--[[
    @object-name: edgerouter
    @object-desc: 旁路由模式
--]]
local uci = require "uci"
local lnet = require "oui.network"
local hardware = require "hardware"
local M = {}

local function file_exists(path)
    local file = io.open(path, "rb")
    if file then file:close() end
    return file ~= nil
end

local function split_ip(ip)
    local fields={}
    for field in ip:gmatch("[^.]+") do
        fields[#fields + 1] = field
    end
    return fields
end

local function get_address_pool(gateway,mask)
    local ret = {}
    local net = lnet.ipcalc({gateway,mask});
    local fileds=split_ip(net.network)
    local start=tonumber(fileds[4])
    local ending=tonumber(split_ip(net.broadcast)[4])
    local gw=tonumber(split_ip(gateway)[4])
    for i=start+1,ending-1,1 do
        if i ~= gw then
            ret["start"]= tostring(i)
            -- ret["start"]= fileds[1] .. "." .. fileds[2] .. "." ..  fileds[3] .. "." ..  tostring(i)
            break
        end
    end
    for i=ending-1,start+1,-1 do
        if i ~= gw then
            ret["end"]= tostring(i)
            -- ret["end"]= fileds[1] .. "." .. fileds[2] .. "." ..  fileds[3] .. "." ..  tostring(i)
            break
        end
    end
    return ret
end

local function check_config_valid(info)
    local c = uci.cursor()

    local ip = c:get("edgerouter", "wandhcp", "ip") or "0.0.0.0"
    local mask = c:get("edgerouter", "wandhcp", "netmask")  or "0.0.0.0"
    local cfg_net = lnet.ipcalc({ip,mask});
    local info_net = lnet.ipcalc({info.ip,info.netmask});
    if cfg_net.network == info_net.network then
        return true
    else
        return false
    end
end

--[[
    @method-type: call
    @method-name: get_status
    @method-desc: 获取局域网中的设备流量通过旁路由的状态

    @out number detected          上级DHCP服务器状态；(0:上级DHCP服务器已关闭，1:上级DHCP服务器开启并且已经将网关指向旁路由，2:上级服务器开启，3：物理网线未连接)
    @out string ?ip       DHCP服务器分配的IP；如果detected字段为2,则该字段有效
    @out string ?netmask       DHCP服务器掩码；如果detected字段为2,则该字段有效
    @out string ?gateway       DHCP服务器地址；如果detected字段为非0值,则该字段有效
    @out array ?dns      DHCP服务器DNS；如果detected字段为2,则该字段有效
    @out bool ?valid      当前配置是否有效；如果detected字段为2,则该字段有效

    @out number ?err_code          错误码
    @out string ?err_msg           错误信息

    @in-example: {"jsonrpc":"2.0","id":1,"method":"call","params":["","edgerouter","get_status",{}]}
    @out-example: {"jsonrpc": "2.0", "id": 1, "result": {"detected":false}}
--]]
function M.get_status()
    local ret = {}
    local s = hardware.platform_get_wan_status()
    if s.cable_enabled == false then
        ret["detected"]=3
        return ret
    end
    os.execute(". /lib/functions/drop-in-function.sh;check_dhcp_server")
    if file_exists("/tmp/drop-in-dhcp-info") then
        ret["detected"]=2
        local dns = {}
        local c = uci.cursor()
        local our_ip = c:get("edgerouter", "wandhcp", "ip")
        for line in io.lines("/tmp/drop-in-dhcp-info") do
            local fields = {}
            for field in line:gmatch("%S+") do
                fields[#fields + 1] = field
            end
            if fields[1] == "router:" then
               if our_ip ~= nil and fields[2] == our_ip then
                 ret["detected"]=1
               end
            end
            if fields[1] == "yiaddr:" then
                ret["ip"] = fields[2]
            end
            if fields[1] == "giaddr:" then
                ret["gateway"] = fields[2]
                -- 使用网关地址作为首先DNS
                dns[1] = fields[2]
            end
            if fields[1] == "netmask:" then
                ret["netmask"] = fields[2]
            end
            -- DHCP 下发的DNS作为备选
            if fields[1] == "dns1:" and fields[2] ~= "0.0.0.0" and fields[2] ~= dns[1] then
                dns[2] = fields[2]
            end
        end
        if #dns then
            ret["dns"] = dns
        end
        ret["valid"] = check_config_valid(ret)
    else
        ret["detected"]=0
    end

    return ret
end

--[[
    @method-type: call
    @method-name: set_config
    @method-desc: 设置旁路由模式相关配置

    @in bool enable          是否使能；false:不使能，true:使能
    @in string ?ip            ip地址,在enable参数为真时为必须参数
    @in string ?netmask       子网掩码,在enable参数为真时为必须参数
    @in string ?gateway       网关地址,在enable参数为真时为必须参数
    @in array ?dns       DNS服务器地址，至少填写一个,在enable参数为真时为必须参数

    @out number ?err_code          错误码
    @out string ?err_msg           错误信息

    @in-example: {"jsonrpc":"2.0","id":1,"method":"call","params":["","edgerouter","set_config",{"enable":true,"ip":"192.168.99.129","netmask":"255.255.255.0","gateway":"192.168.99.1","dns":["192.168.99.1","114.114.114.114"]}]}
    @out-example: {"jsonrpc": "2.0", "id": 1, "result": {}}
--]]
function M.set_config(params)
    if params.enable == nil then
        return {
            err_code = 1,
            err_msg = "parameter missing"
        }
    end

    if params.enable then
        if params.ip == nil or params.netmask == nil or params.gateway == nil  or params.dns == nil then
            return {
                err_code = 1,
                err_msg = "parameter missing"
            }
        end
    end

    local c = uci.cursor()
    c:set("edgerouter", "global", "global")
    c:set("edgerouter", "global", "enabled", params.enable and "1" or "0")

    if params.enable then
        local pool=get_address_pool(params.gateway,params.netmask)
        c:set("edgerouter", "wandhcp", "dhcp")
        c:set("edgerouter", "wandhcp", "ip", params.ip)
        c:set("edgerouter", "wandhcp", "netmask", params.netmask)
        c:set("edgerouter", "wandhcp", "gateway", params.gateway)
        c:set("edgerouter", "wandhcp", "dns", params.dns)
        c:set("edgerouter", "wandhcp", "start", pool.start)
        c:set("edgerouter", "wandhcp", "end", pool["end"])
    end

    c:commit("edgerouter")
    os.execute("/etc/init.d/edgerouter restart &")
    return {}
end


--[[
    @method-type: call
    @method-name: get_config
    @method-desc: 获取旁路由相关配置

    @out bool enable          是否使能；false:不使能，true:使能
    @out string ip            ip地址
    @out string netmask       子网掩码
    @out string gateway       网关地址
    @out array dns       DNS服务器地址，至少返回一个

    @out number ?err_code          错误码
    @out string ?err_msg           错误信息

    @in-example: {"jsonrpc":"2.0","id":1,"method":"call","params":["","edgerouter","get_config",{}]}
    @out-example: {"jsonrpc": "2.0", "id": 1, "result": {"enable":true,"ip":"192.168.99.129","netmask":"255.255.255.0","gateway":"192.168.99.1","dns":["192.168.99.1","114.114.114.114"]}}
--]]
function M.get_config()
    local ret = {}
    local c = uci.cursor()
    local ip
    local netmask
    local gateway
    local dns
    local enable = c:get("edgerouter", "global", "enabled") or '0'
    ip = c:get("edgerouter", "wandhcp", "ip")
    netmask = c:get("edgerouter", "wandhcp", "netmask")
    gateway = c:get("edgerouter", "wandhcp", "gateway")
    dns = c:get("edgerouter", "wandhcp", "dns")

    ret["enable"] = enable ~= "0"
    ret["ip"] = ip
    ret["netmask"] = netmask
    ret["gateway"] = gateway
    ret["dns"] = dns
    return ret
end


return M