--[[
Inventory Tracker by NuAoA
Description:
    Scans an attached inventory for a change in its contents.

]]--

local comp_faces = {"Front","Back","Left","Right","Top","Bottom"}
local inv -- used to attach
local lastInv = {}
local HubComputerID = 57


function attachModem()
    for i=1,#comp_faces do
        if peripheral.isPresent(string.lower(comp_faces[i])) and peripheral.getType(string.lower(comp_faces[i])) == "modem" then
            if rednet.isOpen(string.lower(comp_faces[i])) then
                return true
            else
                rednet.open(string.lower(comp_faces[i]))
                return true
            end
        end
    end
    return false
end

function attachInventory()
    local face = nil
    local function checkGetAllStacks()
        local p = peripheral.wrap(face)
        local _ = p.getAllStacks() -- this will throw a error if the function does not exist.
    end
    for i=1,#comp_faces do
        if peripheral.isPresent(string.lower(comp_faces[i])) and peripheral.getType(string.lower(comp_faces[i])) ~= "modem" then
            face = string.lower(comp_faces[i])
            if pcall(checkGetAllStacks) then
                inv = peripheral.wrap(string.lower(comp_faces[i]))
                if peripheral.getType(string.lower(comp_faces[i])) == "me_interface" then
                    inv.isMe = true
                end
                return true,peripheral.getType(string.lower(comp_faces[i]))
            end
        end
    end
    return false
end

function startup()
    term.clear()
    print("Booting Inventory Tracker")
    local isModem = attachModem()
    print("Locating modem... "..tostring(isModem))
    local isInv,invType = attachInventory()
    print("Locating inventory... "..tostring(isInv))
    print("")
    if isInv then
        print("Inventory name: "..tostring(invType))
    end
    if isInv and isModem then
        term.clear()
        term.setCursorPos(1,1)
        print(invType)
        lastInv = getInv()
    else
        print()
        print("This program requires a wireless modem and a adjacent inventory/me_interface")
        print()
        print()
        term.write("Press any key to reboot")
        os.pullEventRaw("key")
        sleep(1)
        os.reboot()
    end
end

--make a duplicate of a table.
function deepcopy(orig)
    local orig_type = type(orig)
    local copy
    if orig_type == 'table' then
        copy = {}
        for orig_key, orig_value in next, orig, nil do
            copy[deepcopy(orig_key)] = deepcopy(orig_value)
        end
        setmetatable(copy, deepcopy(getmetatable(orig)))
    else -- number, string, boolean, etc
        copy = orig
    end
    return copy
end

function uniqueToID(unique,...)
    if type(unique) ~= "number" or unique == nil then
        if unique == nil then error("[uniqueToID] nil passed to function!",2) end
        error("[uniqueToID] invalid type passed to function! "..type(unique),2)
    end
    local Dam = math.floor(unique/2^15)
    local ID = unique%(2^15)
    if arg[1] then return ID..":"..Dam else return ID,Dam end
end

-- converts a ID,dam to a unique number
function IDtoUnique(ID,...)
    if type(ID) == "string" then
        if string.match(ID,"%d+:%d+") then
            return tonumber(string.match(ID,"(%d+):%d+")) +(2^15)*tonumber(string.match(ID,"%d+:(%d+)"))
        else
            error("[IDtoUnique] Invalid string passed to function. "..ID,2)
        end
    elseif ID == nil or arg[1] == nil then
        term.clear()
        print(ID)
        print(arg[1])
        error("[IDtoUnique] Invalid arguments passed to function.",2)
    else
        return ID+arg[1]*2^15
    end
end

function formatTable(tab)
    -- will format a getAllStacks table into a more usefull format of the form:
    -- table[uniqueID][name] = qty
    local retTab = {}
    for slot,v in pairs(tab) do
        local retTab2 = {}
        local uniqueID = IDtoUnique(v.id,v.dmg)
        if retTab[uniqueID] ~= nil and retTab[uniqueID][v.name] ~= nil then
            retTab[uniqueID][v.name] = retTab[uniqueID][v.name] + v.qty
        elseif retTab[uniqueID] ~= nil then
            retTab[uniqueID][v.name] = v.qty
        else
            retTab2[v.name] = v.qty
            retTab[uniqueID] = retTab2
        end
    end
    return deepcopy(retTab)
end

-- returns the contents of
function getInv()
    if inv.isMe then return formatTable(inv.getAvailableItems())
    else return formatTable(inv.getAllStacks()) end
end

function compareInv(curr,last)
    --Compares tables curr and last for differences.
    --returns a table of items that have been removed.
    local foundChange = false
    local changeTab = {}
    --check if item or qty of item was removed
    for uniqueID,tab1 in pairs(last) do
        for name,qty in pairs(tab1) do
            if curr[uniqueID] == nil or curr[uniqueID][name] == nil then
                foundChange = true
                local tab = {}
                tab.name = name
                tab.id,tab.dmg = uniqueToID(uniqueID)
                tab.qty = -1*qty
                table.insert(changeTab,deepcopy(tab))
                --item does not exist
            elseif curr[uniqueID][name] ~= last[uniqueID][name] then
                foundChange = true
                local tab = {}
                tab.name = name
                tab.id,tab.dmg = uniqueToID(uniqueID)
                tab.qty = curr[uniqueID][name] - last[uniqueID][name]
                table.insert(changeTab,deepcopy(tab))
                --qty change
            end
        end
    end
    --check if new item was inserted
    for uniqueID,tab1 in pairs(curr) do
        for name,qty in pairs(tab1) do
            if last[uniqueID] == nil or last[uniqueID][name] == nil then
                foundChange = true
                local tab = {}
                tab.name = name
                tab.id,tab.dmg = uniqueToID(uniqueID)
                tab.qty = qty
                table.insert(changeTab,deepcopy(tab))
                --item does not exist
            end
        end
    end
    return foundChange,deepcopy(changeTab)
end

function checkChange()
    local invTemp = getInv()
    local change,tab = compareInv(invTemp,lastInv)
    lastInv = deepcopy(invTemp)
    if change then return true,tab
    else return false,nil end
end

function listener()
    while true do
        local ID,mess,dist = rednet.receive()
        if ID == HubComputerID then
            if mess == "scan" then
                local isChange,tab = checkChange()
                if isChange then
                    rednet.send(HubComputerID,textutils.serialize(tab))
                end
            end
        end
    end
end
function antiHack()
    local pullEvent = os.pullEvent
    os.pullEvent = os.pullEventRaw
    while true do
        local event,side = os.pullEventRaw("terminate")
        sleep(0)
        --userInput("terminate command")
    end
end
startup()
parallel.waitForAny(listener,antiHack)