<?php
/**
 * 订阅服务客户端。
 *
 * 与 Aipogeo 翻译服务通讯：用访问密钥激活本站、查询订阅状态、上报用量。
 * 插件只保存这一个密钥，不保存任何 AI 平台的凭据。
 *
 * 所有请求都走 wp_remote_* —— WordPress 自己的 HTTP API，遵循站点的代理与
 * SSL 设置，也便于被 WP_HTTP 的过滤器拦截调试。
 *
 * @package Aipogeo_Context_Translate
 */

defined( 'ABSPATH' ) || exit;

class APGT_Service {

	/** 状态缓存键；服务端状态不会一秒一变，本地缓存一小时足够 */
	const STATUS_TRANSIENT = 'apgt_license_status';
	const STATUS_TTL       = HOUR_IN_SECONDS;

	/** 最近一次用量上报失败的原因，给设置页看 */
	const ERROR_TRANSIENT = 'apgt_service_error';
	const ERROR_TTL       = DAY_IN_SECONDS;

	/**
	 * 代调翻译的超时（秒）。
	 *
	 * 比其它接口宽得多：那些只是查状态、扣额度，而这一条要等模型把一整批
	 * 内容生成完。按 20 秒掐会把正常请求全判成失败。
	 */
	const TRANSLATE_TIMEOUT = 180;

	/**
	 * 记下最近一次上报失败的原因。
	 *
	 * 翻译是在后台任务里跑的，出错时用户不在场，写进 debug.log 也没人看
	 * （而且插件不该往站点日志里写东西）。存一天，设置页打开时显示出来。
	 *
	 * @param string $message 已经翻成人话的原因。
	 * @return void
	 */
	public static function remember_error( $message ) {
		set_transient( self::ERROR_TRANSIENT, (string) $message, self::ERROR_TTL );
	}

	/**
	 * 取出并清掉最近一次上报失败的原因。
	 *
	 * @return string 没有就是空串。
	 */
	public static function take_error() {
		$message = get_transient( self::ERROR_TRANSIENT );
		if ( false === $message || '' === $message ) {
			return '';
		}
		delete_transient( self::ERROR_TRANSIENT );
		return (string) $message;
	}

	/**
	 * 当前是否配置为使用订阅服务。
	 *
	 * @return bool
	 */
	public static function in_use() {
		$ai = APGT_Settings::get_ai();
		return 'service' === ( isset( $ai['provider'] ) ? $ai['provider'] : '' )
			&& '' !== trim( (string) ( isset( $ai['license_key'] ) ? $ai['license_key'] : '' ) );
	}

	/** 服务端地址（去掉尾部斜杠） */
	public static function base_url() {
		$ai  = APGT_Settings::get_ai();
		$url = trim( (string) ( isset( $ai['service_url'] ) ? $ai['service_url'] : '' ) );
		return rtrim( $url, '/' );
	}

	/** 本站地址：服务端按它登记绑定，用 home_url 而不是 site_url，与访客看到的一致 */
	public static function site_url() {
		return home_url( '/' );
	}

	/**
	 * 发一次请求。
	 *
	 * @param string $path   /api/v1/subscription/xxx
	 * @param array  $body   POST 参数；为 null 时发 GET
	 * @param int    $timeout
	 * @return array ['ok'=>bool,'code'=>string,'message'=>string,'data'=>array,'http'=>int]
	 */
	protected static function request( $path, $body = null, $timeout = 20 ) {
		$base = self::base_url();
		if ( '' === $base ) {
			return self::err( 'no_service_url', __( 'No service address has been entered yet', 'aipogeo-context-translate' ) );
		}

		$ai   = APGT_Settings::get_ai();
		$key  = trim( (string) ( isset( $ai['license_key'] ) ? $ai['license_key'] : '' ) );
		$args = array(
			'timeout' => (int) $timeout,
			'headers' => array(
				// 密钥走 Authorization 头；部分主机会吞掉这个头，所以 POST 里再带一份
				'Authorization' => 'Bearer ' . $key,
				'Accept'        => 'application/json',
			),
		);

		if ( null === $body ) {
			$url = $base . $path . ( false === strpos( $path, '?' ) ? '?' : '&' )
				 . 'license_key=' . rawurlencode( $key );
			$res = wp_remote_get( $url, $args );
		} else {
			$body['license_key'] = $key;
			$args['body']        = $body;
			$res                 = wp_remote_post( $base . $path, $args );
		}

		if ( is_wp_error( $res ) ) {
			// 网络层失败：不要当成"密钥无效"，否则用户会被误导去重置密钥
			return self::err( 'network', $res->get_error_message() );
		}

		$http = (int) wp_remote_retrieve_response_code( $res );
		$json = json_decode( (string) wp_remote_retrieve_body( $res ), true );

		if ( ! is_array( $json ) ) {
			return self::err( 'bad_response', sprintf(
				/* translators: %d: HTTP status code */
				__( 'The service returned something that could not be read (HTTP %d)', 'aipogeo-context-translate' ),
				$http
			), $http );
		}

		$data = isset( $json['data'] ) && is_array( $json['data'] ) ? $json['data'] : array();
		$ok   = isset( $json['status'] ) && 'yes' === $json['status'];

		return array(
			'ok'      => $ok,
			'code'    => isset( $data['code'] ) ? (string) $data['code'] : ( $ok ? '' : 'failed' ),
			'message' => isset( $json['message'] ) ? (string) $json['message'] : '',
			'data'    => $data,
			'http'    => $http,
		);
	}

	protected static function err( $code, $message, $http = 0 ) {
		return array( 'ok' => false, 'code' => $code, 'message' => $message, 'data' => array(), 'http' => (int) $http );
	}

	/**
	 * 激活：把本站登记到订阅的绑定列表。
	 *
	 * @return array 同 request()
	 */
	public static function activate() {
		$res = self::request( '/api/v1/subscription/activate', array( 'site_url' => self::site_url() ) );
		if ( $res['ok'] ) {
			self::remember( $res['data'] );
		}
		return $res;
	}

	/** 解绑本站 */
	public static function deactivate() {
		$res = self::request( '/api/v1/subscription/deactivate', array( 'site_url' => self::site_url() ) );
		delete_transient( self::STATUS_TRANSIENT );
		return $res;
	}

	/**
	 * 查询订阅状态。
	 *
	 * @param bool $force 跳过本地缓存
	 */
	public static function status( $force = false ) {
		if ( ! $force ) {
			$cached = get_transient( self::STATUS_TRANSIENT );
			if ( is_array( $cached ) ) {
				return array( 'ok' => true, 'code' => '', 'message' => '', 'data' => $cached, 'http' => 200 );
			}
		}
		$res = self::request( '/api/v1/subscription/status?site_url=' . rawurlencode( self::site_url() ), null );
		if ( $res['ok'] ) {
			self::remember( $res['data'] );
		}
		return $res;
	}

	/**
	 * 上报本次翻译消耗的用量（token）。
	 *
	 * 走 translate() 代理的路径不需要调这里 —— 服务端按上游返回的用量当场扣。
	 * 留着是给自带 Key、自行统计用量的场景用。
	 *
	 * 放在翻译成功之后调用：失败的请求不该计费。服务端的扣减是单条 UPDATE，
	 * 余额不足会直接拒绝并返回 quota_exhausted，插件据此停止后续翻译。
	 *
	 * @param int $tokens
	 * @return array
	 */
	public static function consume( $tokens ) {
		$tokens = (int) $tokens;
		if ( $tokens < 1 ) {
			return array( 'ok' => true, 'code' => '', 'message' => '', 'data' => array(), 'http' => 200 );
		}
		$res = self::request( '/api/v1/subscription/consume', array(
			'tokens'   => $tokens,
			'site_url' => self::site_url(),
		) );
		if ( $res['ok'] ) {
			self::remember( $res['data'] );
		}
		return $res;
	}

	/**
	 * 代调翻译：把渲染好的指令交给服务端，由它转发上游模型并按实际用量扣额度。
	 *
	 * 订阅模式下 AI 凭据只存在服务端，本站不持有 —— 这正是订阅要解决的事。
	 * 用量也由服务端按上游返回的 token 数自己算，不再由本站上报，所以走这条路径的
	 * 翻译不需要另外调 consume()。
	 *
	 * @param string $prompt     完整指令。
	 * @param int    $max_tokens 0 表示不限制，交给服务端与模型的默认值。
	 * @return array 同 request()；成功时 data 含 content / finish_reason / billed。
	 */
	public static function translate( $prompt, $max_tokens = 0 ) {
		$prompt = (string) $prompt;
		if ( '' === trim( $prompt ) ) {
			return self::err( 'empty_prompt', __( 'There is nothing to translate', 'aipogeo-context-translate' ) );
		}

		$body = array(
			'site_url' => self::site_url(),
			'prompt'   => $prompt,
		);
		if ( (int) $max_tokens > 0 ) {
			$body['max_tokens'] = (int) $max_tokens;
		}

		$res = self::request( '/api/v1/subscription/translate', $body, self::TRANSLATE_TIMEOUT );

		// 响应里带着扣减后的额度，顺手刷新快照，省下一次 status 请求
		if ( $res['ok'] ) {
			self::remember( $res['data'] );
		}
		return $res;
	}

	/**
	 * 把最近一次订阅信息记到设置里（设置页展示用，避免每次打开都请求服务端）。
	 */
	protected static function remember( array $data ) {
		set_transient( self::STATUS_TRANSIENT, $data, self::STATUS_TTL );

		$ai = APGT_Settings::get_ai();
		$ai['license_snapshot'] = $data;
		$ai['license_checked']  = time();
		if ( isset( $data['sites'] ) && is_array( $data['sites'] ) ) {
			// 服务端归一化后的本站地址（协议+主机），用于设置页显示"已绑定"
			$ai['license_site'] = isset( $data['site_bound'] ) && $data['site_bound'] ? self::site_url() : '';
		}
		APGT_Settings::save_ai( $ai );
	}

	/**
	 * 额度是否已经不够继续翻译。
	 *
	 * 只看本地快照，不发请求 —— 用在翻译循环里，避免每页都打一次服务端。
	 * 真正的判定以 consume() 的返回为准。
	 *
	 * @return bool
	 */
	public static function out_of_quota() {
		$ai   = APGT_Settings::get_ai();
		$snap = isset( $ai['license_snapshot'] ) && is_array( $ai['license_snapshot'] ) ? $ai['license_snapshot'] : array();
		if ( ! $snap ) {
			return false;   // 还没查过，交给服务端判断
		}
		if ( ! empty( $snap['quota_unlimited'] ) ) {
			return false;
		}
		return isset( $snap['quota_left'] ) && (int) $snap['quota_left'] <= 0;
	}

	/* =====================================================================
	 * 一键连接
	 *
	 * 用户买完订阅后不必再手工复制密钥：从设置页跳到服务站点选订阅授权，
	 * 服务端把一次性 code 回调回来，插件在后台用 code 换密钥。
	 * 密钥因此不经过浏览器地址栏，也就不会落进历史记录、日志或 Referer。
	 * ===================================================================*/

	/** 回调落点：插件设置页；state 存在 transient 里，回来时比对 */
	const STATE_TRANSIENT = 'apgt_connect_state';
	const STATE_TTL       = 900;   // 15 分钟，够用户登录+选订阅

	/**
	 * 生成「去服务站点授权」的跳转地址。
	 *
	 * @return string
	 */
	public static function connect_url() {
		$state = wp_generate_password( 32, false );
		set_transient( self::STATE_TRANSIENT, $state, self::STATE_TTL );

		return add_query_arg( array(
			'site_url'   => rawurlencode( self::site_url() ),
			'return_url' => rawurlencode( self::callback_url() ),
			'state'      => rawurlencode( $state ),
		), self::base_url() . '/connect' );
	}

	/** 授权完成后服务端把用户送回这里 */
	public static function callback_url() {
		return admin_url( 'admin.php?page=' . APGT_Admin::PAGE_SLUG . '&tab=ai' );
	}

	/**
	 * 处理服务端回调：拿 code 换密钥并保存。
	 *
	 * 在 admin_init 里调用。成功后会把 provider 切到 service 并激活本站，
	 * 用户回到设置页时已经是「可以直接翻译」的状态。
	 *
	 * @return array|null ['ok'=>bool,'message'=>string]；没有回调参数时返回 null
	 */
	public static function handle_callback() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- 用 state 比对，见下
		$code = isset( $_GET['code'] ) ? sanitize_text_field( wp_unslash( $_GET['code'] ) ) : '';
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		$state = isset( $_GET['state'] ) ? sanitize_text_field( wp_unslash( $_GET['state'] ) ) : '';
		if ( '' === $code ) {
			return null;
		}

		// state 必须与发起时存的一致：挡住别人构造链接把任意 code 塞进来
		$expect = get_transient( self::STATE_TRANSIENT );
		delete_transient( self::STATE_TRANSIENT );
		if ( ! $expect || ! hash_equals( (string) $expect, $state ) ) {
			return array( 'ok' => false, 'message' => __( 'The connection could not be verified. Start the connection again.', 'aipogeo-context-translate' ) );
		}

		// 换密钥：服务器到服务器，密钥不经过浏览器
		$res = self::request( '/api/v1/subscription/exchange', array( 'code' => $code ) );
		if ( ! $res['ok'] || empty( $res['data']['license_key'] ) ) {
			return array( 'ok' => false, 'message' => self::explain( $res ) );
		}

		$data = $res['data'];
		$ai   = APGT_Settings::get_ai();
		$ai['provider']        = 'service';
		$ai['license_key']     = (string) $data['license_key'];
		$ai['license_checked'] = time();
		unset( $data['license_key'] );          // 快照里不留明文
		$ai['license_snapshot'] = $data;
		$ai['license_site']     = ! empty( $data['site_bound'] ) ? self::site_url() : '';
		APGT_Settings::save_ai( $ai );

		set_transient( self::STATUS_TRANSIENT, $data, self::STATUS_TTL );

		return array(
			'ok'      => true,
			'message' => sprintf(
				/* translators: %s: subscription product name */
				__( 'Connected to "%s". This site can start translating.', 'aipogeo-context-translate' ),
				isset( $data['product_name'] ) ? $data['product_name'] : ''
			),
		);
	}

	/**
	 * 把服务端返回的错误码翻成给站长看的话。
	 *
	 * 关键是让人知道"该去做什么"：是去续费、去重置密钥，还是等一会儿再试。
	 */
	public static function explain( array $res ) {
		$map = array(
			'missing_key'           => __( 'No access key has been entered yet.', 'aipogeo-context-translate' ),
			'bad_key'               => __( 'That access key is not valid. Check that you copied all of it.', 'aipogeo-context-translate' ),
			'key_revoked'           => __( 'That access key has been revoked. Generate a new one in your account.', 'aipogeo-context-translate' ),
			'subscription_inactive' => __( 'The subscription has expired or was cancelled. Renew it to carry on.', 'aipogeo-context-translate' ),
			'quota_exhausted'       => __( 'This billing period\'s translation quota is used up. Upgrade the plan or wait for the next period.', 'aipogeo-context-translate' ),
			'site_limit'            => __( 'The subscription is already linked to as many sites as it allows. Release another site in your account first.', 'aipogeo-context-translate' ),
			'site_not_bound'        => __( 'This site is not activated yet. Press "Activate this site" once.', 'aipogeo-context-translate' ),
			'network'               => __( 'The service could not be reached. Check the service address and the server\'s network access.', 'aipogeo-context-translate' ),
			'bad_response'          => __( 'The service returned an error. Please try again shortly.', 'aipogeo-context-translate' ),
			'prompt_too_large'      => __( 'That batch was too large for one request. It will be split up and retried.', 'aipogeo-context-translate' ),
			'upstream_failed'       => __( 'The translation service could not reach its AI provider. Please try again shortly.', 'aipogeo-context-translate' ),
			'empty_response'        => __( 'The AI returned nothing this time. Please try again shortly.', 'aipogeo-context-translate' ),
			'ai_not_configured'     => __( 'The translation service has no AI model configured yet. Please contact support.', 'aipogeo-context-translate' ),
		);
		$code = isset( $res['code'] ) ? $res['code'] : '';
		if ( isset( $map[ $code ] ) ) {
			return $map[ $code ];
		}
		return '' !== (string) $res['message']
			? (string) $res['message']
			: __( 'That did not work. Please try again shortly.', 'aipogeo-context-translate' );
	}

	/**
	 * 这个失败还值不值得重试。
	 *
	 * 密钥、订阅、站点绑定、配置这几类问题，拆小批次再发一百次也是同样的结果，
	 * 只会白白拖长任务并反复打服务端；网络抖动和上游故障则相反，值得再试。
	 *
	 * @param array $res request() 的返回。
	 * @return bool true = 别再试了。
	 */
	public static function is_fatal( array $res ) {
		$stop = array(
			'missing_key',
			'bad_key',
			'key_revoked',
			'subscription_inactive',
			'quota_exhausted',
			'site_limit',
			'site_not_bound',
			'ai_not_configured',
			'no_service_url',
		);
		return in_array( isset( $res['code'] ) ? $res['code'] : '', $stop, true );
	}
}