<?php

namespace SPC\Services;

use SPC\Builders\Cache_Rule;
use SPC\Constants;
use SPC\Utils\Helpers;

class Cloudflare_Client extends Cloudflare_Rule {
	private const TOKEN_PERMISSIONS = [
		// Transform Rules:
		'#waf:read',
		'#waf:edit',
		// DNS:
		'#dns_records:read',
		'#dns_records:edit',
		'#page_shield:read',
		'#ssl:read',
		'#page_shield:edit',
		'#zone:edit',
		'#zone:read',
		'#zone_settings:read',
		'#zone_settings:edit',
		'#cache_purge:edit',
		// Analytics:
		'#analytics:read',
	];

	// 5 minutes
	private const ANALYTICS_CACHE_TIME = 300;
	private const ANALYTICS_CACHE_KEY  = 'spc_cf_analytics';

	/**
	 * Account IDs list.
	 *
	 * @var array
	 */
	private $account_ids = [];

	/**
	 * Get the ruleset ID setting slug.
	 *
	 * @return string
	 */
	public function get_ruleset_id_setting_slug(): string {
		return Constants::RULESET_ID_CACHE;
	}

	/**
	 * Get the rule ID setting slug.
	 *
	 * @return string
	 */
	public function get_rule_id_setting_slug(): string {
		return Constants::RULE_ID_CACHE;
	}

	/**
	 * Get the rule arguments to be used in the API request.
	 *
	 * @return array
	 */
	protected function get_rule_args(): array {
		return [
			'action'            => 'set_cache_settings',
			'action_parameters' => [
				'cache'       => true,
				'browser_ttl' => array(
					'mode' => 'respect_origin',
				),
			],
			'description'       => $this->build_rule_description(),
			'enabled'           => true,
			'expression'        => $this->get_rule_expression(),
		];
	}

	/**
	 * Get the rule expression.
	 *
	 * @return string
	 */
	public function get_rule_expression() {
		$builder = new Cache_Rule( $this->plugin );

		return $builder->exclude_cookies()
						->exclude_paths()
						->exclude_static_content()
						->build();
	}

	/**
	 * Get the current browser cache TTL value from Cloudflare.
	 *
	 * @param string $error The error message.
	 *
	 * @return false|mixed
	 */
	public function get_current_browser_cache_ttl( &$error = '' ) {
		$args     = $this->get_api_auth_args();
		$url      = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/settings/browser_cache_ttl', $this->plugin->get_cloudflare_api_zone_id() );
		$response = wp_remote_get( $url, $args );

		if ( ! $this->is_success_api_response( $response, 'get_current_browser_cache_ttl', $error ) ) {
			return false;
		}

		$response_body = json_decode( wp_remote_retrieve_body( $response ), true );

		if ( is_array( $response_body ) && isset( $response_body['result']['value'] ) ) {
			return $response_body['result']['value'];
		}

		$error = __( 'Unable to find Browser Cache TTL settings ', 'wp-cloudflare-page-cache' );

		return false;
	}

	/**
	 * Change the browser cache TTL value.
	 *
	 * @param int $ttl The new TTL value.
	 * @param string $error The error message.
	 *
	 * @return bool
	 */
	public function change_browser_cache_ttl( $ttl, &$error = '' ) {
		$url            = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/settings/browser_cache_ttl', $this->plugin->get_cloudflare_api_zone_id() );
		$args           = $this->get_api_auth_args();
		$args['method'] = 'PATCH';
		$args['body']   = wp_json_encode( [ 'value' => $ttl ] );

		$this->log( 'change_browser_cache_ttl', sprintf( 'Request URL: %s', esc_url_raw( $url ) ) );
		$this->log( 'change_browser_cache_ttl', sprintf( 'Request body: %s', wp_json_encode( [ 'value' => $ttl ] ) ) );

		$response = wp_remote_post( $url, $args );

		return $this->is_success_api_response( $response, 'change_browser_cache_ttl', $error );
	}

	/**
	 * Delete a page rule.
	 *
	 * @param string $error The error message.
	 *
	 * @return bool
	 */
	public function delete_cache_rule( &$error ) {
		$rule    = $this->get_rule_id();
		$ruleset = $this->get_ruleset_id();

		if ( empty( $rule ) || empty( $ruleset ) ) {
			$this->log( 'delete_cache_rule', 'Could NOT delete cache rule. No ruleset or rule defined.' );

			return false;
		}

		$url            = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/rulesets/%s/rules/%s', $this->plugin->get_cloudflare_api_zone_id(), $ruleset, $rule );
		$args           = $this->get_api_auth_args();
		$args['method'] = 'DELETE';

		$response = wp_remote_request( $url, $args );

		$this->log( 'delete_cache_rule', sprintf( 'Request URL: %s', esc_url_raw( $url ) ) );

		$response_code = wp_remote_retrieve_response_code( $response );

		if ( ! $this->is_success_api_response( $response, 'delete_cache_rule', $error ) ) {
			if ( $response_code === 404 ) {
				$this->rule_id = '';

				return true;
			}

			return false;
		}

		$this->rule_id        = '';
		$this->cached_ruleset = [];

		return 200 === $response_code;
	}

	/**
	 * Delete the Page Rule.
	 *
	 * @deprecated - The page rule is not used anymore.
	 */
	public function delete_page_rule( $id, &$error = '' ) {
		if ( ! $this->plugin->has_cloudflare_api_zone_id() ) {
			$error = __( 'There is not zone id to use', 'wp-cloudflare-page-cache' );

			return false;
		}

		$url            = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/pagerules/%s', $this->plugin->get_cloudflare_api_zone_id(), $id );
		$args           = $this->get_api_auth_args();
		$args['method'] = 'DELETE';

		$response = wp_remote_post( $url, $args );

		return $this->is_success_api_response( $response, 'delete_page_rule', $error );
	}

	/**
	 * Get the account IDs list.
	 *
	 * @param string $error The error message.
	 *
	 * @return array
	 */
	private function get_account_ids( &$error = '' ) {
		$this->account_ids = [];

		$args = $this->get_api_auth_args();

		$response = wp_remote_get( 'https://api.cloudflare.com/client/v4/accounts?page=1&per_page=20&direction=desc', $args );

		if ( ! $this->is_success_api_response( $response, 'get_account_ids', $error ) ) {
			return [];
		}

		$response_body = json_decode( wp_remote_retrieve_body( $response ), true );

		if ( ! is_array( $response_body ) || ! isset( $response_body['result'] ) || ! is_array( $response_body['result'] ) ) {
			$error = __( 'Unable to retrieve account ID', 'wp-cloudflare-page-cache' );

			return [];
		}

		foreach ( $response_body['result'] as $account_data ) {
			if ( ! isset( $account_data['id'] ) ) {
				$error = __( 'Unable to retrieve account ID', 'wp-cloudflare-page-cache' );

				continue;
			}

			$this->account_ids[] = [
				'id'   => $account_data['id'],
				'name' => $account_data['name'],
			];
		}

		return $this->account_ids;
	}

	/**
	 * Get the Cloudflare account ID.
	 *
	 * @param string $error The error message.
	 *
	 * @return string
	 */
	public function get_account_id( &$error = '' ) {
		$account_id = '';

		if ( empty( $this->account_ids ) ) {
			$this->get_account_ids( $error );
		}

		if ( empty( $this->account_ids ) ) {
			$error = __( 'Unable to retrive account ID', 'wp-cloudflare-page-cache' );

			$this->log( 'get_current_account_id', sprintf( 'Unable to retrive an account ID: %s', $error ) );

			return '';
		}

		if ( count( $this->account_ids ) > 1 ) {
			foreach ( $this->account_ids as $account_data ) {
				if ( strstr( strtolower( $account_data['name'] ), strtolower( $this->plugin->get_cloudflare_api_email() ) ) !== false ) {
					$account_id = $account_data['id'];

					break;
				}
			}
		} else {
			$account_id = $this->account_ids[0]['id'];
		}

		if ( empty( $account_id ) ) {
			$error = __( 'Unable to find a valid account ID.', 'wp-cloudflare-page-cache' );

			return '';
		}

		return $account_id;
	}

	/**
	 * Get the zone ID list.
	 *
	 * @param string $error
	 *
	 * @return array | false
	 */
	public function get_zone_id_list( &$error = '' ) {
		$list         = [];
		$per_page     = 50;
		$current_page = 1;
		$pagination   = false;
		$args         = $this->get_api_auth_args();

		do {
			$url = sprintf( 'https://api.cloudflare.com/client/v4/zones?page=%s&per_page=%s', $current_page, $per_page );

			$this->log( 'get_zone_id_list', sprintf( 'Request for page %s - URL: %s', $current_page, $url ) );

			$response = wp_remote_get( $url, $args );

			if ( ! $this->is_success_api_response( $response, 'get_zone_id_list', $error ) ) {
				return false;
			}

			$response_body = wp_remote_retrieve_body( $response );

			$this->log( 'get_zone_id_list', sprintf( 'Response for page %s: %s', $current_page, $response_body ) );

			$json = json_decode( $response_body, true );

			if ( ! is_array( $json ) ) {
				$error = __( 'Unable to retrieve zone id due to invalid response data', 'wp-cloudflare-page-cache' );

				return false;
			}

			if ( isset( $json['result_info'] ) && is_array( $json['result_info'] ) ) {

				if ( isset( $json['result_info']['total_pages'] ) && (int) $json['result_info']['total_pages'] > $current_page ) {
					$pagination = true;
					$current_page++;
				} else {
					$pagination = false;
				}
			} else {

				if ( $pagination ) {
					$pagination = false;
				}
			}

			if ( isset( $json['result'] ) && is_array( $json['result'] ) ) {

				foreach ( $json['result'] as $domain_data ) {

					if ( ! isset( $domain_data['name'] ) || ! isset( $domain_data['id'] ) ) {
						$error = __( 'Unable to retrieve zone id due to invalid response data', 'wp-cloudflare-page-cache' );

						return false;
					}

					$list[ $domain_data['name'] ] = $domain_data['id'];

				}
			}
		} while ( $pagination );

		if ( empty( $list ) ) {
			$error = __( 'Unable to find domains configured on Cloudflare', 'wp-cloudflare-page-cache' );

			return false;
		}

		return $list;
	}

	/**
	 * Purge the whole cache.
	 *
	 * @param string $error The error message.
	 *
	 * @return bool
	 */
	public function purge_cache( &$error = '' ) {
		do_action( 'swcfpc_cf_purge_whole_cache_before' );

		$args           = $this->get_api_auth_args();
		$args['method'] = 'POST';
		$args['body']   = json_encode( [ 'purge_everything' => true ] );
		$url            = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/purge_cache', $this->plugin->get_cloudflare_api_zone_id() );
		$response       = wp_remote_post( $url, $args );

		if ( ! $this->is_success_api_response( $response, 'purge_cache', $error ) ) {
			return false;
		}

		do_action( 'swcfpc_cf_purge_whole_cache_after' );

		return true;
	}

	/**
	 * Purge URLs from Cloudflare cache asynchronously.
	 *
	 * @param array $urls URLs to purge.
	 *
	 * @return true
	 */
	public function purge_cache_urls_async( $urls ) {
		$args = $this->get_api_auth_args( true );

		$chunks     = array_chunk( $urls, 30 );
		$multi_curl = curl_multi_init();
		$curl_array = [];
		$curl_index = 0;

		foreach ( $chunks as $single_chunk ) {
			$curl_array[ $curl_index ] = curl_init();

			curl_setopt_array(
				$curl_array[ $curl_index ],
				[
					CURLOPT_URL            => "https://api.cloudflare.com/client/v4/zones/{$this->plugin->get_cloudflare_api_zone_id()}/purge_cache",
					CURLOPT_RETURNTRANSFER => 1,
					CURLOPT_MAXREDIRS      => 10,
					CURLOPT_TIMEOUT        => $args['timeout'],
					CURLOPT_CUSTOMREQUEST  => 'POST',
					CURLOPT_POST           => 1,
					CURLOPT_HTTPHEADER     => $args['headers'],
					CURLOPT_POSTFIELDS     => json_encode( [ 'files' => array_values( $single_chunk ) ] ),
				]
			);

			curl_multi_add_handle( $multi_curl, $curl_array[ $curl_index ] );

			$curl_index++;
		}

		// execute the multi handle
		$active = null;

		do {
			$status = curl_multi_exec( $multi_curl, $active );

			if ( $active ) {
				// Wait a short time for more activity
				curl_multi_select( $multi_curl );
			}
		} while ( $active && $status == CURLM_OK );

		// close the handles
		for ( $i = 0; $i < $curl_index; $i++ ) {
			// Get the content of cURL request $curl_array[$i]
			$this->log( 'purge_cache_urls_async', "Response for request {$i}: " . curl_multi_getcontent( $curl_array[ $i ] ) );

			curl_multi_remove_handle( $multi_curl, $curl_array[ $i ] );
		}

		curl_multi_close( $multi_curl );

		// free up additional memory resources
		for ( $i = 0; $i < $curl_index; $i++ ) {
			curl_close( $curl_array[ $i ] );
		}

		return true;
	}

	/**
	 * Purge cache URLs.
	 *
	 * @param array $urls URLs to purge.
	 * @param string $error The error message.
	 *
	 * @return bool
	 */
	public function purge_cache_urls( $urls, &$error = '' ) {
		do_action( 'swcfpc_cf_purge_cache_by_urls_before', $urls );

		if ( count( $urls ) > 30 ) {
			$this->purge_cache_urls_async( $urls );
		} else {
			$url            = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s/purge_cache', $this->plugin->get_cloudflare_api_zone_id() );
			$args           = $this->get_api_auth_args();
			$args['method'] = 'POST';
			$args['body']   = json_encode( [ 'files' => array_values( $urls ) ] );

			$this->log( 'purge_cache_urls', sprintf( 'Request URL: %s', $url ) );
			$this->log( 'purge_cache_urls', sprintf( 'Request Body: %s', $args['body'] ) );

			$response = wp_remote_post( $url, $args );

			if ( ! $this->is_success_api_response( $response, 'purge_cache_urls', $error ) ) {
				return false;
			}
		}

		do_action( 'swcfpc_cf_purge_cache_by_urls_after', $urls );

		return true;
	}

	/**
	 * Verify token permissions.
	 *
	 * @param string $zone_id The zone ID.
	 *
	 * @return array|\WP_Error
	 */
	public function verify_token_permissions( string $zone_id ) {
		$url  = sprintf( 'https://api.cloudflare.com/client/v4/zones/%s', $zone_id );
		$args = $this->get_api_auth_args();

		$response = wp_remote_get( $url, $args );

		if ( is_wp_error( $response ) ) {
			return new \WP_Error( 'cloudflare_error', $response->get_error_message() );
		}

		$response_body = json_decode( wp_remote_retrieve_body( $response ), true );

		if ( ! is_array( $response_body ) || ! isset( $response_body['result'], $response_body['result']['permissions'] ) || ! is_array( $response_body['result']['permissions'] ) ) {
			return new \WP_Error( 'cloudflare_error', __( 'Could not check token permissions.Invalid response from Cloudflare', 'wp-cloudflare-page-cache' ) );
		}
		$permissions         = $response_body['result']['permissions'];
		$missing_permissions = array_diff( self::TOKEN_PERMISSIONS, $permissions );

		if ( empty( $missing_permissions ) ) {
			return [];
		}

		return $missing_permissions;
	}

	/**
	 * Get the analytics.
	 *
	 * @return array|\WP_Error
	 */
	public function get_analytics() {

		$cache = get_transient( self::ANALYTICS_CACHE_KEY );

		if ( $cache ) {
			return $cache;
		}

		// This dates correspond exactly to what cloudflare shows in their dashboard for the last 24 hours.
		$start_date = gmdate( 'Y-m-d\TH:00:00\Z', strtotime( '-24 hours' ) );
		$end_date   = gmdate( 'Y-m-d\TH:00:00\Z', strtotime( 'now' ) );

		$query = '
        query($zoneTag: String!, $dateStart: Time!) {
					viewer {
						zones(filter: {zoneTag: $zoneTag}) {
							httpRequests1hGroups(
								filter: { 
									datetime_geq: $dateStart
									datetime_lt: $dateEnd
								}
								limit: 10000
								orderBy: [datetime_ASC]
							) {
								dimensions{
									datetime
								}
								sum {
									requests
									cachedBytes
									bytes
								}
							}
						}
					}
        }
    ';

		$variables = array(
			'zoneTag'   => $this->plugin->get_cloudflare_api_zone_id(),
			'dateStart' => $start_date,
			'dateEnd'   => $end_date,
		);

		$response = wp_remote_post(
			'https://api.cloudflare.com/client/v4/graphql',
			array_merge(
				$this->get_api_auth_args(),
				[
					'body'    => json_encode(
						[
							'query'     => $query,
							'variables' => $variables,
						]
					),
					'timeout' => 30,
				]
			)
		);

		if ( is_wp_error( $response ) ) {
			return new \WP_Error( 'api_error', 'Failed to connect to Cloudflare API: ' . $response->get_error_message(), array( 'status' => 500 ) );
		}

		$body = wp_remote_retrieve_body( $response );
		$data = json_decode( $body, true );

		if ( isset( $data['errors'] ) ) {
			return new \WP_Error( 'graphql_error', 'GraphQL Error: ' . json_encode( $data['errors'] ), array( 'status' => 400 ) );
		}

		$analytics_data = $data['data']['viewer']['zones'][0]['httpRequests1hGroups'] ?? [];

		$total_requests     = 0;
		$total_bytes        = 0;
		$total_cached_bytes = 0;

		foreach ( $analytics_data as $point ) {
			$total_requests     += $point['sum']['requests'] ?? 0;
			$total_bytes        += $point['sum']['bytes'] ?? 0;
			$total_cached_bytes += $point['sum']['cachedBytes'] ?? 0;
		}

		$data = array(
			'requests'    => $total_requests,
			'bytes'       => $total_bytes,
			'cachedBytes' => $total_cached_bytes,
		);

		set_transient( self::ANALYTICS_CACHE_KEY, $data, self::ANALYTICS_CACHE_TIME );

		return $data;
	}
}