---
---




--- 判断source_str 中是否contains pattern_str
--- @param source_str
--- @param patter_str
local function contains(source_str, sub_str)
    local start_pos, end_pos = string.find(source_str, sub_str);
    if start_pos == nil then
        return false;
    end
    local source_str_len = string.len(source_str);


    if source_str_len == end_pos then
        return true
    elseif string.sub(source_str, end_pos + 1, end_pos + 1) == "," then
        return true
    end
    return false;
end




--- 获取令牌
--- 返回码
--- 0 没有令牌桶配置
--- -1 表示取令牌失败，也就是桶里没有令牌
--- 1 表示取令牌成功
--- @param key 令牌的唯一标识
--- @param permits  请求令牌数量
--- @param curr_mill_second 当前毫秒数
--- @param context 使用令牌的应用标识
local function acquire(key, permits, curr_mill_second, context)
    local rate_limit_info = redis.pcall("HMGET", key, "last_mill_second", "curr_permits", "max_permits", "rate", "apps")
    local last_mill_second = rate_limit_info[1]
    local curr_permits = tonumber(rate_limit_info[2])
    local max_permits = tonumber(rate_limit_info[3])
    local rate = rate_limit_info[4]
    local apps = rate_limit_info[5]


    --- 标识没有配置令牌桶
    if type(apps) == 'boolean' or apps == nil or not contains(apps, context) then
        return 0
    end




    local local_curr_permits = max_permits;




    --- 令牌桶刚刚创建，上一次获取令牌的毫秒数为空
    --- 根据和上一次向桶里添加令牌的时间和当前时间差，触发式往桶里添加令牌，并且更新上一次向桶里添加令牌的时间
    --- 如果向桶里添加的令牌数不足一个，则不更新上一次向桶里添加令牌的时间
    if (type(last_mill_second) ~= 'boolean'  and last_mill_second ~= nil) then
        local reverse_permits = math.floor(((curr_mill_second - last_mill_second) / 1000) * rate)
        local expect_curr_permits = reverse_permits + curr_permits;
        local_curr_permits = math.min(expect_curr_permits, max_permits);


        --- 大于0表示不是第一次获取令牌，也没有向桶里添加令牌
        if (reverse_permits > 0) then
            redis.pcall("HSET", key, "last_mill_second", curr_mill_second)
        end
    else
        redis.pcall("HSET", key, "last_mill_second", curr_mill_second)
    end




    local result = -1
    if (local_curr_permits - permits >= 0) then
        result = 1
        redis.pcall("HSET", key, "curr_permits", local_curr_permits - permits)
    else
        redis.pcall("HSET", key, "curr_permits", local_curr_permits)
    end


    return result
end






--- 初始化令牌桶配置
--- @param key 令牌的唯一标识
--- @param max_permits 桶大小
--- @param rate  向桶里添加令牌的速率
--- @param apps  可以使用令牌桶的应用列表，应用之前用逗号分隔
local function init(key, max_permits, rate, apps)
    local rate_limit_info = redis.pcall("HMGET", key, "last_mill_second", "curr_permits", "max_permits", "rate", "apps")
    local org_max_permits = tonumber(rate_limit_info[3])
    local org_rate = rate_limit_info[4]
    local org_apps = rate_limit_info[5]


    if (org_max_permits == nil) or (apps ~= org_apps or rate ~= org_rate or max_permits ~= org_max_permits) then
        redis.pcall("HMSET", key, "max_permits", max_permits, "rate", rate, "curr_permits", max_permits, "apps", apps)
    end
    return 1;
end


--- 删除令牌桶
local function delete(key)
    redis.pcall("DEL", key)
    return 1;
end

local key = KEYS[1]
local method = ARGV[1]


if method == 'acquire' then
    return acquire(key, ARGV[2], ARGV[3], ARGV[4])
elseif method == 'init' then
    return init(key, ARGV[2], ARGV[3], ARGV[4])
elseif method == 'delete' then
    return delete(key)
else
    --ignore
end