# Copyright (C) 2012 Anaconda, Inc
# SPDX-License-Identifier: BSD-3-Clause
"""Conda-flavored installer."""
import tempfile
from os.path import basename

from boltons.setutils import IndexedSet

from ...base.constants import UpdateModifier
from ...base.context import context
from ...common.constants import NULL
from ...env.env import Environment
from ...exceptions import UnsatisfiableError
from ...models.channel import Channel, prioritize_channels


def _solve(prefix, specs, args, env, *_, **kwargs):
    """Solve the environment"""
    # TODO: support all various ways this happens
    # Including 'nodefaults' in the channels list disables the defaults
    channel_urls = [chan for chan in env.channels if chan != "nodefaults"]

    if "nodefaults" not in env.channels:
        channel_urls.extend(context.channels)
    _channel_priority_map = prioritize_channels(channel_urls)

    channels = IndexedSet(Channel(url) for url in _channel_priority_map)
    subdirs = IndexedSet(basename(url) for url in _channel_priority_map)

    solver_backend = context.plugin_manager.get_cached_solver_backend()
    solver = solver_backend(prefix, channels, subdirs, specs_to_add=specs)
    return solver


def dry_run(specs, args, env, *_, **kwargs):
    """Do a dry run of the environment solve"""
    solver = _solve(tempfile.mkdtemp(), specs, args, env, *_, **kwargs)
    pkgs = solver.solve_final_state()
    solved_env = Environment(
        name=env.name, dependencies=[str(p) for p in pkgs], channels=env.channels
    )
    return solved_env


def install(prefix, specs, args, env, *_, **kwargs):
    """Install packages into an environment"""
    solver = _solve(prefix, specs, args, env, *_, **kwargs)

    try:
        unlink_link_transaction = solver.solve_for_transaction(
            prune=getattr(args, "prune", False),
            update_modifier=UpdateModifier.FREEZE_INSTALLED,
        )
    except (UnsatisfiableError, SystemExit):
        unlink_link_transaction = solver.solve_for_transaction(
            prune=getattr(args, "prune", False), update_modifier=NULL
        )

    if unlink_link_transaction.nothing_to_do:
        return None
    unlink_link_transaction.download_and_extract()
    unlink_link_transaction.execute()
    return unlink_link_transaction._make_legacy_action_groups()[0]
