<?php
// +----------------------------------------------------------------------
// | YwxApp [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2026-2036 http://ywxapp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Author: ywxapp<admin@ywxapp.cn>
// +----------------------------------------------------------------------
namespace addon\mqttbroker\service;

use think\facade\Db;

/**
 * MQTT 持久化服务：保留消息 + 离线消息队列
 *
 * - 保留消息(retained)：broker 重启后从 DB 恢复，保证新订阅者仍能收到最后一条。
 * - 离线消息(offline)：clean=false 会话离线期间投递给它的 QoS1/2 消息入库，
 *   客户端重连后取出补投。
 *
 * 均为二进制安全（longblob）。所有操作 try/catch，DB 不可用不影响 broker 运行。
 * 由 persist_retain / persist_offline 配置开关控制。
 */
class Store
{
    /** @var bool 启用保留消息持久化 */
    protected $persistRetain;

    /** @var bool 启用离线消息持久化 */
    protected $persistOffline;

    /** @var int 单客户端离线消息上限，超出丢弃最旧 */
    protected $offlineLimit;

    
    public function __construct(array $config)
    {
        $this->persistRetain  = (string) ($config['persist_retain'] ?? '1') === '1';
        $this->persistOffline = (string) ($config['persist_offline'] ?? '1') === '1';
        $this->offlineLimit   = (int) ($config['offline_limit'] ?? 1000);
    }

    
    public function ensureTables(): void
    {
        try {
            Db::execute("CREATE TABLE IF NOT EXISTS `wxapp_mqttbroker_retain` (
                `id` int unsigned NOT NULL AUTO_INCREMENT,
                `topic` varchar(255) NOT NULL DEFAULT '',
                `payload` longblob,
                `qos` tinyint(1) NOT NULL DEFAULT '0',
                `update_at` int DEFAULT NULL,
                PRIMARY KEY (`id`), UNIQUE KEY `uk_topic` (`topic`)
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");
            Db::execute("CREATE TABLE IF NOT EXISTS `wxapp_mqttbroker_offline` (
                `id` int unsigned NOT NULL AUTO_INCREMENT,
                `client_id` varchar(191) NOT NULL DEFAULT '',
                `topic` varchar(255) NOT NULL DEFAULT '',
                `payload` longblob,
                `qos` tinyint(1) NOT NULL DEFAULT '0',
                `create_at` int DEFAULT NULL,
                PRIMARY KEY (`id`), KEY `idx_client_id` (`client_id`)
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");
            Db::execute("CREATE TABLE IF NOT EXISTS `wxapp_mqttbroker_outbox` (
                `id` int unsigned NOT NULL AUTO_INCREMENT,
                `topic` varchar(255) NOT NULL DEFAULT '',
                `payload` longblob,
                `qos` tinyint(1) NOT NULL DEFAULT '0',
                `retain` tinyint(1) NOT NULL DEFAULT '0',
                `source` varchar(32) DEFAULT 'manual',
                `create_at` int DEFAULT NULL,
                `status` tinyint(1) NOT NULL DEFAULT '0' COMMENT '0待投递 1已投递',
                PRIMARY KEY (`id`), KEY `idx_status` (`status`)
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");
        } catch (\Throwable $e) {
        }
    }

    /* ---------------- 手动发布出站队列 ---------------- */

    /**
     * 入队一条手动发布（后台/API 发布经 DB 出栈，Broker 消费后内部路由，零外部依赖）
     */
    public static function enqueueManual(string $topic, string $payload, int $qos, int $retain, string $source): bool
    {
        try {
            Db::name('mqttbroker_outbox')->insert([
                'topic'       => $topic,
                'payload'     => $payload,
                'qos'         => $qos,
                'retain'      => $retain ? 1 : 0,
                'source'      => $source,
                'create_at' => time(),
                'status'      => 0,
            ]);
            return true;
        } catch (\Throwable $e) {
            return false;
        }
    }

    /**
     * 取出待投递的出站消息（status=0）
     * @return array
     */
    public function popOutbox(int $limit = 100): array
    {
        $out = [];
        try {
            $out = Db::name('mqttbroker_outbox')->where('status', 0)
                ->order('id', 'asc')->limit($limit)->select()->toArray();
        } catch (\Throwable $e) {
        }
        return $out;
    }

    /**
     * 标记出站消息已投递（避免重复路由）
     */
    public function markOutboxSent(array $ids): void
    {
        if (empty($ids)) {
            return;
        }
        try {
            Db::name('mqttbroker_outbox')->whereIn('id', $ids)->update(['status' => 1]);
        } catch (\Throwable $e) {
        }
    }

    /* ---------------- 保留消息 ---------------- */

    /**
     * 启动时加载全部保留消息
     * @return array topic => ['payload'=>string,'qos'=>int]
     */
    public function loadRetained(): array
    {
        if (!$this->persistRetain) {
            return [];
        }
        $out = [];
        try {
            foreach (Db::name('mqttbroker_retain')->select() as $row) {
                $out[$row['topic']] = ['payload' => (string) $row['payload'], 'qos' => (int) $row['qos']];
            }
        } catch (\Throwable $e) {
        }
        return $out;
    }

    
    public function saveRetained(string $topic, string $payload, int $qos): void
    {
        if (!$this->persistRetain) {
            return;
        }
        try {
            $exists = Db::name('mqttbroker_retain')->where('topic', $topic)->find();
            if ($exists) {
                Db::name('mqttbroker_retain')->where('id', $exists['id'])
                    ->update(['payload' => $payload, 'qos' => $qos, 'update_at' => time()]);
            } else {
                Db::name('mqttbroker_retain')->insert([
                    'topic' => $topic, 'payload' => $payload, 'qos' => $qos, 'update_at' => time(),
                ]);
            }
        } catch (\Throwable $e) {
        }
    }

    
    public function deleteRetained(string $topic): void
    {
        if (!$this->persistRetain) {
            return;
        }
        try {
            Db::name('mqttbroker_retain')->where('topic', $topic)->delete();
        } catch (\Throwable $e) {
        }
    }

    /* ---------------- 离线消息 ---------------- */

    
    public function queueOffline(string $clientId, string $topic, string $payload, int $qos): void
    {
        if (!$this->persistOffline) {
            return;
        }
        try {
            Db::name('mqttbroker_offline')->insert([
                'client_id' => $clientId, 'topic' => $topic,
                'payload' => $payload, 'qos' => $qos, 'create_at' => time(),
            ]);
            // 超限裁剪：保留最新 offlineLimit 条
            $count = Db::name('mqttbroker_offline')->where('client_id', $clientId)->count();
            if ($count > $this->offlineLimit) {
                $ids = Db::name('mqttbroker_offline')->where('client_id', $clientId)
                    ->order('id', 'asc')->limit($count - $this->offlineLimit)->column('id');
                if ($ids) {
                    Db::name('mqttbroker_offline')->whereIn('id', $ids)->delete();
                }
            }
        } catch (\Throwable $e) {
        }
    }

    /**
     * 取出并清空某客户端的离线消息
     * @return array<int,array{topic:string,payload:string,qos:int}>
     */
    public function popOffline(string $clientId): array
    {
        if (!$this->persistOffline) {
            return [];
        }
        $out = [];
        try {
            $rows = Db::name('mqttbroker_offline')->where('client_id', $clientId)->order('id', 'asc')->select();
            foreach ($rows as $r) {
                $out[] = ['topic' => $r['topic'], 'payload' => (string) $r['payload'], 'qos' => (int) $r['qos']];
            }
            if (!empty($out)) {
                Db::name('mqttbroker_offline')->where('client_id', $clientId)->delete();
            }
        } catch (\Throwable $e) {
        }
        return $out;
    }
}