#!/usr/bin/env python3
#
# Copyright (C) 2022 The Android Open Source Project
#
# 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.

"""Audit a prebuilt directory to scan for various build issues"""

import argparse
import inspect
from pathlib import Path
import re
import subprocess
import sys

import context

from android_rust.paths import READELF_PATH, TOOLCHAIN_RESOURCE_PATH
from android_rust.utils import ResolvedPath, print_colored, TERM_GREEN, TERM_RED


ALLOW_LIST_PATH = TOOLCHAIN_RESOURCE_PATH / "shared_library_allow_list.txt"

NEEDED_LIBRARY_PATTERN = re.compile(r"\(NEEDED\)\s+Shared library: \[([\w\-]+\.so(?:\.\d+)?)\]")


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=inspect.getdoc(sys.modules[__name__]))

    parser.add_argument("scandir", type=ResolvedPath, help="Directory to audit")
    parser.add_argument(
        "--map", "-m", action="store_true", help="Produce a map of libs to requirements")

    return parser.parse_args()


def get_allow_list() -> list[str]:
    with open(ALLOW_LIST_PATH, "r") as f:
        return sorted(f.read().splitlines())


def get_required_libs(scandir: Path) -> list[str]:
    requirements_map = get_required_libs_map(scandir)

    required_libs = set()
    for libs in requirements_map.values():
        for lib in libs:
            required_libs.add(lib)

    return sorted(required_libs)


def get_required_libs_map(scandir: Path) -> dict[str, list[str]]:
    lib_paths = list(scandir.glob("**/*.so")) + list(scandir.glob("**/*.so.*"))

    local_libs: list[str] = [p.name for p in lib_paths]
    required_libs: dict[str, list[str]] = {}

    for lib_path in lib_paths:
        local_libs.append(lib_path.name)

        result = subprocess.run([READELF_PATH, "--dynamic", lib_path],
                                stdout=subprocess.PIPE,
                                stderr=subprocess.DEVNULL,
                                text=True)

        if result.returncode != 0:
            sys.exit(f"Failed to run readelf on {lib_path}")

        required_libs[str(lib_path)] = []
        for line in result.stdout.splitlines():
            search_result = NEEDED_LIBRARY_PATTERN.search(line)
            if search_result != None:
                assert search_result is not None
                required_lib = search_result[1]
                if required_lib not in local_libs:
                    required_libs[str(lib_path)].append(required_lib)

    return required_libs


def main() -> None:
    args = parse_args()

    allowed_libs = get_allow_list()

    print("Required shared libraries:")
    if args.map:
        for (local_lib, requirements) in get_required_libs_map(args.scandir).items():
            print(f"{local_lib}:")
            for req in requirements:
                print_colored(f"\t{req}", TERM_GREEN if req in allowed_libs else TERM_RED)
            print("")
    else:
        for lib in get_required_libs(args.scandir):
            print_colored(f"\t{lib}", TERM_GREEN if lib in allowed_libs else TERM_RED)


if __name__ == "__main__":
    main()