import datetime
import os
import pathlib
import re
import subprocess
import sys

import invoke
from parver import Version

from pipenv.__version__ import __version__
from pipenv.utils.shell import temp_environ

from .vendoring import _get_git_root, drop_dir

VERSION_FILE = "pipenv/__version__.py"
ROOT = pathlib.Path(".").parent.parent.absolute()
PACKAGE_NAME = "pipenv"


def log(msg):
    print("[release] %s" % msg)


def get_version_file(ctx):
    return _get_git_root(ctx).joinpath(VERSION_FILE)


def find_version(ctx):
    version_file = get_version_file(ctx).read_text()
    version_match = re.search(r"^__version__ = ['\"]([^'\"]*)['\"]", version_file, re.M)
    if version_match:
        return version_match.group(1)
    raise RuntimeError("Unable to find version string.")


def get_history_file(ctx):
    return _get_git_root(ctx).joinpath("HISTORY.txt")


def get_dist_dir(ctx):
    return _get_git_root(ctx) / "dist"


def get_build_dir(ctx):
    return _get_git_root(ctx) / "build"


def _render_log():
    """Totally tap into Towncrier internals to get an in-memory result."""
    rendered = subprocess.check_output(["towncrier", "--draft"]).decode("utf-8")
    return rendered


release_help = {
    "manual": "Build the man pages.",
    "dry_run": "No-op, simulate what would happen if run for real.",
    "local": "Build package locally and upload to PyPI.",
    "pre": "Build a pre-release version, must be paired with a tag.",
    "tag": "A release tag, e.g. 'a', 'b', 'rc', 'post'.",
    "month_offset": "How many months to offset the release date by.",
}


@invoke.task(help=release_help)
def release(
    ctx,
    manual=False,
    local=False,
    dry_run=False,
    pre=False,
    tag=None,
    month_offset="0",
    version=None,
):
    trunc_month = False
    if pre:
        trunc_month = True
    drop_dist_dirs(ctx)
    if not version:
        version = bump_version(
            ctx,
            dry_run=dry_run,
            pre=pre,
            tag=tag,
            month_offset=month_offset,
            trunc_month=trunc_month,
        )
    version = bump_version(
        ctx,
        dry_run=dry_run,
        pre=pre,
        tag=tag,
        month_offset=month_offset,
        trunc_month=trunc_month,
    )
    tag_content = _render_log()
    if dry_run:
        ctx.run("towncrier --draft > CHANGELOG.draft.md")
        log("would remove: news/*")
        log("would remove: CHANGELOG.draft.md")
        log("would update: pipenv/pipenv.1")
        log(f'Would commit with message: "Release v{version}"')
    else:
        if pre:
            log("generating towncrier draft...")
            ctx.run("towncrier --draft > CHANGELOG.draft.md")
            ctx.run(f"git add {get_version_file(ctx).as_posix()}")
        else:
            ctx.run("towncrier")
            ctx.run(f"git add CHANGELOG.md news/ {get_version_file(ctx).as_posix()}")
            log("removing changelog draft if present")
            draft_changelog = pathlib.Path("CHANGELOG.draft.md")
            if draft_changelog.exists():
                draft_changelog.unlink()
        log("generating man files...")
        generate_manual(ctx)
        ctx.run("git add pipenv/pipenv.1")
        ctx.run(f'git commit -m "Release v{version}"')

    tag_content = tag_content.replace('"', '\\"')
    if dry_run or pre:
        log(f"Generated tag content: {tag_content}")
        # draft_rstfile = "CHANGELOG.draft.rst"
        # markdown_path = pathlib.Path(draft_rstfile).with_suffix(".md")
        # generate_markdown(ctx, source_rstfile=draft_rstfile)
        # clean_mdchangelog(ctx, markdown_path.as_posix())
        # log(f"would generate markdown: {markdown_path.read_text()}")
        if not dry_run:
            ctx.run(f'git tag -a v{version} -m "Version v{version}\n\n{tag_content}"')
    else:
        # generate_markdown(ctx)
        # clean_mdchangelog(ctx)
        ctx.run(f'git tag -a v{version} -m "Version v{version}\n\n{tag_content}"')
    if local:
        build_dists(ctx)
        dist_pattern = f'{PACKAGE_NAME.replace("-", "[-_]")}-*'
        artifacts = list(ROOT.joinpath("dist").glob(dist_pattern))
        if dry_run:
            filename_display = "\n".join(f"  {a}" for a in artifacts)
            log(f"Would upload dists: {filename_display}")
        else:
            upload_dists(ctx)
            bump_version(ctx, dev=True)


def drop_dist_dirs(ctx):
    log("Dropping Dist dir...")
    drop_dir(get_dist_dir(ctx))
    log("Dropping build dir...")
    drop_dir(get_build_dir(ctx))


@invoke.task
def build_dists(ctx):
    drop_dist_dirs(ctx)
    py_version = ".".join(str(v) for v in sys.version_info[:2])
    env = {"PIPENV_PYTHON": py_version}
    with ctx.cd(ROOT.as_posix()), temp_environ():
        executable = ctx.run(
            "python -c 'import sys; print(sys.executable)'", hide=True
        ).stdout.strip()
        log("Building sdist using %s ...." % executable)
        os.environ["PIPENV_PYTHON"] = py_version
        ctx.run("pipenv install --dev", env=env)
        ctx.run("pipenv run pip install -e . --upgrade --upgrade-strategy=eager", env=env)
        log("Building wheel using python %s ...." % py_version)
        ctx.run("pipenv run python -m build", env=env)


@invoke.task(build_dists)
def upload_dists(ctx, repo="pypi"):
    dist_pattern = f'{PACKAGE_NAME.replace("-", "[-_]")}-*'
    artifacts = list(ROOT.joinpath("dist").glob(dist_pattern))
    filename_display = "\n".join(f"  {a}" for a in artifacts)
    print(f"[release] Will upload:\n{filename_display}")
    try:
        input("[release] Release ready. ENTER to upload, CTRL-C to abort: ")
    except KeyboardInterrupt:
        print("\nAborted!")
        return

    arg_display = " ".join(f'"{n}"' for n in artifacts)
    ctx.run(f'twine upload --repository="{repo}" {arg_display}')


@invoke.task
def generate_markdown(ctx, source_rstfile=None):
    log("Generating markdown from changelog...")
    if source_rstfile is None:
        source_rstfile = "CHANGELOG.md"
    source_file = pathlib.Path(source_rstfile)
    dest_file = source_file.with_suffix(".md")
    ctx.run(
        f"pandoc {source_file.as_posix()} -f rst -t markdown -o {dest_file.as_posix()}"
    )


@invoke.task
def generate_manual(ctx, commit=False):
    log("Generating manual from reStructuredText source...")
    ctx.run("make man")
    ctx.run("cp docs/_build/man/pipenv.1 pipenv/")
    if commit:
        log("Committing...")
        ctx.run("git add pipenv/pipenv.1")
        ctx.run('git commit -m "Update manual page."')


@invoke.task
def generate_contributing_md(ctx, commit=False):
    log("Generating CONTRIBUTING.md from reStructuredText source...")
    ctx.run("pandoc docs/dev/contributing.rst -f rst -t markdown -o CONTRIBUTING.md")
    if commit:
        log("Committing...")
        ctx.run("git add CONTRIBUTING.md")
        ctx.run('git commit -m "Update CONTRIBUTING.md."')


@invoke.task
def generate_changelog(ctx, commit=False, draft=False):
    log("Generating changelog...")
    if draft:
        commit = False
        log("Writing draft to file...")
        ctx.run("towncrier --draft > CHANGELOG.draft.md")
    else:
        ctx.run("towncrier")
    if commit:
        log("Committing...")
        ctx.run("git add CHANGELOG.md")
        ctx.run("git rm CHANGELOG.draft.md")
        ctx.run('git commit -m "Update changelog."')


@invoke.task
def clean_mdchangelog(ctx, filename=None, content=None):
    changelog = None
    if not content:
        if filename is not None:
            changelog = pathlib.Path(filename)
        else:
            changelog = _get_git_root(ctx) / "CHANGELOG.md"
        content = changelog.read_text()
    content = re.sub(
        r"([^\n]+)\n?\s+\[[\\]+(#\d+)\]\(https://github\.com/pypa/[\w\-]+/issues/\d+\)",
        r"\1 \2",
        content,
        flags=re.MULTILINE,
    )
    if changelog:
        changelog.write_text(content)
    else:
        return content


@invoke.task
def tag_version(ctx, push=False):
    version = find_version(ctx)
    version = Version.parse(version)
    log("Tagging revision: v%s" % version.normalize())
    ctx.run("git tag v%s" % version.normalize())
    if push:
        log("Pushing tags...")
        ctx.run("git push origin master")
        ctx.run("git push --tags")


def add_one_day(dt):
    return dt + datetime.timedelta(days=1)


def date_offset(dt, month_offset=0, day_offset=0, truncate=False):
    new_month = (dt.month + month_offset) % 12
    year_offset = new_month // 12
    replace_args = {
        "month": dt.month + month_offset,
        "year": dt.year + year_offset,
    }
    log(
        "Getting updated date from date: {} using month offset: {} and year offset {}".format(
            dt, new_month, replace_args["year"]
        )
    )
    if day_offset:
        dt = dt + datetime.timedelta(days=day_offset)
        log(f"updated date using day offset: {day_offset} => {dt}")
    if truncate:
        log("Truncating...")
        replace_args["day"] = 1
    return dt.replace(**replace_args)


@invoke.task
def bump_version(
    ctx,
    dry_run=False,
    dev=False,
    pre=False,
    tag=None,
    commit=False,
    month_offset="0",
    trunc_month=False,
):
    current_version = Version.parse(__version__)
    current_date = datetime.date(*current_version.release)
    today = datetime.date.today()
    day_offset = 0
    month_offset = int(month_offset)
    if month_offset:
        # if we are offsetting by a month, grab the first day of the month
        trunc_month = True
    elif (
        current_date == today
        and not current_version.is_prerelease
        and not current_version.is_release_candidate
    ):
        day_offset = 1
    target_day = date_offset(
        today, month_offset=month_offset, day_offset=day_offset, truncate=trunc_month
    )
    log(f"target_day: {target_day}")
    target_timetuple = target_day.timetuple()[:3]
    new_version = current_version.replace(release=target_timetuple)
    if pre and dev:
        raise RuntimeError("Can't use 'pre' and 'dev' together!")
    if dev:
        new_version = new_version.replace(pre=None).bump_dev()
    elif pre:
        if not tag:
            print('Using "pre" requires a corresponding tag.')
            return
        tag_version = re.match(
            r"(?P<tag>alpha|a|beta|b|c|preview|pre|rc)(?P<version>[0-9]+)?", tag
        )
        tag_dict = tag_version.groupdict()
        tag = tag_dict.get("tag", tag)
        tag_version = int(tag_dict["version"]) if tag_dict["version"] is not None else 0
        if new_version.dev is not None:
            new_version = new_version.replace(dev=None)
        if new_version.pre_tag:
            if new_version.pre_tag != tag:
                log(f"Swapping prerelease tag: {new_version.pre_tag} for {tag}")
                new_version = new_version.replace(pre_tag=tag, pre=tag_version)
        else:
            new_version = new_version.replace(pre_tag=tag, pre=tag_version)
        if tag_version == 0:
            new_version = new_version.bump_pre(tag=tag)
    else:
        new_version = new_version.replace(pre=None, dev=None)
    log("Updating version to %s" % new_version.normalize())
    version = find_version(ctx)
    log("Found current version: %s" % version)
    if dry_run:
        log("Would update to: %s" % new_version.normalize())
    else:
        log("Updating to: %s" % new_version.normalize())
        version_file = get_version_file(ctx)
        file_contents = version_file.read_text()
        version_file.write_text(
            file_contents.replace(version, str(new_version.normalize()))
        )
        if commit:
            ctx.run(f"git add {version_file.as_posix()}")
            log("Committing...")
            ctx.run('git commit -s -m "Bumped version."')
    return str(new_version)
