<?php

/**
 * Helper class for dealing with common API requests.
 */
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 bool $update_existing Update information if this email is already on list?
	 * @param bool $replace_interests Replace interest groupings, only if update_existing is true.
	 *
	 * @return object
	 * @throws Exception
	 */
	public function list_subscribe($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,
		);
		$existing_member_data = null;

		// setup default args
		$args = array_merge($default_args, $args);
		$api  = $this->get_api();

		// first, check if subscriber is already on the given list
		try {
			$existing_member_data = $api->get_list_member($list_id, $email_address);
			if ($existing_member_data->status === 'subscribed') {
				// 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);
					}

					$args['interests'] = array_replace($existing_interests, $args['interests']);
				}
			} elseif ($args['status'] === 'pending' && $existing_member_data->status === 'pending') {
				// this ensures that a new double opt-in email is send out
				$api->update_list_member(
					$list_id,
					$email_address,
					array(
						'status' => 'unsubscribed',
					)
				);
			}
		} 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 {
			if ($existing_member_data) {
				$data                      = $api->update_list_member($list_id, $email_address, $args);
				$data->was_already_on_list = $existing_member_data->status === 'subscribed';

				if (isset($args['tags']) && is_array($args['tags'])) {
					$this->list_add_tags_to_subscriber($list_id, $data, $args['tags']);
				}
			} else {
				$data                      = $api->add_new_list_member($list_id, $args);
				$data->was_already_on_list = false;
			}
		} catch (MC4WP_API_Exception $e) {
			$this->error_code    = $e->getCode();
			$this->error_message = $e;
			return null;
		}

		return $data;
	}

	/**
	 * Format tags to send to Mailchimp.
	 *
	 * @param $mailchimp_tags array existent user tags
	 * @param $new_tags array new tags to add
	 *
	 * @return array
	 * @since 4.7.9
	 */
	private function merge_and_format_member_tags($mailchimp_tags, $new_tags)
	{
		$mailchimp_tags = array_map(
			function ($tag) {
				return $tag->name;
			},
			$mailchimp_tags
		);

		$tags = array_unique(array_merge($mailchimp_tags, $new_tags), SORT_REGULAR);

		return array_map(
			function ($tag) {
				return array(
					'name'   => $tag,
					'status' => 'active',
				);
			},
			$tags
		);
	}

	/**
	 *  Post the tags on a list member.
	 *
	 * @param $mailchimp_list_id string The list id to subscribe to
	 * @param $mailchimp_member stdClass mailchimp user informations
	 * @param $new_tags array tags to add to the user
	 *
	 * @return bool
	 * @throws Exception
	 * @since 4.7.9
	 */
	private function list_add_tags_to_subscriber($mailchimp_list_id, $mailchimp_member, array $new_tags)
	{
		// do nothing if no tags given
		if (count($new_tags) === 0) {
			return true;
		}

		$api  = $this->get_api();
		$data = array(
			'tags' => $this->merge_and_format_member_tags($mailchimp_member->tags, $new_tags),
		);

		try {
			$api->update_list_member_tags($mailchimp_list_id, $mailchimp_member->email_address, $data);
		} catch (MC4WP_API_Exception $ex) {
			// fail silently
			return false;
		}

		return true;
	}

	/**
	 * 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;
	}

	/**
	 * Checks if an email address is on a given list with status "subscribed"
	 *
	 * @param string $list_id
	 * @param string $email_address
	 *
	 * @return boolean
	 * @throws Exception
	 */
	public function list_has_subscriber($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';
	}

	/**
	 * @param string $list_id
	 *
	 * @return array
	 * @throws Exception
	 */
	public function get_list_merge_fields($list_id)
	{
		$transient_key = "mc4wp_list_{$list_id}_mf";
		$cached        = get_transient($transient_key);
		if (is_array($cached)) {
			return $cached;
		}

		$api = $this->get_api();

		try {
			// fetch list merge fields
			$merge_fields = $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',
				)
			);
		} catch (MC4WP_API_Exception $e) {
			return array();
		}

		// add EMAIL field
		array_unshift(
			$merge_fields,
			(object) array(
				'tag'      => 'EMAIL',
				'name'     => __('Email address', 'mailchimp-for-wp'),
				'required' => true,
				'type'     => 'email',
				'options'  => array(),
				'public'   => true,
			)
		);

		set_transient($transient_key, $merge_fields, HOUR_IN_SECONDS * 24);

		return $merge_fields;
	}

	/**
	 * @param string $list_id
	 *
	 * @return array
	 * @throws Exception
	 */
	public function get_list_interest_categories($list_id)
	{
		$transient_key = "mc4wp_list_{$list_id}_ic";
		$cached        = get_transient($transient_key);
		if (is_array($cached)) {
			return $cached;
		}

		$api = $this->get_api();

		try {
			// fetch list interest categories
			$interest_categories = $api->get_list_interest_categories(
				$list_id,
				array(
					'count'  => 100,
					'fields' => 'categories.id,categories.title,categories.type',
				)
			);
		} catch (MC4WP_API_Exception $e) {
			return array();
		}

		foreach ($interest_categories as $interest_category) {
			$interest_category->interests = array();

			try {
				// fetch groups for this interest
				$interests_data = $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;
				}
			} catch (MC4WP_API_Exception $e) {
				// ignore
			}
		}

		set_transient($transient_key, $interest_categories, HOUR_IN_SECONDS * 24);

		return $interest_categories;
	}

	/**
	 * Gets marketing permissions from a Mailchimp list.
	 * The list needs to have at least 1 member for this to work.
	 *
	 * @param string $list_id
	 *
	 * @return array
	 * @throws Exception
	 */
	public function get_list_marketing_permissions($list_id)
	{
		$transient_key = "mc4wp_list_{$list_id}_mp";
		$cached        = get_transient($transient_key);
		if (is_array($cached)) {
			return $cached;
		}

		try {
			$api  = $this->get_api();
			$data = $api->get_list_members(
				$list_id,
				array(
					'fields' => array( 'members.marketing_permissions' ),
					'count'  => 1,
				)
			);

			$marketing_permissions = array();
			if (count($data->members) > 0 && $data->members[0]->marketing_permissions) {
				foreach ($data->members[0]->marketing_permissions as $mp) {
					$marketing_permissions[] = (object) array(
						'marketing_permission_id' => $mp->marketing_permission_id,
						'text'                    => $mp->text,
					);
				}
			}
		} catch (MC4WP_API_Exception $e) {
			return array();
		}

		set_transient($transient_key, $marketing_permissions, HOUR_IN_SECONDS * 24);
		return $marketing_permissions;
	}

	/**
	 * Get Mailchimp lists, from cache or remote API.
	 *
	 * @param boolean $skip_cache Whether to force a result by hitting Mailchimp API
	 *
	 * @return array
	 */
	public function get_lists($skip_cache = false)
	{
		$cache_key = 'mc4wp_mailchimp_lists';
		$cached    = get_transient($cache_key);

		if (is_array($cached) && ! $skip_cache) {
			return $cached;
		}

		$lists = $this->fetch_lists();

		/**
		 * Filters the cache time for Mailchimp lists configuration, in seconds. Defaults to 24 hours.
		 */
		$cache_ttl = (int) apply_filters('mc4wp_lists_count_cache_time', HOUR_IN_SECONDS * 24);

		// make sure cache ttl is not lower than 60 seconds
		$cache_ttl = max(60, $cache_ttl);
		set_transient($cache_key, $lists, $cache_ttl);

		return $lists;
	}

	private function fetch_lists()
	{
		$client             = $this->get_api()->get_client();
		$lists_data         = array();
		$offset             = 0;
		$count              = 10;
		$exceptions_skipped = 0;

		// increase total time limit to 3 minutes
		@set_time_limit(180);

		// increase HTTP timeout to 30s as MailChimp is super slow to calculate dynamic fields
		add_filter(
			'mc4wp_http_request_args',
			function ($args) {
				$args['timeout'] = 30;
				return $args;
			}
		);

		// collect all lists in separate HTTP requests
		do {
			try {
				$data = $client->get(
					'/lists',
					array(
						'count'  => $count,
						'offset' => $offset,
						'fields' => 'total_items,lists.id,lists.name,lists.web_id,lists.stats.member_count,lists.marketing_permissions',
					)
				);

				$lists_data = array_merge($lists_data, $data->lists);
				$offset    += $count;
			} catch (MC4WP_API_Connection_Exception $e) {
				// ignore timeout errors as this is likely due to mailchimp being slow to calculate the lists.stats.member_count property
				// keep going so we can at least pull-in all other lists
				$offset += $count;
				++$exceptions_skipped;

				// failsafe against infinite loop
				// bail after 5 skipped exceptions
				if ($exceptions_skipped >= 5) {
					break;
				}

				continue;
			} catch (MC4WP_API_Exception $e) {
				// break on other errors, like "API key missing"etc.
				break;
			}
		} while ($data->total_items >= $offset);

		// key by list ID
		$lists = array();
		foreach ($lists_data as $list_data) {
			$lists["$list_data->id"] = $list_data;
		}

		return $lists;
	}

	/**
	 * @param string $list_id
	 *
	 * @return object|null
	 */
	public function get_list($list_id)
	{
		$lists = $this->get_lists();

		return isset($lists["$list_id"]) ? $lists["$list_id"] : null;
	}

	/**
	 * Fetch lists data from Mailchimp.
	 */
	public function refresh_lists()
	{
		$lists = $this->get_lists(true);

		foreach ($lists as $list_id => $list) {
			// delete cached merge fields
			delete_transient("mc4wp_list_{$list_id}_mf");

			// delete cached interest categories
			delete_transient("mc4wp_list_{$list_id}_ic");

			// delete cached marketing permissions
			delete_transient("mc4wp_list_{$list_id}_mp");
		}

		return ! empty($lists);
	}


	/**
	 * 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;
		}

		$lists = $this->get_lists();

		// start calculating subscribers count for all given list ID's combined
		$count = 0;
		foreach ($list_ids as $list_id) {
			if (! isset($lists["$list_id"])) {
				continue;
			}

			$list   = $lists["$list_id"];
			$count += $list->stats->member_count;
		}

		/**
		 * Filters the total subscriber_count for the given List ID's.
		 *
		 * @param string $count
		 * @param array $list_ids
		 *
		 * @since 2.0
		 */
		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
	 * @throws Exception
	 */
	private function get_api()
	{
		return mc4wp('api');
	}
}