local component = require("component")
local modem = component.modem
local fs = require("filesystem")
local event = require("event")
local serial = require("serialization")
require("functions") --helper functions

--These need to be the same between the client and server
local portNum = 462
local msgDelim = "[:|:]"

--This one can be different from client / server
local programDir = "programs/"

if not fs.isDirectory("programs") then
    fs.makeDirectory("programs")
end

function getFileList()
    local files = fs.list("programs/")

    local out = {}
    for file in files do
        if not fs.isDirectory(file) then
            out[fs.name(file)] = fs.lastModified(file)
        end
    end
end

function getFile(file)
    local fl = io.open(file, "r")
    local out = ""

    local buffer = ""
    while true do
        buffer = fl:read(1024)
        if buffer == nil then break end
        out = out .. buffer
    end

    fl:close()
    return out
end

function putFile(file, data)
    local fl = io.open(file, "w")
    local out = fl:write(data) --get the output in case it fails
    fl:close()

    return out
end

function handleClient(localAddress, remoteAddress, port, distance, message)
    if(port ~= portNum) then return end

    local arg = explode(msgDelim, message)
    if arg[1] == "getFileList" then
        modem.send(remoteAddress, portNum, "fileList" .. msgDelim .. serial.serialize(getFileList()))
    elseif arg[1] == "getFile" then
        local file = programDir .. fs.name(arg[2]) --make sure they don't try and get files elsewhere
        if fs.exists(file) and not fs.isDirectory(file) then
            modem.send(remoteAddress, portNum, "putFile" .. msgDelim .. arg[2] .. msgDelim .. getFile(file))
        else
            modem.send(remoteAddress, portNum, "error" .. msgDelim .. "Invalid file.")
        end
    elseif arg[1] == "putFile" then
        local file = programDir .. fs.name(arg[2]) --make sure they don't try and put files elsewhere
        local marg = explode(msgDelim,message,2) --only split the first two(command, file, then code)
        local out = putFile(file, marg[3])
        local ret = "success"..msgDelim.."Successfully saved file"
        if not out then
            ret = "error"..msgDelim.."Failed to save file"
        end
        modem.send(remoteAddress, portNum, ret)
    end
end

local args = {...}
if(#args < 1) then
    print("Usage: fileserver [start/stop]")
else
    if args[1] == "start" then
        event.listen("modem_message", handleClient)
    elseif args[1] == "stop" then
        event.ignore("modem_message", handleClient)
    end
end