<?php

namespace traits;

use bw\Redis;


/**
 * 缓存
 */
trait CacheTrait
{


    private $cache_lock_error_msg = "获取锁失败！";

    private $cache_lock_thorws_excption = true;

    public function setCacheLockThorwsExcption($cache_lock_thorws_excption){
        $this->cache_lock_thorws_excption = $cache_lock_thorws_excption;
        return $this;
    }


    public function getCacheLockThorwsExcption(){
        return $this->cache_lock_thorws_excption;
    }


    public function hasRedis($is_interrupt = false) {
        $error_msg = '';
        try {
            $redis = $this->getRedis();

            // 检测连接是否正常
            $redis->ping();
        } catch (\BadFunctionCallException $e) {
            // 缺少扩展
            $error_msg = $e->getMessage() ? $e->getMessage() : "缺少 redis 扩展";
        } catch (\RedisException $e) {
            // 连接拒绝
            \think\Log::write('redis connection redisException fail: ' . $e->getMessage());
            $error_msg = $e->getMessage() ? $e->getMessage() : "redis 连接失败";
        } catch (\Exception $e) {
            // 异常
            \think\Log::write('redis connection fail: ' . $e->getMessage());
            $error_msg = $e->getMessage() ? $e->getMessage() : "redis 连接异常";
        }

        if ($error_msg) {
            if ($is_interrupt || $this->cache_lock_thorws_excption) {
                throw new \Exception($error_msg);
            } else {
                $this->setCacheLockErrorMsg($error_msg);
                return false;
            }
        }

        return true;
    }


    public function getRedis() {
        if (!isset($GLOBALS['SPREDIS'])) {
            $GLOBALS['SPREDIS'] = (new Redis())->getRedis();
        }

        return $GLOBALS['SPREDIS'];
    }


    public function getLock($key, $suffix = "-lock-suffix", $timeout = 120, $lock_num = 1) {
        $this->hasRedis(true);
        $redis = $this->getRedis();
        $hashKey = $key . $suffix;

        if ($lock_num == 1) { // 单令牌
            $nxLock = $redis->set($hashKey, 1, ['nx', 'ex' => $timeout]);
            if ($nxLock == 1) {
                return true;
            } else {
                if ($this->cache_lock_thorws_excption) {
                    throw new \Exception($this->cache_lock_error_msg);
                } else {
                    return false;
                }
            }
        } else {
            // 多令牌
            $lua = 'local hash_key = KEYS[1]
local max_tokens = tonumber(ARGV[3])
local token_value = ARGV[1]
local token_timeout = tonumber(ARGV[2])

-- 获取当前令牌数
local current_value = redis.call("hget", hash_key, "count")

if not current_value then
    -- 锁不存在，初始化锁并设置过期时间
    redis.call("hset", hash_key, "count", 1)
    redis.call("expire", hash_key, token_timeout)
    return 1
else
    -- 锁存在，增加计数器
    local new_value = tonumber(current_value) + 1
    if new_value > max_tokens then
        return 0
    else
        redis.call("hset", hash_key, "count", new_value)
        redis.call("expire", hash_key, token_timeout)
        return new_value
    end
end';

            $result = $redis->eval($lua, [$hashKey, $timeout, $lock_num], 1);
            if ($result >= 1 && $result <= $lock_num) {
                return true;
            } else {
                if ($this->cache_lock_thorws_excption) {
                    throw new \Exception($this->cache_lock_error_msg);
                } else {
                    return false;
                }
            }
        }
    }


    public function setCacheLockErrorMsg($cache_lock_error_msg){
        $this->cache_lock_error_msg = $cache_lock_error_msg;
        return $this;
    }


    public function getCacheLockErrorMsg(){
        return $this->cache_lock_error_msg;
    }


    public function freeLock($key, $suffix = "-lock-suffix", $lock_num = 1, $timeout = 120) {
        $this->hasRedis(true);
        $redis = $this->getRedis();
        if (!$key || !$suffix) return true;
        $hashKey = $key . $suffix;

        if ($lock_num == 1) { // 单令牌
            // 执行lua脚本，确保删除锁是原子操作
            $lua = 'if redis.call("get", KEYS[1]) == ARGV[1]
        then
            return redis.call("del", KEYS[1])
        else
            return 0
        end';
            $result = $redis->eval($lua, [$hashKey, 1], 1);

            if ('1' == $result) {
                return true;
            }
            return false;
        } else { // 多令牌
            $lua = 'local hash_key = KEYS[1]
local token_value = ARGV[1]
local token_timeout = tonumber(ARGV[2])

-- 获取当前令牌数
local current_value = redis.call("hget", hash_key, "count")

if not current_value then
    -- 锁不存在，无需释放
    return 0
else
    -- 锁存在，减少计数器
    local new_value = tonumber(current_value) - 1
    if new_value < 1 then
        -- 计数器小于1，删除锁
        local result = redis.call("del", hash_key)
        return result
    else
        -- 计数器大于等于1，更新锁
        redis.call("hset", hash_key, "count", new_value)
        redis.call("expire", hash_key, token_timeout)
        return new_value
    end
end';

            $result = $redis->eval($lua, [$hashKey, $timeout, $lock_num], 1);
            if ($result >= 1 && $result <= $lock_num) {
                return true;
            } else {
                return false;
            }
        }
    }


}