import itertools
import os
import shlex
import sys
import tempfile
from typing import IO, Any, BinaryIO, List, Optional, Tuple, Union, cast

import click
from click.utils import LazyFile, safecall
from pep517 import meta
from pip._internal.commands import create_command
from pip._internal.req import InstallRequirement
from pip._internal.req.constructors import install_req_from_line
from pip._internal.utils.misc import redact_auth_from_url

from .._compat import IS_CLICK_VER_8_PLUS, parse_requirements
from ..cache import DependencyCache
from ..exceptions import PipToolsError
from ..locations import CACHE_DIR
from ..logging import log
from ..repositories import LocalRequirementsRepository, PyPIRepository
from ..repositories.base import BaseRepository
from ..resolver import Resolver
from ..utils import (
    UNSAFE_PACKAGES,
    dedup,
    drop_extras,
    is_pinned_requirement,
    key_from_ireq,
)
from ..writer import OutputWriter

DEFAULT_REQUIREMENTS_FILE = "requirements.in"
DEFAULT_REQUIREMENTS_OUTPUT_FILE = "requirements.txt"
METADATA_FILENAMES = frozenset({"setup.py", "setup.cfg", "pyproject.toml"})

# TODO: drop click 7 and remove this block, pass directly to version_option
version_option_kwargs = {"package_name": "pip-tools"} if IS_CLICK_VER_8_PLUS else {}


def _get_default_option(option_name: str) -> Any:
    """
    Get default value of the pip's option (including option from pip.conf)
    by a given option name.
    """
    install_command = create_command("install")
    default_values = install_command.parser.get_default_values()
    return getattr(default_values, option_name)


@click.command(context_settings={"help_option_names": ("-h", "--help")})
@click.version_option(**version_option_kwargs)
@click.pass_context
@click.option("-v", "--verbose", count=True, help="Show more output")
@click.option("-q", "--quiet", count=True, help="Give less output")
@click.option(
    "-n",
    "--dry-run",
    is_flag=True,
    help="Only show what would happen, don't change anything",
)
@click.option(
    "-p",
    "--pre",
    is_flag=True,
    default=None,
    help="Allow resolving to prereleases (default is not)",
)
@click.option(
    "-r",
    "--rebuild",
    is_flag=True,
    help="Clear any caches upfront, rebuild from scratch",
)
@click.option(
    "--extra",
    "extras",
    multiple=True,
    help="Name of an extras_require group to install; may be used more than once",
)
@click.option(
    "-f",
    "--find-links",
    multiple=True,
    help="Look for archives in this directory or on this HTML page; may be used more than once",
)
@click.option(
    "-i",
    "--index-url",
    help="Change index URL (defaults to {index_url})".format(
        index_url=redact_auth_from_url(_get_default_option("index_url"))
    ),
)
@click.option(
    "--extra-index-url",
    multiple=True,
    help="Add another index URL to search; may be used more than once",
)
@click.option("--cert", help="Path to alternate CA bundle.")
@click.option(
    "--client-cert",
    help="Path to SSL client certificate, a single file containing "
    "the private key and the certificate in PEM format.",
)
@click.option(
    "--trusted-host",
    multiple=True,
    help="Mark this host as trusted, even though it does not have "
    "valid or any HTTPS; may be used more than once",
)
@click.option(
    "--header/--no-header",
    is_flag=True,
    default=True,
    help="Add header to generated file",
)
@click.option(
    "--emit-trusted-host/--no-emit-trusted-host",
    is_flag=True,
    default=True,
    help="Add trusted host option to generated file",
)
@click.option(
    "--annotate/--no-annotate",
    is_flag=True,
    default=True,
    help="Annotate results, indicating where dependencies come from",
)
@click.option(
    "--annotation-style",
    type=click.Choice(("line", "split")),
    default="split",
    help="Choose the format of annotation comments",
)
@click.option(
    "-U",
    "--upgrade/--no-upgrade",
    is_flag=True,
    default=False,
    help="Try to upgrade all dependencies to their latest versions",
)
@click.option(
    "-P",
    "--upgrade-package",
    "upgrade_packages",
    nargs=1,
    multiple=True,
    help="Specify a particular package to upgrade; may be used more than once",
)
@click.option(
    "-o",
    "--output-file",
    nargs=1,
    default=None,
    type=click.File("w+b", atomic=True, lazy=True),
    help=(
        "Output file name. Required if more than one input file is given. "
        "Will be derived from input file otherwise."
    ),
)
@click.option(
    "--allow-unsafe/--no-allow-unsafe",
    is_flag=True,
    default=False,
    help=(
        "Pin packages considered unsafe: {}.\n\n"
        "WARNING: Future versions of pip-tools will enable this behavior by default. "
        "Use --no-allow-unsafe to keep the old behavior. It is recommended to pass the "
        "--allow-unsafe now to adapt to the upcoming change.".format(
            ", ".join(sorted(UNSAFE_PACKAGES))
        )
    ),
)
@click.option(
    "--strip-extras",
    is_flag=True,
    default=False,
    help="Assure output file is constraints compatible, avoiding use of extras.",
)
@click.option(
    "--generate-hashes",
    is_flag=True,
    default=False,
    help="Generate pip 8 style hashes in the resulting requirements file.",
)
@click.option(
    "--reuse-hashes/--no-reuse-hashes",
    is_flag=True,
    default=True,
    help=(
        "Improve the speed of --generate-hashes by reusing the hashes from an "
        "existing output file."
    ),
)
@click.option(
    "--max-rounds",
    default=10,
    help="Maximum number of rounds before resolving the requirements aborts.",
)
@click.argument("src_files", nargs=-1, type=click.Path(exists=True, allow_dash=True))
@click.option(
    "--build-isolation/--no-build-isolation",
    is_flag=True,
    default=True,
    help="Enable isolation when building a modern source distribution. "
    "Build dependencies specified by PEP 518 must be already installed "
    "if build isolation is disabled.",
)
@click.option(
    "--emit-find-links/--no-emit-find-links",
    is_flag=True,
    default=True,
    help="Add the find-links option to generated file",
)
@click.option(
    "--cache-dir",
    help="Store the cache data in DIRECTORY.",
    default=CACHE_DIR,
    envvar="PIP_TOOLS_CACHE_DIR",
    show_default=True,
    show_envvar=True,
    type=click.Path(file_okay=False, writable=True),
)
@click.option(
    "--pip-args", "pip_args_str", help="Arguments to pass directly to the pip command."
)
@click.option(
    "--emit-index-url/--no-emit-index-url",
    is_flag=True,
    default=True,
    help="Add index URL to generated file",
)
@click.option(
    "--emit-options/--no-emit-options",
    is_flag=True,
    default=True,
    help="Add options to generated file",
)
def cli(
    ctx: click.Context,
    verbose: int,
    quiet: int,
    dry_run: bool,
    pre: bool,
    rebuild: bool,
    extras: Tuple[str, ...],
    find_links: Tuple[str, ...],
    index_url: str,
    extra_index_url: Tuple[str, ...],
    cert: Optional[str],
    client_cert: Optional[str],
    trusted_host: Tuple[str, ...],
    header: bool,
    emit_trusted_host: bool,
    annotate: bool,
    annotation_style: str,
    upgrade: bool,
    upgrade_packages: Tuple[str, ...],
    output_file: Union[LazyFile, IO[Any], None],
    allow_unsafe: bool,
    strip_extras: bool,
    generate_hashes: bool,
    reuse_hashes: bool,
    src_files: Tuple[str, ...],
    max_rounds: int,
    build_isolation: bool,
    emit_find_links: bool,
    cache_dir: str,
    pip_args_str: Optional[str],
    emit_index_url: bool,
    emit_options: bool,
) -> None:
    """Compiles requirements.txt from requirements.in specs."""
    log.verbosity = verbose - quiet

    if len(src_files) == 0:
        if os.path.exists(DEFAULT_REQUIREMENTS_FILE):
            src_files = (DEFAULT_REQUIREMENTS_FILE,)
        elif os.path.exists("setup.py"):
            src_files = ("setup.py",)
        else:
            raise click.BadParameter(
                (
                    "If you do not specify an input file, "
                    "the default is {} or setup.py"
                ).format(DEFAULT_REQUIREMENTS_FILE)
            )

    if not output_file:
        # An output file must be provided for stdin
        if src_files == ("-",):
            raise click.BadParameter("--output-file is required if input is from stdin")
        # Use default requirements output file if there is a setup.py the source file
        elif os.path.basename(src_files[0]) in METADATA_FILENAMES:
            file_name = os.path.join(
                os.path.dirname(src_files[0]), DEFAULT_REQUIREMENTS_OUTPUT_FILE
            )
        # An output file must be provided if there are multiple source files
        elif len(src_files) > 1:
            raise click.BadParameter(
                "--output-file is required if two or more input files are given."
            )
        # Otherwise derive the output file from the source file
        else:
            base_name = src_files[0].rsplit(".", 1)[0]
            file_name = base_name + ".txt"

        output_file = click.open_file(file_name, "w+b", atomic=True, lazy=True)

        # Close the file at the end of the context execution
        assert output_file is not None
        # only LazyFile has close_intelligently, newer IO[Any] does not
        if isinstance(output_file, LazyFile):  # pragma: no cover
            ctx.call_on_close(safecall(output_file.close_intelligently))

    ###
    # Setup
    ###

    right_args = shlex.split(pip_args_str or "")
    pip_args = []
    for link in find_links:
        pip_args.extend(["-f", link])
    if index_url:
        pip_args.extend(["-i", index_url])
    for extra_index in extra_index_url:
        pip_args.extend(["--extra-index-url", extra_index])
    if cert:
        pip_args.extend(["--cert", cert])
    if client_cert:
        pip_args.extend(["--client-cert", client_cert])
    if pre:
        pip_args.extend(["--pre"])
    for host in trusted_host:
        pip_args.extend(["--trusted-host", host])

    if not build_isolation:
        pip_args.append("--no-build-isolation")
    pip_args.extend(right_args)

    repository: BaseRepository
    repository = PyPIRepository(pip_args, cache_dir=cache_dir)

    # Parse all constraints coming from --upgrade-package/-P
    upgrade_reqs_gen = (install_req_from_line(pkg) for pkg in upgrade_packages)
    upgrade_install_reqs = {
        key_from_ireq(install_req): install_req for install_req in upgrade_reqs_gen
    }

    existing_pins_to_upgrade = set()

    # Proxy with a LocalRequirementsRepository if --upgrade is not specified
    # (= default invocation)
    if not upgrade and os.path.exists(output_file.name):
        # Use a temporary repository to ensure outdated(removed) options from
        # existing requirements.txt wouldn't get into the current repository.
        tmp_repository = PyPIRepository(pip_args, cache_dir=cache_dir)
        ireqs = parse_requirements(
            output_file.name,
            finder=tmp_repository.finder,
            session=tmp_repository.session,
            options=tmp_repository.options,
        )

        # Exclude packages from --upgrade-package/-P from the existing
        # constraints, and separately gather pins to be upgraded
        existing_pins = {}
        for ireq in filter(is_pinned_requirement, ireqs):
            key = key_from_ireq(ireq)
            if key in upgrade_install_reqs:
                existing_pins_to_upgrade.add(key)
            else:
                existing_pins[key] = ireq
        repository = LocalRequirementsRepository(
            existing_pins, repository, reuse_hashes=reuse_hashes
        )

    ###
    # Parsing/collecting initial requirements
    ###

    constraints: List[InstallRequirement] = []
    setup_file_found = False
    for src_file in src_files:
        is_setup_file = os.path.basename(src_file) in METADATA_FILENAMES
        if src_file == "-":
            # pip requires filenames and not files. Since we want to support
            # piping from stdin, we need to briefly save the input from stdin
            # to a temporary file and have pip read that.  also used for
            # reading requirements from install_requires in setup.py.
            tmpfile = tempfile.NamedTemporaryFile(mode="wt", delete=False)
            tmpfile.write(sys.stdin.read())
            comes_from = "-r -"
            tmpfile.flush()
            reqs = list(
                parse_requirements(
                    tmpfile.name,
                    finder=repository.finder,
                    session=repository.session,
                    options=repository.options,
                )
            )
            for req in reqs:
                req.comes_from = comes_from
            constraints.extend(reqs)
        elif is_setup_file:
            setup_file_found = True
            dist = meta.load(os.path.dirname(os.path.abspath(src_file)))
            comes_from = f"{dist.metadata.get_all('Name')[0]} ({src_file})"
            constraints.extend(
                [
                    install_req_from_line(req, comes_from=comes_from)
                    for req in dist.requires or []
                ]
            )
        else:
            constraints.extend(
                parse_requirements(
                    src_file,
                    finder=repository.finder,
                    session=repository.session,
                    options=repository.options,
                )
            )

    extras = tuple(itertools.chain.from_iterable(ex.split(",") for ex in extras))

    if extras and not setup_file_found:
        msg = "--extra has effect only with setup.py and PEP-517 input formats"
        raise click.BadParameter(msg)

    primary_packages = {
        key_from_ireq(ireq) for ireq in constraints if not ireq.constraint
    }

    allowed_upgrades = primary_packages | existing_pins_to_upgrade
    constraints.extend(
        ireq for key, ireq in upgrade_install_reqs.items() if key in allowed_upgrades
    )

    constraints = [req for req in constraints if req.match_markers(extras)]
    for req in constraints:
        drop_extras(req)

    log.debug("Using indexes:")
    with log.indentation():
        for index_url in dedup(repository.finder.index_urls):
            log.debug(redact_auth_from_url(index_url))

    if repository.finder.find_links:
        log.debug("")
        log.debug("Using links:")
        with log.indentation():
            for find_link in dedup(repository.finder.find_links):
                log.debug(redact_auth_from_url(find_link))

    try:
        resolver = Resolver(
            constraints,
            repository,
            prereleases=repository.finder.allow_all_prereleases or pre,
            cache=DependencyCache(cache_dir),
            clear_caches=rebuild,
            allow_unsafe=allow_unsafe,
        )
        results = resolver.resolve(max_rounds=max_rounds)
        hashes = resolver.resolve_hashes(results) if generate_hashes else None
    except PipToolsError as e:
        log.error(str(e))
        sys.exit(2)

    log.debug("")

    ##
    # Output
    ##

    writer = OutputWriter(
        cast(BinaryIO, output_file),
        click_ctx=ctx,
        dry_run=dry_run,
        emit_header=header,
        emit_index_url=emit_index_url,
        emit_trusted_host=emit_trusted_host,
        annotate=annotate,
        annotation_style=annotation_style,
        strip_extras=strip_extras,
        generate_hashes=generate_hashes,
        default_index_url=repository.DEFAULT_INDEX_URL,
        index_urls=repository.finder.index_urls,
        trusted_hosts=repository.finder.trusted_hosts,
        format_control=repository.finder.format_control,
        allow_unsafe=allow_unsafe,
        find_links=repository.finder.find_links,
        emit_find_links=emit_find_links,
        emit_options=emit_options,
    )
    writer.write(
        results=results,
        unsafe_requirements=resolver.unsafe_constraints,
        markers={
            key_from_ireq(ireq): ireq.markers for ireq in constraints if ireq.markers
        },
        hashes=hashes,
    )

    if dry_run:
        log.info("Dry-run, so nothing updated.")