#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2019 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Build script that copies the go sources to a build destination."""


import argparse
import os.path
import re
import shutil
import subprocess
import sys


def parse_args():
    parser = argparse.ArgumentParser()
    default_output_dir = os.path.normpath(
        os.path.join(
            os.path.dirname(os.path.realpath(__file__)),
            "../../chromiumos-overlay/sys-devel/llvm/files/compiler_wrapper",
        )
    )
    parser.add_argument(
        "--output_dir",
        default=default_output_dir,
        help="Output directory to place bundled files (default: %(default)s)",
    )
    parser.add_argument(
        "--create",
        action="store_true",
        help="Create output_dir if it does not already exist",
    )
    return parser.parse_args()


def copy_files(input_dir, output_dir):
    for filename in os.listdir(input_dir):
        if (
            filename.endswith(".go") and not filename.endswith("_test.go")
        ) or filename in ("build.py", "go.mod"):
            shutil.copy(
                os.path.join(input_dir, filename),
                os.path.join(output_dir, filename),
            )


def read_change_id(input_dir):
    last_commit_msg = subprocess.check_output(
        ["git", "-C", input_dir, "log", "-1", "--pretty=%B"], encoding="utf-8"
    )
    # Use last found change id to support reverts as well.
    change_ids = re.findall(r"Change-Id: (\w+)", last_commit_msg)
    if not change_ids:
        sys.exit("Couldn't find Change-Id in last commit message.")
    return change_ids[-1]


def write_readme(input_dir, output_dir, change_id):
    with open(
        os.path.join(input_dir, "bundle.README"), "r", encoding="utf-8"
    ) as r:
        with open(
            os.path.join(output_dir, "README"), "w", encoding="utf-8"
        ) as w:
            content = r.read()
            w.write(content.format(change_id=change_id))


def write_version(output_dir, change_id):
    with open(os.path.join(output_dir, "VERSION"), "w", encoding="utf-8") as w:
        w.write(change_id)


def main():
    args = parse_args()
    input_dir = os.path.dirname(__file__)
    change_id = read_change_id(input_dir)
    if not args.create:
        assert os.path.exists(
            args.output_dir
        ), f"Specified output directory ({args.output_dir}) does not exist"
    shutil.rmtree(args.output_dir, ignore_errors=True)
    os.makedirs(args.output_dir)
    copy_files(input_dir, args.output_dir)
    write_readme(input_dir, args.output_dir, change_id)
    write_version(args.output_dir, change_id)


if __name__ == "__main__":
    main()