Email server

-- Server-Side Code for Doggy Mail Server
-- Manages user accounts, email storage, and handles login/registration.

local fs = require("fs")
local emails = {}  -- Stores emails indexed by email addresses

-- Function to 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 and rednet opened.")
    else
        print("No modem found.")
        return false
    end
    return true
end

-- Function to create a new account
local function createAccount(email, password)
    local accountDir = "/users/" .. email
    if not fs.exists(accountDir) then
        fs.makeDir(accountDir)  -- Create the user's directory
        -- Store the password in a file
        local passwordFile = accountDir .. "/password.txt"
        local emailFile = accountDir .. "/email.txt"
        fs.writeFile(passwordFile, password)
        fs.writeFile(emailFile, email)
        emails[email] = {}  -- Initialize empty inbox
        print("Account created successfully!")
    else
        print("Account already exists for " .. email)
    end
end

-- Function to login an account
local function loginAccount(email, password)
    local accountDir = "/users/" .. email
    if fs.exists(accountDir) then
        local storedPassword = fs.readFile(accountDir .. "/password.txt")
        if storedPassword == password then
            print("Login successful!")
            return true
        else
            print("Incorrect password.")
            return false
        end
    else
        print("Account does not exist.")
        return false
    end
end

-- Function to send an email
local function sendEmail(sender, recipient, content)
    -- If recipient doesn't exist, create an account for them
    if not emails[recipient] then
        createAccount(recipient, "")  -- Create an account with an empty password
    end

    -- Store the email in the recipient's inbox
    table.insert(emails[recipient], {sender = sender, content = content})
    print("Email sent from " .. sender .. " to " .. recipient)
end

-- Function to check for emails for a specific account
local function checkEmails(recipient)
    if emails[recipient] then
        print("\n--- New Emails for " .. recipient .. " ---")
        local page = 1
        local emailsPerPage = 3
        local totalEmails = #emails[recipient]
        local totalPages = math.ceil(totalEmails / emailsPerPage)

        while true do
            term.clear()
            print("Checking emails for " .. recipient .. " - 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 = emails[recipient][i]
                print("\nFrom: " .. email.sender)
                print("Content: \n" .. email.content)
                print("-------------------")
            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 emails found for " .. recipient)
    end
end

-- Main loop to handle requests from clients
while true do
    local senderID, message = rednet.receive()
    if message.request == "register" then
        -- Register a new account
        createAccount(message.email, message.password)
    elseif message.request == "login" then
        -- Login to an account
        if loginAccount(message.email, message.password) then
            rednet.send(senderID, {status = "success"})
        else
            rednet.send(senderID, {status = "failure"})
        end
    elseif message.request == "sendEmail" then
        -- Send an email
        sendEmail(message.sender, message.recipient, message.content)
    elseif message.request == "getEmails" then
        -- Send emails to client
        rednet.send(senderID, emails[message.recipient] or {})
    end
end