# 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.

import argparse
import base64
import collections
import hashlib
import os
import re
import sys
import zipfile
from pathlib import Path


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"""
    return re.sub(r"[^\w\d.]+", "_", segment, re.UNICODE)


class WheelMaker(object):
    def __init__(
        self,
        name,
        version,
        build_tag,
        python_tag,
        abi,
        platform,
        outfile=None,
        strip_path_prefixes=None,
    ):
        self._name = name
        self._version = 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 if strip_path_prefixes is not None else []
        )

        self._distinfo_dir = (
            escape_filename_segment(self._name)
            + "-"
            + escape_filename_segment(self._version)
            + ".dist-info/"
        )
        self._zipfile = None
        # Entries for the RECORD file as (filename, hash, size) tuples.
        self._record = []

    def __enter__(self):
        self._zipfile = zipfile.ZipFile(
            self.filename(), mode="w", compression=zipfile.ZIP_DEFLATED
        )
        return self

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

    def wheelname(self) -> str:
        components = [self._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._distinfo_dir + basename

    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_string(self, filename, contents):
        """Add given 'contents' as filename to the distribution."""
        if sys.version_info[0] > 2 and isinstance(contents, str):
            contents = contents.encode("utf-8", "surrogateescape")
        self._zipfile.writestr(filename, contents)
        hash = hashlib.sha256()
        hash.update(contents)
        self._add_to_record(filename, self._serialize_digest(hash), len(contents))

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

        def arcname_from(name):
            # Always use unix path separators.
            normalized_arcname = name.replace(os.path.sep, "/")
            # Don't manipulate names filenames in the .distinfo directory.
            if normalized_arcname.startswith(self._distinfo_dir):
                return normalized_arcname
            for prefix in self._strip_path_prefixes:
                if normalized_arcname.startswith(prefix):
                    return normalized_arcname[len(prefix) :]

            return normalized_arcname

        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)

        self._zipfile.write(real_filename, arcname=arcname)
        # Find the hash and length
        hash = hashlib.sha256()
        size = 0
        with open(real_filename, "rb") as f:
            while True:
                block = f.read(2**20)
                if not block:
                    break
                hash.update(block)
                size += len(block)
        self._add_to_record(arcname, self._serialize_digest(hash), size)

    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.add_string(self.distinfo_path("WHEEL"), wheel_contents)

    def add_metadata(
        self,
        extra_headers,
        description,
        classifiers,
        python_requires,
        requires,
        extra_requires,
    ):
        """Write METADATA file to the distribution."""
        # https://www.python.org/dev/peps/pep-0566/
        # https://packaging.python.org/specifications/core-metadata/
        metadata = []
        metadata.append("Metadata-Version: 2.1")
        metadata.append("Name: %s" % self._name)
        metadata.append("Version: %s" % self._version)
        metadata.extend(extra_headers)
        for classifier in classifiers:
            metadata.append("Classifier: %s" % classifier)
        if python_requires:
            metadata.append("Requires-Python: %s" % python_requires)
        for requirement in requires:
            metadata.append("Requires-Dist: %s" % requirement)

        extra_requires = sorted(extra_requires.items())
        for option, option_requires in extra_requires:
            metadata.append("Provides-Extra: %s" % option)
            for requirement in option_requires:
                metadata.append(
                    "Requires-Dist: %s; extra == '%s'" % (requirement, option)
                )

        metadata = "\n".join(metadata) + "\n\n"
        # setuptools seems to insert UNKNOWN as description when none is
        # provided.
        metadata += description if description else "UNKNOWN"
        metadata += "\n"
        self.add_string(self.distinfo_path("METADATA"), metadata)

    def add_recordfile(self):
        """Write RECORD file to the distribution."""
        record_path = self.distinfo_path("RECORD")
        entries = self._record + [(record_path, b"", b"")]
        entries.sort()
        contents = b""
        for filename, digest, size in entries:
            if sys.version_info[0] > 2 and isinstance(filename, str):
                filename = filename.lstrip("/").encode("utf-8", "surrogateescape")
            contents += b"%s,%s,%s\n" % (filename, digest, size)
        self.add_string(record_path, contents)

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


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

    Args:
        version (str): The raw version 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 version 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 + "}"
        version = version.replace(stamp, value)

    return version


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(
        "--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(
        "--header",
        action="append",
        help="Additional headers to be embedded in the package metadata. "
        "Can be supplied multiple times.",
    )
    wheel_group.add_argument(
        "--classifier",
        action="append",
        help="Classifiers to embed in package metadata. "
        "Can be supplied multiple times",
    )
    wheel_group.add_argument(
        "--python_requires", help="Version of python that the wheel will work with"
    )
    wheel_group.add_argument(
        "--description_file", help="Path to the file with 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.",
    )

    requirements_group = parser.add_argument_group("Package requirements")
    requirements_group.add_argument(
        "--requires",
        type=str,
        action="append",
        help="List of package requirements. Can be supplied multiple times.",
    )
    requirements_group.add_argument(
        "--extra_requires",
        type=str,
        action="append",
        help="List of optional requirements in a 'requirement;option name'. "
        "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 main() -> None:
    arguments = parse_args()

    if arguments.input_file:
        input_files = [i.split(";") for i in arguments.input_file]
    else:
        input_files = []

    if arguments.extra_distinfo_file:
        extra_distinfo_file = [i.split(";") for i in
                               arguments.extra_distinfo_file]
    else:
        extra_distinfo_file = []

    if arguments.input_file_list:
        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:
        version = resolve_version_stamp(
            arguments.version,
            arguments.volatile_status_file,
            arguments.stable_status_file,
        )
    else:
        version = arguments.version

    with WheelMaker(
        name=arguments.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,
    ) 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:
            if sys.version_info[0] == 2:
                with open(arguments.description_file, "rt") as description_file:
                    description = description_file.read()
            else:
                with open(
                    arguments.description_file, "rt", encoding="utf-8"
                ) as description_file:
                    description = description_file.read()

        extra_requires = collections.defaultdict(list)
        if arguments.extra_requires:
            for extra in arguments.extra_requires:
                req, option = extra.rsplit(";", 1)
                extra_requires[option].append(req)
        classifiers = arguments.classifier or []
        python_requires = arguments.python_requires or ""
        requires = arguments.requires or []
        extra_headers = arguments.header or []

        maker.add_metadata(
            extra_headers=extra_headers,
            description=description,
            classifiers=classifiers,
            python_requires=python_requires,
            requires=requires,
            extra_requires=extra_requires,
        )

        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(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()