--
-- author: Joshua Zhu (http://www.zhuzhaoyuan.com)
-- 

local string = require("string")

local is_debug = true

local cli_svr_map

function get_server(client)
	-- initialize the map table
	if not cli_svr_map then
		-- note: you should modify the client IPs and the backend addresses below!!!
		cli_svr_map = {
			["192.168.0.189"] = { 
				address = "192.168.0.192:3306", 
				backend_ndx = -1 },
			["192.168.0.192"] = { 
				address = "192.168.0.189:3306", 
				backend_ndx = -1 },
		 }

		for _, v in pairs(cli_svr_map) do
			for i = 1, #proxy.global.backends do
				local backend = proxy.global.backends[i]
				if v.address == backend.address then
					v.backend_ndx = i
					break
				end
			end
		end

		if is_debug then
			print("map table: ")
			for k, v in pairs(cli_svr_map) do
				print("   [" .. k .. "] = {" .. v.address .. ", " .. v.backend_ndx .. "}")
			end
		end
	end

	local host = string.match(client, "([^:]+):")
	if cli_svr_map[host] then
		return cli_svr_map[host].backend_ndx
	end

	return -1
end

function connect_server()
	if is_debug then
		print("[connect_server] " .. proxy.connection.client.address)
		print("we have " .. #proxy.global.backends .. " backends:")

		for i = 1, #proxy.global.backends do
			local backend = proxy.global.backends[i]
			print("   [" .. i .. "].connected_clients = " .. backend.connected_clients)
			print("   [" .. i .. "].address = " .. backend.address)
			print("   [" .. i .. "].state = " .. backend.state)
			print("   [" .. i .. "].type = " .. backend.type)
			print("   [" .. i .. "].uuid = " .. (backend.uuid or "(nil)"))
		end
	end

	local index = get_server(proxy.connection.client.address)
	if index > 0 and index <= #proxy.global.backends then
		if proxy.global.backends[index].state ~= proxy.BACKEND_STATE_DOWN then
			if is_debug then
				print("redirect the client to backends[" .. proxy.global.backends[index].address .. "]")
			end

			proxy.connection.backend_ndx = index
		end
	end
end