args = {...}

url = "http://lua.gaywine.org"

path = "bin/"
if not fs.exists(path) then
    fs.makeDir(path)
end
temp = "temp/"
if not fs.exists(temp) then
    fs.makeDir(temp)
end

if #args > 0 then
    programToInstall = args[1]
end
if #args > 1 then
    print("WARNING: custom paths are currently not supported.")
    customPath = shell.resolve(args[2])
end

local function downloadFile(filename)
    print("downloading " .. filename .. "...")
    local fileUrl = url .. "/files/" .. programToInstall .. "/" .. filename

    local result = http.get(fileUrl)
    local resultText = result.readAll()

    local file = fs.open(temp .. filename, "w")
    file.write(resultText)
    file.close()
end

local function split(pString, pPattern)
    local Table = {} -- NOTE: use {n = 0} in Lua-5.0
    local fpat = "(.-)" .. pPattern
    local last_end = 1
    local s, e, cap = pString:find(fpat, 1)
    while s do
        if s ~= 1 or cap ~= "" then
            table.insert(Table, cap)
        end
        last_end = e + 1
        s, e, cap = pString:find(fpat, last_end)
    end
    if last_end <= #pString then
        cap = pString:sub(last_end)
        table.insert(Table, cap)
    end
    return Table
end

local function getAllFiles()
    local indexesUrl = url .. "/indexes/" .. programToInstall
    local updateUrl = url .. "/updates/" .. programToInstall

    local currentFiles = ""
    if fs.exists(path .. "indexes.dat") then
        local indexesFile = fs.open(path .. "indexes.dat", "r")
        currentFiles = indexesFile.readAll()
        indexesFile.close()
    end

    local result = http.post(updateUrl, currentFiles)
    if result == nil then
      print("error! getting updates for " .. programToInstall)
      error()
    end
    local resultText = result.readAll()
    local resultTable = split(resultText, "\n")

    local result2 = http.get(indexesUrl)
    if result2 == nil then
      print("error! getting indexes for " .. programToInstall)
      error()
    end
    local resultText2 = result2.readAll()
    local resultTable2 = split(resultText2, "\n")

    local newIndexesFile = fs.open(path .. "indexes.dat", "w")
    newIndexesFile.write(resultText)
    newIndexesFile.close()

    local finalResult = {}
    for key, value in ipairs(resultTable2) do
        local filename = split(value, " ")[1]
        for key2, value2 in ipairs(resultTable) do
            local valueTable = split(value2, " ")
            local filePath = path .. programToInstall .. "/" .. valueTable[1]
            if valueTable[2] == "delete" and fs.exists(filePath) then
                fs.delete(filePath)
            elseif valueTable[2] == "download" then
                finalResult[#finalResult + 1] = valueTable[1]
            end
        end
    end

    return finalResult
end

local function finishInstall(files)
    for key, file in ipairs(files) do
        if customPath ~= nil then
            print("moving " .. file .. " to " .. customPath .. "...")
            if fs.exists(customPath .. "/" .. file) then
              fs.delete(customPath .. "/" .. file)
            end
            fs.move(temp .. file, customPath .. "/" .. file)
        else
            print("moving " .. file .. " to " .. path .. programToInstall .. "...")
            if fs.exists(path .. programToInstall .. "/" .. file) then
              fs.delete(path .. programToInstall .. "/" .. file)
            end
            fs.move(temp .. file, path .. programToInstall .. "/" .. file)
        end
    end

    if customPath ~= nil then
        local program = "shell.run(" .. customPath .. "/run.lua)"
        file = fs.open(path .. programToInstall .. "/run.lua")
        file.write(program)
        file.close()
    end

    fs.delete(temp)
end

if programToInstall == nil then
    print("no program specified, updating all...")
    local programsFile = fs.open(path .. "programs.dat", "r")
    local programsText = programsFile.readAll()
    local programsTable = split(programsText, "\n")
    for _, value in ipairs(programsTable) do
        programToInstall = value
        local files = getAllFiles()
        for _, value in ipairs(files) do
            downloadFile(value)
        end
        finishInstall(files)
    end
else
    print("getting updates...")
    local files = getAllFiles()

    if #files == 0 then
        print("no updates found.")
    else
        for _, value in ipairs(files) do
            downloadFile(value)
        end
        finishInstall(files)
    end
end