<?php
/**
 * Aoedia site report ability.
 *
 * One read-only ability gathers the numbers an editor checks regularly, so
 * the model can answer "how is the blog doing?" in a single call.
 *
 * @package Aoedia
 */

defined( 'ABSPATH' ) || exit;

/** Report sections, in output order. */
const AOEDIA_REPORT_SECTIONS = array( 'content', 'comments', 'taxonomies', 'usage' );

/** Drafts not touched for this many days count as stale. */
const AOEDIA_STALE_DRAFT_DAYS = 30;

/**
 * Registers the site report ability.
 */
function aoedia_register_report_abilities(): void {
	wp_register_ability(
		'aoedia/site-report',
		array(
			'label'               => __( 'Site Report', 'aoedia' ),
			'description'         => __( 'Reports on the last N days: posts published (by category), drafts, scheduled posts, stale drafts, posts without an excerpt; comments received, waiting and marked as spam, and the most commented posts; unused categories and tags used on at most one post; and, for administrators, Aoedia requests and tokens per user. Choose only the sections you need.', 'aoedia' ),
			'category'            => 'aoedia-content',
			'input_schema'        => array(
				'type'                 => 'object',
				'properties'           => array(
					'days'     => array(
						'type'        => 'integer',
						'minimum'     => 1,
						'maximum'     => 365,
						'description' => __( 'Optional: How many days back to report on. Default 30.', 'aoedia' ),
					),
					'sections' => array(
						'type'        => 'array',
						'items'       => array(
							'type' => 'string',
							'enum' => AOEDIA_REPORT_SECTIONS,
						),
						'uniqueItems' => true,
						'description' => __( 'Optional: content, comments, taxonomies and/or usage. Default all.', 'aoedia' ),
					),
				),
				'additionalProperties' => false,
				'default'              => array(),
			),
			'output_schema'       => array(
				'type'       => 'object',
				'properties' => array(
					'period'     => array( 'type' => 'object' ),
					'content'    => array( 'type' => 'object' ),
					'comments'   => array( 'type' => 'object' ),
					'taxonomies' => array( 'type' => 'object' ),
					'usage'      => array( 'type' => 'object' ),
				),
			),
			'execute_callback'    => 'aoedia_ability_site_report',
			// The report lists other people's drafts.
			'permission_callback' => static function (): bool {
				return current_user_can( 'edit_others_posts' );
			},
			'meta'                => array(
				'annotations'  => array(
					'readonly'    => true,
					'destructive' => false,
					'idempotent'  => true,
				),
				'show_in_rest' => true,
			),
		)
	);
}

/**
 * Executes aoedia/site-report.
 *
 * @param array<string, mixed> $input The ability input.
 * @return array<string, mixed> The report.
 */
function aoedia_ability_site_report( $input = array() ): array {
	$input    = is_array( $input ) ? $input : array();
	$days     = isset( $input['days'] ) ? min( 365, max( 1, (int) $input['days'] ) ) : 30;
	$sections = ! empty( $input['sections'] ) ? array_intersect( AOEDIA_REPORT_SECTIONS, (array) $input['sections'] ) : AOEDIA_REPORT_SECTIONS;
	$since    = gmdate( 'Y-m-d H:i:s', time() - $days * DAY_IN_SECONDS );

	$report = array(
		'period' => array(
			'days' => $days,
			'from' => wp_date( 'Y-m-d', time() - $days * DAY_IN_SECONDS ),
			'to'   => wp_date( 'Y-m-d' ),
		),
	);

	if ( in_array( 'content', $sections, true ) ) {
		$report['content'] = aoedia_report_content( $since );
	}
	if ( in_array( 'comments', $sections, true ) ) {
		$report['comments'] = aoedia_report_comments( $since );
	}
	if ( in_array( 'taxonomies', $sections, true ) ) {
		$report['taxonomies'] = aoedia_report_taxonomies();
	}
	if ( in_array( 'usage', $sections, true ) ) {
		$report['usage'] = current_user_can( 'manage_options' )
			? aoedia_report_usage( $since )
			: array( 'note' => 'Only administrators can see Aoedia usage.' );
	}

	return $report;
}

/**
 * Counts posts matching a query without loading them.
 *
 * @param array<string, mixed> $args WP_Query arguments.
 * @return int The number of posts.
 */
function aoedia_report_count_posts( array $args ): int {
	$query = new WP_Query(
		array_merge(
			array(
				'post_type'      => 'post',
				'posts_per_page' => 1,
				'fields'         => 'ids',
			),
			$args
		)
	);

	return (int) $query->found_posts;
}

/**
 * Builds the content section of the report.
 *
 * @param string $since Start of the period, as a GMT MySQL date.
 * @return array<string, mixed> The section.
 */
function aoedia_report_content( string $since ): array {
	$in_period = array(
		'post_status' => 'publish',
		'date_query'  => array(
			array(
				'column' => 'post_date_gmt',
				'after'  => $since,
			),
		),
	);

	// Enough IDs to count categories on any normal blog.
	$published_ids = get_posts(
		array_merge(
			$in_period,
			array(
				'post_type'      => 'post',
				'posts_per_page' => 2000, // phpcs:ignore WordPress.WP.PostsPerPage -- IDs only, for counting.
				'fields'         => 'ids',
				'no_found_rows'  => true,
			)
		)
	);

	$by_category = array();
	foreach ( $published_ids ? wp_get_object_terms( $published_ids, 'category', array( 'fields' => 'all_with_object_id' ) ) : array() as $term ) {
		$name                 = aoedia_plain_text( $term->name );
		$by_category[ $name ] = ( $by_category[ $name ] ?? 0 ) + 1;
	}
	arsort( $by_category );

	$stale = get_posts(
		array(
			'post_type'      => 'post',
			'post_status'    => 'draft',
			'posts_per_page' => 10,
			'orderby'        => 'modified',
			'order'          => 'ASC',
			'date_query'     => array(
				// Local time: drafts that were never updated have no GMT modified date.
				array(
					'column' => 'post_modified',
					'before' => wp_date( 'Y-m-d H:i:s', time() - AOEDIA_STALE_DRAFT_DAYS * DAY_IN_SECONDS ),
				),
			),
		)
	);

	$without_excerpt = count(
		array_filter(
			$published_ids,
			static function ( int $id ): bool {
				return '' === trim( get_post_field( 'post_excerpt', $id ) );
			}
		)
	);

	return array(
		'published'       => count( $published_ids ),
		'by_category'     => array_map(
			static function ( string $name, int $count ): array {
				return array(
					'name'  => $name,
					'count' => $count,
				);
			},
			array_keys( $by_category ),
			array_values( $by_category )
		),
		'without_excerpt' => $without_excerpt,
		'drafts'          => aoedia_report_count_posts( array( 'post_status' => 'draft' ) ),
		'pending_review'  => aoedia_report_count_posts( array( 'post_status' => 'pending' ) ),
		'scheduled'       => aoedia_report_count_posts( array( 'post_status' => 'future' ) ),
		'stale_drafts'    => array_map(
			static function ( WP_Post $post ): array {
				return array(
					'id'       => $post->ID,
					'title'    => aoedia_plain_title( $post ),
					'modified' => (string) get_post_modified_time( 'Y-m-d', false, $post ),
				);
			},
			$stale
		),
	);
}

/**
 * Builds the comments section of the report.
 *
 * @param string $since Start of the period, as a GMT MySQL date.
 * @return array<string, mixed> The section.
 */
function aoedia_report_comments( string $since ): array {
	$in_period = array(
		'type'       => 'comment',
		'date_query' => array(
			array(
				'column' => 'comment_date_gmt',
				'after'  => $since,
			),
		),
	);

	$approved = get_comments(
		array_merge(
			$in_period,
			array(
				'status' => 'approve',
				'fields' => 'ids',
				'number' => 2000,
			)
		)
	);

	$per_post = array();
	foreach ( $approved as $comment_id ) {
		$post_id              = (int) get_comment( $comment_id )->comment_post_ID;
		$per_post[ $post_id ] = ( $per_post[ $post_id ] ?? 0 ) + 1;
	}
	arsort( $per_post );

	$most_commented = array();
	foreach ( array_slice( $per_post, 0, 5, true ) as $post_id => $count ) {
		$most_commented[] = array(
			'id'       => $post_id,
			'title'    => aoedia_plain_title( $post_id ),
			'comments' => $count,
		);
	}

	$counts = wp_count_comments();

	return array(
		'received'       => count( $approved ) + (int) get_comments(
			array_merge(
				$in_period,
				array(
					'status' => 'hold',
					'count'  => true,
				)
			)
		),
		'approved'       => count( $approved ),
		'spam'           => (int) get_comments(
			array_merge(
				$in_period,
				array(
					'status' => 'spam',
					'count'  => true,
				)
			)
		),
		'waiting_now'    => (int) $counts->moderated,
		'most_commented' => $most_commented,
	);
}

/**
 * Builds the taxonomies section of the report.
 *
 * @return array<string, mixed> The section.
 */
function aoedia_report_taxonomies(): array {
	$categories = get_terms(
		array(
			'taxonomy'   => 'category',
			'hide_empty' => false,
		)
	);
	$unused     = array();
	foreach ( is_array( $categories ) ? $categories : array() as $category ) {
		if ( 0 === (int) $category->count && (int) get_option( 'default_category' ) !== $category->term_id ) {
			$unused[] = array(
				'id'   => $category->term_id,
				'name' => aoedia_plain_text( $category->name ),
			);
		}
	}

	$rare_tags = get_terms(
		array(
			'taxonomy'   => 'post_tag',
			'hide_empty' => false,
			'orderby'    => 'count',
			'order'      => 'ASC',
			'number'     => 200,
		)
	);
	$rare_tags = array_values(
		array_filter(
			is_array( $rare_tags ) ? $rare_tags : array(),
			static function ( WP_Term $tag ): bool {
				return (int) $tag->count <= 1;
			}
		)
	);

	return array(
		'categories'        => (int) wp_count_terms( array( 'taxonomy' => 'category' ) ),
		'tags'              => (int) wp_count_terms( array( 'taxonomy' => 'post_tag' ) ),
		'unused_categories' => $unused,
		// Tags on at most one post: candidates for merging or deleting.
		'rare_tags'         => count( $rare_tags ),
		'rare_tags_list'    => array_map(
			static function ( WP_Term $tag ): array {
				return array(
					'id'    => $tag->term_id,
					'name'  => aoedia_plain_text( $tag->name ),
					'count' => (int) $tag->count,
				);
			},
			array_slice( $rare_tags, 0, 20 )
		),
	);
}

/**
 * Builds the Aoedia usage section of the report.
 *
 * @param string $since Start of the period, as a GMT MySQL date.
 * @return array<string, mixed> The section.
 */
function aoedia_report_usage( string $since ): array {
	global $wpdb;

	// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Plugin table; a report is always fresh.
	$rows = $wpdb->get_results(
		$wpdb->prepare(
			"SELECT user_id, COUNT(*) AS requests, COALESCE( SUM( tokens ), 0 ) AS tokens FROM %i WHERE event = 'request' AND created_at >= %s GROUP BY user_id ORDER BY tokens DESC",
			aoedia_log_table(),
			$since
		)
	);

	$by_user = array();
	foreach ( $rows as $row ) {
		$user      = get_userdata( (int) $row->user_id );
		$by_user[] = array(
			'user'     => $user ? $user->display_name : '#' . $row->user_id,
			'requests' => (int) $row->requests,
			'tokens'   => (int) $row->tokens,
		);
	}

	return array(
		'requests' => array_sum( wp_list_pluck( $by_user, 'requests' ) ),
		'tokens'   => array_sum( wp_list_pluck( $by_user, 'tokens' ) ),
		'by_user'  => $by_user,
	);
}