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-- sys - a package that provides simple system (unix) tools
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local os = require 'os'
local io = require 'io'
local paths = require 'paths'

sys = {}

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-- load all functions from lib
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local _lib = require 'libsys'
for k,v in pairs(_lib) do
   sys[k] = v
end

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-- tic/toc (matlab-like) timers
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local __t__
function sys.tic()
   __t__ = sys.clock()
end
function sys.toc(verbose)
   local __dt__ = sys.clock() - __t__
   if verbose then print(__dt__) end
   return __dt__
end

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-- execute an OS command, but retrieves the result in a string
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local function execute(cmd)
   local cmd = cmd .. ' 2>&1'
   local f = io.popen(cmd)
   local s = f:read('*all')
   f:close()
   s = s:gsub('^%s*',''):gsub('%s*$','')
   return s
end
sys.execute = execute

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-- execute an OS command, but retrieves the result in a string
-- side effect: file in /tmp
-- this call is typically more robust than the one above (on some systems)
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function sys.fexecute(cmd, readwhat)
   readwhat = readwhat or '*all'
   local tmpfile = os.tmpname()
   local cmd = cmd .. ' >'.. tmpfile..' 2>&1'
   os.execute(cmd)
   local file = _G.assert(io.open(tmpfile))
   local s= file:read(readwhat)
   file:close()
   s = s:gsub('^%s*',''):gsub('%s*$','')
   os.remove(tmpfile)
   return s
end

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-- returns the name of the OS in use
-- warning, this method is extremely dumb, and should be replaced by something
-- more reliable
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function sys.uname()
   if paths.dirp('C:\\') then
      return 'windows'
   else
      local ffi = require 'ffi'
      local os = ffi.os
      if os:find('Linux') then
         return 'linux'
      elseif os:find('OSX') then
         return 'macos'
      else
         return '?'
      end
   end
end
sys.OS = sys.uname()

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-- ls (list dir)
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sys.ls  = function(d) d = d or ' ' return execute('ls '    ..d) end
sys.ll  = function(d) d = d or ' ' return execute('ls -l ' ..d) end
sys.la  = function(d) d = d or ' ' return execute('ls -a ' ..d) end
sys.lla = function(d) d = d or ' ' return execute('ls -la '..d) end

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-- prefix
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local function find_prefix()
   if arg then
      for i, v in pairs(arg) do
	 if type(i) == "number" and type(v) == "string" and i <= 0 then
	    local lua_path = paths.basename(v)
	    if lua_path == "luajit" or lua_path == "lua" then
	       local bin_dir = paths.dirname(v)
	       if paths.basename(bin_dir) == "bin" then
		  return paths.dirname(bin_dir)
	       else
		  return bin_dir
	       end
	    end
	 end
      end
   end
   return ""
end
sys.prefix = find_prefix()

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-- always returns the path of the file running
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sys.fpath = require 'sys.fpath'

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-- split string based on pattern pat
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function sys.split(str, pat)
   local t = {}  -- NOTE: use {n = 0} in Lua-5.0
   local fpat = "(.-)" .. pat
   local last_end = 1
   local s, e, cap = str:find(fpat, last_end)
   while s do
      if s ~= 1 or cap ~= "" then
         _G.table.insert(t,cap)
      end
      last_end = e+1
      s, e, cap = str:find(fpat, last_end)
   end
   if last_end <= #str then
      cap = str:sub(last_end)
      _G.table.insert(t, cap)
   end
   return t
end

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-- check if a number is NaN
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function sys.isNaN(number)
   -- We rely on the property that NaN is the only value that doesn't equal itself.
   return (number ~= number)
end

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-- sleep
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function sys.sleep(seconds)
   sys.usleep(seconds*1000000)
end

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-- colors, can be used to print things in color
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sys.COLORS = require 'sys.colors'

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-- backward compat
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sys.dirname = paths.dirname
sys.concat = paths.concat

return sys