# Copyright 2023 The Bazel Authors. All rights reserved.
#
# 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.

"""
Regenerate a whl file after patching and cleanup the patched contents.

This script will take contents of the current directory and create a new wheel
out of it and will remove all files that were written to the wheel.
"""

from __future__ import annotations

import argparse
import difflib
import logging
import pathlib
import sys
import tempfile

from tools.wheelmaker import _WhlFile

# NOTE: Implement the following matching of what goes into the RECORD
# https://peps.python.org/pep-0491/#the-dist-info-directory
_EXCLUDES = [
    "RECORD",
    "INSTALLER",
    "RECORD.jws",
    "RECORD.p7s",
    "REQUESTED",
]

_DISTINFO = "dist-info"


def _unidiff_output(expected, actual, record):
    """
    Helper function. Returns a string containing the unified diff of two
    multiline strings.
    """

    expected = expected.splitlines(1)
    actual = actual.splitlines(1)

    diff = difflib.unified_diff(
        expected, actual, fromfile=f"a/{record}", tofile=f"b/{record}"
    )

    return "".join(diff)


def _files_to_pack(dir: pathlib.Path, want_record: str) -> list[pathlib.Path]:
    """Check that the RECORD file entries are correct and print a unified diff on failure."""

    # First get existing files by using the RECORD file
    got_files = []
    got_distinfos = []
    for line in want_record.splitlines():
        rec, _, _ = line.partition(",")
        path = dir / rec

        if not path.exists():
            # skip files that do not exist as they won't be present in the final
            # RECORD file.
            continue

        if not path.parent.name.endswith(_DISTINFO):
            got_files.append(path)
        elif path.name not in _EXCLUDES:
            got_distinfos.append(path)

    # Then get extra files present in the directory but not in the RECORD file
    extra_files = []
    extra_distinfos = []
    for path in dir.rglob("*"):
        if path.is_dir():
            continue

        elif path.parent.name.endswith(_DISTINFO):
            if path.name in _EXCLUDES:
                # NOTE: we implement the following matching of what goes into the RECORD
                # https://peps.python.org/pep-0491/#the-dist-info-directory
                continue
            elif path not in got_distinfos:
                extra_distinfos.append(path)

        elif path not in got_files:
            extra_files.append(path)

    # sort the extra files for reproducibility
    extra_files.sort()
    extra_distinfos.sort()

    # This order ensures that the structure of the RECORD file is always the
    # same and ensures smaller patchsets to the RECORD file in general
    return got_files + extra_files + got_distinfos + extra_distinfos


def main(sys_argv):
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "whl_path",
        type=pathlib.Path,
        help="The original wheel file that we have patched.",
    )
    parser.add_argument(
        "--record-patch",
        type=pathlib.Path,
        help="The output path that we are going to write the RECORD file patch to.",
    )
    parser.add_argument(
        "output",
        type=pathlib.Path,
        help="The output path that we are going to write a new file to.",
    )
    args = parser.parse_args(sys_argv)

    cwd = pathlib.Path.cwd()
    logging.debug("=" * 80)
    logging.debug("Repackaging the wheel")
    logging.debug("=" * 80)

    with tempfile.TemporaryDirectory(dir=cwd) as tmpdir:
        patched_wheel_dir = cwd / tmpdir
        logging.debug(f"Created a tmpdir: {patched_wheel_dir}")

        excludes = [args.whl_path, patched_wheel_dir]

        logging.debug("Moving whl contents to the newly created tmpdir")
        for p in cwd.glob("*"):
            if p in excludes:
                logging.debug(f"Ignoring: {p}")
                continue

            rel_path = p.relative_to(cwd)
            dst = p.rename(patched_wheel_dir / rel_path)
            logging.debug(f"mv {p} -> {dst}")

        distinfo_dir = next(iter(patched_wheel_dir.glob("*dist-info")))
        logging.debug(f"Found dist-info dir: {distinfo_dir}")
        record_path = distinfo_dir / "RECORD"
        record_contents = record_path.read_text() if record_path.exists() else ""
        distribution_prefix = distinfo_dir.with_suffix("").name

        with _WhlFile(
            args.output, mode="w", distribution_prefix=distribution_prefix
        ) as out:
            for p in _files_to_pack(patched_wheel_dir, record_contents):
                rel_path = p.relative_to(patched_wheel_dir)
                out.add_file(str(rel_path), p)

            logging.debug(f"Writing RECORD file")
            got_record = out.add_recordfile().decode("utf-8", "surrogateescape")

    if got_record == record_contents:
        logging.info(f"Created a whl file: {args.output}")
        return

    record_diff = _unidiff_output(
        record_contents,
        got_record,
        out.distinfo_path("RECORD"),
    )
    args.record_patch.write_text(record_diff)
    logging.warning(
        f"Please apply patch to the RECORD file ({args.record_patch}):\n{record_diff}"
    )


if __name__ == "__main__":
    logging.basicConfig(
        format="%(module)s: %(levelname)s: %(message)s", level=logging.DEBUG
    )

    sys.exit(main(sys.argv[1:]))