ENDER_NETWORK

local component = require("component")
local str       = require("string")
local sides     = require("sides")
local math      = require("math")
local table     = require("table")

local transposer = component.transposer
local ender_chest = component.ender_chest

local DATA = sides.up



local bufferStart = 1
local bufferEnd = 27

local messageIdSlot = 28
local chestBlockerSlot = 29
local msgCodeSlot = 30
local dataTypeSlot = 31
local dataStart = 32
local dataEnd = 54
local dataSize = dataEnd - dataStart + 1

local lastMessage = -1



local function moveItem(from, to, count) transposer.transferItem(DATA, DATA, count, from, to) end

local function clearData()
    ender_chest.condenseItems()
end
local function readData(slot, data)
    if data ~= nil then
        local val = data[slot]
        if val == nil then return 0 end
        return val.basic().qty
    end
    return transposer.getSlotStackSize(DATA, slot)
end

local function writeToSlot(slot, val) moveItem(slot - bufferEnd, slot, val) end

local function unblockChest() moveItem(chestBlockerSlot, 2, 64) end
local function blockChest() writeToSlot(chestBlockerSlot, 1) end
local function chestBlocked() return readData(chestBlockerSlot) > 0 end

local function incMessageId(counter)
    if counter == 63 then counter = 0 end
    writeToSlot(messageIdSlot, counter + 1)
    return counter + 1
end

local function convertNumberToMessage(number, base)
    local msg, ch = {}, false
    for i = 23, 1, -1 do
        local k = base ^ i
        if k <= number then do
            ch = true
            local n = math.floor(number / k)
            number = number - n * k
            table.insert(msg, n)
        end
        elseif ch then table.insert(msg, 0) end
    end
    table.insert(msg, number)
    for i = 1, #msg do msg[i] = msg[i] + 1 end
    return msg
end
local function convertMessageToNumber(m, base)
    local n = 0
    for i = 1, #m do m[i] = m[i] - 1 end
    for i = 1, #m do n = n + base ^ (#m - i) * m[i] end
    return n
end
local function writeData(data, msgCode)
    writeToSlot(msgCodeSlot, msgCode)
    if type(data) == "number" then
        data = convertNumberToMessage(data, 64)
        writeToSlot(dataTypeSlot, 1)
    end
    for i = 1, math.min(dataSize, #data) do writeToSlot(i + dataStart - 1, data[i]) end
end

local function readMessage()
    local data, message, num = ender_chest.getAllStacks(), {}

    local msgCode = readData(msgCodeSlot, data)
    local dataType = readData(dataTypeSlot, data)
    for i = dataStart, math.min(#data, dataEnd) do
        num = readData(i, data)
        message[i - dataStart + 1] = num
    end
    if dataType == 1 then message = convertMessageToNumber(message, 64) end
    return msgCode, message
end


local function sendMessage(msgCode, data, timeout)
    if timeout == nil then timeout = 0.75 end
    while true do
        if not chestBlocked() then
            local lastMessageId = readData(messageIdSlot)
            clearData()
            blockChest()
            writeData(data, msgCode)
            lastMessage = incMessageId(lastMessageId)
            os.sleep(timeout)
            unblockChest()
            break
        end
    end
end

local function pullMessage()
    local messageId = readData(messageIdSlot)

    if lastMessage ~= messageId and messageId > 0 then
        lastMessage = messageId
        return true, readMessage()
    end
    return false
end

return {["sendMessage"]=sendMessage, ["pullMessage"]=pullMessage, ["maxMessageSize"]=dataSize}