-- Function to draw the title bar with the red "X"
local function drawTitleBar()
    local width, _ = term.getSize()
    term.setBackgroundColor(colors.blue)
    term.setTextColor(colors.white)
    term.setCursorPos(1, 1)
    term.write("Doggy OS Browser")
    term.setCursorPos(width, 1)
    term.write("X")
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
end

-- Function to check if a mouse click is on the red "X" in the title bar
local function isCloseButtonClicked(x, y)
    local width, _ = term.getSize()
    return x == width and y == 1
end

-- Function to wait for a mouse click event
local function waitForClick()
    while true do
        local event, button, x, y = os.pullEvent("mouse_click")
        if isCloseButtonClicked(x, y) then
            return true
        end
    end
end

-- Function to display an error message and wait
local function displayError(message)
    term.clear()
    drawTitleBar()
    print("Error: " .. message)
    print("Press any key to return to the main menu.")
    os.pullEvent("key")  -- Wait for any key press
end

-- Function to get URL from user
local function getURL()
    term.clear()
    drawTitleBar()
    print("Enter URL:")
    return read()
end

-- Automatically find and open the first available modem
local function openModem()
    local sides = {"top", "bottom", "left", "right", "front", "back"}
    for _, side in ipairs(sides) do
        if peripheral.isPresent(side) and peripheral.getType(side) == "modem" then
            rednet.open(side)
            return side
        end
    end
    displayError("No modem found.")
    return nil
end

-- Load DNS Provider ID from file
local function loadDNSProviderID()
    local filePath = "DNS-Provider.txt"
    if not fs.exists(filePath) then
        displayError("DNS-Provider.txt not found.")
        return nil
    end
    local file = fs.open(filePath, "r")
    local id = file.readAll()
    file.close()
    return tonumber(id)
end

-- Save DNS Provider ID to file
local function saveDNSProviderID(id)
    local filePath = "DNS-Provider.txt"
    local file = fs.open(filePath, "w")
    file.write(id)
    file.close()
    print("DNS Provider ID updated.")
end

-- Connect to DNS and get IP address
local function connectToDNS(url, dnsID)
    local modemSide = openModem()
    if not modemSide then return nil end

    term.clear()
    drawTitleBar()
    print("Connecting to DNS...")

    rednet.send(dnsID, url)
    local timer = os.startTimer(5)
    while true do
        local event, p1, p2 = os.pullEvent()
        if event == "rednet_message" and p1 == dnsID then
            rednet.close(modemSide)
            return p2
        elseif event == "timer" and p1 == timer then
            rednet.close(modemSide)
            displayError("DNS Timeout.")
            return nil
        elseif event == "mouse_click" and isCloseButtonClicked(p1, p2) then
            rednet.close(modemSide)
            return nil
        end
    end
end

-- Check for banned scripts in the code
local function checkForBannedScripts(code)
    local bannedPatterns = {
        {pattern = "fs%.", allowed = {"exists"}},
        {pattern = "shell%.run"},
        {pattern = "fs%.open"},
        {pattern = "fs%.delete"},
        {pattern = "fs%.write"},
        {pattern = "fs%.move"},
        {pattern = "fs%.copy"}
    }

    for _, entry in ipairs(bannedPatterns) do
        for line in code:gmatch("([^"]+)") do
            if line:match(entry.pattern) and not (entry.allowed and line:match(entry.allowed[1])) then
                return false, "Banned operation found: " .. line
            end
        end
    end
    return true
end

-- Connect to webserver and get website code
local function connectToWebserver(ip)
    local modemSide = openModem()
    if not modemSide then return nil end

    term.clear()
    drawTitleBar()
    print("Connecting to Webserver...")

    rednet.send(tonumber(ip), "GET")
    local timer = os.startTimer(5)
    while true do
        local event, p1, p2 = os.pullEvent()
        if event == "rednet_message" and p1 == tonumber(ip) then
            rednet.close(modemSide)
            return p2
        elseif event == "timer" and p1 == timer then
            rednet.close(modemSide)
            displayError("Connection timed out.")
            return nil
        elseif event == "mouse_click" and isCloseButtonClicked(p1, p2) then
            rednet.close(modemSide)
            return nil
        end
    end
end

-- Execute website code and render it
local function runWebsite(code)
    local isSafe, errorMessage = checkForBannedScripts(code)
    if not isSafe then
        displayError(errorMessage)
        return
    end

    local func, err = load(code, "website", "t", _ENV)
    if func then
        term.clear()
        drawTitleBar()
        func()  -- Run the website code
        -- Continuously check for user interaction (mouse clicks) to close the browser
        while not waitForClick() do
            -- Keep checking for click events to close the browser
        end
        term.clear()
    else
        displayError("Error loading website: " .. err)
    end
end

-- Main menu function
local function mainMenu()
    term.clear()
    drawTitleBar()
    print("Select an option:")
    print("1. Enter URL")
    print("2. Edit DNS Provider ID")
    print("3. Exit")
    local choice = tonumber(read())

    if choice == 1 then
        -- Enter URL
        while true do
            local url = getURL()
            if url == nil then
                break
            end

            local dnsID = loadDNSProviderID()
            if not dnsID then
                displayError("Failed to load DNS Provider ID.")
                return
            end

            local ip = connectToDNS(url, dnsID)
            if ip == "404_NOT_FOUND" then
                displayError("Error 404: Webpage cannot be found!")
                return
            elseif not ip then
                displayError("Failed to connect to DNS.")
                return
            end

            local code = connectToWebserver(ip)
            if not code then
                displayError("Failed to connect to Webserver.")
                return
            end

            -- Write code to file and then delete it
            local tempFile = "received_code.lua"
            local tempFileHandle = fs.open(tempFile, "w")
            tempFileHandle.write(code)
            tempFileHandle.close()

            -- Immediately delete the file after writing
            local success, err = pcall(function() fs.delete(tempFile) end)
            if success then
                print("Temporary file deleted successfully.")
            else
                displayError("Error deleting temporary file: " .. err)
            end

            runWebsite(code)
            -- After running the website, return to the main menu
            term.clear()
            drawTitleBar()
            print("Returning to main menu...")
            os.sleep(2)  -- Pause to allow the user to see the message
            break
        end
    elseif choice == 2 then
        -- Edit DNS Provider ID
        term.clear()
        drawTitleBar()
        print("Current DNS Provider ID: " .. (loadDNSProviderID() or "Not set"))
        print("Enter new DNS Provider ID:")
        local newID = tonumber(read())
        if newID then
            saveDNSProviderID(newID)
        else
            displayError("Invalid DNS Provider ID.")
        end
    elseif choice == 3 then
        print("Exiting...")
        shell.run("/disk/os/gui")
        return true  -- Indicate exit
    else
        displayError("Invalid option. Please select 1, 2, or 3.")
    end

    return false  -- Continue showing menu
end

-- Main execution loop
while true do
    local exit = mainMenu()
    if exit then
        break  -- Exit the loop if the user chose to exit
    end
end