Email client

-- Function to display a header with a simple divider
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 and open the modem
local function setupModem()
    local modemSide = nil
    for _, side in pairs({"left", "right", "top", "bottom", "front", "back"}) do
        if peripheral.isPresent(side) and peripheral.getType(side) == "modem" then
            modemSide = side
            break
        end
    end

    if modemSide then
        rednet.open(modemSide)
        print("Modem found on " .. modemSide .. " and rednet opened.")
    else
        print("No modem found.")
        return false
    end
    return true
end

-- Function to load the server ID from the file
local function loadServerID()
    local filePath = "/dogchat/services/Dmail/ServerID.txt"
    local file = fs.open(filePath, "r")
    if file then
        local serverID = file.readLine()
        file.close()
        return serverID
    else
        return nil
    end
end

-- Function to ask the user for the server ID if not found
local function askForServerID()
    print("Server ID not found.")
    print("Please enter the server ID:")
    local serverID = read()

    -- Save the server ID for future use
    local filePath = "/dogchat/services/Dmail/ServerID.txt"
    local file = fs.open(filePath, "w")
    if file then
        file.writeLine(serverID)
        file.close()
    else
        print("Error saving the ServerID.")
    end

    return serverID
end

-- Function to get the server ID (load or ask for it)
local function getServerID()
    local serverID = loadServerID()
    if not serverID then
        serverID = askForServerID()
    end
    return serverID
end

-- Function to get the Client ID from the computer ID
local function getClientID()
    return tostring(os.getComputerID())  -- Use the computer's ID as the client ID
end

-- Function to load account credentials from file
local function loadCredentials()
    local credsFilePath = "/dogchat/accounts/credentials.txt"
    if fs.exists(credsFilePath) then
        local file = fs.open(credsFilePath, "r")
        local username = file.readLine()
        local password = file.readLine()
        file.close()
        return {username = username, password = password}
    else
        return nil
    end
end

-- Function to create a new account
local function createAccount()
    print("No account found. Please create a new account.")
    print("Enter your username:")
    local username = read()
    print("Enter your password:")
    local password = read("*")

    -- Save credentials to file
    local credsFilePath = "/dogchat/accounts/credentials.txt"
    local file = fs.open(credsFilePath, "w")
    if file then
        file.writeLine(username)
        file.writeLine(password)
        file.close()
    else
        print("Error saving credentials.")
    end

    return {username = username, password = password}
end

-- Function to login using credentials
local function login()
    local creds = loadCredentials()
    if not creds then
        return createAccount()  -- If no credentials exist, create a new account
    end

    print("Enter your username:")
    local inputUsername = read()
    print("Enter your password:")
    local inputPassword = read("*")

    if inputUsername == creds.username and inputPassword == creds.password then
        print("Login successful!")
        return creds
    else
        print("Incorrect credentials. Please try again.")
        return login()  -- Retry if credentials are incorrect
    end
end

-- Function to send an email to the server
local function sendEmailToServer(user)
    -- Get the server ID (or prompt if it's not available)
    local serverID = getServerID()

    -- Get recipient email and content
    displayHeader("Send Email")
    print("Enter recipient's email address:")
    local recipientEmail = read()
    print("Enter your email content:")
    local emailContent = read()

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

    -- Debugging message before sending
    print("\nPreparing to send email to server ID: " .. serverID)
    print("Sender: " .. emailData.senderID)
    print("Recipient: " .. emailData.recipientEmail)
    print("Content: \n" .. emailData.emailContent)

    -- Send the email to the server
    print("\nSending email to server (ID: " .. serverID .. ")...")
    rednet.send(tonumber(serverID), emailData)
    print("\nEmail sent to server.")
end

-- Function to check and read emails from the server
local function checkAndReadEmails(user)
    -- Get the server ID (or prompt if it's not available)
    local serverID = getServerID()

    -- Get the client ID automatically from the computer's ID
    local clientID = getClientID()

    displayHeader("Check for New Emails")
    print("Checking for new emails for client ID: " .. clientID)

    -- Request emails from the server for this client
    rednet.send(tonumber(serverID), {request = "getEmails", clientID = clientID})

    -- Wait for the server to send emails
    local senderID, emailData = rednet.receive()

    -- Check if the server sent any emails
    if emailData then
        print("\n--- New Emails ---")
        local page = 1
        local emailsPerPage = 3
        local totalEmails = #emailData
        local totalPages = math.ceil(totalEmails / emailsPerPage)

        while true do
            term.clear()
            displayHeader("Emails - Page " .. page .. "/" .. totalPages)

            -- Calculate the start and end indices for the emails to display
            local startIndex = (page - 1) * emailsPerPage + 1
            local endIndex = math.min(page * emailsPerPage, totalEmails)

            -- Display the emails for this page
            for i = startIndex, endIndex do
                local email = emailData[i]
                if email.recipientEmail == user.username then
                    print("\nFrom: " .. email.senderID)
                    print("To: " .. email.recipientEmail)
                    print("Content: \n" .. email.emailContent)
                    print("-------------------")
                end
            end

            -- Prompt user for navigation
            print("\nPage " .. page .. "/" .. totalPages)
            print("Press 'n' for next page, 'p' for previous page, or 'q' to exit.")
            local choice = read()

            if choice == "n" and page < totalPages then
                page = page + 1
            elseif choice == "p" and page > 1 then
                page = page - 1
            elseif choice == "q" then
                break
            end
        end
    else
        print("\nNo new emails.")
    end
end

-- Main logic
local function mainMenu(user)
    displayHeader("Doggy Mail Client")
    print("Welcome to Doggy Mail!")
    print("1. Send Email")
    print("2. Check Emails")
    print("3. Exit")

    local choice = tonumber(read())

    if choice == 1 then
        sendEmailToServer(user)
    elseif choice == 2 then
        checkAndReadEmails(user)
    elseif choice == 3 then
        print("\nExiting...")
        return
    else
        print("Invalid choice, please try again.")
        mainMenu(user)
    end
end

-- Ensure modem setup is correct before starting
if not setupModem() then
    print("Modem setup failed. Please connect a modem and try again.")
    return
end

-- Login or Create Account
local user = login()

-- Start the main menu
mainMenu(user)