--use coroutine,watch realtime
local _M = {}

local json = require "cjson"
local shell = require "resty.shell"

local function print_map_keys()
	local storage = _M.conf.storage

	local keys = storage:get_keys(1024)
	if #keys > 0 then
		ngx.log(ngx.ERR, table.concat(storage:get_keys(1024),","))
	else 
		ngx.log(ngx.ERR, "storage empty")
	end
end

local function clean_keys(keys, storage)
	for k, v in pairs(keys) do
		if not v then
			ngx.log(ngx.ERR, "delete:" .. k)
			storage:delete(k)
		end
	end
end

local function get_nodes(key, storage)
	local key_map = {}
	local stor_keys = storage:get_keys(1024)
	for k, v in pairs(stor_keys) do
		key_map[v] = false
	end

    local status, stdout, err, reason, status = shell.run("docker exec etcd etcdctl get --prefix " .. key .. " -w=json")
    --ngx.log(ngx.ERR, stdout)
	
	local resp = json.decode(stdout)

	if not resp then
		ngx.log(ngx.ERR, "cli:get resp is nil")
		return
	end

	local kvs = resp.kvs or {}
	if not kvs or #kvs == 0 then
		ngx.log(ngx.ERR, "resp.body.kvs is nil")
		return
	end
	
	for i = 1, #kvs do
		local kv = kvs[i]
		if kv.value then
			local node_key = ngx.decode_base64(kv.key)
			local node_value = ngx.decode_base64(kv.value)
			
			storage:set(node_key, node_value)
			if key_map[node_key] ~= nil then
				key_map[node_key] = true
			end
		end
	end

	clean_keys(key_map, storage)

	-- 打印测试
	print_map_keys()
end

local function watch(premature, tkey, storage)	
	get_nodes(tkey, storage)

	local ok, err = ngx.timer.at(5, watch, tkey, storage)
	if not ok then
		ngx.log(ngx.ERR, "Restart watch err:"..err)
	end
end

-- 在nginx.conf中设置一个全局的aps_nodes_map
-- 通过连接etcd, 并监听/aps/nodes/ 前缀的key, 将注册到etcd的apsServer节点添加到aps_nodes_map中
function _M.init(conf)
	-- Only one worker start the syncer, here will use worker_id == 0
	if ngx.worker.id() ~= 0 then
		return
	end

	_M.conf = conf

	local storage = _M.conf.storage
	local data = storage:get("init")
	if data then
		ngx.log(ngx.ERR, "watch etcd already started")
		return
	else 
		storage:set("init", true)
	end

	local ok, err = ngx.timer.at(0, watch, conf.key_node, storage)
	if not ok then
		ngx.log(ngx.ERR, "Error start api watch:"..err)
	end
end

return _M