# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible 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 3 of the License, or
# (at your option) any later version.
#
# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.

# Make coding more python3-ish
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import collections
import os

from ansible.compat.six import iteritems, binary_type, text_type
from ansible.errors import AnsibleError, AnsibleParserError
from ansible.playbook.attribute import FieldAttribute
from ansible.playbook.base import Base
from ansible.playbook.become import Become
from ansible.playbook.conditional import Conditional
from ansible.playbook.helpers import load_list_of_blocks
from ansible.playbook.role.metadata import RoleMetadata
from ansible.playbook.taggable import Taggable
from ansible.plugins import get_all_plugin_loaders
from ansible.utils.vars import combine_vars


__all__ = ['Role', 'hash_params']

# TODO: this should be a utility function, but can't be a member of
#       the role due to the fact that it would require the use of self
#       in a static method. This is also used in the base class for
#       strategies (ansible/plugins/strategy/__init__.py)

def hash_params(params):
    """
    Construct a data structure of parameters that is hashable.

    This requires changing any mutable data structures into immutable ones.
    We chose a frozenset because role parameters have to be unique.

    .. warning::  this does not handle unhashable scalars.  Two things
        mitigate that limitation:

        1) There shouldn't be any unhashable scalars specified in the yaml
        2) Our only choice would be to return an error anyway.
    """
    # Any container is unhashable if it contains unhashable items (for
    # instance, tuple() is a Hashable subclass but if it contains a dict, it
    # cannot be hashed)
    if isinstance(params, collections.Container) and not isinstance(params, (text_type, binary_type)):
        if isinstance(params, collections.Mapping):
            try:
                # Optimistically hope the contents are all hashable
                new_params = frozenset(params.items())
            except TypeError:
                new_params = set()
                for k, v in params.items():
                    # Hash each entry individually
                    new_params.update((k, hash_params(v)))
                new_params = frozenset(new_params)

        elif isinstance(params, (collections.Set, collections.Sequence)):
            try:
                # Optimistically hope the contents are all hashable
                new_params = frozenset(params)
            except TypeError:
                new_params = set()
                for v in params:
                    # Hash each entry individually
                    new_params.update(hash_params(v))
                new_params = frozenset(new_params)
        else:
            # This is just a guess.
            new_params = frozenset(params)
        return new_params

    # Note: We do not handle unhashable scalars but our only choice would be
    # to raise an error there anyway.
    return frozenset((params,))


class Role(Base, Become, Conditional, Taggable):

    _delegate_to = FieldAttribute(isa='string')
    _delegate_facts = FieldAttribute(isa='bool', default=False)

    def __init__(self, play=None, from_files=None):
        self._role_name        = None
        self._role_path        = None
        self._role_params      = dict()
        self._loader           = None

        self._metadata         = None
        self._play             = play
        self._parents          = []
        self._dependencies     = []
        self._task_blocks      = []
        self._handler_blocks   = []
        self._default_vars     = dict()
        self._role_vars        = dict()
        self._had_task_run     = dict()
        self._completed        = dict()

        if from_files is None:
            from_files = {}
        self._from_files = from_files

        super(Role, self).__init__()

    def __repr__(self):
        return self.get_name()

    def get_name(self):
        return self._role_name

    @staticmethod
    def load(role_include, play, parent_role=None, from_files=None):

        if from_files is None:
            from_files = {}
        try:
            # The ROLE_CACHE is a dictionary of role names, with each entry
            # containing another dictionary corresponding to a set of parameters
            # specified for a role as the key and the Role() object itself.
            # We use frozenset to make the dictionary hashable.

            params = role_include.get_role_params()
            if role_include.when is not None:
                params['when'] = role_include.when
            if role_include.tags is not None:
                params['tags'] = role_include.tags
            if from_files is not None:
                params['from_files'] = from_files
            if role_include.vars:
                params['vars'] = role_include.vars
            hashed_params = hash_params(params)
            if role_include.role in play.ROLE_CACHE:
                for (entry, role_obj) in iteritems(play.ROLE_CACHE[role_include.role]):
                    if hashed_params == entry:
                        if parent_role:
                            role_obj.add_parent(parent_role)
                        return role_obj

            r = Role(play=play, from_files=from_files)
            r._load_role_data(role_include, parent_role=parent_role)

            if role_include.role not in play.ROLE_CACHE:
                play.ROLE_CACHE[role_include.role] = dict()

            play.ROLE_CACHE[role_include.role][hashed_params] = r
            return r

        except RuntimeError:
            raise AnsibleError("A recursion loop was detected with the roles specified. Make sure child roles do not have dependencies on parent roles", obj=role_include._ds)

    def _load_role_data(self, role_include, parent_role=None):
        self._role_name        = role_include.role
        self._role_path        = role_include.get_role_path()
        self._role_params      = role_include.get_role_params()
        self._variable_manager = role_include.get_variable_manager()
        self._loader           = role_include.get_loader()

        if parent_role:
            self.add_parent(parent_role)

        # copy over all field attributes, except for when and tags, which
        # are special cases and need to preserve pre-existing values
        for (attr_name, _) in iteritems(self._valid_attrs):
            if attr_name not in ('when', 'tags'):
                setattr(self, attr_name, getattr(role_include, attr_name))

        current_when = getattr(self, 'when')[:]
        current_when.extend(role_include.when)
        setattr(self, 'when', current_when)

        current_tags = getattr(self, 'tags')[:]
        current_tags.extend(role_include.tags)
        setattr(self, 'tags', current_tags)

        # dynamically load any plugins from the role directory
        for name, obj in get_all_plugin_loaders():
            if obj.subdir:
                plugin_path = os.path.join(self._role_path, obj.subdir)
                if os.path.isdir(plugin_path):
                    obj.add_directory(plugin_path)

        # load the role's other files, if they exist
        metadata = self._load_role_yaml('meta')
        if metadata:
            self._metadata = RoleMetadata.load(metadata, owner=self, variable_manager=self._variable_manager, loader=self._loader)
            self._dependencies = self._load_dependencies()
        else:
            self._metadata = RoleMetadata()

        task_data = self._load_role_yaml('tasks', main=self._from_files.get('tasks'))
        if task_data:
            try:
                self._task_blocks = load_list_of_blocks(task_data, play=self._play, role=self, loader=self._loader, variable_manager=self._variable_manager)
            except AssertionError:
                raise AnsibleParserError("The tasks/main.yml file for role '%s' must contain a list of tasks" % self._role_name , obj=task_data)

        handler_data = self._load_role_yaml('handlers')
        if handler_data:
            try:
                self._handler_blocks = load_list_of_blocks(handler_data, play=self._play, role=self, use_handlers=True, loader=self._loader, variable_manager=self._variable_manager)
            except AssertionError:
                raise AnsibleParserError("The handlers/main.yml file for role '%s' must contain a list of tasks" % self._role_name , obj=handler_data)

        # vars and default vars are regular dictionaries
        self._role_vars  = self._load_role_yaml('vars', main=self._from_files.get('vars'))
        if self._role_vars is None:
            self._role_vars = dict()
        elif not isinstance(self._role_vars, dict):
            raise AnsibleParserError("The vars/main.yml file for role '%s' must contain a dictionary of variables" % self._role_name)

        self._default_vars = self._load_role_yaml('defaults', main=self._from_files.get('defaults'))
        if self._default_vars is None:
            self._default_vars = dict()
        elif not isinstance(self._default_vars, dict):
            raise AnsibleParserError("The defaults/main.yml file for role '%s' must contain a dictionary of variables" % self._role_name)

    def _load_role_yaml(self, subdir, main=None):
        file_path = os.path.join(self._role_path, subdir)
        if self._loader.path_exists(file_path) and self._loader.is_directory(file_path):
            main_file = self._resolve_main(file_path, main)
            if self._loader.path_exists(main_file):
                return self._loader.load_from_file(main_file)
            elif main is not None:
                raise AnsibleParserError("Could not find specified file in role: %s/%s" % (subdir,main))
        return None

    def _resolve_main(self, basepath, main=None):
        ''' flexibly handle variations in main filenames '''

        post = False
        # allow override if set, otherwise use default
        if main is None:
            main = 'main'
            post = True

        bare_main = os.path.join(basepath, main)

        possible_mains = (
            os.path.join(basepath, '%s.yml' % main),
            os.path.join(basepath, '%s.yaml' % main),
            os.path.join(basepath, '%s.json' % main),
        )

        if post:
            possible_mains = possible_mains + (bare_main,)
        else:
            possible_mains = (bare_main,) + possible_mains

        if sum([self._loader.is_file(x) for x in possible_mains]) > 1:
            raise AnsibleError("found multiple main files at %s, only one allowed" % (basepath))
        else:
            for m in possible_mains:
                if self._loader.is_file(m):
                    return m # exactly one main file
            return possible_mains[0] # zero mains (we still need to return something)

    def _load_dependencies(self):
        '''
        Recursively loads role dependencies from the metadata list of
        dependencies, if it exists
        '''

        deps = []
        if self._metadata:
            for role_include in self._metadata.dependencies:
                r = Role.load(role_include, play=self._play, parent_role=self)
                deps.append(r)

        return deps

    #------------------------------------------------------------------------------
    # other functions

    def add_parent(self, parent_role):
        ''' adds a role to the list of this roles parents '''
        assert isinstance(parent_role, Role)

        if parent_role not in self._parents:
            self._parents.append(parent_role)

    def get_parents(self):
        return self._parents

    def get_default_vars(self, dep_chain=[]):
        default_vars = dict()
        for dep in self.get_all_dependencies():
            default_vars = combine_vars(default_vars, dep.get_default_vars())
        if dep_chain:
            for parent in dep_chain:
                default_vars = combine_vars(default_vars, parent._default_vars)
        default_vars = combine_vars(default_vars, self._default_vars)
        return default_vars

    def get_inherited_vars(self, dep_chain=[]):
        inherited_vars = dict()

        if dep_chain:
            for parent in dep_chain:
                inherited_vars = combine_vars(inherited_vars, parent._role_vars)
        return inherited_vars

    def get_role_params(self, dep_chain=[]):
        params = {}
        if dep_chain:
            for parent in dep_chain:
                params = combine_vars(params, parent._role_params)
        params = combine_vars(params, self._role_params)
        return params

    def get_vars(self, dep_chain=[], include_params=True):
        all_vars = self.get_inherited_vars(dep_chain)

        for dep in self.get_all_dependencies():
            all_vars = combine_vars(all_vars, dep.get_vars(include_params=include_params))

        all_vars = combine_vars(all_vars, self.vars)
        all_vars = combine_vars(all_vars, self._role_vars)
        if include_params:
            all_vars = combine_vars(all_vars, self.get_role_params(dep_chain=dep_chain))

        return all_vars

    def get_direct_dependencies(self):
        return self._dependencies[:]

    def get_all_dependencies(self):
        '''
        Returns a list of all deps, built recursively from all child dependencies,
        in the proper order in which they should be executed or evaluated.
        '''

        child_deps  = []

        for dep in self.get_direct_dependencies():
            for child_dep in dep.get_all_dependencies():
                child_deps.append(child_dep)
            child_deps.append(dep)

        return child_deps

    def get_task_blocks(self):
        return self._task_blocks[:]

    def get_handler_blocks(self, play, dep_chain=None):
        block_list = []

        # update the dependency chain here
        if dep_chain is None:
            dep_chain = []
        new_dep_chain = dep_chain + [self]

        for dep in self.get_direct_dependencies():
            dep_blocks = dep.get_handler_blocks(play=play, dep_chain=new_dep_chain)
            block_list.extend(dep_blocks)

        for task_block in self._handler_blocks:
            new_task_block = task_block.copy()
            new_task_block._dep_chain = new_dep_chain
            new_task_block._play = play
            block_list.append(new_task_block)

        return block_list

    def has_run(self, host):
        '''
        Returns true if this role has been iterated over completely and
        at least one task was run
        '''

        return host.name in self._completed and not self._metadata.allow_duplicates

    def compile(self, play, dep_chain=None):
        '''
        Returns the task list for this role, which is created by first
        recursively compiling the tasks for all direct dependencies, and
        then adding on the tasks for this role.

        The role compile() also remembers and saves the dependency chain
        with each task, so tasks know by which route they were found, and
        can correctly take their parent's tags/conditionals into account.
        '''

        block_list = []

        # update the dependency chain here
        if dep_chain is None:
            dep_chain = []
        new_dep_chain = dep_chain + [self]

        deps = self.get_direct_dependencies()
        for dep in deps:
            dep_blocks = dep.compile(play=play, dep_chain=new_dep_chain)
            block_list.extend(dep_blocks)

        for idx, task_block in enumerate(self._task_blocks):
            new_task_block = task_block.copy(exclude_parent=True)
            if task_block._parent:
                new_task_block._parent = task_block._parent.copy()
            new_task_block._dep_chain = new_dep_chain
            new_task_block._play = play
            if idx == len(self._task_blocks) - 1:
                new_task_block._eor = True
            block_list.append(new_task_block)

        return block_list

    def serialize(self, include_deps=True):
        res = super(Role, self).serialize()

        res['_role_name']    = self._role_name
        res['_role_path']    = self._role_path
        res['_role_vars']    = self._role_vars
        res['_role_params']  = self._role_params
        res['_default_vars'] = self._default_vars
        res['_had_task_run'] = self._had_task_run.copy()
        res['_completed']    = self._completed.copy()

        if self._metadata:
            res['_metadata'] = self._metadata.serialize()

        if include_deps:
            deps = []
            for role in self.get_direct_dependencies():
                deps.append(role.serialize())
            res['_dependencies'] = deps

        parents = []
        for parent in self._parents:
            parents.append(parent.serialize(include_deps=False))
        res['_parents'] = parents

        return res

    def deserialize(self, data, include_deps=True):
        self._role_name    = data.get('_role_name', '')
        self._role_path    = data.get('_role_path', '')
        self._role_vars    = data.get('_role_vars', dict())
        self._role_params  = data.get('_role_params', dict())
        self._default_vars = data.get('_default_vars', dict())
        self._had_task_run = data.get('_had_task_run', dict())
        self._completed    = data.get('_completed', dict())

        if include_deps:
            deps = []
            for dep in data.get('_dependencies', []):
                r = Role()
                r.deserialize(dep)
                deps.append(r)
            setattr(self, '_dependencies', deps)

        parent_data = data.get('_parents', [])
        parents = []
        for parent in parent_data:
            r = Role()
            r.deserialize(parent, include_deps=False)
            parents.append(r)
        setattr(self, '_parents', parents)

        metadata_data = data.get('_metadata')
        if metadata_data:
            m = RoleMetadata()
            m.deserialize(metadata_data)
            self._metadata = m

        super(Role, self).deserialize(data)

    def set_loader(self, loader):
        self._loader = loader
        for parent in self._parents:
            parent.set_loader(loader)
        for dep in self.get_direct_dependencies():
            dep.set_loader(loader)

