#!/usr/bin/python3
# Copyright (C) 2019 Jelmer Vernooij
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA


"""Debhelper utility functions."""

import json
import os
import subprocess
from functools import cache
from typing import Callable, Dict, List, Optional, Tuple

from debmutate._rules import (
    dh_invoke_add_with,
    dh_invoke_drop_with,
    update_rules,
)
from debmutate.control import add_dependency, drop_dependency

from debian.changelog import Version

DEBHELPER_BUILD_STEPS = ["configure", "build", "test", "install", "clean"]


def detect_debhelper_buildsystem(step: Optional[str] = None) -> Optional[str]:
    """Detect the build system for debhelper.

    Args:
      step: Optional step to determine the buildsystem for
    Returns:
      Build system name or None, if none could be found
    """
    if os.path.exists("configure.ac") or os.path.exists("configure.in"):
        return "autoconf"
    env = {'PATH': os.environ['PATH']}
    # Necessary for debhelper (<= 13.5.2), or it'll write debian/.debhelper
    # files.
    env["DH_NO_ACT"] = "1"
    output = subprocess.check_output(
        ["dh_assistant", "which-build-system"], env=env
    ).decode()
    return json.loads(output)["build-system"]


@cache
def _get_lintian_compat_levels() -> Dict[str, int]:
    # TODO(jelmer): ideally we should be getting these numbers from the
    # compat-release dh_assistant, rather than what's on the system
    output = subprocess.check_output(
        ["dh_assistant", "supported-compat-levels"]
    ).decode()
    return json.loads(output)


def lowest_non_deprecated_compat_level() -> int:
    """Find the lowest non-deprecated debhelper compat level."""
    return _get_lintian_compat_levels()["LOWEST_NON_DEPRECATED_COMPAT_LEVEL"]


def highest_stable_compat_level() -> int:
    """Find the highest stable debhelper compat level."""
    return _get_lintian_compat_levels()["HIGHEST_STABLE_COMPAT_LEVEL"]


def maximum_debhelper_compat_version(compat_release: str) -> int:
    """Retrieve the maximum supported debhelper compat version fior a release.

    Args:
      compat_release: A release name (Debian or Ubuntu, currently)

    Returns:
      debhelper compat version
    """
    from .release_info import key_package_version

    debhelper_version = key_package_version("debhelper", compat_release)
    if debhelper_version is None:
        max_version = lowest_non_deprecated_compat_level()
    else:
        max_version = int(str(debhelper_version).split(".")[0])
    return max_version


def write_rules_template(
    path: str,
    buildsystem: Optional[str] = None,
    addons: Optional[List[str]] = None,
    env: Optional[Dict[str, str]] = None,
) -> None:
    if addons is None:
        addons = []
    dh_args = ["$@"]
    if buildsystem:
        dh_args.append(f"--buildsystem={buildsystem}")
    for addon in addons:
        dh_args.append(f"--with={addon}")

    with open(path, "w") as f:
        f.write(
            """\
#!/usr/bin/make -f

"""
        )
        if env:
            for key, value in env.items():
                f.write(f"export {key} := {value}\n")
            f.write("\n")

        f.write(
            """\
%:
\tdh """
            + " ".join(dh_args)
            + """
"""
        )
    os.chmod(path, 0o755)


def drop_obsolete_maintscript_entries(
    editor, should_remove: Callable[[str, Version], bool]
) -> List[Tuple[int, str, Version]]:
    """Drop obsolete entries from a maintscript file.

    Args:
      editor: editor to use to access the maintscript
      should_remove: callable to check whether a package/version tuple is
        obsolete
    Returns:
      list of tuples with index, package, version of entries that were removed
    """
    remove: List[Tuple[int, Optional[str], Optional[Version]]] = []
    comments = []
    ret = []
    for i, entry in enumerate(list(editor.lines)):
        if isinstance(entry, str):
            comments.append((i, None, None))
            continue
        prior_version = getattr(entry, "prior_version", None)
        if prior_version is not None and should_remove(
            entry.package, Version(prior_version)
        ):
            remove.extend(comments)
            remove.append((i, entry.package, Version(prior_version)))
            ret.append((i, entry.package, Version(prior_version)))
        comments = []
    for i, _pkg, _version in reversed(remove):
        del editor.lines[i]
    return ret


def drop_sequence(control, rules, sequence):
    new_depends = drop_dependency(
        control.source.get("Build-Depends", ""), "dh-" + sequence
    )
    if new_depends != control.source["Build-Depends"]:

        def drop_with(line, target):
            return dh_invoke_drop_with(
                line, sequence.replace("-", "_").encode()
            )

        update_rules(drop_with)
    new_depends = drop_dependency(new_depends, "dh-sequence-" + sequence)
    if control["Build-Depends"] == new_depends:
        return False
    control["Build-Depends"] = new_depends
    return True


def add_sequence(control, rules, sequence):
    control.source["Build-Depends"] = add_dependency(
        control.source.get("Build-Depends"), "dh-vim-addon"
    )

    def add_with(line, target):
        if line.startswith(b"dh ") or line.startswith(b"dh_"):
            return dh_invoke_add_with(
                line, sequence.replace("-", "_").encode()
            )
        return line

    update_rules(add_with)
