--
-- ~~~ fetch a pawsd service
--

-- require a name & service index to fetch
if not arg[1] or not arg[2] then
    error("server name & index required")
end

-- imports
local PawSD = require("src/pawsd")
local Servers = require("src/servers")
require("src/utils")

local socket = require("socket")
local client = assert(socket.tcp())

-- get arguments & check validity
local server = Servers[arg[1]]
local index = arg[2]

if not server then
    error("server not found")
end

-- connect to client
client:connect(server.host, server.port)

-- send request
local request = string.fromhex(PawSD.Magic.REQUEST .. PawSD.Version .. PawSD.Verbs.FETCH_SERVICE .. server.keyalg .. "0020" .. server.key .. index)
client:send(request)

-- print response
local response = {}

while true do
    local packet, status = client:receive(1)

    -- if packet then print(response) end
    table.insert(response, packet)
    if status == "closed" then break end
end

-- check that the response is correct
local responseMagic = extractfromresponse(response, 1, 8)
if not responseMagic == PawSD.Magic.RESPONSE then
    error("invalid response")
end

-- check that the status is okay
local responseStatus = extractfromresponse(response, 11, 12)
if not responseStatus == PawSD.Responses.OK then
    error("unsuccessful request")
end

-- get signature information
local responseSignatureLength = tonumber(extractfromresponse(response, 13, 14), 16)
local responseSignatureEnd = 14 + responseSignatureLength
local responseSignature = extractfromresponse(response, 15, responseSignatureEnd)

print("Signature: " .. responseSignature)
-- todo: check this?

-- get service index
local responseIndexStart = responseSignatureEnd + 1
local responseIndex = extractfromresponse(response, responseIndexStart, responseIndexStart + 1)

-- get service flags
local responseFlagsStart = responseIndexStart + 2
local responseFlags = extractfromresponse(response, responseFlagsStart, responseFlagsStart + 3)

-- get number of records
local responseRecordCountStart = responseFlagsStart + 4
local responseRecordCount = tonumber(extractfromresponse(response, responseRecordCountStart, responseRecordCountStart + 1), 16)

-- store offset
local recordOffset = responseRecordCountStart + 2

-- loop through each record
for recordNumber = 1, responseRecordCount, 1 do

    print("\n--- Record Number " .. recordNumber .. " ---")

    -- get number of tags
    local responseTagCountStart = recordOffset
    local responseTagCount = tonumber(extractfromresponse(response, responseTagCountStart, responseTagCountStart + 1), 16)

    -- store offset
    local tagOffset = recordOffset + 2

    -- loop through each tag
    for tagNumber = 1, responseTagCount, 1 do

        print("\n    - Tag Number " .. tagNumber .. " -\n")

        -- high tag
        local responseTagHighStart = tagOffset
        local responseTagHigh = extractfromresponse(response, responseTagHighStart, responseTagHighStart + 7)
        print("      High Tag: " .. responseTagHigh)

        -- low tag
        local responseTagLowStart = responseTagHighStart + 8
        local responseTagLow = extractfromresponse(response, responseTagLowStart, responseTagLowStart + 7)
        print("      Low Tag:  " .. responseTagLow)

        -- get value length
        local responseTagValueLength = {}
        local responseTagValueLengthStart = responseTagLowStart + 8
        local responseTagValueLength = tonumber(extractfromresponse(response, responseTagValueLengthStart, responseTagValueLengthStart + 3), 16)

        -- only check if value actually exists
        if responseTagValueLength > 0 then

            -- get value
            local responseTagValueStart = responseTagValueLengthStart + 4
            local responseTagValueEnd = responseTagValueStart + responseTagValueLength
            local responseTagValue = string.fromhex(extractfromresponse(response, responseTagValueStart, responseTagValueEnd))

            print("      Value:    " .. responseTagValue)

            -- adjust offset
            tagOffset = responseTagValueEnd

        else

            -- adjust offset
            tagOffset = responseTagValueLengthStart + 4

        end
    end

    -- adjust offset
    recordOffset = tagOffset
end

-- close connection
client:close()