<?php
/**
 * Queries against the occurrence index.
 *
 * @package BeariusCalendar
 */

defined( 'ABSPATH' ) || exit;

/**
 * Occurrence queries.
 */
class BCal_Query {

	/**
	 * Returns occurrence rows or a count.
	 *
	 * Arguments:
	 * - from, to        Local "Y-m-d H:i:s" range. "from" matches events still running.
	 * - day             "Y-m-d": events running on that day.
	 * - city, venue     Term IDs.
	 * - categories      Term IDs (children included).
	 * - organizers      Term IDs.
	 * - event           Only this event.
	 * - exclude_event   Skip this event.
	 * - featured        Featured or picked only.
	 * - include_hidden  Include rows hidden by moderation.
	 * - orderby         start|score.
	 * - limit, offset   Paging.
	 * - count           Return a number instead of rows.
	 * - fields          all|light (light = without flags, for month grids).
	 *
	 * @param array $args Arguments.
	 * @return array|int
	 */
	public static function get( $args = array() ) {
		global $wpdb;

		$args = wp_parse_args(
			$args,
			array(
				'from'           => substr( bcal_now(), 0, 16 ) . ':00',
				'to'             => '',
				'day'            => '',
				'city'           => 0,
				'venue'          => 0,
				'categories'     => array(),
				'organizers'     => array(),
				'event'          => 0,
				'exclude_event'  => 0,
				'featured'       => false,
				'include_hidden' => false,
				'orderby'        => 'start',
				'limit'          => 20,
				'offset'         => 0,
				'count'          => false,
				'fields'         => 'all',
			)
		);

		$table  = BCal_Install::table();
		$where  = array( '1=1' );
		$params = array();

		if ( $args['day'] ) {
			$where[]  = 'o.start_dt <= %s AND o.end_dt >= %s';
			$params[] = $args['day'] . ' 23:59:59';
			$params[] = $args['day'] . ' 00:00:00';
		} else {
			if ( $args['from'] ) {
				$where[]  = 'o.end_dt >= %s';
				$params[] = $args['from'];
			}
			if ( $args['to'] ) {
				$where[]  = 'o.start_dt <= %s';
				$params[] = $args['to'];
			}
		}

		foreach ( array( 'city' => 'city_id', 'venue' => 'venue_id', 'event' => 'event_id' ) as $arg => $column ) {
			if ( $args[ $arg ] ) {
				$where[]  = "o.{$column} = %d";
				$params[] = (int) $args[ $arg ];
			}
		}

		if ( $args['exclude_event'] ) {
			$where[]  = 'o.event_id <> %d';
			$params[] = (int) $args['exclude_event'];
		}

		if ( $args['featured'] ) {
			$where[] = '( o.featured = 1 OR o.pick = 1 )';
		}

		if ( ! $args['include_hidden'] ) {
			$where[] = 'o.hidden = 0';
		}

		foreach ( array( 'categories' => 'bcal_category', 'organizers' => 'bcal_organizer' ) as $arg => $taxonomy ) {
			$tt_ids = self::tt_ids( (array) $args[ $arg ], $taxonomy );
			if ( $args[ $arg ] && ! $tt_ids ) {
				return $args['count'] ? 0 : array();
			}
			if ( $tt_ids ) {
				$where[] = "EXISTS ( SELECT 1 FROM {$wpdb->term_relationships} tr WHERE tr.object_id = o.event_id AND tr.term_taxonomy_id IN (" . implode( ',', array_map( 'intval', $tt_ids ) ) . ') )';
			}
		}

		// Every fragment in $where is a fixed string with placeholders; all
		// values travel through $params and $wpdb->prepare() below.
		$where_sql = implode( ' AND ', $where );
		array_unshift( $params, $table );

		if ( $args['count'] ) {
			$sql = $wpdb->prepare( 'SELECT COUNT(*) FROM %i o WHERE ' . $where_sql, ...$params ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Fixed fragments built above, values are placeholders.
		} else {
			$select   = 'light' === $args['fields'] ? 'o.id, o.event_id, o.start_dt, o.end_dt, o.start_date, o.all_day' : 'o.*';
			$order    = 'score' === $args['orderby'] ? 'o.score IS NULL, o.score DESC, o.start_dt ASC' : 'o.start_dt ASC, o.id ASC';
			$params[] = max( 1, (int) $args['limit'] );
			$params[] = max( 0, (int) $args['offset'] );
			$sql      = $wpdb->prepare( 'SELECT ' . $select . ' FROM %i o WHERE ' . $where_sql . ' ORDER BY ' . $order . ' LIMIT %d OFFSET %d', ...$params ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Fixed fragments built above, values are placeholders.
		}

		$last_changed = wp_cache_get( 'last_changed', 'bcal' );
		if ( ! $last_changed ) {
			$last_changed = microtime();
			wp_cache_set( 'last_changed', $last_changed, 'bcal' );
		}
		$cache_key = 'q:' . md5( $sql ) . ':' . $last_changed;
		$cached    = wp_cache_get( $cache_key, 'bcal' );
		if ( false !== $cached ) {
			return $cached;
		}

		if ( $args['count'] ) {
			$result = (int) $wpdb->get_var( $sql ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Prepared above.
		} else {
			$result = (array) $wpdb->get_results( $sql ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.NotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Prepared above.
			$ids    = array_values( array_unique( wp_list_pluck( $result, 'event_id' ) ) );
			if ( $ids ) {
				_prime_post_caches( array_map( 'intval', $ids ), true, true );
			}
		}

		wp_cache_set( $cache_key, $result, 'bcal', 5 * MINUTE_IN_SECONDS );

		return $result;
	}

	/**
	 * Term taxonomy IDs including children.
	 *
	 * @param array  $term_ids Term IDs.
	 * @param string $taxonomy Taxonomy.
	 * @return array
	 */
	private static function tt_ids( $term_ids, $taxonomy ) {
		$out = array();
		foreach ( array_filter( array_map( 'intval', $term_ids ) ) as $term_id ) {
			$ids = array( $term_id );
			if ( is_taxonomy_hierarchical( $taxonomy ) ) {
				$children = get_term_children( $term_id, $taxonomy );
				if ( ! is_wp_error( $children ) ) {
					$ids = array_merge( $ids, $children );
				}
			}
			foreach ( $ids as $id ) {
				$term = get_term( (int) $id, $taxonomy );
				if ( $term && ! is_wp_error( $term ) ) {
					$out[] = (int) $term->term_taxonomy_id;
				}
			}
		}
		return array_values( array_unique( $out ) );
	}

	/**
	 * Keeps the first occurrence of each event.
	 *
	 * @param array $rows  Rows.
	 * @param int   $limit Max rows.
	 * @return array
	 */
	public static function unique_events( $rows, $limit = 0 ) {
		$seen = array();
		$out  = array();
		foreach ( $rows as $row ) {
			if ( isset( $seen[ $row->event_id ] ) ) {
				continue;
			}
			$seen[ $row->event_id ] = true;
			$out[]                  = $row;
			if ( $limit && count( $out ) >= $limit ) {
				break;
			}
		}
		return $out;
	}
}