import argparse
import os
import subprocess
import sys

FILE_EXTENSIONS = [".h", ".hpp", ".c", ".cc", ".cpp"]


def do_clang_tidy(args):
    ret = False

    merge_base_cmd = [
        "git",
        "merge-base",
        "origin/{}".format(args.base_branch),
        args.branch,
    ]
    print(merge_base_cmd)
    base_commit = subprocess.check_output(merge_base_cmd, cwd=args.src_dir)
    base_commit = base_commit.rstrip()

    changed_files = os.path.join(args.builder_dir, "clang_tidy_changed_files.txt")
    if os.path.isfile(changed_files):
        os.remove(changed_files)

    diff_cmd = ["git", "--no-pager", "diff", base_commit, args.branch, "--name-only"]
    print(diff_cmd)
    with open(changed_files, "w") as f:
        subprocess.check_call(
            merge_base_cmd, cwd=args.src_dir, stdout=f, stderr=subprocess.STDOUT
        )

    if os.path.isfile(changed_files):
        clang_tidy_binary = os.path.join(args.obj_dir, "bin", "clang-tidy")
        if os.path.isfile(clang_tidy_binary):
            with open(changed_files, "r") as f:
                for line in f:
                    filename, file_extension = os.path.splitext(line)
                    if file_extension.lower() in FILE_EXTENSIONS:
                        clang_tidy_cmd = [clang_tidy_binary, line]
                        print(clang_tidy_cmd)
                        subprocess.run(clang_tidy_binary, cwd=args.src_dir)
            ret = True
        else:
            print("no such file:{}".format(clang_tidy_binary))
            # TODO report error when clang-tidy is ready
            print("clang-tidy is not get built, always return success for now.")
            ret = True

    return ret


def main():
    parser = argparse.ArgumentParser(
        prog="clang_tidy.py",
        description="script to do clang_tidy",
        formatter_class=argparse.RawTextHelpFormatter,
    )
    parser.add_argument(
        "-n", "--build-number", metavar="BUILD_NUM", help="build number"
    )
    parser.add_argument(
        "-b", "--branch", metavar="BRANCH", required=True, help="pull request branch"
    )
    parser.add_argument(
        "-d",
        "--base-branch",
        metavar="BASE_BRANCH",
        required=True,
        help="pull request base branch",
    )
    parser.add_argument(
        "-r", "--pr-number", metavar="PR_NUM", help="pull request number"
    )
    parser.add_argument(
        "-w",
        "--builder-dir",
        metavar="BUILDER_DIR",
        required=True,
        help="builder directory, which is the directory containing source and build directories",
    )
    parser.add_argument(
        "-s", "--src-dir", metavar="SRC_DIR", required=True, help="source directory"
    )
    parser.add_argument(
        "-o", "--obj-dir", metavar="OBJ_DIR", required=True, help="build directory"
    )

    args = parser.parse_args()

    print("args:{}".format(args))

    return do_clang_tidy(args)


if __name__ == "__main__":
    ret = main()
    exit_code = 0 if ret else 1
    sys.exit(exit_code)