local lpeg = require('lpeg')
local re = require('re')
local Files = { }
local run_cmd
run_cmd = function(cmd)
  local f = io.popen(cmd .. ' 2>/dev/null')
  local lines
  do
    local _accum_0 = { }
    local _len_0 = 1
    for line in f:lines() do
      _accum_0[_len_0] = line
      _len_0 = _len_0 + 1
    end
    lines = _accum_0
  end
  if not (f:close()) then
    return nil
  end
  return lines
end
local _SPOOFED_FILES = { }
local _BROWSE_CACHE = { }
local _anon_number = 0
Files.spoof = function(filename, contents)
  if not contents then
    filename, contents = "<anonymous file #" .. tostring(_anon_number) .. ">", filename
    _anon_number = _anon_number + 1
  end
  _SPOOFED_FILES[filename] = contents
  return filename
end
Files.read = function(filename)
  do
    local contents = _SPOOFED_FILES[filename]
    if contents then
      return contents
    end
  end
  if filename == 'stdin' or filename == '-' then
    local contents = io.read('*a')
    Files.spoof('stdin', contents)
    Files.spoof('-', contents)
    return contents
  end
  local file = io.open(filename)
  if not (file) then
    return nil
  end
  local contents = file:read("*a")
  file:close()
  return contents or nil
end
local match, gsub
do
  local _obj_0 = string
  match, gsub = _obj_0.match, _obj_0.gsub
end
local sanitize
sanitize = function(path)
  path = gsub(path, "\\", "\\\\")
  path = gsub(path, "`", "")
  path = gsub(path, '"', '\\"')
  path = gsub(path, "$", "")
  return path
end
Files.exists = function(path)
  if _SPOOFED_FILES[path] then
    return true
  end
  if path == 'stdin' or path == '-' then
    return true
  end
  if run_cmd("ls " .. tostring(sanitize(path))) then
    return true
  end
  return false
end
Files.list = function(path)
  if not (_BROWSE_CACHE[path]) then
    local files
    if _SPOOFED_FILES[path] or path == 'stdin' or path == '-' then
      _BROWSE_CACHE[path] = {
        path
      }
    else
      _BROWSE_CACHE[path] = run_cmd('find -L "' .. path .. '" -not -path "*/\\.*" -type f') or false
    end
  end
  return _BROWSE_CACHE[path]
end
Files.make_directory = function(path)
  return run_cmd('mkdir ' .. path)
end
local ok, lfs = pcall(require, "lfs")
if ok then
  local raw_file_exists
  raw_file_exists = function(filename)
    local mode = lfs.attributes(filename, 'mode')
    if mode == 'file' or mode == 'directory' or mode == 'link' then
      return true
    else
      return false
    end
  end
  Files.exists = function(path)
    if _SPOOFED_FILES[path] then
      return true
    end
    if path == 'stdin' or path == '-' or raw_file_exists(path) then
      return true
    end
    return false
  end
  Files.list = function(path)
    if not (_BROWSE_CACHE[path]) then
      if _SPOOFED_FILES[path] or path == 'stdin' or path == '-' then
        _BROWSE_CACHE[path] = {
          path
        }
      else
        local file_type, err = lfs.attributes(path, 'mode')
        local _exp_0 = file_type
        if "file" == _exp_0 or "char device" == _exp_0 then
          _BROWSE_CACHE[path] = {
            path
          }
        elseif "directory" == _exp_0 or "link" == _exp_0 then
          local files = { }
          for subfile in lfs.dir(path) do
            local _continue_0 = false
            repeat
              if subfile == "." or subfile == ".." then
                _continue_0 = true
                break
              end
              local _list_0 = (Files.list(path .. "/" .. subfile) or { })
              for _index_0 = 1, #_list_0 do
                local f = _list_0[_index_0]
                files[#files + 1] = f
              end
              _continue_0 = true
            until true
            if not _continue_0 then
              break
            end
          end
          _BROWSE_CACHE[path] = files
        else
          _BROWSE_CACHE[path] = false
        end
      end
      if _BROWSE_CACHE[path] then
        for i, f in ipairs(_BROWSE_CACHE[path]) do
          if f:match("^%./") then
            _BROWSE_CACHE[path][i] = f:sub(3)
          end
        end
      end
    end
    return _BROWSE_CACHE[path]
  end
  Files.make_directory = lfs.mkdir
else
  if not (run_cmd('find . -maxdepth 0')) then
    local url
    if jit then
      url = 'https://github.com/spacewander/luafilesystem'
    else
      url = 'https://github.com/keplerproject/luafilesystem'
    end
    error("Could not find 'luafilesystem' module and couldn't run system command `find` (this might happen on Windows). Please install `luafilesystem` (which can be found at: " .. tostring(url) .. " or `luarocks install luafilesystem`)\n" .. tostring(lfs) .. "\npackage.cpath: " .. tostring(package.cpath), 0)
  end
end
local line_counter = re.compile([[    lines <- {| line (%nl line)* |}
    line <- {} (!%nl .)*
]], {
  nl = lpeg.P("\r") ^ -1 * lpeg.P("\n")
})
local _LINE_STARTS = { }
Files.get_line_starts = function(str)
  if type(str) ~= 'string' then
    str = tostring(str)
  end
  do
    local starts = _LINE_STARTS[str]
    if starts then
      return starts
    end
  end
  local line_starts = line_counter:match(str)
  _LINE_STARTS[str] = line_starts
  return line_starts
end
Files.get_line_number = function(str, pos)
  local line_starts = Files.get_line_starts(str)
  local lo, hi = 1, #line_starts
  while lo <= hi do
    local mid = math.floor((lo + hi) / 2)
    if line_starts[mid] > pos then
      hi = mid - 1
    else
      lo = mid + 1
    end
  end
  return hi
end
Files.get_line = function(str, line_no)
  local line_starts = Files.get_line_starts(str)
  local start = line_starts[line_no]
  if not (start) then
    return 
  end
  local stop = line_starts[line_no + 1]
  if not (stop) then
    return 
  end
  return (str:sub(start, stop - 2))
end
return Files