# Copyright 2018 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.

from __future__ import annotations

import argparse
import base64
import csv
import hashlib
import io
import os
import re
import stat
import sys
import zipfile
from collections.abc import Iterable
from pathlib import Path

_ZIP_EPOCH = (1980, 1, 1, 0, 0, 0)


def commonpath(path1, path2):
    ret = []
    for a, b in zip(path1.split(os.path.sep), path2.split(os.path.sep)):
        if a != b:
            break
        ret.append(a)
    return os.path.sep.join(ret)


def escape_filename_segment(segment):
    """Escapes a filename segment per https://www.python.org/dev/peps/pep-0427/#escaping-and-unicode

    This is a legacy function, kept for backwards compatibility,
    and may be removed in the future. See `escape_filename_distribution_name`
    and `normalize_pep440` for the modern alternatives.
    """
    return re.sub(r"[^\w\d.]+", "_", segment, re.UNICODE)


def normalize_package_name(name):
    """Normalize a package name according to the Python Packaging User Guide.

    See https://packaging.python.org/en/latest/specifications/name-normalization/
    """
    return re.sub(r"[-_.]+", "-", name).lower()


def escape_filename_distribution_name(name):
    """Escape the distribution name component of a filename.

    See https://packaging.python.org/en/latest/specifications/binary-distribution-format/#escaping-and-unicode
    """
    return normalize_package_name(name).replace("-", "_")


def normalize_pep440(version):
    """Normalize version according to PEP 440, with fallback for placeholders.

    If there's a placeholder in braces, such as {BUILD_TIMESTAMP},
    replace it with 0. Such placeholders can be used with stamping, in
    which case they would have been resolved already by now; if they
    haven't, we're doing an unstamped build, but we still need to
    produce a valid version. If such replacements are made, the
    original version string, sanitized to dot-separated alphanumerics,
    is appended as a local version segment, so you understand what
    placeholder was involved.

    If that still doesn't produce a valid version, use version 0 and
    append the original version string, sanitized to dot-separated
    alphanumerics, as a local version segment.

    """

    import packaging.version

    try:
        return str(packaging.version.Version(version))
    except packaging.version.InvalidVersion:
        pass

    sanitized = re.sub(r"[^a-z0-9]+", ".", version.lower()).strip(".")
    substituted = re.sub(r"\{\w+\}", "0", version)
    delimiter = "." if "+" in substituted else "+"
    try:
        return str(packaging.version.Version(f"{substituted}{delimiter}{sanitized}"))
    except packaging.version.InvalidVersion:
        return str(packaging.version.Version(f"0+{sanitized}"))


def arcname_from(
    name: str, distribution_prefix: str, strip_path_prefixes: Sequence[str] = ()
) -> str:
    """Return the within-archive name for a given file path name.

    Prefixes to strip are checked in order and only the first match will be used.

    Args:
        name: The file path eg 'mylib/a/b/c/file.py'
        distribution_prefix: The
        strip_path_prefixes: Remove these prefixes from names.
    """
    # Always use unix path separators.
    normalized_arcname = name.replace(os.path.sep, "/")
    # Don't manipulate names filenames in the .distinfo or .data directories.
    if distribution_prefix and normalized_arcname.startswith(distribution_prefix):
        return normalized_arcname
    for prefix in strip_path_prefixes:
        if normalized_arcname.startswith(prefix):
            return normalized_arcname[len(prefix) :]

    return normalized_arcname


class _WhlFile(zipfile.ZipFile):
    def __init__(
        self,
        filename,
        *,
        mode,
        distribution_prefix: str,
        strip_path_prefixes=None,
        compression=zipfile.ZIP_DEFLATED,
        **kwargs,
    ):
        self._distribution_prefix = distribution_prefix

        self._strip_path_prefixes = strip_path_prefixes or []
        # Entries for the RECORD file as (filename, hash, size) tuples.
        self._record = []

        super().__init__(filename, mode=mode, compression=compression, **kwargs)

    def distinfo_path(self, basename):
        return f"{self._distribution_prefix}.dist-info/{basename}"

    def data_path(self, basename):
        return f"{self._distribution_prefix}.data/{basename}"

    def add_file(self, package_filename, real_filename):
        """Add given file to the distribution."""

        if os.path.isdir(real_filename):
            directory_contents = os.listdir(real_filename)
            for file_ in directory_contents:
                self.add_file(
                    "{}/{}".format(package_filename, file_),
                    "{}/{}".format(real_filename, file_),
                )
            return

        arcname = arcname_from(
            package_filename,
            distribution_prefix=self._distribution_prefix,
            strip_path_prefixes=self._strip_path_prefixes,
        )
        zinfo = self._zipinfo(arcname)

        # Write file to the zip archive while computing the hash and length
        hash = hashlib.sha256()
        size = 0
        with open(real_filename, "rb") as fsrc:
            with self.open(zinfo, "w", force_zip64=True) as fdst:
                while True:
                    block = fsrc.read(2**20)
                    if not block:
                        break
                    fdst.write(block)
                    hash.update(block)
                    size += len(block)

        self._add_to_record(arcname, self._serialize_digest(hash), size)

    def add_string(self, filename, contents):
        """Add given 'contents' as filename to the distribution."""
        if isinstance(contents, str):
            contents = contents.encode("utf-8", "surrogateescape")
        zinfo = self._zipinfo(filename)
        self.writestr(zinfo, contents)
        hash = hashlib.sha256()
        hash.update(contents)
        self._add_to_record(filename, self._serialize_digest(hash), len(contents))

    def _serialize_digest(self, hash):
        # https://www.python.org/dev/peps/pep-0376/#record
        # "base64.urlsafe_b64encode(digest) with trailing = removed"
        digest = base64.urlsafe_b64encode(hash.digest())
        digest = b"sha256=" + digest.rstrip(b"=")
        return digest

    def _add_to_record(self, filename, hash, size):
        size = str(size).encode("ascii")
        self._record.append((filename, hash, size))

    def _zipinfo(self, filename):
        """Construct deterministic ZipInfo entry for a file named filename"""
        # Strip leading path separators to mirror ZipInfo.from_file behavior
        separators = os.path.sep
        if os.path.altsep is not None:
            separators += os.path.altsep
        arcname = filename.lstrip(separators)

        zinfo = zipfile.ZipInfo(filename=arcname, date_time=_ZIP_EPOCH)
        zinfo.create_system = 3  # ZipInfo entry created on a unix-y system
        # Both pip and installer expect the regular file bit to be set in order for the
        # executable bit to be preserved after extraction
        # https://github.com/pypa/pip/blob/23.3.2/src/pip/_internal/utils/unpacking.py#L96-L100
        # https://github.com/pypa/installer/blob/0.7.0/src/installer/sources.py#L310-L313
        zinfo.external_attr = (
            stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO | stat.S_IFREG
        ) << 16  # permissions: -rwxrwxrwx
        zinfo.compress_type = self.compression
        return zinfo

    def add_recordfile(self):
        """Write RECORD file to the distribution."""
        record_path = self.distinfo_path("RECORD")
        entries = self._record + [(record_path, b"", b"")]
        with io.StringIO() as contents_io:
            writer = csv.writer(contents_io, lineterminator="\n")
            for filename, digest, size in entries:
                if isinstance(filename, str):
                    filename = filename.lstrip("/")
                writer.writerow(
                    (
                        (
                            c
                            if isinstance(c, str)
                            else c.decode("utf-8", "surrogateescape")
                        )
                        for c in (filename, digest, size)
                    )
                )

            contents = contents_io.getvalue()
            self.add_string(record_path, contents)
            return contents.encode("utf-8", "surrogateescape")


class WheelMaker(object):
    def __init__(
        self,
        name,
        version,
        build_tag,
        python_tag,
        abi,
        platform,
        compress,
        outfile=None,
        strip_path_prefixes=None,
    ):
        self._name = name
        self._version = normalize_pep440(version)
        self._build_tag = build_tag
        self._python_tag = python_tag
        self._abi = abi
        self._platform = platform
        self._outfile = outfile
        self._strip_path_prefixes = strip_path_prefixes
        self._compress = compress
        self._wheelname_fragment_distribution_name = escape_filename_distribution_name(
            self._name
        )

        self._distribution_prefix = (
            self._wheelname_fragment_distribution_name + "-" + self._version
        )

        self._whlfile = None

    def __enter__(self):
        self._whlfile = _WhlFile(
            self.filename(),
            mode="w",
            distribution_prefix=self._distribution_prefix,
            strip_path_prefixes=self._strip_path_prefixes,
            compression=zipfile.ZIP_DEFLATED if self._compress else zipfile.ZIP_STORED,
        )
        return self

    def __exit__(self, type, value, traceback):
        self._whlfile.close()
        self._whlfile = None

    def wheelname(self) -> str:
        components = [
            self._wheelname_fragment_distribution_name,
            self._version,
        ]
        if self._build_tag:
            components.append(self._build_tag)
        components += [self._python_tag, self._abi, self._platform]
        return "-".join(components) + ".whl"

    def filename(self) -> str:
        if self._outfile:
            return self._outfile
        return self.wheelname()

    def disttags(self):
        return ["-".join([self._python_tag, self._abi, self._platform])]

    def distinfo_path(self, basename):
        return self._whlfile.distinfo_path(basename)

    def data_path(self, basename):
        return self._whlfile.data_path(basename)

    def add_file(self, package_filename, real_filename):
        """Add given file to the distribution."""
        self._whlfile.add_file(package_filename, real_filename)

    def add_wheelfile(self):
        """Write WHEEL file to the distribution"""
        # TODO(pstradomski): Support non-purelib wheels.
        wheel_contents = """\
Wheel-Version: 1.0
Generator: bazel-wheelmaker 1.0
Root-Is-Purelib: {}
""".format(
            "true" if self._platform == "any" else "false"
        )
        for tag in self.disttags():
            wheel_contents += "Tag: %s\n" % tag
        self._whlfile.add_string(self.distinfo_path("WHEEL"), wheel_contents)

    def add_metadata(self, metadata, name, description):
        """Write METADATA file to the distribution."""
        # https://www.python.org/dev/peps/pep-0566/
        # https://packaging.python.org/specifications/core-metadata/
        metadata = re.sub("^Name: .*$", "Name: %s" % name, metadata, flags=re.MULTILINE)
        metadata += "Version: %s\n\n" % self._version
        # setuptools seems to insert UNKNOWN as description when none is
        # provided.
        metadata += description if description else "UNKNOWN"
        metadata += "\n"
        self._whlfile.add_string(self.distinfo_path("METADATA"), metadata)

    def add_recordfile(self):
        """Write RECORD file to the distribution."""
        self._whlfile.add_recordfile()


def get_files_to_package(input_files):
    """Find files to be added to the distribution.

    input_files: list of pairs (package_path, real_path)
    """
    files = {}
    for package_path, real_path in input_files:
        files[package_path] = real_path
    return files


def resolve_argument_stamp(
    argument: str, volatile_status_stamp: Path, stable_status_stamp: Path
) -> str:
    """Resolve workspace status stamps format strings found in the argument string

    Args:
        argument (str): The raw argument represenation for the wheel (may include stamp variables)
        volatile_status_stamp (Path): The path to a volatile workspace status file
        stable_status_stamp (Path): The path to a stable workspace status file

    Returns:
        str: A resolved argument string
    """
    lines = (
        volatile_status_stamp.read_text().splitlines()
        + stable_status_stamp.read_text().splitlines()
    )
    for line in lines:
        if not line:
            continue
        key, value = line.split(" ", maxsplit=1)
        stamp = "{" + key + "}"
        argument = argument.replace(stamp, value)

    return argument


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Builds a python wheel")
    metadata_group = parser.add_argument_group("Wheel name, version and platform")
    metadata_group.add_argument(
        "--name", required=True, type=str, help="Name of the distribution"
    )
    metadata_group.add_argument(
        "--version", required=True, type=str, help="Version of the distribution"
    )
    metadata_group.add_argument(
        "--build_tag",
        type=str,
        default="",
        help="Optional build tag for the distribution",
    )
    metadata_group.add_argument(
        "--python_tag",
        type=str,
        default="py3",
        help="Python version, e.g. 'py2' or 'py3'",
    )
    metadata_group.add_argument("--abi", type=str, default="none")
    metadata_group.add_argument(
        "--platform", type=str, default="any", help="Target platform. "
    )

    output_group = parser.add_argument_group("Output file location")
    output_group.add_argument(
        "--out", type=str, default=None, help="Override name of ouptut file"
    )
    output_group.add_argument(
        "--no_compress",
        action="store_true",
        help="Disable compression of the final archive",
    )
    output_group.add_argument(
        "--name_file",
        type=Path,
        help="A file where the canonical name of the " "wheel will be written",
    )

    output_group.add_argument(
        "--strip_path_prefix",
        type=str,
        action="append",
        default=[],
        help="Path prefix to be stripped from input package files' path. "
        "Can be supplied multiple times. Evaluated in order.",
    )

    wheel_group = parser.add_argument_group("Wheel metadata")
    wheel_group.add_argument(
        "--metadata_file",
        type=Path,
        help="Contents of the METADATA file (before appending contents of "
        "--description_file)",
    )
    wheel_group.add_argument(
        "--description_file", help="Path to the file with package description"
    )
    wheel_group.add_argument(
        "--description_content_type", help="Content type of the package description"
    )
    wheel_group.add_argument(
        "--entry_points_file",
        help="Path to a correctly-formatted entry_points.txt file",
    )

    contents_group = parser.add_argument_group("Wheel contents")
    contents_group.add_argument(
        "--input_file",
        action="append",
        help="'package_path;real_path' pairs listing "
        "files to be included in the wheel. "
        "Can be supplied multiple times.",
    )
    contents_group.add_argument(
        "--input_file_list",
        action="append",
        help="A file that has all the input files defined as a list to avoid "
        "the long command",
    )
    contents_group.add_argument(
        "--extra_distinfo_file",
        action="append",
        help="'filename;real_path' pairs listing extra files to include in"
        "dist-info directory. Can be supplied multiple times.",
    )
    contents_group.add_argument(
        "--data_files",
        action="append",
        help="'filename;real_path' pairs listing data files to include in"
        "data directory. Can be supplied multiple times.",
    )

    build_group = parser.add_argument_group("Building requirements")
    build_group.add_argument(
        "--volatile_status_file",
        type=Path,
        help="Pass in the stamp info file for stamping",
    )
    build_group.add_argument(
        "--stable_status_file",
        type=Path,
        help="Pass in the stamp info file for stamping",
    )

    return parser.parse_args(sys.argv[1:])


def _parse_file_pairs(content: List[str]) -> List[List[str]]:
    """
    Parse ; delimited lists of files into a 2D list.
    """
    return [i.split(";", maxsplit=1) for i in content or []]


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

    input_files = _parse_file_pairs(arguments.input_file)
    extra_distinfo_file = _parse_file_pairs(arguments.extra_distinfo_file)
    data_files = _parse_file_pairs(arguments.data_files)

    for input_file in arguments.input_file_list:
        with open(input_file) as _file:
            input_file_list = _file.read().splitlines()
        for _input_file in input_file_list:
            input_files.append(_input_file.split(";"))

    all_files = get_files_to_package(input_files)
    # Sort the files for reproducible order in the archive.
    all_files = sorted(all_files.items())

    strip_prefixes = [p for p in arguments.strip_path_prefix]

    if arguments.volatile_status_file and arguments.stable_status_file:
        name = resolve_argument_stamp(
            arguments.name,
            arguments.volatile_status_file,
            arguments.stable_status_file,
        )
    else:
        name = arguments.name

    if arguments.volatile_status_file and arguments.stable_status_file:
        version = resolve_argument_stamp(
            arguments.version,
            arguments.volatile_status_file,
            arguments.stable_status_file,
        )
    else:
        version = arguments.version

    with WheelMaker(
        name=name,
        version=version,
        build_tag=arguments.build_tag,
        python_tag=arguments.python_tag,
        abi=arguments.abi,
        platform=arguments.platform,
        outfile=arguments.out,
        strip_path_prefixes=strip_prefixes,
        compress=not arguments.no_compress,
    ) as maker:
        for package_filename, real_filename in all_files:
            maker.add_file(package_filename, real_filename)
        maker.add_wheelfile()

        description = None
        if arguments.description_file:
            with open(
                arguments.description_file, "rt", encoding="utf-8"
            ) as description_file:
                description = description_file.read()

        metadata = arguments.metadata_file.read_text(encoding="utf-8")

        # This is not imported at the top of the file due to the reliance
        # on this file in the `whl_library` repository rule which does not
        # provide `packaging` but does import symbols defined here.
        from packaging.requirements import Requirement

        # Search for any `Requires-Dist` entries that refer to other files and
        # expand them.

        def get_new_requirement_line(reqs_text, extra):
            req = Requirement(reqs_text.strip())
            req_extra_deps = f"[{','.join(req.extras)}]" if req.extras else ""
            if req.marker:
                if extra:
                    return f"Requires-Dist: {req.name}{req_extra_deps}{req.specifier}; ({req.marker}) and {extra}"
                else:
                    return f"Requires-Dist: {req.name}{req_extra_deps}{req.specifier}; {req.marker}"
            else:
                return f"Requires-Dist: {req.name}{req_extra_deps}{req.specifier}; {extra}".strip(
                    " ;"
                )

        for meta_line in metadata.splitlines():
            if not meta_line.startswith("Requires-Dist: "):
                continue

            if not meta_line[len("Requires-Dist: ") :].startswith("@"):
                # This is a normal requirement.
                package, _, extra = meta_line[len("Requires-Dist: ") :].rpartition(";")
                if not package:
                    # This is when the package requirement does not have markers.
                    continue
                extra = extra.strip()
                metadata = metadata.replace(
                    meta_line, get_new_requirement_line(package, extra)
                )
                continue

            # This is a requirement that refers to a file.
            file, _, extra = meta_line[len("Requires-Dist: @") :].partition(";")
            extra = extra.strip()

            reqs = []
            for reqs_line in Path(file).read_text(encoding="utf-8").splitlines():
                reqs_text = reqs_line.strip()
                if not reqs_text or reqs_text.startswith(("#", "-")):
                    continue

                # Strip any comments
                reqs_text, _, _ = reqs_text.partition("#")

                reqs.append(get_new_requirement_line(reqs_text, extra))

            if reqs:
                metadata = metadata.replace(meta_line, "\n".join(reqs))
            # File is empty
            # So replace the meta_line entirely, including removing newline chars
            else:
                metadata = re.sub(
                    re.escape(meta_line) + r"(?:\r?\n)?", "", metadata, count=1
                )

        maker.add_metadata(
            metadata=metadata,
            name=name,
            description=description,
        )

        if arguments.entry_points_file:
            maker.add_file(
                maker.distinfo_path("entry_points.txt"), arguments.entry_points_file
            )

        # Sort the files for reproducible order in the archive.
        for filename, real_path in sorted(data_files):
            maker.add_file(maker.data_path(filename), real_path)
        for filename, real_path in sorted(extra_distinfo_file):
            maker.add_file(maker.distinfo_path(filename), real_path)

        maker.add_recordfile()

        # Since stamping may otherwise change the target name of the
        # wheel, the canonical name (with stamps resolved) is written
        # to a file so consumers of the wheel can easily determine
        # the correct name.
        arguments.name_file.write_text(maker.wheelname())


if __name__ == "__main__":
    main()