#!/usr/bin/env python3
"""Check or fix the code style by running Uncrustify.
"""
# Copyright The Mbed TLS Contributors
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import argparse
import io
import os
import subprocess
import sys
from typing import List

CONFIG_FILE = "codestyle.cfg"
UNCRUSTIFY_EXE = "uncrustify"
UNCRUSTIFY_ARGS = ["-c", CONFIG_FILE]
STDOUT_UTF8 = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8')
STDERR_UTF8 = io.TextIOWrapper(sys.stderr.buffer, encoding='utf-8')

def print_err(*args):
    print("Error: ", *args, file=STDERR_UTF8)

def get_src_files() -> List[str]:
    """
    Use git ls-files to get a list of the source files
    """
    git_ls_files_cmd = ["git", "ls-files",
            "*.[hc]",
            "tests/suites/*.function",
            "scripts/data_files/*.fmt"]

    result = subprocess.run(git_ls_files_cmd, stdout=subprocess.PIPE, \
            stderr=STDERR_UTF8, check=False)

    if result.returncode != 0:
        print_err("git ls-files returned: "+str(result.returncode))
        return []
    else:
        src_files = str(result.stdout, "utf-8").split()
        # Don't correct style for files in 3rdparty/
        src_files = list(filter( \
                lambda filename: not filename.startswith("3rdparty/"), \
                src_files))
        return src_files

def get_uncrustify_version() -> str:
    """
    Get the version string from Uncrustify
    """
    result = subprocess.run([UNCRUSTIFY_EXE, "--version"], \
            stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=False)
    if result.returncode != 0:
        print_err("Could not get Uncrustify version:", str(result.stderr, "utf-8"))
        return ""
    else:
        return str(result.stdout, "utf-8")

def check_style_is_correct(src_file_list: List[str]) -> bool:
    """
    Check the code style and output a diff foir each file whose style is
    incorrect.
    """
    style_correct = True
    for src_file in src_file_list:
        uncrustify_cmd = [UNCRUSTIFY_EXE] + UNCRUSTIFY_ARGS + [src_file]
        subprocess.run(uncrustify_cmd, stdout=subprocess.PIPE, \
                stderr=subprocess.PIPE, check=False)

        # Uncrustify makes changes to the code and places the result in a new
        # file with the extension ".uncrustify". To get the changes (if any)
        # simply diff the 2 files.
        diff_cmd = ["diff", "-u", src_file, src_file+".uncrustify"]
        result = subprocess.run(diff_cmd, stdout=subprocess.PIPE, \
                stderr=STDERR_UTF8, check=False)
        if len(result.stdout) > 0:
            print(src_file+" - Incorrect code style.", file=STDOUT_UTF8)
            print("File changed - diff:", file=STDOUT_UTF8)
            print(str(result.stdout, "utf-8"), file=STDOUT_UTF8)
            style_correct = False
        else:
            print(src_file+" - OK.", file=STDOUT_UTF8)

        # Tidy up artifact
        os.remove(src_file+".uncrustify")

    return style_correct

def fix_style_single_pass(src_file_list: List[str]) -> None:
    """
    Run Uncrustify once over the source files.
    """
    code_change_args = UNCRUSTIFY_ARGS + ["--no-backup"]
    for src_file in src_file_list:
        uncrustify_cmd = [UNCRUSTIFY_EXE] + code_change_args + [src_file]
        subprocess.run(uncrustify_cmd, check=False, stdout=STDOUT_UTF8, \
                stderr=STDERR_UTF8)

def fix_style(src_file_list: List[str]) -> int:
    """
    Fix the code style. This takes 2 passes of Uncrustify.
    """
    fix_style_single_pass(src_file_list)
    fix_style_single_pass(src_file_list)

    # Guard against future changes that cause the codebase to require
    # more passes.
    if not check_style_is_correct(src_file_list):
        print("Code style still incorrect after second run of Uncrustify.")
        return 1
    else:
        return 0

def main() -> int:
    """
    Main with command line arguments.
    """
    uncrustify_version = get_uncrustify_version()
    if "0.75.1" not in uncrustify_version:
        print("Warning: Using unsupported Uncrustify version '" \
                + uncrustify_version + "'", file=STDOUT_UTF8)

    src_files = get_src_files()

    parser = argparse.ArgumentParser()
    parser.add_argument('-f', '--fix', action='store_true', \
            help='modify source files to fix the code style')

    args = parser.parse_args()

    if args.fix:
        # Fix mode
        return fix_style(src_files)
    else:
        # Check mode
        if check_style_is_correct(src_files):
            return 0
        else:
            return 1

if __name__ == '__main__':
    sys.exit(main())