Doggy Netowork Email Service

-- Client-side program with black and white UI and email scrolling functionality
-- Doggy Mail Branding

-- 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()
    -- Try to find a modem connected to the system
    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 a modem is found, open it with rednet
    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 ask for the server ID and save it to a file
local function setupServerID()
    local serverIDFile = "/dogchat/services/email/server.ID"
    if not fs.exists(serverIDFile) then
        -- If it doesn't exist, prompt the user for the server ID
        displayHeader("Setup Doggy Mail Server ID")
        print("Server ID not found. Please enter the server ID:")
        local serverID = read()

        -- Save the server ID to the file
        local file = fs.open(serverIDFile, "w")
        file.write(serverID)
        file.close()

        print("\nServer ID saved.")
    else
        print("Server ID already exists.")
    end
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 send email to the server
local function sendEmailToServer()
    -- Check for server ID before sending email
    setupServerID()

    -- Read the server ID from the saved file
    local serverIDFile = "/dogchat/services/email/server.ID"
    local serverID = fs.open(serverIDFile, "r").readLine()

    -- 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 = getClientID(),
        recipientID = recipientID,
        emailContent = emailContent
    }

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

    -- Send the email to the server
    print("\nSending email to server (ID: " .. serverID .. ") via Doggy Mail...")
    rednet.send(tonumber(serverID), emailData)

    -- Debug message after sending
    print("\nEmail sent via Doggy Mail.")
end

-- Function to check and read emails from the server
local function checkAndReadEmails()
    -- Check for server ID before checking emails
    setupServerID()

    -- Read the server ID from the saved file
    local serverIDFile = "/dogchat/services/email/server.ID"
    local serverID = fs.open(serverIDFile, "r").readLine()

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

    displayHeader("Check for New Emails - Doggy Mail")
    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 .. " - Doggy Mail")

            -- 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.recipientID == clientID then
                    print("\nFrom: " .. email.senderID)
                    print("To: " .. email.recipientID)
                    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()
    displayHeader("Doggy Mail Client")
    print("Welcome to Doggy Mail!")
    print("1. Send Email")
    print("2. Read Emails")
    print("3. Exit")

    local choice = tonumber(read())

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

-- Start the main menu
mainMenu()