#!/usr/bin/env fuchsia-vendored-python
# Copyright 2023 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""bb_fetch_rbe_cas

Given a bbid and the path of an intermediate output that was remote-built
using RBE, fetch the blob from the RBE CAS.
Note: permissions are not set, so the caller might need to set executable bits.
"""

import argparse
import json
import os
import sys
import tempfile

import bbtool
import cl_utils
import fuchsia
import remotetool
import reproxy_logs

# This requires python pb2 in build/rbe/proto (generated).

from pathlib import Path
from typing import Any, Dict, Optional, Sequence, Tuple

_SCRIPT_BASENAME = Path(__file__).name
_SCRIPT_DIR = Path(__file__).parent

PROJECT_ROOT = fuchsia.project_root_dir()
PROJECT_ROOT_REL = cl_utils.relpath(PROJECT_ROOT, start=os.curdir)

_REPROXY_CFG = _SCRIPT_DIR / "fuchsia-reproxy.cfg"


def msg(text: str):
    print(f"[{_SCRIPT_BASENAME}] {text}")


def _main_arg_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        description="Fetch build artifacts from RBE CAS.",
        argument_default=None,
    )
    parser.add_argument(
        "--bb",
        type=Path,
        default=bbtool._BB_TOOL,
        help="Path to 'bb' CLI tool.",
        metavar="PATH",
    )
    parser.add_argument(
        "--cfg",
        type=Path,
        default=_REPROXY_CFG,
        help="Reproxy configuration file.",
        metavar="FILE",
    )

    # Require one of the following:
    input_group = parser.add_mutually_exclusive_group(required=True)
    input_group.add_argument(
        "--bbid",
        type=str,
        help="Buildbucket ID (leading 'b' optional/permitted).  Begin search fore reproxy log here.",
        metavar="ID",
    )
    input_group.add_argument(
        "--reproxy_log",
        type=Path,
        help="Use this reproxy log directly instead of searching from bbid.",
        metavar="LOG",
    )

    parser.add_argument(
        "--path",
        type=Path,
        help="Path of artifact under the build output directory.  If omitted, print the path to the cached reproxy log and exit without downloading anything.",
        default=None,
    )
    parser.add_argument(
        "-o",
        dest="output",
        type=Path,
        default=None,
        help="Local output location to fetch to.  If omitted, use the basename of the --path argument.",
        metavar="PATH",
    )
    parser.add_argument(
        "--verbose",
        default=False,
        action=argparse.BooleanOptionalAction,
        help="Print step details.",
    )
    return parser


_MAIN_ARG_PARSER = _main_arg_parser()


def download_artifact(
    downloader: remotetool.RemoteTool, digest: str, destination: Path
) -> int:
    if destination.exists():
        destination.unlink()

    dl_result = downloader.download_blob(path=destination, digest=digest)
    if dl_result.returncode != 0:
        msg(f"Error downloading blob from CAS with digest {digest}")
        return dl_result.returncode

    return 0


def fetch_artifact_from_reproxy_log(
    reproxy_log: Path,
    artifact_path: Path,
    cfg: Path,
    output: Path,
    verbose: bool = False,
) -> int:
    digest = reproxy_logs.lookup_output_file_digest(
        log=reproxy_log,
        path=artifact_path,
    )
    if digest is None:
        msg(f"Unable to find output file {artifact_path} in the reproxy log.")
        return 1

    if verbose:
        msg(f"Digest of {artifact_path} is {digest}")

    downloader = remotetool.configure_remotetool(cfg)

    output = output or Path(artifact_path.name)
    exit_code = download_artifact(downloader, digest, output)
    if exit_code != 0:
        return exit_code

    msg(f"Artifact {artifact_path} downloaded to {output}.\n  digest: {digest}")
    return 0


def _main(
    bbpath: Path,
    cfg: Path,
    bbid: str = None,
    reproxy_log: Path = None,
    artifact_path: Path = None,
    output: Path = None,
    verbose: bool = False,
) -> int:
    reproxy_log = reproxy_log or bbtool.fetch_reproxy_log_from_bbid(
        bbpath=bbpath,
        bbid=bbid,
        verbose=verbose,
    )
    if reproxy_log is None:
        return 1

    if artifact_path is None:
        # print the path to the log and exit without downloading anything
        msg(f"reproxy log: {reproxy_log}")
        return 0

    return fetch_artifact_from_reproxy_log(
        reproxy_log=reproxy_log,
        artifact_path=artifact_path,
        cfg=cfg,
        output=output or Path(artifact_path.name),
        verbose=verbose,
    )


def main(argv: Sequence[str]) -> int:
    args = _MAIN_ARG_PARSER.parse_args(argv)
    if args.output is not None and args.path is None:
        _MAIN_ARG_PARSER.error("-o requires --path")
        return 1
    try:
        return _main(
            bbpath=args.bb,
            bbid=args.bbid.lstrip("b") if args.bbid else None,
            artifact_path=args.path,
            reproxy_log=args.reproxy_log,
            cfg=args.cfg,
            output=args.output,
            verbose=args.verbose,
        )
    except bbtool.BBError as e:
        msg(f"Error: {e}")
        return 1


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))