#! /usr/bin/python -B

# Copyright (C) 2016 and later: Unicode, Inc. and others.
# License & terms of use: http://www.unicode.org/copyright.html

# Copyright (C) 2009-2011, International Business Machines Corporation, Google and Others.
# All rights reserved.

#
#  Script to check that ICU source files contain only valid UTF-8 encoded text,
#  and that all files except '.txt' files do not contain a Byte Order Mark (BOM).
#
#  THIS SCRIPT DOES NOT WORK ON WINDOWS
#     It only works correctly on platforms where the native line ending is a plain \n
#
#  usage:
#     icu-file-utf8-check.py  [options]
#
#  options:
#     -h | --help    Print a usage line and exit.
#
#  The tool operates recursively on the directory from which it is run.
#  Only files from the ICU github repository are checked.
#  No changes are made to the repository; only the working copy will be altered.
#  The script checks all source files and returns a non-zero exit code if any of
#  the checked files contain a non-UTF-8 character.

from __future__ import print_function

import sys
import os
import os.path
import re
import getopt


# List of directories to check for UTF-8 and BOM. Currently covers
# all of icu/. Modify as needed.
icu_directories_to_be_scanned = ["."]

# Files that are allowed to contain \r line endings. If this list
# grows too long consider a file instead.
ignore_cr_in_files = [
    "vendor/double-conversion/upstream/msvc/testrunner.cmd"
    ]

def runCommand(cmd):
    output_file = os.popen(cmd);
    output_text = output_file.read();
    exit_status = output_file.close();

    return output_text, exit_status


def usage():
    print("usage: " + sys.argv[0] + " [-h | --help]")


#
#  File check.         Check source code files for UTF-8 and all except text files for not containing a BOM
#    file_name:        name of a text file.
#    is_source:        Flag, set to True if file is a source code file (.c, .cpp, .h, .java).
#
def check_file(file_name, is_source):
    rc = 0
    f = open(file_name, 'rb')
    bytes = f.read()
    f.close()

    if is_source:
        try:
            bytes.decode("UTF-8")
        except UnicodeDecodeError:
            print("Error: %s is a source code file but contains non-utf-8 bytes." % file_name)
            rc = 1

    if bytes[0] == 0xef:
        if not (file_name.endswith(".txt") or file_name.endswith(".sln")
                    or file_name.endswith(".targets") or ".vcxproj" in file_name):
            print("Warning: file %s contains a UTF-8 BOM: " % file_name)
            rc = 1

    return rc

def main(argv):
    exit_status = 0
    rc = 0

    try:
        opts, args = getopt.getopt(argv, "h", ("help"))
    except getopt.GetoptError:
        print("unrecognized option: " + argv[0])
        usage()
        sys.exit(2)
    for opt, arg in opts:
        if opt in ("-h", "--help"):
            usage()
            sys.exit()
    if args:
        print("unexpected command line argument")
        usage()
        sys.exit(2)

    source_file_re = re.compile(".*((?:\\.c$)|(?:\\.cpp$)|(?:\\.h$)|(?:\\.java$))")
    git_cmd = "git ls-files DIR"

    for dir in icu_directories_to_be_scanned:
        print('Scanning ' + dir)
        cmd = git_cmd.replace("DIR", dir)
        output, rc = runCommand(cmd)
        if rc:
            print('"', cmd, '" failed. Exiting.', file=sys.stderr)
        file_list = output.splitlines()

        for f in file_list:
            if os.path.isdir(f):
                print("Skipping dir " + f)
                continue
            if not os.path.isfile(f):
                print("Repository file not in working copy: " + f)
                continue;

            source_file = source_file_re.match(f)
            if check_file(f, source_file) != 0:
                exit_status = 1

            # Lastly, check the line endings of the file.
            # Note that 'grep' returns null if it reports a file,
            # a non-null value otherwise.
            output, rc = runCommand("grep -rPIl \"\\r\" " + f)
            if (rc is None):
                if f not in ignore_cr_in_files:
                    print("File ", f, " has \\r line ending")
                    exit_status = 1

    print(exit_status)
    sys.exit(exit_status)

if __name__ == "__main__":
    main(sys.argv[1:])