--[[
    @object-name: tethering
    @object-desc: this is the API related to tethering internet access
--]]

local utils = require "oui.utils"
local fs = require "oui.fs"
local ubus = require "ubus"
local uci = require "uci"
local hardware = require "hardware"

local ERR_TETHERING_UNSUPPORT      = -1
local ERR_TETHERING_NO_DEVICE      = -2
local ERR_TETHERING_PARAM_MISSING  = -3

local M = {}

--[[
    @method-name: get_status
    @method-desc: get tethering info

    @out array    devices        device list
    @out string   devices.device device name
    @out number   devices.type   device type [0: Android; 1:Apple; 2:unknow]
    @out bool     devices.use    working status [ture: enable; false: disable]
    @out number   status         device status [0: disconnected; 1: connected; 2: connecting]
    @out object   ?ipv6          IPv6 info
    @out string   ?ipv6.ip       IPv6 address
    @out string   ?ipv6.gateway  IPv6 gateway
    @out array    ?ipv6.dns      IPv6 DNS
    @out object   ?ipv4          IPv4 info
    @out string   ?ipv4.ip       IPv4 address
    @out string   ?ipv4.gateway  IPv4 gateway
    @out array    ?ipv4.dns      IPv4 DNS
    @out number   ?err_code      error code [-1: This feature is not supported; -2: The device is not plugged in]
    @out string   ?err_msg       error message
    @in-example:  {\"jsonrpc\":\"2.0\",\"method\":\"call\",\"params\":[\"\",\"tethering\",\"get_status\",{}],\"id\":1}
    @out-example: {\"jsonrpc\":\"2.0\",\"id\":1,\"result\":{\"devices\":[{\"name\":\"usb0\",\"tyep\":0,\"use\":true},{\"device\":\"usb1\",\"tyep\":0,\"use\":false}],\"status\":1,\"ipv4\":{\"ip\":\"192.168.42.38/24\",\"gateway\":\"192.168.42.129\",\"dns\":[\"192.168.42.129\"]}}}
--]]

M.get_status = function()
    if not fs.access("/proc/gl-hw-info/usb-port") then
        return {
            err_code = ERR_TETHERING_UNSUPPORT,
            err_msg = "Unsupported features"
        }
    end

    local devices = {}

    for ifname in fs.dir("/sys/class/net") do
        local s = hardware.platform_telething_whether_removing_usb0()
        if s ~= ifname then
            if not ifname:match("^wwan") then
                local link = fs.readlink("/sys/class/net/" .. ifname)
                if link and link:match("usb") then
                    local typ = 2

                    if ifname:match("^eth%d") then
                        if utils.readfile("/sys/kernel/debug/usb/devices"):match("ipheth") then
                            typ = 1
                        end
                    elseif ifname:match("^usb%d") then
                        typ = 0
                    end

                    devices[#devices + 1] = {
                        device = ifname,
                        type = typ,
                        use = false
                    }
                end
            end
        end
    end

    if #devices == 0 then
        return {
            err_code = ERR_TETHERING_NO_DEVICE,
            err_msg = "No device found. Please insert"
        }
    end

    local res = {
        devices = devices,
        status = 0
    }

    local conn = ubus.connect()

    local s = conn:call("network.interface.tethering", "status", {}) or {}
    if s.up == nil then
        return res
    end

    if s["ipv4-address"] and #s["ipv4-address"] > 0 then
        res.ipv4 = {}
        res.status = 1
        res.ipv4.ip = s["ipv4-address"][1].address .. "/" .. s["ipv4-address"][1].mask
    else
        res.status = 2
        return res
    end

    for _, r in ipairs(s.route) do
        if r.target == "0.0.0.0" then
            res.ipv4.gateway = r.nexthop
        end
    end

    if s.device then
        for _, dev in ipairs(res.devices) do
            if s.device == dev.device then
                dev.use = true
            end
        end
    end

    local c = uci.cursor()

    local manual_dns = c:get("glconfig", "general", "manual_dns")

    if manual_dns == "1" then
        local server = c:get("dhcp", "@dnsmasq[0]", "server") or ""
        for dns in server:gmatch("%S+") do
            res.ipv4.dns[#res.ipv4.dns + 1] = dns
        end
    else
        res.ipv4.dns = s["dns-server"]
    end

    s = conn:call("network.interface.tethering6", "status", {}) or {}
    if not s.up then
        return res
    end

    res.ipv6 = {}

    if #s["ipv6-address"] > 0 then
        res.ipv6.ip = s["ipv6-address"][1].address .. "/" .. s["ipv6-address"][1].mask
    end

    for _, r in ipairs(s.route) do
        if r.target == "::" then
            res.ipv6.gateway = r.nexthop
        end
    end

    res.ipv6.dns = s["dns-server"]

    return res
end

--[[
    @method-name: set_connect
    @method-desc: connect or disconnect tethering

    @in  string   device      device name

    @out number   ?err_code   error code [-3: missing parameters]
    @out string   ?err_msg    error message
    @in-example:  {\"jsonrpc\":\"2.0\",\"method\":\"call\",\"params\":[\"\",\"tethering\",\"set_connect\",{\"device\":\"usb0\"}],\"id\":1}
    @out-example: {\"jsonrpc\":\"2.0\",\"id\":1,\"result\":{}}
--]]
M.set_connect = function(params)
    local device = params.device
    local c = uci.cursor()

    if not device or device == "" then
        return {
            err_code = ERR_TETHERING_PARAM_MISSING,
            err_msg = "No parameter (device)"
        }
    end

    c:delete("network", "tethering")
    c:set("network", "tethering", "interface")
    c:set("network", "tethering", "proto", "dhcp")
    c:set("network", "tethering", "ifname", device)
    c:set("network", "tethering", "metric", "30")
    c:commit("network")
    fs.sync()

    c:foreach("firewall", "zone", function(s)
        if s.name == "wan" then
            local nets = s.network or {}
            if type(nets) == "string" then
                local iterator = nets:gmatch("%S+")
                nets = {}
                for net in iterator do
                    nets[#nets + 1] = net
                end
            end

            for _, net in ipairs(nets) do
                if net == "tethering" then
                    return false
                end
            end

            nets[#nets + 1] = "tethering"
            c:set("firewall", s[".name"], "network", nets)

            return false
        end
    end)

    c:commit("firewall")
    fs.sync()

    local conn = ubus.connect()
    conn:call("network", "reload", {})
    conn:close()

    ngx.pipe.spawn({"/etc/init.d/firewall", "reload"})
end

--[[
    @method-name: disconnect
    @method-desc: disconnect tethering

    @in-example:  {\"jsonrpc\":\"2.0\",\"method\":\"call\",\"params\":[\"\",\"tethering\",\"disconnect\"],\"id\":1}
    @out-example: {\"jsonrpc\":\"2.0\",\"id\":1,\"result\":{}}
--]]
M.disconnect = function()
    local c = uci.cursor()

    c:set("network", "tethering", "disabled", 1)
    c:commit("network")
    fs.sync()

    local conn = ubus.connect()
    conn:call("network", "reload", {})
    conn:close()

    ngx.pipe.spawn("kill $(pgrep -f \"mwan3track tethering\")")
end

return M