gitget

--[[ gitget
  An updater for ComputerCraft scripts stored on a github.com
]]--
 
-- Configuration variables
local sConfigName = "gitget.cfg"
 
-- Returns full GitHub address
function createAddress(tConfig)
  local sUrl = "https://raw.github.com"
  tConfig["filename"] = string.gsub(tConfig["filename"], "%s", "%%20")
  return (sUrl .. "/" .. tConfig["user"] .. "/" .. tConfig["project"] .. "/" .. tConfig["branch"] .. "/" .. tConfig["filename"])
end
 
-- Loads a table from file
function loadTable(sPath)
  if not fs.exists(sPath) then
    error("loadTable() file not found: " .. sPath)
  end
 
  if fs.isDir(sPath) then
    error("loadTable() cannot open a directory")
  end
 
  local file = fs.open(sPath, "r")
  local sTable = file.readAll()
  file.close()
  return textutils.unserialize(sTable)
end
 
-- Saves a table to file
-- Uses saveString()
function saveTable(tData, sPath)
  local sSerializedData = textutils.serialize(tData)
  return saveString(sSerializedData, sPath)
end
 
-- Saves a string to file
function saveString(sData, sPath)
  if fs.isDir(sPath) then
    error("saveString() cannot save over a directory")
  end
 
  local file = fs.open(sPath, "w")
  file.write(sData)
  file.close()
  return true
end
 
-- Downloads a file from url provided
function download(sUrl, sPath)
  print("Downloading: " .. sUrl)
  if http then
    local sData = http.get(sUrl)
   
    if sData then
      print("Fetched file")
      return saveString(sData.readAll(), sPath)
    else
      print("Failed to fetch file: " .. sUrl)
      return false
    end
   
  else
    error("download() needs http api enabled to fetch files")
  end
end
 
-- Writes a prompt at pos
function promptPos(sPrompt, nX, nY)
  term.setCursorPos(nX, nY)
  term.clearLine()
  term.write(sPrompt)
  return true
end
 
function assemblePromptTable(tConfig)
  tPrompt = {
    "Gitget - a github file fetcher.",
    "Filename [" .. tConfig["filename"] .. "]: ",
    "Branch [" .. tConfig["branch"] .. "]: ",
    "Project [" .. tConfig["project"] .. "]: ",
    "User [" .. tConfig["user"] .. "]: ",
    "Press enter with no input to download.",
  }
  return tPrompt
end
 
-- Draws the config settings on the screen
-- returns prompt table
function drawPrompt(tPrompt)
  for nKey, sValue in ipairs(tPrompt) do
    promptPos(sValue, 1, nKey)
  end
  return true
end
 
-- Invokes read() after the line given
function userInput(nPos, tPrompt)
  term.setCursorPos((#tPrompt[nPos] + 1), nPos)
  return read()
end
 
-- Checks for first run and creates config file
function checkFirstInit()
  if not fs.exists(sConfigName) then
    tInit = {["filename"] = "", ["branch"] = "master", ["project"] = "swarm", ["user"] = githubUser or "keneo",}
    saveTable(tInit, sConfigName)
  end
end

function string.ends(String,End)
   return End=='' or string.sub(String,-string.len(End))==End
end

-- Set some global variables
local nInputPos = 2
local tConfig
local tPrompt
local sInput
local tInputRow = {"prompt", "filename", "branch", "project", "user"}
 
-- Runtime section
checkFirstInit()

local filename = ({...})[1]
if not filename then
  term.clear()
  while true do
    tConfig = loadTable(sConfigName)
    tPrompt = assemblePromptTable(tConfig)
    drawPrompt(tPrompt)
    sInput = userInput(nInputPos, tPrompt)
   
    if sInput == "" then
      sInput = tConfig[tInputRow[nInputPos]]
      break
    elseif sInput == " " then
        nInputPos = nInputPos + 1
        if nInputPos > #tInputRow then nInputPos = 2 end
    else
      tConfig[tInputRow[nInputPos]] = sInput
      saveTable(tConfig, sConfigName)
      nInputPos = nInputPos + 1
      if nInputPos > #tInputRow then nInputPos = 2 end
    end
  end
  filename = tConfig["filename"]
end

tConfig["filename"]=filename
 
term.setCursorPos(1, (#tPrompt + 1))
download(createAddress(tConfig), filename)

if (string.ends(filename,".lua")) then
  shell.run("rm " ..filename:gsub(".lua",""))
  shell.run("mv " ..filename.. " " .. filename:gsub(".lua",""))
end