sethmc server.lua

-- Server startup.lua

local modem = peripheral.find("modem")
if not modem then error("No modem found. Please attach a wireless modem.") end

local disk = peripheral.find("drive")
if not disk then error("No disk drive found. Please attach a disk drive.") end

modem.open(1) -- Use channel 1 for all communications

local diskMount = disk.getMountPath()
if not diskMount then error("No disk inserted. Please insert a disk.") end

local function setup()
    if not fs.exists(diskMount .. "/students") then fs.makeDir(diskMount .. "/students") end
    if not fs.exists(diskMount .. "/news.txt") then
        local file = fs.open(diskMount .. "/news.txt", "w")
        file.write("Welcome to the college!")
        file.close()
    end
    if not fs.exists(diskMount .. "/student.lua") then
        error("student.lua not found on the disk. Please create this file.")
    end

    -- Launch Dashboard in new tab if multishell is available
    if multishell then
        -- Check if already running? uniqueID?
        -- Simply launching it is fine, user can close duplicate tabs.
        -- We'll just assume server runs once.
        local dashboardPath = diskMount .. "/tracking_dashboard.lua"
        if fs.exists(dashboardPath) then
            multishell.launch({}, dashboardPath)
            print("Launched Tracking Dashboard in background tab.")
        else
            print("Dashboard not found at: " .. dashboardPath)
        end
    else
        print("Multishell not available.")
    end
    print("Server setup complete. Files stored on disk.")
end

local function createAccount(studentId, password)
    local studentDir = diskMount .. "/students/" .. studentId
    if fs.exists(studentDir) then
        return false, "Account already exists"
    end
    fs.makeDir(studentDir)
    local passFile = fs.open(studentDir .. "/password.txt", "w")
    passFile.write(password)
    passFile.close()
    local balanceFile = fs.open(studentDir .. "/balance.txt", "w")
    balanceFile.write("0") -- Initial balance of 0
    balanceFile.close()
    return true, "Account created successfully"
end

local function verifyLogin(studentId, password)
    local studentDir = diskMount .. "/students/" .. studentId
    if not fs.exists(studentDir) then return false, "Account not found" end
    local passFile = fs.open(studentDir .. "/password.txt", "r")
    local storedPass = passFile.readAll():gsub("%s+$", "") -- Trim trailing whitespace
    passFile.close()
    return storedPass == password, storedPass == password and "Login successful" or "Incorrect password"
end



local function handleBalance(studentId, action, amount)
    local balanceFile = fs.open(diskMount .. "/students/" .. studentId .. "/balance.txt", "r")
    local balance = tonumber(balanceFile.readAll()) or 0
    balanceFile.close()
    print("Processing balance update for " .. studentId)
    print("Current balance: " .. balance)
    print("Action: " .. action .. ", Amount: " .. amount)
    if action == "deposit" then
        balance = balance + amount
    elseif action == "withdraw" then
        if balance >= amount then
            balance = balance - amount
        else
            print("Insufficient funds. Transaction failed.")
            return false, "Insufficient funds"
        end
    end
    balanceFile = fs.open(diskMount .. "/students/" .. studentId .. "/balance.txt", "w")
    balanceFile.write(tostring(balance))
    balanceFile.close()
    print("New balance: " .. balance)
    print("Transaction successful")
    return true, balance
end

local function getEmails(studentId)
    local emailPath = diskMount .. "/students/" .. studentId .. "/emails.txt"
    if not fs.exists(emailPath) then return {} end
    local file = fs.open(emailPath, "r")
    local data = file.readAll()
    file.close()
    return textutils.unserialize(data) or {}
end

local function saveEmails(studentId, emails)
    local emailPath = diskMount .. "/students/" .. studentId .. "/emails.txt"
    local file = fs.open(emailPath, "w")
    file.write(textutils.serialize(emails))
    file.close()
end

local function sendEmail(senderId, recipientId, subject, body)
    local recipientDir = diskMount .. "/students/" .. recipientId
    if not fs.exists(recipientDir) then
        return false, "Recipient not found"
    end

    local emails = getEmails(recipientId)
    table.insert(emails, 1, { -- Insert at beginning (newest first)
        id = os.epoch("utc"), -- Simple unique ID logic
        sender = senderId,
        subject = subject,
        body = body,
        timestamp = os.epoch("local"), -- Use local time for display
        read = false
    })
    saveEmails(recipientId, emails)
    return true, "Email sent successfully"
end

local function deleteEmail(studentId, emailIndex)
    local emails = getEmails(studentId)
    if emails[emailIndex] then
        table.remove(emails, emailIndex)
        saveEmails(studentId, emails)
        return true, "Email deleted"
    else
        return false, "Email not found"
    end
end

local function handleRequests()
    print("Server is running. Waiting for requests...")
    while true do
        local event, side, channel, replyChannel, message, distance = os.pullEvent("modem_message")
        if type(message) == "table" then
            if message.type == "request_update" then
                local file = fs.open(diskMount .. "/student.lua", "r")
                local content = file.readAll()
                file.close()
                modem.transmit(replyChannel, 1, {type = "update", content = content})
                print("Sent student.lua update to a device")
            elseif message.type == "create_account" then
                if message.studentId and message.password then
                    local success, msg = createAccount(message.studentId, message.password)
                    modem.transmit(replyChannel, 1, {type = "account_response", success = success, message = msg})
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid account creation request"})
                end
            elseif message.type == "login" then
                if message.studentId and message.password then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    modem.transmit(replyChannel, 1, {type = "login_response", success = success, message = msg})
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid login request"})
                end
            elseif message.type == "get_news" then
                local newsFile = fs.open(diskMount .. "/news.txt", "r")
                local news = newsFile.readAll()
                newsFile.close()
                modem.transmit(replyChannel, 1, {type = "news", content = news})

            elseif message.type == "get_balance" then
                if message.studentId and message.password then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local balanceFile = fs.open(diskMount .. "/students/" .. message.studentId .. "/balance.txt", "r")
                        local balance = balanceFile.readAll()
                        balanceFile.close()
                        modem.transmit(replyChannel, 1, {type = "balance_response", balance = balance})
                    else
                        modem.transmit(replyChannel, 1, {type = "error", message = msg})
                    end
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid balance request"})
                end
            elseif message.type == "update_balance" then
                if message.studentId and message.password and message.action and message.amount then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local success, result = handleBalance(message.studentId, message.action, message.amount)
                        modem.transmit(replyChannel, 1, {type = "balance_update_response", success = success, result = result})
                    else
                        modem.transmit(replyChannel, 1, {type = "error", message = msg})
                    end
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid balance update request"})
                end
            elseif message.type == "verify_student" then
                if message.recipientId then
                    local recipientDir = diskMount .. "/students/" .. message.recipientId
                    local exists = fs.exists(recipientDir)
                    modem.transmit(replyChannel, 1, {exists = exists})
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid student verification request"})
                end
            elseif message.type == "transfer_money" then
                if message.studentId and message.password and message.recipientId and message.amount then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local senderBalanceFile = fs.open(diskMount .. "/students/" .. message.studentId .. "/balance.txt", "r")
                        local senderBalance = tonumber(senderBalanceFile.readAll()) or 0
                        senderBalanceFile.close()

                        local recipientBalanceFile = fs.open(diskMount .. "/students/" .. message.recipientId .. "/balance.txt", "r")
                        local recipientBalance = tonumber(recipientBalanceFile.readAll()) or 0
                        recipientBalanceFile.close()

                        local expectedSenderBalance = senderBalance - message.amount
                        local expectedRecipientBalance = recipientBalance + message.amount

                        if expectedSenderBalance >= 0 then
                            local withdrawSuccess, _ = handleBalance(message.studentId, "withdraw", message.amount)
                            if withdrawSuccess then
                                local depositSuccess, _ = handleBalance(message.recipientId, "deposit", message.amount)
                                if depositSuccess then
                                    -- Verify balances
                                    senderBalanceFile = fs.open(diskMount .. "/students/" .. message.studentId .. "/balance.txt", "r")
                                    local newSenderBalance = tonumber(senderBalanceFile.readAll()) or 0
                                    senderBalanceFile.close()

                                    recipientBalanceFile = fs.open(diskMount .. "/students/" .. message.recipientId .. "/balance.txt", "r")
                                    local newRecipientBalance = tonumber(recipientBalanceFile.readAll()) or 0
                                    recipientBalanceFile.close()

                                    if newSenderBalance == expectedSenderBalance and newRecipientBalance == expectedRecipientBalance then
                                        modem.transmit(replyChannel, 1, {success = true, newBalance = newSenderBalance})
                                    else
                                        -- Revert transaction
                                        handleBalance(message.studentId, "deposit", message.amount)
                                        handleBalance(message.recipientId, "withdraw", message.amount)
                                        modem.transmit(replyChannel, 1, {success = false, message = "Transaction verification failed"})
                                    end
                                else
                                    handleBalance(message.studentId, "deposit", message.amount)
                                    modem.transmit(replyChannel, 1, {success = false, message = "Failed to deposit to recipient"})
                                end
                            else
                                modem.transmit(replyChannel, 1, {success = false, message = "Failed to withdraw from sender"})
                            end
                        else
                            modem.transmit(replyChannel, 1, {success = false, message = "Insufficient funds"})
                        end
                    else
                        modem.transmit(replyChannel, 1, {success = false, message = msg})
                    end
                else
                    modem.transmit(replyChannel, 1, {success = false, message = "Invalid transfer request"})
                end
            elseif message.type == "send_email" then
                if message.studentId and message.password and message.recipientId and message.subject and message.body then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local sent, result = sendEmail(message.studentId, message.recipientId, message.subject, message.body)
                        modem.transmit(replyChannel, 1, {type = "email_response", success = sent, message = result})
                    else
                        modem.transmit(replyChannel, 1, {type = "error", message = msg})
                    end
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid send email request"})
                end
            elseif message.type == "get_inbox" then
                if message.studentId and message.password then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local emails = getEmails(message.studentId)
                        modem.transmit(replyChannel, 1, {type = "inbox_response", emails = emails})
                    else
                        modem.transmit(replyChannel, 1, {type = "error", message = msg})
                    end
                else
                    modem.transmit(replyChannel, 1, {type = "error", message = "Invalid inbox request"})
                end
            elseif message.type == "delete_email" then
                if message.studentId and message.password and message.emailIndex then
                    local success, msg = verifyLogin(message.studentId, message.password)
                    if success then
                        local deleted, result = deleteEmail(message.studentId, message.emailIndex)
                        modem.transmit(replyChannel, 1, {type = "email_response", success = deleted, message = result})
                    else
                        modem.transmit(replyChannel, 1, {type = "error", message = msg})
                    end
                else
                     modem.transmit(replyChannel, 1, {type = "error", message = "Invalid delete email request"})
                end
            elseif message.type == "track_location" then
                if message.studentId and message.x and message.y and message.z then
                     -- No login required for tracking? Or should we verify password?
                     -- Ideally verify, but passive tracking might lack access to password constant?
                     -- Let's Require studentId. We'll verify existence of folder.
                     local studentDir = diskMount .. "/students/" .. message.studentId
                     if fs.exists(studentDir) then
                         local historyPath = studentDir .. "/location_history.txt"
                         local file = fs.open(historyPath, "a")
                         -- Format: Timestamp | x,y,z
                         file.writeLine(os.epoch("local") .. "|" .. message.x .. "," .. message.y .. "," .. message.z)
                         file.close()
                         -- Also update 'current' for fast lookup? Dashboard can just read last line.
                     end
                end
            end
        end
    end
end

setup()
handleRequests()