-- LemonOS 3.0 -- Integrated client & UI with built-in DM system
-- by ChatGPT (GPT-5)
-- Features: integrated DMs (phone numbers s-xxxx-xxxx), registration, always-listening chat listener,
-- beep on incoming messages, unread indicator, signal bars (async), persistent config.

-- ===== CONFIG PATHS & PROTOCOL =====
local CONFIG_PATH = "/lemonos.cfg"
local MESSAGES_PATH = "/lemonos_messages.db"
local CHAT_PROTOCOL = "lemonos-net"

-- ===== FIRMWARE INFO =====
local firmware = {
    device = "Lemonphone",
    version = "LemonOS 3.0"
}

-- ===== DEFAULT SETTINGS =====
local config = {
    username = "User",
    accentColor = colors.yellow,
    bgColor = colors.black,
    rednetSide = "back",
    serverNode = nil,       -- preferred server node ID (can be nil; will auto-discover on register)
    phoneNumber = nil       -- assigned phone number (persisted after register)
}

-- ===== LOAD / SAVE CONFIG & MESSAGES =====
local function saveConfig()
    local f = fs.open(CONFIG_PATH, "w")
    if not f then return false end
    f.write(textutils.serialize(config))
    f.close()
    return true
end

local function loadConfig()
    if fs.exists(CONFIG_PATH) then
        local f = fs.open(CONFIG_PATH, "r")
        if f then
            local ok, t = pcall(textutils.unserialize, f.readAll())
            f.close()
            if ok and type(t) == "table" then
                for k,v in pairs(t) do config[k] = v end
            end
        end
    end
end
loadConfig()

-- optional persistent message store (very small)
local function saveMessages(tbl)
    local f = fs.open(MESSAGES_PATH, "w")
    if not f then return false end
    f.write(textutils.serialize(tbl))
    f.close()
    return true
end

local function loadMessages()
    if fs.exists(MESSAGES_PATH) then
        local f = fs.open(MESSAGES_PATH, "r")
        if f then
            local ok, t = pcall(textutils.unserialize, f.readAll())
            f.close()
            if ok and type(t) == "table" then return t end
        end
    end
    return {}
end

-- ===== GLOBAL STATE =====
local messages = loadMessages() -- { {from=phone, to=phone, text=..., ts=...}, ... }
local unreadCount = 0
local unreadIndicator = nil -- {from, text, expires}
local signalStrength = 0     -- 0..3
local myPhoneNumber = config.phoneNumber -- convenience local
local clientMsgCounter = 0

-- ===== UTILITIES =====
local function mkClientID()
    clientMsgCounter = clientMsgCounter + 1
    return tostring(os.getComputerID()) .. "-" .. tostring(os.time()) .. "-" .. tostring(clientMsgCounter)
end

local function centerText(y, txt, clr)
    local w = term.getSize()
    local x = math.floor((w - #txt) / 2) + 1
    term.setCursorPos(x, y)
    if clr then term.setTextColor(clr) end
    term.write(txt)
    term.setTextColor(colors.white)
end

local function beep()
    -- try speaker peripheral
    local ok, s = pcall(function() return peripheral.find("speaker") end)
    if ok and s and type(s.playSound) == "function" then
        pcall(function() s.playSound("note.harp", 1, 1) end)
        return
    end
    -- fallback: BEL character (may beep in some terminals)
    pcall(function() io.write("\7") end)
end

-- ===== SIGNAL (ASYNC) =====
local function distanceToBars(distance)
    if distance <= 5 then return 3
    elseif distance <= 20 then return 2
    else return 1 end
end

local function updateSignal()
    while true do
        local strength = 0
        if rednet.isOpen(config.rednetSide) then
            local ids = rednet.lookup("lemonphone_ping") or {}
            local peers = {}
            for _, id in ipairs(ids) do
                -- try a non-fatal send to see if reachable quickly
                local ok = pcall(rednet.send, id, textutils.serialize({ ping=true }), CHAT_PROTOCOL)
                if ok then
                    table.insert(peers, math.abs(os.getComputerID() - id))
                end
            end
            if #peers > 0 then
                table.sort(peers)
                strength = distanceToBars(peers[1])
            end
        end
        signalStrength = strength
        sleep(5)
    end
end

local function drawSignalBarsInline()
    local barChar = "|"
    for i = 1, 3 do
        if i <= signalStrength then term.setTextColor(colors.lime) else term.setTextColor(colors.gray) end
        term.write(barChar)
    end
    term.setTextColor(colors.white)
end

-- ===== TOP BAR DRAW =====
local function drawTopBar()
    local w = term.getSize()
    -- draw full background of top line with accent color
    term.setCursorPos(1,1)
    term.setBackgroundColor(config.accentColor)
    term.setTextColor(colors.white)
    local blank = string.rep(" ", w)
    term.write(blank)
    -- left: signal + label
    term.setCursorPos(2,1)
    if rednet.isOpen(config.rednetSide) then
        drawSignalBarsInline()
        term.write(" Net")
    else
        term.setTextColor(colors.red)
        term.write("X NoNet")
        term.setTextColor(colors.white)
    end
    -- right: time/date
    local timeStr = textutils.formatTime(os.time(), true)
    local dateStr = os.date("%b %d")
    local clock = timeStr .. " | " .. dateStr
    term.setCursorPos(w - #clock - 1, 1)
    term.setTextColor(colors.white)
    term.write(clock)
    -- unread badge (top-right, just left of clock if any)
    if unreadCount > 0 then
        local badge = "[" .. tostring(unreadCount) .. "]"
        term.setCursorPos(w - #clock - #badge - 3, 1)
        term.setTextColor(colors.red)
        term.write(badge)
        term.setTextColor(colors.white)
    end
    term.setBackgroundColor(config.bgColor)
    term.setTextColor(colors.white)
end

-- ===== CHAT: register, send, process incoming =====
local function sendToNode(node, tbl)
    local ok, ser = pcall(textutils.serialize, tbl)
    if not ok then return false end
    rednet.send(node, ser, CHAT_PROTOCOL)
    return true
end

-- Broadcast registration request and wait a short time for a server to respond
local function registerWithAnyServer(serviceType)
    serviceType = tostring(serviceType or "2")
    local req = {
        msgType = "register_req",
        id = mkClientID(),
        serviceType = serviceType,
        clientInfo = { nodeID = os.getComputerID(), username = config.username },
        timestamp = os.time()
    }
    -- broadcast and wait
    local ok = pcall(rednet.broadcast, textutils.serialize(req), CHAT_PROTOCOL)
    if not ok then return false, "broadcast-failed" end
    local sender, raw = rednet.receive(CHAT_PROTOCOL, 5)
    if not sender or not raw then return false, "no-response" end
    local ok2, tbl = pcall(textutils.unserialize, raw)
    if not ok2 or type(tbl) ~= "table" then return false, "bad-response" end
    if tbl.msgType == "register_res" and tbl.inReplyTo == req.id and tbl.assigned then
        myPhoneNumber = tbl.assigned
        config.phoneNumber = tbl.assigned
        config.serverNode = sender
        saveConfig()
        return true
    end
    return false, "unexpected-response"
end

-- direct register to configured server (if server node set)
local function registerWithServerNode(node, serviceType)
    serviceType = tostring(serviceType or "2")
    local req = {
        msgType = "register_req",
        id = mkClientID(),
        serviceType = serviceType,
        clientInfo = { nodeID = os.getComputerID(), username = config.username },
        timestamp = os.time()
    }
    if not node then return false, "no-node" end
    local ok = sendToNode(tonumber(node), req)
    if not ok then return false, "send-failed" end
    local sender, raw = rednet.receive(CHAT_PROTOCOL, 5)
    if not sender or not raw then return false, "no-response" end
    local ok2, tbl = pcall(textutils.unserialize, raw)
    if ok2 and type(tbl) == "table" and tbl.msgType == "register_res" and tbl.inReplyTo == req.id then
        myPhoneNumber = tbl.assigned
        config.phoneNumber = tbl.assigned
        config.serverNode = node
        saveConfig()
        return true
    end
    return false, "bad-response"
end

local function sendDM(toPhone, text)
    if not myPhoneNumber then return false, "not-registered" end
    local node = config.serverNode
    if not node then return false, "no-server" end
    local msg = {
        msgType = "dm",
        id = mkClientID(),
        fromPhone = myPhoneNumber,
        toPhone = toPhone,
        body = { text = tostring(text) },
        ttl = 8,
        path = {},
        timestamp = os.time()
    }
    -- send to server node
    return sendToNode(tonumber(node), msg)
end

-- handle incoming chat messages (called from chatListener)
local function handleIncomingChat(tbl, sender)
    if type(tbl) ~= "table" then return end
    if tbl.msgType == "dm" then
        if tbl.toPhone == myPhoneNumber then
            table.insert(messages, { from = tbl.fromPhone, to = tbl.toPhone, text = tbl.body and tbl.body.text or "", ts = tbl.timestamp or os.time() })
            saveMessages(messages)
            -- queue event for UI/main loop
            os.queueEvent("lemonos_new_message", tbl.fromPhone, tbl.body and tbl.body.text or "")
        end
    elseif tbl.msgType == "register_res" then
        -- could also be handled by register functions which wait for receive
    end
end

-- chat listener (background)
local function chatListener()
    while true do
        local sender, raw = rednet.receive(CHAT_PROTOCOL)
        if sender and raw then
            local ok, tbl = pcall(textutils.unserialize, raw)
            if ok and type(tbl) == "table" then
                handleIncomingChat(tbl, sender)
            end
        end
    end
end

-- ===== UI: Menu, Settings, About & Chat UI =====
local function drawMenu(selected)
    local apps = {
        {name="Messages", cmd="messages"},
        {name="Worm", cmd="worm"},
        {name="Falling Blocks", cmd="falling"},
        {name="Redirection", cmd="redirection"},
        {name="Settings", cmd="settings"},
        {name="About Lemonphone", cmd="about"},
        {name="Shutdown", cmd="shutdown"}
    }
    local startY = 4
    for i, app in ipairs(apps) do
        term.setCursorPos(4, startY + i - 1)
        if i == selected then
            term.setBackgroundColor(colors.gray)
            term.setTextColor(colors.black)
        else
            term.setBackgroundColor(config.bgColor)
            term.setTextColor(colors.white)
        end
        term.clearLine()
        term.setCursorPos(4, startY + i - 1)
        term.write(app.name)
    end
    term.setBackgroundColor(config.bgColor)
    term.setTextColor(colors.white)
    return apps
end

local function openSettings()
    while true do
        term.setBackgroundColor(config.bgColor)
        term.clear()
        centerText(3, "Settings", config.accentColor)
        term.setCursorPos(2,5)
        term.write("1. Change Username")
        term.setCursorPos(2,6)
        term.write("2. Change Accent Color")
        term.setCursorPos(2,7)
        term.write("3. Set Server Node")
        term.setCursorPos(2,8)
        term.write("4. Register (auto-discover)")
        term.setCursorPos(2,9)
        term.write("5. Back")

        local _, key = os.pullEvent("key")
        if key == keys.one then
            term.setCursorPos(2,11) term.clearLine() term.write("Enter new username: ")
            config.username = read()
            saveConfig()
        elseif key == keys.two then
            term.setCursorPos(2,11) term.clearLine() term.write("Color name: ")
            local c = read()
            if colors[c] then config.accentColor = colors[c] saveConfig() else term.setCursorPos(2,12) term.write("Invalid color") sleep(1) end
        elseif key == keys.three then
            term.setCursorPos(2,11) term.clearLine() term.write("Enter server node ID (or blank to clear): ")
            local v = read()
            if v == "" then config.serverNode = nil else config.serverNode = tonumber(v) end
            saveConfig()
        elseif key == keys.four then
            term.setCursorPos(2,11) term.clearLine() term.write("Registering (broadcast)...")
            local ok, err = registerWithAnyServer("2")
            term.setCursorPos(2,12)
            if ok then term.write("Registered as " .. tostring(myPhoneNumber)) else term.write("Failed: " .. tostring(err)) end
            sleep(1.5)
        elseif key == keys.five then
            return
        end
    end
end

local function aboutPage()
    term.setBackgroundColor(config.bgColor)
    term.clear()
    centerText(3, "About Lemonphone", config.accentColor)
    term.setCursorPos(2,5) term.write("Device: " .. firmware.device)
    term.setCursorPos(2,6) term.write("Firmware: " .. firmware.version)
    term.setCursorPos(2,7) term.write("Phone: " .. tostring(myPhoneNumber or "<unregistered>"))
    term.setCursorPos(2,9) term.write("Press any key to return...")
    os.pullEvent("key")
end

local function messagesUI()
    -- simple chat UI: list last 12 messages and an input to send DM
    while true do
        term.setBackgroundColor(config.bgColor)
        term.clear()
        centerText(2, "Messages", config.accentColor)
        local start = math.max(1, #messages - 11)
        local y = 4
        for i = start, #messages do
            local m = messages[i]
            term.setCursorPos(2, y)
            term.clearLine()
            term.setTextColor(colors.white)
            term.write(("[%s] %s: %s"):format(os.date("%H:%M", m.ts or os.time()), m.from, m.text))
            y = y + 1
        end
        term.setCursorPos(2, y+1)
        term.setTextColor(colors.gray)
        term.write("Send DM (phone s-xxxx-xxxx) or type 'back':")
        term.setTextColor(colors.white)
        term.setCursorPos(2, y+2)
        term.write("To: ")
        local to = read()
        if to == "back" then return end
        term.setCursorPos(2, y+3) term.clearLine() term.write("Message: ")
        local txt = read()
        if txt and #txt > 0 then
            local ok, err = sendDM(to, txt)
            term.setCursorPos(2, y+4)
            if ok then term.write("Sent!") else term.write("Failed: " .. tostring(err)) end
            sleep(1)
        end
    end
end

-- ===== MAIN LOOP (handles UI and queued message events) =====
local function mainLoop()
    local selected = 1
    local refreshRate = 1.0
    local timer = os.startTimer(refreshRate)

    while true do
        -- draw screen
        term.setBackgroundColor(config.bgColor)
        term.clear()
        drawTopBar()
        centerText(3, (config.username or "User") .. "'s Lemonphone", config.accentColor)
        local apps = drawMenu(selected)

        local event, a, b = os.pullEvent()
        if event == "timer" then
            if a == timer then
                timer = os.startTimer(refreshRate)
                -- refresh just top bar to update clock/unread
                drawTopBar()
                -- expire banner if needed
                if unreadIndicator and os.time() >= unreadIndicator.expires then unreadIndicator = nil unreadCount = math.max(0, unreadCount - 1) end
            end
        elseif event == "key" then
            local key = a
            if key == keys.up then selected = math.max(1, selected - 1)
            elseif key == keys.down then selected = math.min(7, selected + 1)
            elseif key == keys.enter then
                local appsList = apps
                local chosen = appsList[selected]
                if chosen.name == "Settings" then openSettings()
                elseif chosen.name == "About Lemonphone" then aboutPage()
                elseif chosen.name == "Messages" then
                    -- if not registered, prompt to register
                    if not myPhoneNumber then
                        term.setCursorPos(2, 12) term.clearLine() term.write("You are not registered. Register now? (y/n): ")
                        local c = read()
                        if c == "y" then registerWithAnyServer("2") end
                    end
                    messagesUI()
                else
                    -- run external apps by name (if present) else ignore
                    term.setBackgroundColor(config.bgColor) term.clear()
                    term.setCursorPos(1,1)
                    -- we run shell.run on a filename: attempt to shell.run(chosen.cmd)
                    pcall(shell.run, chosen.cmd)
                end
            end
        elseif event == "lemonos_new_message" then
            local fromPhone, text = a, b
            -- bump unread & banner, beep
            unreadCount = unreadCount + 1
            unreadIndicator = { from = fromPhone, text = text, expires = os.time() + 3 }
            beep()
            -- redraw top bar to show badge immediately
            drawTopBar()
        end
    end
end

-- ===== START BACKGROUND TASKS AND UI =====
-- ensure rednet open
if peripheral.find("modem") then rednet.open(config.rednetSide) end

-- try to set myPhoneNumber from config
myPhoneNumber = config.phoneNumber

-- run everything in parallel: updateSignal, chatListener, mainLoop
parallel.waitForAny(updateSignal, chatListener, mainLoop)