-- Doggy Mail Account System

-- File paths for storing user data
local accountsFile = "/dogchat/accounts.txt"  -- Stores account information (username and password)

-- Function to display a header with the program name
local function displayHeader(title)
    term.clear()
    term.setCursorPos(1, 1)
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.write(string.rep("=", 50))  -- Top divider line
    term.setCursorPos(2, 2)
    term.write(" " .. title)
    term.setCursorPos(50, 2)
    term.write("v1.0")
    term.setCursorPos(1, 3)
    term.write(string.rep("=", 50))  -- Bottom divider line
    term.setCursorPos(1, 5)
end

-- Function to setup the account system
local function setupAccountSystem()
    -- Check if the accounts file exists
    if not fs.exists(accountsFile) then
        -- If it doesn't exist, create the file
        local file = fs.open(accountsFile, "w")
        file.close()
        print("Accounts file created.")
    end
end

-- Function to register a new account
local function registerAccount()
    displayHeader("Doggy Mail - Register Account")
    print("Please enter a username (alphanumeric only):")
    local username = read()

    -- Check if the username already exists
    local file = fs.open(accountsFile, "r")
    local accountExists = false
    while true do
        local line = file.readLine()
        if not line then break end
        if string.match(line, "^" .. username .. ":") then
            accountExists = true
            break
        end
    end
    file.close()

    if accountExists then
        print("\nUsername already exists. Please try again.")
        return
    end

    -- Request password
    print("Enter a password:")
    local password = read("*")

    -- Save the username and password
    file = fs.open(accountsFile, "a")
    file.writeLine(username .. ":" .. password)
    file.close()

    print("\nAccount successfully created!")
end

-- Function to log in with an existing account
local function loginAccount()
    displayHeader("Doggy Mail - Log In")
    print("Please enter your username:")
    local username = read()

    -- Check if the username exists and validate password
    local file = fs.open(accountsFile, "r")
    local accountValid = false
    while true do
        local line = file.readLine()
        if not line then break end
        local storedUsername, storedPassword = string.match(line, "(.*):(.*)")
        if storedUsername == username then
            print("Enter your password:")
            local password = read("*")
            if password == storedPassword then
                accountValid = true
            end
            break
        end
    end
    file.close()

    if accountValid then
        print("\nLogin successful! Welcome, " .. username .. "!")
        return username  -- Return the logged-in username
    else
        print("\nInvalid username or password.")
        return nil
    end
end

-- Main program to handle login or registration
local function accountMenu()
    displayHeader("Doggy Mail - Account Menu")
    print("1. Register a new account")
    print("2. Log in")
    print("3. Exit")

    local choice = tonumber(read())

    if choice == 1 then
        registerAccount()
    elseif choice == 2 then
        local loggedInUsername = loginAccount()
        if loggedInUsername then
            return loggedInUsername
        end
    elseif choice == 3 then
        print("Exiting Doggy Mail...")
        return nil
    else
        print("Invalid choice. Please try again.")
        return accountMenu()
    end
end

-- Function to send email
local function sendEmailToServer(user)
    -- Setup for the email client (similar to previous)
    setupServerID()

    -- Get recipient ID and sender ID
    displayHeader("Send Email via Doggy Mail")
    print("Enter recipient's ID:")
    local recipientID = read()
    print("Enter your email content:")
    local emailContent = read()

    -- Prepare the email data to send to the server
    local emailData = {
        senderID = user,
        recipientID = recipientID,
        emailContent = emailContent
    }

    -- Send the email to the server
    local serverIDFile = "/dogchat/services/email/server.ID"
    local serverID = fs.open(serverIDFile, "r").readLine()

    print("\nSending email...")
    rednet.send(tonumber(serverID), emailData)
    print("\nEmail sent.")
end

-- Function to check and read emails
local function checkAndReadEmails(user)
    -- Request emails from the server for the logged-in user
    displayHeader("Check Emails - Doggy Mail")
    print("Checking for new emails for " .. user .. "...")

    -- Setup server and check emails (similar to previous)
    setupServerID()
    local serverIDFile = "/dogchat/services/email/server.ID"
    local serverID = fs.open(serverIDFile, "r").readLine()

    -- Request and display emails
    rednet.send(tonumber(serverID), {request = "getEmails", clientID = user})
    local senderID, emailData = rednet.receive()

    if emailData then
        print("\n--- New Emails ---")
        for _, email in ipairs(emailData) do
            if email.recipientID == user then
                print("\nFrom: " .. email.senderID)
                print("Content: \n" .. email.emailContent)
                print("-------------------")
            end
        end
    else
        print("\nNo new emails.")
    end
end

-- Main menu
local function mainMenu(user)
    displayHeader("Doggy Mail Client - Welcome " .. user)
    print("1. Send Email")
    print("2. Read Emails")
    print("3. Logout")

    local choice = tonumber(read())

    if choice == 1 then
        sendEmailToServer(user)
    elseif choice == 2 then
        checkAndReadEmails(user)
    elseif choice == 3 then
        print("\nLogging out...")
        return nil
    else
        print("Invalid choice. Please try again.")
        return mainMenu(user)
    end
end

-- Ensure account system is ready
setupAccountSystem()

-- Main program logic
local loggedInUser = nil

while not loggedInUser do
    loggedInUser = accountMenu()
end

-- After login or registration, enter the main menu
while loggedInUser do
    loggedInUser = mainMenu(loggedInUser)
end