from __future__ import print_function

import __main__
import argparse
import multiprocessing
import os
import re
import signal
import stat
import sys

from pybin import settings
from subprocess import Popen, PIPE, STDOUT

################################################################################
#               shell helpers
################################################################################

# helper functions to run terminal commands
def sh(cmd, print2stdout = True, input = None):
	# add input redirection if needed
	if input and os.path.isfile(input):
		cmd += " < %s" % input

	# if this is a dry_run, only print the commands that would be ran
	if settings.dry_run :
		print("cmd: %s" % cmd)
		return 0, None

	# otherwise create a pipe and run the desired command
	else :
		proc = Popen(cmd, stdout=None if print2stdout else PIPE, stderr=STDOUT, shell=True)
		out, err = proc.communicate()
		return proc.returncode, out

# Remove 1 or more files silently
def rm( files ):
	try:
		for file in files:
			sh("rm -f %s > /dev/null 2>&1" % file )
	except TypeError:
		sh("rm -f %s > /dev/null 2>&1" % files )

def chdir( dest = __main__.__file__ ):
	abspath = os.path.abspath(dest)
	dname = os.path.dirname(abspath)
	os.chdir(dname)

# diff two files
def diff( lhs, rhs ):
	# diff the output of the files
	diff_cmd = ("diff --ignore-all-space "
				"--ignore-blank-lines "
				"--old-group-format='\t\tmissing lines :\n"
				"%%<' \\\n"
				"--new-group-format='\t\tnew lines :\n"
				"%%>' \\\n"
				"--unchanged-group-format='%%=' \\"
				"--changed-group-format='\t\texpected :\n"
				"%%<"
				"\t\tgot :\n"
				"%%>\n' \\\n"
				"--new-line-format='\t\t%%dn\t%%L' \\\n"
				"--old-line-format='\t\t%%dn\t%%L' \\\n"
				"--unchanged-line-format='' \\\n"
				"%s %s")

	# fetch return code and error from the diff command
	return sh(diff_cmd % (lhs, rhs), False)

# call make
def make(target, flags = '', redirects = '', error_file = None, silent = False):
	test_param = """test="%s" """ % (error_file) if error_file else ''
	cmd = ' '.join([
		settings.make,
		'-s' if silent else '',
		test_param,
		settings.debug.flags,
		flags,
		target,
		redirects
	])
	return sh(cmd)

################################################################################
#               file handling
################################################################################

# helper function to replace patterns in a file
def file_replace(fname, pat, s_after):
    # first, see if the pattern is even in the file.
    with open(fname) as f:
        if not any(re.search(pat, line) for line in f):
            return # pattern does not occur in file so we are done.

    # pattern is in the file, so perform replace operation.
    with open(fname) as f:
        out_fname = fname + ".tmp"
        out = open(out_fname, "w")
        for line in f:
            out.write(re.sub(pat, s_after, line))
        out.close()
        os.rename(out_fname, fname)

# helper function to check if a files contains only a specific string
def fileContainsOnly(file, text) :
	with open(file) as f:
		ff = f.read().strip()
		result = ff == text.strip()

		return result;

# check whether or not a file is executable
def fileIsExecutable(file) :
	try :
		fileinfo = os.stat(file)
		return bool(fileinfo.st_mode & stat.S_IXUSR)
	except Exception as inst:
		print(type(inst))    # the exception instance
		print(inst.args)     # arguments stored in .args
		print(inst)
		return False

# transform path to canonical form
def canonicalPath(path):
	return os.path.join('.', os.path.normpath(path) )

# compare path even if form is different
def pathCmp(lhs, rhs):
	return canonicalPath( lhs ) == canonicalPath( rhs )

# walk all files in a path
def pathWalk( op ):
	def step(_, dirname, names):
		for name in names:
			path = os.path.join(dirname, name)

			op( path )

	# Start the walk
	os.path.walk('.', step, '')

################################################################################
#               system
################################################################################

# parses the Makefile to find the machine type (32-bit / 64-bit)
def getMachineType():
	sh('echo "void ?{}(int&a,int b){}int main(){return 0;}" > .dummy.c')
	ret, out = make('.dummy', silent = True)

	if ret != 0:
		print("Failed to identify architecture:")
		print(out)
		print("Stopping")
		rm( (".dummy.c",".dummy") )
		sys.exit(1)

	_, out = sh("file .dummy", print2stdout=False)
	rm( (".dummy.c",".dummy") )

	if settings.dry_run :
		return 'x64'

	return re.search(r"[^,]+,([^,]+),", out).group(1).strip()

# count number of jobs to create
def jobCount( options, tests ):
	# check if the user already passed in a number of jobs for multi-threading
	make_flags = os.environ.get('MAKEFLAGS')
	make_jobs_fds = re.search("--jobserver-(auth|fds)=\s*([0-9]+),([0-9]+)", make_flags) if make_flags else None
	if make_jobs_fds :
		tokens = os.read(int(make_jobs_fds.group(2)), 1024)
		options.jobs = len(tokens)
		os.write(int(make_jobs_fds.group(3)), tokens)
	else :
		options.jobs = multiprocessing.cpu_count()

	# make sure we have a valid number of jobs that corresponds to user input
	if options.jobs <= 0 :
		print('ERROR: Invalid number of jobs', file=sys.stderr)
		sys.exit(1)

	return min( options.jobs, len(tests) ), True if make_flags else False

# setup a proper processor pool with correct signal handling
def setupPool(jobs):
	original_sigint_handler = signal.signal(signal.SIGINT, signal.SIG_IGN)
	pool = multiprocessing.Pool(jobs)
	signal.signal(signal.SIGINT, original_sigint_handler)

	return pool

# handle signals in scope
class SignalHandling():
	def __enter__(self):
		# enable signal handling
	    	signal.signal(signal.SIGINT, signal.SIG_DFL)

	def __exit__(self, type, value, traceback):
		# disable signal handling
		signal.signal(signal.SIGINT, signal.SIG_IGN)

################################################################################
#               misc
################################################################################

# check if arguments is yes or no
def yes_no(string):
	if string == "yes" :
		return True
	if string == "no" :
		return False
	raise argparse.ArgumentTypeError(msg)
	return False


settings.set_machine_default( getMachineType )