Backup Server

local args = {...}
-- backup packet structure:
-- {identifier, originator_id, files}

local function getDriveOne()
    for i,v in ipairs(rs.getSides()) do
        if peripheral.isPresent(v) and peripheral.getType(v) == "drive" and disk.getMountPath(v) == "disk" then
            return v
        end
    end
end

local restoreProgram = [[

local function getDriveOne()
    for i,v in ipairs(rs.getSides()) do
        if peripheral.isPresent(v) and peripheral.getType(v) == "drive" and disk.getMountPath(v) == "disk" then
            return v
        end
    end
end

local function restore()
    if fs.exists("disk/backup") then
        local backup = fs.open("disk/backup", "r")
        local fileTable = backup.readAll()
        backup.close()
        local fileTable = textutils.unserialize(fileTable)
        print("This disk contains a stored backup of computer "..tostring(fileTable[1])..".")
        if type(fileTable[4]) == "string" then
            print("Label: "..fileTable[4]..".")
            os.setComputerLabel(fileTable[4])
            hasLabel = true
        end
        print("Total files: "..tostring(fileTable[3]))
        print("Total file size: "..tostring(fileTable[2]))
        while true do
            print("Restore from backup? (Y/N) >")
            local yn = read()
            yn = string.upper(yn)
            if yn == "Y" then
                break
            elseif yn == "N" then
                return
            else
                print("Please provide a valid response.")
            end
        end
        os.sleep(1.5)
        for i,v in ipairs(fileTable) do
            if i ~= 1 and i~= 2 and i ~= 3 then
                term.clear()
                term.setCursorPos(1,1)
                print("Restoring file.")
                print("ID: "..v[1])
                print("Path: "..v[2])
                if v[3] then
                    print("Is a directory.")
                else
                    print("Is a file.")
                    print("Size: "..tostring(v[4]))
                end

                if v[3] then
                    fs.makeDir(v[2])
                else
                    local file = fs.open(v[2], "w")
                    file.write(v[5])
                    file.close()
                end
                os.sleep(0.5)
            end
        end
        print("Restore complete.")
        os.sleep(1)
        disk.eject(getDriveOne())
        os.reboot()
    end
end

restore()
]]

local function writeBackupToDisk(entries, id)
    local backup = fs.open("disk/backup", "w")
    backup.write(entries)
    backup.close()
    disk.setLabel(getDriveOne(), "Backup of computer "..id)
    local programHandle = fs.open("disk/startup", "w")
    programHandle.write(restoreProgram)
    programHandle.close()
    disk.eject(getDriveOne())
end

local function handleIncomingPackets()
    for i,v in ipairs(rs.getSides()) do
        rednet.open(v)
    end
    while true do
        id, message = rednet.receive()
        local packet = textutils.unserialize(message)
        if type(packet) == "table" then -- valid packet
            if packet[1] == "backup" then
                if not fs.exists("backups") then
                    fs.makeDir("backups")
                end
                print("Received backup from computer "..tostring(id)..".")
                local backupHandle = fs.open("backups/"..tostring(id), "w")
                backupHandle.write(packet[2])
                backupHandle.close()
            end
        end
    end
end

local function handleInput()
    while true do
        term.clear()
        term.setCursorPos(1,1)
        print("Please enter a backup ID:")
        local backup = read()
        if type(tonumber(backup)) == "number" then
            if fs.exists("backups/"..backup) then
                local handle = fs.open("backups/"..backup, "r")
                local files = handle.readAll()
                handle.close()
                writeBackupToDisk(files, backup)
            else
                print("That backup does not exist.")
                os.sleep(2)
            end
        else
            print("Please type in a valid ID.")
            os.sleep(2)
        end
    end
end

parallel.waitForAny(handleIncomingPackets, handleInput)