appstore (localhost testing version)

--[[ TurtleAppstore.com client program by Al Sweigart
Used to download/upload files from Minecraft to TurtleAppstore.com

The appstore program uses a hidden file named .appstoreusername

Usage:
  > appstore <permalink>
  > appstore get <appname>              # uses set username
  > appstore get <username> <appname>   # also sets the username
  > appstore run <appname>
  > appstore run <username> <appname>
  > appstore put <username> <filename> <otp>       # uses set username
  > appstore put <filename> <otp>       # uses set username
  > appstore update <filename>          # doesn't cache the username
  > appstore updateAll                  # doesn't cache the username

]]

-- TODO: what happens if we can't write to the turtle's harddrive due to lack of disk space?
-- TODO: set up otp with a certain checksum so we can tell if the user might have typed their real turtleappstore.com password instead of an otp
-- TODO:
-- TODO: figure out where the error messages should go. in functions? after returning?

-- Note that TAS_HOST does *not* have the "https://" or "http://" prefix.
--local TAS_HOST = 'turtleappstore.com'
local TAS_HOST = 'localhost:8000'
local PERMALINK_LEN = 6
local cliArgs = {...}


-- START OF CLI COMPLETION FUNCTION
-- Copied from http://www.computercraft.info/wiki/Shell.setCompletionFunction
function tabCompletionFunction(shell, parNumber, curText, lastText)
  -- Check that the parameters entered so far are valid:
  local curParam = { ['get '] = {}, ['run '] = {}, ['put '] = {}, ['update '] = {}, ['updateall '] = {},  }
  for i = 2, #lastText do
    if curParam[lastText[i] .. " "] then
      curParam = curParam[lastText[i] .. " "]
    else
      return {}
    end
  end

  -- Check for suitable words for the current parameter:
  local results = {}
  for word, _ in pairs(curParam) do
    if word:sub(1, #curText) == curText then
      results[#results + 1] = word:sub(#curText + 1)
    end
  end
  return results
end

shell.setCompletionFunction("appstore", tabCompletionFunction)
-- END OF CLI COMPLETION FUNCTION


function main()
  local result, username, filename, otp, fo, sourceCode, appname
  -- handle command line arguments

  -- display usage
  if cliArgs[1] == nil then
    printUsage()
    return
  end

  if not canConnect() then
    print('Failed to connect to')
    print('turtleappstore.com.')
    error()
  end

  local cmd = cliArgs[1]

  if cmd == 'get' or cmd == 'run' then
    if cliArgs[3] ~= nil then
      -- Download an app via username & appname
      username = cliArgs[2]
      appname = cliArgs[3]
      username, appname = getAppByName(username, appname)
      if username == false then -- TODO: add failure
        print('Could not find an app with that name')
        print('from that user. Did you type the name')
        print('of the user and app correctly?')
        error()
      end
      cacheUsername(username)
      if cmd == 'run' then
        shell.run(appname) -- run the downloaded program
      end

    elseif cliArgs[2] ~= nil then
      -- Download an app via appname & cached username
      username = getCachedUsername()
      appname = cliArgs[2]
      if username == nil then
        print('Please specify a username & appname.')
        error()
      end
      print('Using username ' .. username) -- tell the user what cached user we're using

      username, appname = getAppByName(username, appname)
      if username == false then -- TODO add failure if not connected or site is down, etc.
        print('TODO failed msg2')
        error()
      end
      cacheUsername(username)
      if cmd == 'run' then
        shell.run(cliArgs[2]) -- run the downloaded program
      end
    end

  elseif cmd == 'put' then
    -- Upload an app via filename

    if cliArgs[2] == nil then
      -- user didn't supply anything after "put"
      print('Usage:')
      print('  appstore put <username> <filename> <otp>')
      error()

    elseif cliArgs[4] == nil then
      -- user supplied 3 things, we assume they are 'put', filename, and otp (and assume the username is cached)
      username = getCachedUsername()
      if username == nil then
        print('Usage:')
        print('  appstore put <username> <filename> <otp>')
        error()
      end
      print('Using username ' .. username) -- tell the user what cached user we're using

      filename = cliArgs[2]
      otp = cliArgs[3]
    else
      -- user supplied 'put', username, filename, and otp
      username = cliArgs[2]
      filename = cliArgs[3]
      otp = cliArgs[4]
    end

    print('Connecting to turtleappstore.com...')
    result = putAppByName(username, filename, otp)
    print(result)
    if result ~= 'Uploaded ' .. filename then
      error()
    end


  elseif cmd == 'update' then
    filename = cliArgs[2]
    local result, errMsg = updateApp(filename)
    if not result then
      print(errMsg)
      error()
    end


  elseif cmd == 'updateall' then
    updateAllApps('.')


  elseif string.len(cmd) == PERMALINK_LEN then
    -- Download an app via permalink
    local permalink = cliArgs[1]
    if getAppByPermalink(permalink) == false then
      error()
    end
    return true

  else
    print('Command not understood.')
    printUsage()
    error()
  end
end


function canConnect()
  return http.get('https://' .. TAS_HOST) ~= nil or http.get('http://' .. TAS_HOST) ~= nil
end


function getCachedUsername()
  if not fs.exists('.appstoreusername') then
    return nil
  end

  local fo = fs.open('.appstoreusername', 'r')
  local cachedUsername = fo.readLine()
  fo.close()

  if cachedUsername == '' then
    return nil
  end

  return cachedUsername
end


function cacheUsername(username)
  writeFile('.appstoreusername', username) -- TODO: make sure username is always in the proper case here
end


function printUsage()
  print('Usage:')
  -- TODO
  print('  appstore <permalink>')
  print('  appstore get <username> <appname>')
  print('  appstore run <username> <appname>')
  print('  appstore put <filename> <otp>')
  print('  appstore update <filename>')
  print('  appstore updateall')
end


function updateApp(filename)
  if not fs.exists(filename) then
    return false, 'File ' .. filename .. ' doesn\'t exist on this turtle.'
  end

  local username, appname, sourceCode = readApp(filename)
  if not username then
    return false, appstore .. ' couldn\'t be updated because it wasn\'t originally downloaded from turtleappstore.com.'
  end

  local username, appname = getAppByName(username, appname)
  if not username then
    return false, 'Couldn\'t download ' .. appname .. ' from user ' .. username .. '. Does this user and app still exist on turtleappstore.com?'
  end

  return username, appname
end


function updateAllApps(folder)
  -- autodetects appstore apps in the folder and updates them it there's a new version in the appstore
  -- TODO: I need an implementation of CRC32 or Adler32 that matches the output of Python's CRC32 and Adler32. For now, we update all apps regardless of changes or not.

  -- Note: CC uses only absolute paths, so `updateall` will only update apps in the root folder.
  local updatedAtLeastOneApp = false
  for i, v in pairs(fs.list(folder)) do
    if not fs.isDir(v) then
      local username, appname = updateApp(v)
      if username then
        updatedAtLeastOneApp = true
      end
    end
  end

  if not updatedAtLeastOneApp then
    print('No apps to update in this folder.')
    error()
  end

  return true
end


function downloadApp(username, appname)
  -- On success, returns the username, appname, source code of the app.
  -- On failure, returns false.
  -- `username` and `appname` will have the correct casing
  return _download(TAS_HOST .. '/u/' .. username .. '/a/' .. appname .. '/raw')
end


function downloadPermalink(permalink)
  -- On success, returns the username, appname, source code of the app.
  -- On failure, returns false.
  -- `username` and `appname` will have the correct casing
  return _download(TAS_HOST .. '/permalink/' .. permalink .. '/raw')
end


function _download(url)
  -- On success, returns the username, appname, source code of the app.
  -- On failure, returns false.
  -- `url` parameter will *not* have the "https://" or "http://" prefix, so
  -- that we can try both. (Dan suspects that some Java configs disallow SSL,
  -- so we try https first and fall back to http.)
  -- This is the helper function called by downloadApp() and downloadPermalink()
  local response = http.get('https://' .. url) -- attempt https
  if response == nil then
    response = http.get('http://' .. url) -- attempt http as fallback
    if response == nil then
      return false
    end
  end
  local sourceCode = response.readAll()
  response.close()

  local username, appname = readAppHeader(sourceCode)
  return username, appname, sourceCode
end


function getAppByPermalink(permalink)
  local username, appname, sourceCode = downloadPermalink(permalink)
  if username == false then
    print('Permalink "' .. permalink .. '" doesn\'t exist.')
    return false
  end

  writeFile(appname, sourceCode)
  print('Downloaded ' .. appname .. ' by ' .. username)
  cacheUsername(username)
  return true
end


function writeFile(filename, content)
  -- TODO: handle out of memory error
  -- TODO: what should the return value of this be?
  local fo = fs.open(filename, 'w')
  fo.write(content)
  fo.close()
end


function getAppByName(username, appname)
  local username, appname, sourceCode = downloadApp(username, appname)
  if username == false then
    return false
  end
  writeFile(appname, sourceCode)

  print('Downloaded ' .. appname .. ' by ' .. username)
  return username, appname -- returns correct case of username and appname
end


function putApp(filename, otp)

end


function readApp(filename)
  local fo = fs.open(filename, 'r')
  local sourceCode = fo.readAll()
  fo.close()
  local username, appname = readAppHeader(sourceCode)
  return username, appname, sourceCode
end


function readAppHeader(sourceCode)
  -- returns false, false if there is no header, otherwise returns the username, appname
  if string.sub(sourceCode, 1, 32) ~= '-- https://turtleappstore.com/u/' then
    return false
  end

  local usernameEnd = string.find(string.sub(sourceCode, 33), '/')
  local username = string.sub(sourceCode, 33, 33+usernameEnd-2)
  local appnameEnd = string.find(sourceCode, '\n')
  local appname = string.sub(sourceCode, 33+usernameEnd+2, appnameEnd - 1)

  return username, appname
end


function putAppByName(username, filename, otp)
  -- returns the result as a string
  if not fs.exists(filename) then
    return 'Cannot find file ' .. filename
  end

  local fo = fs.open(filename, 'r')
  local content = fo.readAll()
  fo.close()

  local response = http.post('https://' .. TAS_HOST .. '/put/', 'username=' .. textutils.urlEncode(username) ..
                                                                '&filename=' .. textutils.urlEncode(filename) ..
                                                                '&otp=' .. textutils.urlEncode(otp) ..
                                                                '&content=' .. textutils.urlEncode(content))

  if response == nil then
    -- Fallback to http if https failed.
    response = http.post('http://' .. TAS_HOST .. '/put/', 'username=' .. textutils.urlEncode(username) ..
                                                                  '&filename=' .. textutils.urlEncode(filename) ..
                                                                  '&otp=' .. textutils.urlEncode(otp) ..
                                                                  '&content=' .. textutils.urlEncode(content))
    if response == nil then
      return 'Failed to connect.'
    end
  end

  local result = response.readAll()
  response.close()
  cacheUsername(username)
  addAppHeader(filename, username)
  return result
end


function addAppHeader(filename, username)
  local fo = fs.open(filename, 'r')
  local content = fo.readAll()
  fo.close()

  if string.sub(content, 1, 32) ~= '-- https://turtleappstore.com/u/' then
    local appHeader = '-- https://turtleappstore.com/u/' .. username .. '/a/' .. filename .. '\n'
    writeFile(filename, appHeader .. content)
  end
end


main()