user client (pocket computer)

-- Pocket Client
local PROTOCOL = "room_mgmt"
peripheral.find("modem", rednet.open)

-- Setup Username
settings.load()
local USER_ID = settings.get("room_username")
if not USER_ID then
    term.clear()
    term.setCursorPos(1,1)
    print("Welcome to Room Network!")
    write("Enter your User Name:\n> ")
    USER_ID = read()
    settings.set("room_username", USER_ID)
    settings.save()
end

local function getServer()
    local id = rednet.lookup(PROTOCOL, "server")
    return id
end

local function fetchList()
    local server = getServer()
    if not server then return {}, 0, 0 end
    rednet.send(server, { type = "request_list", user = USER_ID }, PROTOCOL)
    local id, msg = rednet.receive(PROTOCOL, 2)
    if msg and msg.type == "list_response" then
        return msg.data, msg.balance, msg.time
    end
    return {}, 0, 0
end

local function sendAction(action, roomId, extra)
    local payload = { type = action, id = roomId, user = USER_ID }
    if extra then
        for k,v in pairs(extra) do payload[k] = v end
    end
    rednet.send(getServer(), payload, PROTOCOL)
    local id, msg = rednet.receive(PROTOCOL, 5)
    if msg then
        term.clear()
        term.setCursorPos(1,1)
        print(msg.msg)
        sleep(2)
    end
end

local function formatTime(ms)
    if ms < 0 then return "OVERDUE!" end
    local s = math.floor(ms / 1000)
    return string.format("%02dh %02dm %02ds", math.floor(s/3600), math.floor((s%3600)/60), s%60)
end

local function viewOwnedRoom(id, room)
    local timerId = os.startTimer(1)
    while true do
        term.clear()
        term.setCursorPos(1,1)
        print("--- Room " .. id .. " ---")
        print("Status: " .. room.state)

        local now = os.epoch("utc")
        if room.state == "rented" then
            local left = room.due - now
            print("Rent Due: " .. formatTime(left))
            if left < 0 then
                local graceLeft = (room.due + room.info.grace_period) - now
                print("Eviction in: " .. formatTime(graceLeft))
            end
        end

        print("\n[T] Toggle Door")
        print("[K] Set Password")
        if room.state == "rented" then print("[C] Cancel Rent") end
        if room.state == "sold" then print("[S] Sell Back") end
        print("[BACKSPACE] Return")

        local e, p1 = os.pullEvent()
        if e == "timer" and p1 == timerId then
            timerId = os.startTimer(1)
        elseif e == "key" then
            if p1 == keys.backspace then break end
            if p1 == keys.t then sendAction("toggle_door", id); break end
            if p1 == keys.c and room.state == "rented" then sendAction("cancel", id); break end
            if p1 == keys.s and room.state == "sold" then sendAction("sell", id); break end
            if p1 == keys.k then
                term.clear()
                term.setCursorPos(1,1)
                write("Enter new numeric PIN:\n> ")
                local pw = read()
                sendAction("set_password", id, { password = pw })
                break
            end
        end
    end
end

local function drawMenu(title, options, selected, balance)
    term.clear()
    term.setCursorPos(1,1)
    print("--- " .. title .. " ---")
    print("Bank Balance: " .. balance)
    if #options == 0 then
        print("\nNo rooms found.")
        print("\n[BACKSPACE] Return")
        return
    end
    for i, opt in ipairs(options) do
        if i == selected then print("> " .. opt.label) else print("  " .. opt.label) end
    end
    print("\n[ENTER] Select  [BACK] Return")
end

local function browseList(isOwned)
    local db, bal, now = fetchList()
    if not db then return end

    local options = {}
    for id, room in pairs(db) do
        if isOwned and room.owner == USER_ID then
            table.insert(options, {label = id .. " [" .. room.state .. "]", id = id, room = room})
        elseif not isOwned and room.state == "available" then
            table.insert(options, {label = id .. " (" .. room.info.mode .. ")", id = id, room = room})
        end
    end

    local selected = 1
    while true do
        drawMenu(isOwned and "My Rooms" or "Available", options, selected, bal)
        local _, k = os.pullEvent("key")

        if #options == 0 and k == keys.backspace then return end
        if #options > 0 then
            if k == keys.up and selected > 1 then selected = selected - 1
            elseif k == keys.down and selected < #options then selected = selected + 1
            elseif k == keys.enter then
                if isOwned then viewOwnedRoom(options[selected].id, options[selected].room)
                else
                    term.clear()
                    term.setCursorPos(1,1)
                    local r = options[selected].room
                    print("Rent: " .. r.info.rent_price .. " | Buy: " .. r.info.sale_price)
                    print("\n[R] Rent  [B] Buy")
                    local _, ch = os.pullEvent("char")
                    if ch == "r" then sendAction("rent", options[selected].id) end
                    if ch == "b" then sendAction("buy", options[selected].id) end
                end
                return
            elseif k == keys.backspace then return end
        end
    end
end

local mainSelection = 1
local mainOptions = {"Available Rooms", "My Rooms", "Deposit to Bank", "Refresh/Exit"}
while true do
    local db, bal, now = fetchList()
    term.clear()
    term.setCursorPos(1,1)
    print("User: " .. USER_ID .. " | Bal: " .. (bal or 0))
    print("-------------------------")
    for i, opt in ipairs(mainOptions) do
        if i == mainSelection then print("> " .. opt) else print("  " .. opt) end
    end

    local _, k = os.pullEvent("key")
    if k == keys.up and mainSelection > 1 then mainSelection = mainSelection - 1
    elseif k == keys.down and mainSelection < #mainOptions then mainSelection = mainSelection + 1
    elseif k == keys.enter then
        if mainSelection == 1 then browseList(false)
        elseif mainSelection == 2 then browseList(true)
        elseif mainSelection == 3 then
            term.clear()
            term.setCursorPos(1,1)
            print("Place items in the Server")
            print("Drop Box chest.")
            print("\nPress ENTER to process...")
            local _, keyWait = os.pullEvent("key")
            if keyWait == keys.enter then sendAction("deposit") end
        elseif mainSelection == 4 then fetchList() end
    end
end