<?php

/**
* Class MC4WP_MailChimp
*
* @access private
* @ignore
*/
class MC4WP_MailChimp {

	/**
	* @var string
	*/
	public $error_code = '';

	/**
	* @var string
	*/
	public $error_message = '';

	/**
	*
	* Sends a subscription request to the MailChimp API
	*
	* @param string  $list_id           The list id to subscribe to
	* @param string  $email_address             The email address to subscribe
	* @param array    $args
	* @param boolean $update_existing   Update information if this email is already on list?
	* @param boolean $replace_interests Replace interest groupings, only if update_existing is true.
	*
	* @return object
	*/
	public function list_subscribe( $list_id, $email_address, array $args = array(), $update_existing = false, $replace_interests = true ) {
		$this->reset_error();

		$default_args = array(
			'status' => 'pending',
			'email_address' => $email_address,
			'interests' => array(),
			'merge_fields' => array(),
		);
		$already_on_list = false;

		// setup default args
		$args = $args + $default_args;

		// first, check if subscriber is already on the given list
		try {
			$existing_member_data = $this->get_api()->get_list_member( $list_id, $email_address );

			if( $existing_member_data->status === 'subscribed' ) {
				$already_on_list = true;

				// if we're not supposed to update, bail.
				if( ! $update_existing ) {
					$this->error_code = 214;
					$this->error_message = 'That subscriber already exists.';
					return null;
				}

				$args['status'] = 'subscribed';

				// this key only exists if list actually has interests
				if( isset( $existing_member_data->interests ) ) {
					$existing_interests = (array) $existing_member_data->interests;

					// if replace, assume all existing interests disabled
					if( $replace_interests ) {
						$existing_interests = array_fill_keys( array_keys( $existing_interests ), false );
					}

					// TODO: Use array_replace here (PHP 5.3+)
					$new_interests = $args['interests'];
					$args['interests'] = $existing_interests;
					foreach( $new_interests as $interest_id => $interest_status ) {
						$args['interests']["{$interest_id}"] = $interest_status;
					}
				}
			} else if( $args['status']  === 'pending' && $existing_member_data->status === 'pending' ) {
				// if status is "pending", delete & then re-subscribe
				// this ensures that a new double opt-in email is send out
				$this->get_api()->delete_list_member( $list_id, $email_address );
			}
		} catch( MC4WP_API_Resource_Not_Found_Exception $e ) {
			// subscriber does not exist (not an issue in this case)
		} catch( MC4WP_API_Exception $e ) {
			// other errors.
			$this->error_code = $e->getCode();
			$this->error_message = $e;
			return null;
		}

		try {
			$data = $this->get_api()->add_list_member( $list_id, $args );
		} catch ( MC4WP_API_Exception $e ) {
			$this->error_code = $e->getCode();
			$this->error_message = $e;
			return null;
		}

		$data->was_already_on_list = $already_on_list;

		return $data;
	}

	/**
	* Changes the subscriber status to "unsubscribed" 
	*
	* @param string $list_id
	* @param string $email_address
	*
	* @return boolean
	*/
	public function list_unsubscribe( $list_id, $email_address ) {
		$this->reset_error();

		try {
			$this->get_api()->update_list_member( $list_id, $email_address, array( 'status' => 'unsubscribed' ) );
		} catch( MC4WP_API_Resource_Not_Found_Exception $e ) {
			// if email wasn't even on the list: great.
			return true;
		} catch( MC4WP_API_Exception $e ) {
			$this->error_code = $e->getCode();
			$this->error_message = $e;
			return false;
		}

		return true;
	}

	/**
	* Deletes the subscriber from the given list.
	*
	* @param string $list_id
	* @param string $email_address
	*
	* @return boolean
	*/
	public function list_unsubscribe_delete( $list_id, $email_address ) {
		$this->reset_error();

		try {
			$this->get_api()->delete_list_member( $list_id, $email_address );
		} catch( MC4WP_API_Resource_Not_Found_Exception $e ) {
			// if email wasn't even on the list: great.
			return true;
		} catch( MC4WP_API_Exception $e ) {
			$this->error_code = $e->getCode();
			$this->error_message = $e;
			return false;
		}

		return true;
	}

	/**
	* Checks if an email address is on a given list with status "subscribed"
	*
	* @param string $list_id
	* @param string $email_address
	*
	* @return boolean
	*/
	public function list_has_subscriber( $list_id, $email_address ) {
		try{
			$data = $this->get_api()->get_list_member( $list_id, $email_address );
		} catch( MC4WP_API_Resource_Not_Found_Exception $e ) {
			return false;
		}

		return ! empty( $data->id ) && $data->status === 'subscribed';
	}


	/**
	* Empty the Lists cache
	*/
	public function empty_cache() {
		global $wpdb;

		delete_option( 'mc4wp_mailchimp_list_ids' );
		$wpdb->query( "DELETE FROM {$wpdb->options} WHERE option_name LIKE 'mc4wp_mailchimp_list_%'" );
		delete_transient( 'mc4wp_list_counts' );
	}

	/**
	* Get MailChimp lists from cache.
	*
	* @param boolean deprecated parameter.
	* @return array
	*/
	public function get_cached_lists() {
		return $this->get_lists( false );
	}

	/**
	* Get a specific MailChimp list from local DB.
	*
	* @param string $list_id
	* @return MC4WP_MailChimp_List
	*/
	public function get_cached_list( $list_id ) {
		return $this->get_list( $list_id, false );
	}

	/**
	* Get MailChimp lists, from cache or remote API.
	*
	* @param boolean $force Whether to force a result by hitting MailChimp API
	* @return array
	*/
	public function get_lists( $force = true ) {

		// first, get all list id's
		$list_ids = $this->get_list_ids( $force );

		// then, fill $lists array with individual list details
		$lists = array();
		foreach( $list_ids as $list_id ) {
			$list = $this->get_list( $list_id, $force );
			$lists["{$list_id}"] = $list;
		}

		return $lists;
	}

	/**
	* @param string $list_id
	*
	* @return MC4WP_MailChimp_List
	*/
	private function fetch_list( $list_id ) {
		try{
			$list_data = $this->get_api()->get_list( $list_id, array( 'fields' => 'id,name,stats,web_id,campaign_defaults.from_name,campaign_defaults.from_email' ) );

			// create local object
			$list = new MC4WP_MailChimp_List( $list_data->id, $list_data->name );
			$list->subscriber_count = $list_data->stats->member_count;
			$list->web_id = $list_data->web_id;
			$list->campaign_defaults = $list_data->campaign_defaults;

			// get merge fields (if any)
			if( $list_data->stats->merge_field_count > 0 ) {
				$field_data = $this->get_api()->get_list_merge_fields( $list->id, array( 'count' => 100, 'fields' => 'merge_fields.name,merge_fields.tag,merge_fields.type,merge_fields.required,merge_fields.default_value,merge_fields.options,merge_fields.public' ) );

				// hydrate data into object
				foreach( $field_data as $data ) {
					$object = MC4WP_MailChimp_Merge_Field::from_data( $data );
					$list->merge_fields[] = $object;
				}
			}

			// get interest categories
			$interest_categories_data = $this->get_api()->get_list_interest_categories( $list->id, array( 'count' => 100, 'fields' => 'categories.id,categories.title,categories.type' ) );
			foreach( $interest_categories_data as $interest_category_data ) {
				$interest_category = MC4WP_MailChimp_Interest_Category::from_data( $interest_category_data );

				// fetch groups for this interest
				$interests_data = $this->get_api()->get_list_interest_category_interests( $list->id, $interest_category->id, array( 'count' => 100, 'fields' => 'interests.id,interests.name') );
				foreach( $interests_data as $interest_data ) {
					$interest_category->interests[ (string) $interest_data->id ] = $interest_data->name;
				}

				$list->interest_categories[] = $interest_category;
			}
		} catch( MC4WP_API_Exception $e ) {
			return null;
		}

		// save in option
		update_option( 'mc4wp_mailchimp_list_' . $list_id, $list, false );
		return $list;
	}

	/**
	* Get MailChimp list ID's
	*
	* @param bool $force Force result by hitting MailChimp API
	* @return array
	*/
	public function get_list_ids( $force = false ) {
		$list_ids = (array) get_option( 'mc4wp_mailchimp_list_ids', array() );

		if( empty( $list_ids ) && $force ) {
			$list_ids = $this->fetch_list_ids();
		}

		return $list_ids;
	}

	/**
	* @return array
	*/
	public function fetch_list_ids() {
		/**
		 * Filters the amount of MailChimp lists to fetch.
		 *
		 * If you increase this, it might be necessary to increase your PHP configuration to allow for a higher max_execution_time.
		 *
		 * @param int 
		 */
		$limit = apply_filters( 'mc4wp_mailchimp_list_limit', 200 );

		try{
			$lists_data = $this->get_api()->get_lists( array( 'count' => $limit, 'fields' => 'lists.id' ) );
		} catch( MC4WP_API_Exception $e ) {
			return array();
		}

		$list_ids = wp_list_pluck( $lists_data, 'id' );

		// store list id's
		update_option( 'mc4wp_mailchimp_list_ids', $list_ids, false );

		return $list_ids;
	}

	/**
	* Fetch list ID's + lists from MailChimp.
	*
	* @return bool
	*/
	public function fetch_lists() {
		// try to increase time limit as this can take a while
		@set_time_limit(300);
		$list_ids = $this->fetch_list_ids();

		// randomize array order
		shuffle( $list_ids );

		// fetch individual list details
		foreach ( $list_ids as $list_id ) {
			$list = $this->fetch_list( $list_id );
		}

		return ! empty( $list_ids );
	}

	/**
	* Get a given MailChimp list
	*
	* @param string $list_id
	* @param bool $force Whether to force a result by hitting remote API
	* @return MC4WP_MailChimp_List
	*/
	public function get_list( $list_id, $force = false ) {
		$list = get_option( 'mc4wp_mailchimp_list_' . $list_id );

		if( empty( $list ) && $force ) {
			$list = $this->fetch_list( $list_id );
		}

		if( empty( $list ) ) {
			return new MC4WP_MailChimp_List( $list_id, 'Unknown List' );
		}

		return $list;
	}

	/**
	* Get an array of list_id => number of subscribers
	*
	* @return array
	*/
	public function get_subscriber_counts() {

		// get from transient
		$list_counts = get_transient( 'mc4wp_list_counts' );
		if( is_array( $list_counts ) ) {
			return $list_counts;
		}

		// transient not valid, fetch from API
		try {
			$lists = $this->get_api()->get_lists(  array( 'count' => 100, 'fields' => 'lists.id,lists.stats' ) );
		} catch( MC4WP_API_Exception $e ) {
			return array();
		}

		$list_counts = array();

		// we got a valid response
		foreach ( $lists as $list ) {
			$list_counts["{$list->id}"] = $list->stats->member_count;
		}

		$seconds = 3600;

		/**
		* Filters the cache time for MailChimp lists configuration, in seconds. Defaults to 3600 seconds (1 hour).
		*
		* @since 2.0
		* @param int $seconds
		*/
		$transient_lifetime = (int) apply_filters( 'mc4wp_lists_count_cache_time', $seconds );
		set_transient( 'mc4wp_list_counts', $list_counts, $transient_lifetime );

		// bail
		return $list_counts;
	}


	/**
	* Returns number of subscribers on given lists.
	*
	* @param array|string $list_ids Array of list ID's, or single string.
	* @return int Total # subscribers for given lists.
	*/
	public function get_subscriber_count( $list_ids ) {

		// make sure we're getting an array
		if( ! is_array( $list_ids ) ) {
			$list_ids = array( $list_ids );
		}

		// if we got an empty array, return 0
		if( empty( $list_ids ) ) {
			return 0;
		}

		// get total number of subscribers for all lists
		$counts = $this->get_subscriber_counts();

		// start calculating subscribers count for all given list ID's combined
		$count = 0;
		foreach ( $list_ids as $id ) {
			$count += ( isset( $counts["{$id}"] ) ) ? $counts["{$id}"] : 0;
		}

		/**
		* Filters the total subscriber_count for the given List ID's.
		*
		* @since 2.0
		* @param string $count
		* @param array $list_ids
		*/
		return apply_filters( 'mc4wp_subscriber_count', $count, $list_ids );
	}

	/**
	* Resets error properties.
	*/
	public function reset_error() {
		$this->error_message = '';
		$this->error_code = '';
	}

	/**
	* @return bool
	*/
	public function has_error() {
		return ! empty( $this->error_code );
	}

	/**
	* @return string
	*/
	public function get_error_message() {
		return $this->error_message;
	}

	/**
	* @return string
	*/
	public function get_error_code() {
		return $this->error_code;
	}

	/**
	* @return MC4WP_API_v3
	*/
	private function get_api() {
		return mc4wp( 'api' );
	}

}
