<?php

if (!defined('ABSPATH')) exit;

class AsgarosForumUserQuery {
	// TODO: Check required variables.
	// Array of variables to query with.
	public $query_vars = array();

	// List of found users and their respective data.
	public $results = array();

	// Total number of found users for the current query.
	public $total_users = 0;

	// List of found user IDs.
	public $user_ids = array();

	// SQL clauses for the user ID query.
	public $uid_clauses = array();

	// Standard response when the query should not return any rows.
	protected $no_results = array('join' => '', 'where' => '0 = 1');

	// Constructor.
	public function __construct($query = null) {
		// Cancel if no query is given.
		if (empty($query)) {
			return;
		}

		// TODO: Check required arguments.
		$this->query_vars = wp_parse_args($query, array(
			'fields'            => array('ID'),
			'type'              => 'default',
			'per_page'          => 0,
			'page'              => 1,
			'search_terms'      => false,
			'include'           => false,
			'exclude'           => false,
			'user_ids'          => false,
			'meta_key'          => false,
			'meta_value'        => false,
			'meta_compare'      => '=',
			'role'              => false,
			'populate_extras'   => false
		));

		// Get user ids. If the user_ids param is present, we skip the query.
		// TODO: Check if necessary.
		if ($this->query_vars['user_ids'] !== false) {
			$this->user_ids = wp_parse_id_list($this->query_vars['user_ids']);
		} else {
			$this->prepare_user_ids_query();
			$this->do_user_ids_query();
		}

		// Cancel if no user IDs were found.
		if (empty($this->user_ids)) {
			return;
		}

		// Fetch additional data. First, using WP_User_Query.
		$this->do_wp_user_query();

		// Get BuddyPress specific user data.
		$this->populate_extras();
	}

	// Prepare the query for user_ids.
	public function prepare_user_ids_query() {
		global $wpdb;

		extract($this->query_vars);

		// Setup the main SQL query container.
		$sql = array(
			'select'  => '',
			'where'   => array('1=1'),
			'orderby' => '',
			'order'   => '',
			'limit'   => ''
		);

		// Determines the sort order, which means it also determines where the
		// user IDs are drawn from (the SELECT and WHERE statements).
		switch ($type) {
			// 'alphabetical' sorts depend on the xprofile setup.
			case 'alphabetical' :
				$sql['select'] = "SELECT u.ID FROM {$wpdb->users} u";
				$sql['orderby'] = "ORDER BY u.display_name";
				$sql['order'] = "ASC";

				// To ensure that spam/deleted/non-activated users
				// are filtered out, we add an appropriate sub-query.
				$user_status_filter = 'user_status = 0';

				if (is_multisite()) {
					$user_status_filter = 'spam = 0 AND deleted = 0 AND user_status = 0';
				}

				$sql['where'][] = "u.ID IN ( SELECT ID FROM {$wpdb->users} WHERE {$user_status_filter} )";
				break;
			// Any other 'type' falls through.
			default :
				$sql['select'] = "SELECT u.ID FROM {$wpdb->users} u";
				break;
		}

		// 'include' - User ids to include in the results.
		$include_ids = $include !== false ? wp_parse_id_list($include) : array();

		// An array containing nothing but 0 should always fail.
		if (count($include_ids) === 1 && reset($include_ids) === 0) {
			$sql['where'][] = $this->no_results['where'];
		} else if (!empty($include_ids)) {
			$include_ids = implode(',', wp_parse_id_list($include_ids));
			$sql['where'][] = "u.ID IN ({$include_ids})";
		}

		// 'exclude' - User ids to exclude from the results.
		if ($exclude !== false) {
			$exclude_ids = implode(',', wp_parse_id_list($exclude));
			$sql['where'][] = "u.ID NOT IN ({$exclude_ids})";
		}

		// 'search_terms' searches user_login and user_nicename.
		if ($search_terms !== false) {
			$search_terms = $wpdb->esc_like(wp_kses_normalize_entities($search_terms));
			$search_terms_nospace = $search_terms.'%';
			$search_terms_space = '% '.$search_terms.'%';

			$matched_user_ids = $wpdb->get_col($wpdb->prepare(
				"SELECT ID FROM {$wpdb->users} WHERE ( user_login LIKE %s OR user_login LIKE %s OR user_nicename LIKE %s OR user_nicename LIKE %s )",
				$search_terms_nospace,
				$search_terms_space,
				$search_terms_nospace,
				$search_terms_space
			));

			$match_in_clause = empty($matched_user_ids) ? 'NULL' : implode(',', $matched_user_ids);
			$sql['where']['search'] = "u.ID IN ({$match_in_clause})";
		}

		// 'meta_key', 'meta_value' allow usermeta search.
		// To avoid global joins, do a separate query.
		if ($meta_key !== false) {
			$meta_sql = $wpdb->prepare("SELECT user_id FROM {$wpdb->usermeta} WHERE meta_key = %s", $meta_key);

			if ($meta_value !== false) {
				$meta_sql .= $wpdb->prepare(" AND meta_value {$meta_compare} %s", $meta_value);
			}

			$found_user_ids = $wpdb->get_col($meta_sql);

			if (!empty($found_user_ids)) {
				$sql['where'][] = "u.ID IN (".implode(',', wp_parse_id_list($found_user_ids)).")";
			} else {
				$sql['where'][] = '1 = 0';
			}
		}

		if ($role !== false) {
			$meta_sql = "SELECT user_id FROM {$wpdb->usermeta} WHERE meta_key = 'wp_capabilities' AND meta_value LIKE '%\"{$role}\"%'";

			$found_user_ids = $wpdb->get_col($meta_sql);

			if (!empty($found_user_ids)) {
				$sql['where'][] = "u.ID IN (".implode(',', wp_parse_id_list($found_user_ids)).")";
			} else {
				$sql['where'][] = '1 = 0';
			}
		}

		// 'per_page', 'page' - handles LIMIT.
		if (!empty($per_page) && !empty($page)) {
			$sql['limit'] = $wpdb->prepare("LIMIT %d, %d", (int) (($page - 1)*$per_page), (int) $per_page);
		} else {
			$sql['limit'] = '';
		}

		// Assemble the query chunks.
		$this->uid_clauses['select']  = $sql['select'];
		$this->uid_clauses['where']   = !empty($sql['where']) ? 'WHERE '.implode(' AND ', $sql['where']) : '';
		$this->uid_clauses['orderby'] = $sql['orderby'];
		$this->uid_clauses['order']   = $sql['order'];
		$this->uid_clauses['limit']   = $sql['limit'];
	}

	// Query for IDs of users that match the query parameters.
	public function do_user_ids_query() {
		global $wpdb;

		// Get the specific user ids.
		$this->user_ids = $wpdb->get_col("{$this->uid_clauses['select']} {$this->uid_clauses['where']} {$this->uid_clauses['orderby']} {$this->uid_clauses['order']} {$this->uid_clauses['limit']}");
	}

	// Use WP_User_Query() to pull data for the user IDs retrieved in the main query.
	public function do_wp_user_query() {
		$wp_user_query = new WP_User_Query(array(
			'fields'      => $this->query_vars['fields'],
			'include'     => $this->user_ids,
			'count_total' => false,
			'orderby'     => 'ID'
		));

		$this->total_users = count($wp_user_query->results);

		// Reindex for easier matching.
		$r = array();
		foreach ($wp_user_query->results as $u) {
			$r[$u->ID] = $u;
		}

		// Match up to the user ids from the main query.
		foreach ($this->user_ids as $key => $uid) {
			if (isset($r[$uid])) {
				$r[$uid]->ID = (int)$uid;
				$this->results[$uid] = $r[$uid];
			// Remove user ID from original user_ids property.
			} else {
				unset($this->user_ids[$key]);
			}
		}
	}

	// Perform a database query to populate any extra metadata we might need.
	public function populate_extras() {
		global $wpdb;

		// Bail if no users.
		if (empty($this->user_ids) || empty($this->results)) {
			return;
		}

		// Bail if the populate_extras flag is set to false.
		if (!(bool)$this->query_vars['populate_extras']) {
			return;
		}

		// Turn user ID's into a query-usable, comma separated value.
		$user_ids_sql = implode(',', wp_parse_id_list($this->user_ids));

		// When meta_key or meta_value have been passed to the query,
		// fetch the resulting values for use in the template functions.
		if (!empty($this->query_vars['meta_key'])) {
			$meta_sql = array(
				'select' => "SELECT user_id, meta_key, meta_value",
				'from'   => "FROM $wpdb->usermeta",
				'where'  => $wpdb->prepare("WHERE meta_key = %s", $this->query_vars['meta_key'])
			);

			if ($this->query_vars['meta_value'] !== false) {
				$meta_sql['where'] .= $wpdb->prepare(" AND meta_value {$this->query_vars['meta_compare']} %s", $this->query_vars['meta_value']);
			}

			$metas = $wpdb->get_results("{$meta_sql['select']} {$meta_sql['from']} {$meta_sql['where']}");

			if (!empty($metas)) {
				foreach ($metas as $meta) {
					if (isset($this->results[$meta->user_id])) {
						$this->results[$meta->user_id]->meta_key = $meta->meta_key;

						if (!empty($meta->meta_value)) {
							$this->results[$meta->user_id]->meta_value = $meta->meta_value;
						}
					}
				}
			}
		}
	}
}