<?php
/**
 * Library statistics.
 *
 * @package FlipWebP
 */

namespace FlipWebP;

defined( 'ABSPATH' ) || exit;

/**
 * Counts images and bytes saved for the current user scope.
 */
class Stats {

	const CACHE_KEY = 'flipwebp_stats_cache';

	/**
	 * Forget the cached counts after a conversion changes them.
	 *
	 * @return void
	 */
	public static function flush() {
		delete_transient( self::cache_key() );
	}

	/**
	 * Counts and display labels.
	 *
	 * @return array<string, int|string>
	 */
	public static function get() {
		$cached = get_transient( self::cache_key() );
		if ( is_array( $cached ) && isset( $cached['total'], $cached['pending'], $cached['converted'], $cached['saved_bytes'] ) ) {
			return self::present( $cached );
		}

		$counts = self::query();
		set_transient( self::cache_key(), $counts, 30 );

		return self::present( $counts );
	}

	/**
	 * Cache key scoped to the user when they cannot see the whole library.
	 *
	 * @return string
	 */
	private static function cache_key() {
		if ( Capabilities::can_see_all() ) {
			return self::CACHE_KEY;
		}

		return self::CACHE_KEY . '_' . get_current_user_id();
	}

	/**
	 * Run the count queries.
	 *
	 * @return array<string, int>
	 */
	private static function query() {
		global $wpdb;

		// Zero means every author. The comparison stays inside prepare() so no SQL fragment is concatenated.
		$author_id = Capabilities::can_see_all() ? 0 : get_current_user_id();

		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Aggregate counts have no API. Results are cached by this class.
		$total = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT(*) FROM {$wpdb->posts} p WHERE p.post_type = 'attachment' AND p.post_status != 'trash' AND p.post_mime_type IN ( %s, %s, %s, %s ) AND ( %d = 0 OR p.post_author = %d )",
				'image/jpeg',
				'image/png',
				'image/gif',
				'image/webp',
				$author_id,
				$author_id
			)
		);

		$pending = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT( DISTINCT p.ID )
				FROM {$wpdb->posts} p
				LEFT JOIN {$wpdb->postmeta} m ON m.post_id = p.ID AND m.meta_key = %s
				WHERE p.post_type = 'attachment'
					AND p.post_status != 'trash'
					AND p.post_mime_type IN ( %s, %s, %s )
					AND ( m.meta_id IS NULL OR m.meta_value NOT IN ( %s, %s ) )
					AND ( %d = 0 OR p.post_author = %d )",
				'_flipwebp_status',
				'image/jpeg',
				'image/png',
				'image/gif',
				'converted',
				'skipped',
				$author_id,
				$author_id
			)
		);

		$converted = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT( DISTINCT p.ID )
				FROM {$wpdb->posts} p
				INNER JOIN {$wpdb->postmeta} m ON m.post_id = p.ID AND m.meta_key = %s AND m.meta_value = %s
				WHERE p.post_type = 'attachment' AND p.post_status != 'trash' AND ( %d = 0 OR p.post_author = %d )",
				'_flipwebp_status',
				'converted',
				$author_id,
				$author_id
			)
		);

		$saved = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COALESCE( SUM( CAST( m.meta_value AS UNSIGNED ) ), 0 )
				FROM {$wpdb->postmeta} m
				INNER JOIN {$wpdb->posts} p ON p.ID = m.post_id
				WHERE m.meta_key = %s AND p.post_type = 'attachment' AND p.post_status != 'trash' AND ( %d = 0 OR p.post_author = %d )",
				'_flipwebp_saved_bytes',
				$author_id,
				$author_id
			)
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching

		return array(
			'total'       => max( 0, $total ),
			'pending'     => max( 0, $pending ),
			'converted'   => max( 0, $converted ),
			'saved_bytes' => max( 0, $saved ),
		);
	}

	/**
	 * Add translated labels to raw counts.
	 *
	 * @param array<string, int> $counts Raw counts.
	 * @return array<string, int|string>
	 */
	private static function present( $counts ) {
		$saved = (int) $counts['saved_bytes'];

		return array(
			'total'       => (int) $counts['total'],
			'pending'     => (int) $counts['pending'],
			'converted'   => (int) $counts['converted'],
			'saved_bytes' => $saved,
			'total_label' => number_format_i18n( (int) $counts['total'] ),
			'pending_label' => number_format_i18n( (int) $counts['pending'] ),
			'converted_label' => number_format_i18n( (int) $counts['converted'] ),
			'saved_label' => size_format( $saved, 1 ),
		);
	}
}