_types,
			'post_status'    => 'publish',
			'posts_per_page' => -1,
			'orderby'        => 'modified',
			'order'          => 'DESC',
			'fields'         => 'ids',
		] );

		if ( empty( $posts ) ) {
			return 0;
		}

		// One query for everything already tracked, rather than is_enrolled()
		// per post — this now walks the whole library, not the first 25.
		global $wpdb;
		$existing = $wpdb->get_col(
			$wpdb->prepare( 'SELECT post_id FROM %i', $wpdb->prefix . 'fpca_posts' )
		);
		$existing = array_flip( array_map( 'intval', (array) $existing ) );

		$enrolled = 0;
		foreach ( $posts as $post_id ) {
			if ( isset( $existing[ (int) $post_id ] ) ) {
				continue;
			}
			if ( $this->enroll( (int) $post_id ) ) {
				$enrolled++;
			}
		}

		return $enrolled;
	}
}