#
#  Copyright (C) 2018 Codethink Limited
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU Lesser General Public
#  License as published by the Free Software Foundation; either
#  version 2 of the License, or (at your option) any later version.
#
#  This library 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
#  Lesser General Public License for more details.
#
#  You should have received a copy of the GNU Lesser General Public
#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
#
#  Authors:
#        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>

from collections.abc import Mapping

from .._exceptions import LoadError, LoadErrorReason
from .. import _yaml


# Symbol():
#
# A simple object to denote the symbols we load with from YAML
#
class Symbol():
    FILENAME = "filename"
    KIND = "kind"
    DEPENDS = "depends"
    BUILD_DEPENDS = "build-depends"
    RUNTIME_DEPENDS = "runtime-depends"
    SOURCES = "sources"
    CONFIG = "config"
    VARIABLES = "variables"
    ENVIRONMENT = "environment"
    ENV_NOCACHE = "environment-nocache"
    PUBLIC = "public"
    TYPE = "type"
    BUILD = "build"
    RUNTIME = "runtime"
    ALL = "all"
    DIRECTORY = "directory"
    JUNCTION = "junction"
    SANDBOX = "sandbox"
    STRICT = "strict"


# Dependency()
#
# A simple object describing a dependency
#
# Args:
#    name (str): The element name
#    dep_type (str): The type of dependency, can be
#                    Symbol.ALL, Symbol.BUILD, or Symbol.RUNTIME
#    junction (str): The element name of the junction, or None
#    provenance (Provenance): The YAML node provenance of where this
#                             dependency was declared
#
class Dependency():
    def __init__(self, dep, provenance, default_dep_type=None):
        self.provenance = provenance

        if isinstance(dep, str):
            self.name = dep
            self.dep_type = default_dep_type
            self.junction = None
            self.strict = False

        elif isinstance(dep, Mapping):
            if default_dep_type:
                _yaml.node_validate(dep, ['filename', 'junction', 'strict'])
                dep_type = default_dep_type
            else:
                _yaml.node_validate(dep, ['filename', 'type', 'junction', 'strict'])

                # Make type optional, for this we set it to None
                dep_type = _yaml.node_get(dep, str, Symbol.TYPE, default_value=None)
                if dep_type is None or dep_type == Symbol.ALL:
                    dep_type = None
                elif dep_type not in [Symbol.BUILD, Symbol.RUNTIME]:
                    provenance = _yaml.node_get_provenance(dep, key=Symbol.TYPE)
                    raise LoadError(LoadErrorReason.INVALID_DATA,
                                    "{}: Dependency type '{}' is not 'build', 'runtime' or 'all'"
                                    .format(provenance, dep_type))

            self.name = _yaml.node_get(dep, str, Symbol.FILENAME)
            self.dep_type = dep_type
            self.junction = _yaml.node_get(dep, str, Symbol.JUNCTION, default_value=None)
            self.strict = _yaml.node_get(dep, bool, Symbol.STRICT, default_value=False)

            # Here we disallow explicitly setting 'strict' to False.
            #
            # This is in order to keep the door open to allowing the project.conf
            # set the default of dependency 'strict'-ness which might be useful
            # for projects which use mostly static linking and the like, in which
            # case we can later interpret explicitly non-strict dependencies
            # as an override of the project default.
            #
            if self.strict is False and Symbol.STRICT in dep:
                provenance = _yaml.node_get_provenance(dep, key=Symbol.STRICT)
                raise LoadError(LoadErrorReason.INVALID_DATA,
                                "{}: Setting 'strict' to False is unsupported"
                                .format(provenance))

        else:
            raise LoadError(LoadErrorReason.INVALID_DATA,
                            "{}: Dependency is not specified as a string or a dictionary".format(provenance))

        # Only build dependencies are allowed to be strict
        #
        if self.strict and self.dep_type == Symbol.RUNTIME:
            raise LoadError(LoadErrorReason.INVALID_DATA,
                            "{}: Runtime dependency {} specified as `strict`.".format(self.provenance, self.name),
                            detail="Only dependencies required at build time may be declared `strict`.")

        # `:` characters are not allowed in filename if a junction was
        # explicitly specified
        if self.junction and ':' in self.name:
            raise LoadError(LoadErrorReason.INVALID_DATA,
                            "{}: Dependency {} contains `:` in its name. "
                            "`:` characters are not allowed in filename when "
                            "junction attribute is specified.".format(self.provenance, self.name))

        # Name of the element should never contain more than one `:` characters
        if self.name.count(':') > 1:
            raise LoadError(LoadErrorReason.INVALID_DATA,
                            "{}: Dependency {} contains multiple `:` in its name. "
                            "Recursive lookups for cross-junction elements is not "
                            "allowed.".format(self.provenance, self.name))

        # Attempt to split name if no junction was specified explicitly
        if not self.junction and self.name.count(':') == 1:
            self.junction, self.name = self.name.split(':')