#!/usr/bin/env python3
##
## This file is part of the sigrok-util project.
##
## Copyright (C) 2015 Daniel Elstner <daniel.kitta@gmail.com>
##
## This program is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program.  If not, see <http://www.gnu.org/licenses/>.
##

import os
import sys
import subprocess
import tempfile
import re

"""
Make sure that every source file has <config.h> as first include, and that
no header file includes <config.h>. Pass the source directories to process
as command-line arguments.
"""

file_patterns = ["*.[ch]", "*.cc", "*.hh", "*.[ch]pp", "*.[ch]xx", "*.h.in"]
source_regex  = re.compile(r'\.c[^.]*$')

config_include = "#include <config.h>\n"
config_h_regex = re.compile(r'\s*#\s*include\s+[<"]config\.h[>"]')

def create_tmpfile(tmpdir):
    return tempfile.NamedTemporaryFile('w', dir=tmpdir, delete=False)

def process_file(filename, tmpdir, is_source):
    changed = False
    with open(filename, 'r') as srcfile, create_tmpfile(tmpdir) as tmpfile:
        tmpfilename = tmpfile.name
        for line in srcfile:
            if is_source and not changed and line.startswith("#"):
                if line == config_include:
                    break
                tmpfile.write(config_include)
                changed = True
            if config_h_regex.match(line) is None:
                tmpfile.write(line)
            else:
                changed = True
    if changed:
        os.replace(tmpfilename, filename)
    else:
        os.remove(tmpfilename)
    return changed

def process_directory(srcdir):
    filelist = subprocess.check_output(["git",
            "-C", srcdir, "ls-files"] + file_patterns).decode()
    with tempfile.TemporaryDirectory(dir=srcdir) as tmpdir:
        for filename in filelist.splitlines():
            if process_file(os.path.join(srcdir, filename), tmpdir,
                            source_regex.search(filename) is not None):
                print("Rewrote file", filename)

if len(sys.argv) < 2:
    sys.exit("Usage: include-config-header DIRECTORY...")

for arg in sys.argv[1:]:
    process_directory(arg)