--------------------------------------------------------------------------------
--  Copyright (c) 2012-2014 Sierra Wireless.
--  All rights reserved. This program and the accompanying materials
--  are made available under the terms of the Eclipse Public License v1.0
--  which accompanies this distribution, and is available at
--  http://www.eclipse.org/legal/epl-v10.html
--
--  Contributors:
--       Kevin KIN-FOO <kkinfoo@sierrawireless.com>
--           - initial API and implementation and initial documentation
--------------------------------------------------------------------------------
local lfs = require 'lfs'
local M = {}
local function iswindows()
  local p = io.popen("echo %os%")
  if not p then
    return false
  end
  local result =p:read("*l")
  p:close()
  return result == "Windows_NT"
end
M.separator = iswindows() and [[\]] or [[/]]
---
-- Will recursively browse given directories and list files encountered
-- @param tab Table, list where files will be added
-- @param dirorfiles list of path to browse in order to build list.
--	Files from this list will be added to <code>tab</code> list.
-- @return <code>tab</code> list, table containing all files from directories
--	and files contained in <code>dirorfile</code>
local function appendfiles(tab, dirorfile)

  -- Nothing to process
  if #dirorfile < 1 then return tab end

  -- Append all files to list
  local dirs = {}
  for _, path in ipairs( dirorfile ) do
    -- Determine element nature
    local elementnature = lfs.attributes (path, "mode")

    -- Handle files
    if elementnature == 'file' then
      table.insert(tab, path)
    else if elementnature == 'directory' then

        -- Check if folder is accessible
        local status, error = pcall(lfs.dir, path)
        if not status then return nil, error end

        --
        -- Handle folders
        --
        for diskelement in lfs.dir(path) do

          -- Format current file name
          local currentfilename
          if path:sub(#path) == M.separator then
            currentfilename = path  .. diskelement
          else
            currentfilename = path  .. M.separator .. diskelement
          end

          -- Handle folder elements
          local nature, err = lfs.attributes (currentfilename, "mode")
          -- Append file to current list
          if nature == 'file' then
            table.insert(tab, currentfilename)
          elseif nature == 'directory' then
            -- Avoid current and parent directory in order to avoid
            -- endless recursion
            if diskelement ~= '.' and diskelement ~= '..' then
              -- Handle subfolders
              table.insert(dirs, currentfilename)
            end
          end
        end
    end
    end
  end
  -- If we only encountered files, going deeper is useless
  if #dirs == 0 then return tab end
  -- Append files from encountered directories
  return appendfiles(tab, dirs)
end
---
-- Provide a list of files from a directory
-- @param list Table of directories to browse
-- @return table of string, path to files contained in given directories
function M.filelist(list)
  if not list	then return nil, 'No directory list provided' end
  return appendfiles({}, list)
end
function M.checkdirectory( dirlist )
  if not dirlist then return false end
  local missingdirs = {}
  for _, filename in ipairs( dirlist ) do
    if not lfs.attributes(filename, 'mode') then
      table.insert(missingdirs, filename)
    end
  end
  if #missingdirs > 0 then
    return false, missingdirs
  end
  return true
end
function M.fill(filename, content)
  --
  -- Ensure parent directory exists
  --
  local parent = filename:gmatch([[(.*)]] .. M.separator ..[[(.+)]])()
  local parentnature = lfs.attributes(parent, 'mode')
  -- Create parent directory while absent
  if not parentnature then
    lfs.mkdir( parent )
  elseif parentnature ~= 'directory' then
    -- Notify that disk element already exists
    return nil, parent..' is a '..parentnature..'.'
  end

  -- Create actual file
  local file, error = io.open(filename, 'w')
  if not file then
    return nil, error
  end
  file:write( content )
  file:close()
  return true
end
return M