#!/usr/bin/env python3
#
#===- google-java-format-diff.py - google-java-format Diff Reformatter -----===#
#
#                     The LLVM Compiler Infrastructure
#
# This file is distributed under the University of Illinois Open Source
# License. See LICENSE.TXT for details.
#
#===------------------------------------------------------------------------===#
"""
google-java-format Diff Reformatter
============================

This script reads input from a unified diff and reformats all the changed
lines. This is useful to reformat all the lines touched by a specific patch.
Example usage for git/svn users:

  git diff -U0 HEAD^ | google-java-format-diff.py -p1 -i
  svn diff --diff-cmd=diff -x-U0 | google-java-format-diff.py -i

For perforce users:

  P4DIFF="git --no-pager diff --no-index" p4 diff | ./google-java-format-diff.py -i -p7

"""

import argparse
import difflib
import re
import subprocess
import io
import os
import sys
from shutil import which


def main():
    parser = argparse.ArgumentParser(
        description='Reformat changed lines in diff. Without -i '
        'option just output the diff that would be '
        'introduced.')
    parser.add_argument(
        '-i',
        action='store_true',
        default=False,
        help='apply edits to files instead of displaying a diff')

    parser.add_argument('-p',
                        metavar='NUM',
                        default=0,
                        help='strip the smallest prefix containing P slashes')
    parser.add_argument('-regex',
                        metavar='PATTERN',
                        default=None,
                        help='custom pattern selecting file paths to reformat '
                        '(case sensitive, overrides -iregex)')
    parser.add_argument('-iregex',
                        metavar='PATTERN',
                        default=r'.*\.java',
                        help='custom pattern selecting file paths to reformat '
                        '(case insensitive, overridden by -regex)')
    parser.add_argument('-v',
                        '--verbose',
                        action='store_true',
                        help='be more verbose, ineffective without -i')
    parser.add_argument(
        '-a',
        '--aosp',
        action='store_true',
        help='use AOSP style instead of Google Style (4-space indentation)')
    parser.add_argument('--skip-sorting-imports',
                        action='store_true',
                        help='do not fix the import order')
    parser.add_argument('--skip-removing-unused-imports',
                        action='store_true',
                        help='do not remove ununsed imports')
    parser.add_argument('--skip-javadoc-formatting',
                        action='store_true',
                        default=False,
                        help='do not reformat javadoc')
    parser.add_argument('-b',
                        '--binary',
                        help='path to google-java-format binary')
    parser.add_argument('--google-java-format-jar',
                        metavar='ABSOLUTE_PATH',
                        default=None,
                        help='use a custom google-java-format jar')

    args = parser.parse_args()

    # Extract changed lines for each file.
    filename = None
    lines_by_file = {}

    for line in sys.stdin:
        match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
        if match:
            filename = match.group(2)
        if filename == None:
            continue

        if args.regex is not None:
            if not re.match('^%s$' % args.regex, filename):
                continue
        else:
            if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
                continue

        match = re.search(r'^@@.*\+(\d+)(,(\d+))?', line)
        if match:
            start_line = int(match.group(1))
            line_count = 1
            if match.group(3):
                line_count = int(match.group(3))
            if line_count == 0:
                continue
            end_line = start_line + line_count - 1
            lines_by_file.setdefault(filename, []).extend(
                ['-lines', str(start_line) + ':' + str(end_line)])

    if args.binary:
        base_command = [args.binary]
    elif args.google_java_format_jar:
        base_command = [
            os.path.join('third_party', 'openjdk', 'jdk-17', 'linux', 'bin',
                         'java'), '-jar',
            '--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED',
            '--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED',
            '--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED',
            '--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED',
            '--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED',
            '--add-opens=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED',
            args.google_java_format_jar
        ]
    else:
        binary = which('google-java-format') or '/usr/bin/google-java-format'
        base_command = [binary]

    # Reformat files containing changes in place.
    for filename, lines in lines_by_file.items():
        if args.i and args.verbose:
            print('Formatting', filename)
        command = base_command[:]
        if args.i:
            command.append('-i')
        if args.aosp:
            command.append('--aosp')
        if args.skip_sorting_imports:
            command.append('--skip-sorting-imports')
        if args.skip_removing_unused_imports:
            command.append('--skip-removing-unused-imports')
        if args.skip_javadoc_formatting:
            command.append('--skip-javadoc-formatting')
        command.extend(lines)
        command.append(filename)
        p = subprocess.Popen(command,
                             stdout=subprocess.PIPE,
                             stderr=None,
                             stdin=subprocess.PIPE)
        stdout, stderr = p.communicate()
        if p.returncode != 0:
            sys.exit(p.returncode)

        if not args.i:
            with open(filename) as f:
                code = f.readlines()
            formatted_code = io.StringIO(stdout.decode('utf-8')).readlines()
            diff = difflib.unified_diff(code, formatted_code, filename,
                                        filename, '(before formatting)',
                                        '(after formatting)')
            diff_string = ''.join(diff)
            if len(diff_string) > 0:
                sys.stdout.write(diff_string)


if __name__ == '__main__':
    main()