format(Util)

---------------------
--Created by Savior67
--Version: 0.4
---------------------
local indent = 2 --number of spaces to indent by


local tArgs = { ... }
if #tArgs ~= 1 then
  print("Usage: "..shell.getRunningProgram().." <file>")
  return
end
local file = tArgs[1]

function main()
  local formatted = {}
  local currentIndent = 0 --how many indents are active
  local exception = false --true if else or elseif after if
  if not fs.exists(file) then
    print("File not found.")
    return
  else
    local h = fs.open(file,"r")
    local line = h.readLine()
    while line~=nil do
      formatted,currentIndent = keyFinder(line,currentIndent,formatted)
      line = h.readLine()
    end
    h.close()
    overwrite(formatted,file)
  end
  print(file.." was successfully formatted.")
end

function overwrite(lines,file)
  local h = fs.open(file,"w")
  for i,line in ipairs(lines) do
    h.writeLine(line)
  end
  h.close()
end

function formatLine(s,currIn)
  local whitespace = ""
  for i=1,currIn do
    whitespace = whitespace.." "
  end
  return(whitespace..trim(s))
end

function keyFinder(s,currentIndent,f)
  local inWrds = {"if","do","repeat","function"}
  local deWrds = {"end","until"}
  local specialCase = {"elseif","else"}

  local ded = findCases(s,deWrds)
  local ind = findCases(s,inWrds)
  local spe = findCases(s,specialCase)

  if ind and ded then
    table.insert(f,formatLine(s,currentIndent))
  elseif spe then
    table.insert(f,formatLine(s,currentIndent-indent))
  elseif ded then
    currentIndent = currentIndent-indent
    table.insert(f,formatLine(s,currentIndent))
  elseif ind then
    table.insert(f,formatLine(s,currentIndent))
    currentIndent = currentIndent+indent
  else
    table.insert(f,formatLine(s,currentIndent))
  end
  return f,currentIndent
end

function findCases(s,t)
  for k,v in ipairs(t) do
    if string.find(s,v) then
      if not inQuotes(s,v) and not isComment(s,v) then
         return true
      end
    end
  end
  return false
end

function inQuotes(s,word)
  local p1 = string.find(s,"\"")
  if p1 ~= nil then
    local p2 = string.find(s,"\"",p1+1)
    if not p2 then return false end
    local start,finish = string.find(s,word)
    if p1<start and p2>finish then return true end
  end
  return false
end

function isComment(s,word)
  local p1=0
  while true do
    p1 = string.find(s,"-",p1+1)
    if p1~= nil then
      local p2 = string.sub(s,p1+1,p1+1)
      if p2=="-" then
        local start,finish = string.find(s,word)
        if p1<start then return true end
      end
    else
      break
    end
  end
  return false
end

--removes leading and trailing whitespace
function trim(s)
  -- from PiL2 20.4
  return (s:gsub("^%s*(.-)%s*$", "%1"))
end

main()