# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

'''Produce a "view" of a Spack DAG.

A "view" is file hierarchy representing the union of a number of
Spack-installed package file hierarchies.  The union is formed from:

- specs resolved from the package names given by the user (the seeds)

- all dependencies of the seeds unless user specifies `--no-dependencies`

- less any specs with names matching the regular expressions given by
  `--exclude`

The `view` can be built and tore down via a number of methods (the "actions"):

- symlink :: a file system view which is a directory hierarchy that is
  the union of the hierarchies of the installed packages in the DAG
  where installed files are referenced via symlinks.

- hardlink :: like the symlink view but hardlinks are used.

- statlink :: a view producing a status report of a symlink or
  hardlink view.

The file system view concept is imspired by Nix, implemented by
brett.viren@gmail.com ca 2016.

All operations on views are performed via proxy objects such as
YamlFilesystemView.

'''
import os

import llnl.util.tty as tty
from llnl.util.link_tree import MergeConflictError
from llnl.util.tty.color import colorize

import spack.environment as ev
import spack.cmd
import spack.store
import spack.schema.projections
from spack.config import validate
from spack.filesystem_view import YamlFilesystemView
from spack.util import spack_yaml as s_yaml

description = "project packages to a compact naming scheme on the filesystem."
section = "environments"
level = "short"

actions_link = ["symlink", "add", "soft", "hardlink", "hard"]
actions_remove = ["remove", "rm"]
actions_status = ["statlink", "status", "check"]


def disambiguate_in_view(specs, view):
    """
        When dealing with querying actions (remove/status) we only need to
        disambiguate among specs in the view
    """
    view_specs = set(view.get_all_specs())

    def squash(matching_specs):
        if not matching_specs:
            tty.die("Spec matches no installed packages.")

        matching_in_view = [ms for ms in matching_specs if ms in view_specs]

        if len(matching_in_view) > 1:
            args = ["Spec matches multiple packages.",
                    "Matching packages:"]
            args += [colorize("  @K{%s} " % s.dag_hash(7)) +
                     s.cformat('$_$@$%@$=') for s in matching_in_view]
            args += ["Use a more specific spec."]
            tty.die(*args)

        return matching_in_view[0] if matching_in_view else matching_specs[0]

    # make function always return a list to keep consistency between py2/3
    return list(map(squash, map(spack.store.db.query, specs)))


def setup_parser(sp):
    setup_parser.parser = sp

    sp.add_argument(
        '-v', '--verbose', action='store_true', default=False,
        help="If not verbose only warnings/errors will be printed.")
    sp.add_argument(
        '-e', '--exclude', action='append', default=[],
        help="exclude packages with names matching the given regex pattern")
    sp.add_argument(
        '-d', '--dependencies', choices=['true', 'false', 'yes', 'no'],
        default='true',
        help="Link/remove/list dependencies.")

    ssp = sp.add_subparsers(metavar='ACTION', dest='action')

    specs_opts = dict(metavar='spec', action='store',
                      help="seed specs of the packages to view")

    # The action parameterizes the command but in keeping with Spack
    # patterns we make it a subcommand.
    file_system_view_actions = {
        "symlink": ssp.add_parser(
            'symlink', aliases=['add', 'soft'],
            help='add package files to a filesystem view via symbolic links'),
        "hardlink": ssp.add_parser(
            'hardlink', aliases=['hard'],
            help='add packages files to a filesystem via via hard links'),
        "remove": ssp.add_parser(
            'remove', aliases=['rm'],
            help='remove packages from a filesystem view'),
        "statlink": ssp.add_parser(
            'statlink', aliases=['status', 'check'],
            help='check status of packages in a filesystem view')
    }

    # All these options and arguments are common to every action.
    for cmd, act in file_system_view_actions.items():
        act.add_argument('path', nargs=1,
                         help="path to file system view directory")

        if cmd in ("symlink", "hardlink"):
            # invalid for remove/statlink, for those commands the view needs to
            # already know its own projections.
            help_msg = "Initialize view using projections from file."
            act.add_argument('--projection-file', dest='projection_file',
                             type=spack.cmd.extant_file, help=help_msg)

        if cmd == "remove":
            grp = act.add_mutually_exclusive_group(required=True)
            act.add_argument(
                '--no-remove-dependents', action="store_true",
                help="Do not remove dependents of specified specs.")

            # with all option, spec is an optional argument
            so = specs_opts.copy()
            so["nargs"] = "*"
            so["default"] = []
            grp.add_argument('specs', **so)
            grp.add_argument("-a", "--all", action='store_true',
                             help="act on all specs in view")

        elif cmd == "statlink":
            so = specs_opts.copy()
            so["nargs"] = "*"
            act.add_argument('specs', **so)

        else:
            # without all option, spec is required
            so = specs_opts.copy()
            so["nargs"] = "+"
            act.add_argument('specs', **so)

    for cmd in ["symlink", "hardlink"]:
        act = file_system_view_actions[cmd]
        act.add_argument("-i", "--ignore-conflicts", action='store_true')

    return


def view(parser, args):
    'Produce a view of a set of packages.'

    specs = spack.cmd.parse_specs(args.specs)
    path = args.path[0]

    if args.action in actions_link and args.projection_file:
        # argparse confirms file exists
        with open(args.projection_file, 'r') as f:
            projections_data = s_yaml.load(f)
            validate(projections_data, spack.schema.projections.schema)
            ordered_projections = projections_data['projections']
    else:
        ordered_projections = {}

    view = YamlFilesystemView(
        path, spack.store.layout,
        projections=ordered_projections,
        ignore_conflicts=getattr(args, "ignore_conflicts", False),
        link=os.link if args.action in ["hardlink", "hard"] else os.symlink,
        verbose=args.verbose)

    # Process common args and specs
    if getattr(args, "all", False):
        specs = view.get_all_specs()
        if len(specs) == 0:
            tty.warn("Found no specs in %s" % path)

    elif args.action in actions_link:
        # only link commands need to disambiguate specs
        env = ev.get_env(args, 'view link')
        specs = [spack.cmd.disambiguate_spec(s, env) for s in specs]

    elif args.action in actions_status:
        # no specs implies all
        if len(specs) == 0:
            specs = view.get_all_specs()
        else:
            specs = disambiguate_in_view(specs, view)

    else:
        # status and remove can map a partial spec to packages in view
        specs = disambiguate_in_view(specs, view)

    with_dependencies = args.dependencies.lower() in ['true', 'yes']

    # Map action to corresponding functionality
    if args.action in actions_link:
        try:
            view.add_specs(*specs,
                           with_dependencies=with_dependencies,
                           exclude=args.exclude)
        except MergeConflictError:
            tty.info("Some file blocked the merge, adding the '-i' flag will "
                     "ignore this conflict. For more information see e.g. "
                     "https://github.com/spack/spack/issues/9029")
            raise

    elif args.action in actions_remove:
        view.remove_specs(*specs,
                          with_dependencies=with_dependencies,
                          exclude=args.exclude,
                          with_dependents=not args.no_remove_dependents)

    elif args.action in actions_status:
        view.print_status(*specs, with_dependencies=with_dependencies)

    else:
        tty.error('Unknown action: "%s"' % args.action)
