# (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

from ansible.compat.six.moves import queue as Queue
from ansible.compat.six import iteritems, text_type, string_types

import json
import time
import zlib

from jinja2.exceptions import UndefinedError

from ansible import constants as C
from ansible.errors import AnsibleError, AnsibleParserError, AnsibleUndefinedVariable
from ansible.executor.play_iterator import PlayIterator
from ansible.executor.process.worker import WorkerProcess
from ansible.executor.task_result import TaskResult
from ansible.inventory.host import Host
from ansible.inventory.group import Group
from ansible.playbook.helpers import load_list_of_blocks
from ansible.playbook.included_file import IncludedFile
from ansible.plugins import action_loader, connection_loader, filter_loader, lookup_loader, module_loader, test_loader
from ansible.template import Templar
from ansible.vars.unsafe_proxy import wrap_var

try:
    from __main__ import display
except ImportError:
    from ansible.utils.display import Display
    display = Display()

__all__ = ['StrategyBase']


# TODO: this should probably be in the plugins/__init__.py, with
#       a smarter mechanism to set all of the attributes based on
#       the loaders created there
class SharedPluginLoaderObj:
    '''
    A simple object to make pass the various plugin loaders to
    the forked processes over the queue easier
    '''
    def __init__(self):
        self.action_loader = action_loader
        self.connection_loader = connection_loader
        self.filter_loader = filter_loader
        self.test_loader   = test_loader
        self.lookup_loader = lookup_loader
        self.module_loader = module_loader


class StrategyBase:

    '''
    This is the base class for strategy plugins, which contains some common
    code useful to all strategies like running handlers, cleanup actions, etc.
    '''

    def __init__(self, tqm):
        self._tqm               = tqm
        self._inventory         = tqm.get_inventory()
        self._workers           = tqm.get_workers()
        self._notified_handlers = tqm.get_notified_handlers()
        self._variable_manager  = tqm.get_variable_manager()
        self._loader            = tqm.get_loader()
        self._final_q           = tqm._final_q
        self._step              = getattr(tqm._options, 'step', False)
        self._diff              = getattr(tqm._options, 'diff', False)
        # Backwards compat: self._display isn't really needed, just import the global display and use that.
        self._display           = display

        # internal counters
        self._pending_results   = 0
        self._cur_worker        = 0

        # this dictionary is used to keep track of hosts that have
        # outstanding tasks still in queue
        self._blocked_hosts     = dict()

    def run(self, iterator, play_context, result=True):
        # save the failed/unreachable hosts, as the run_handlers()
        # method will clear that information during its execution
        failed_hosts      = self._tqm._failed_hosts.keys()
        unreachable_hosts = self._tqm._unreachable_hosts.keys()

        display.debug("running handlers")
        result &= self.run_handlers(iterator, play_context)

        # now update with the hosts (if any) that failed or were
        # unreachable during the handler execution phase
        failed_hosts      = set(failed_hosts).union(self._tqm._failed_hosts.keys())
        unreachable_hosts = set(unreachable_hosts).union(self._tqm._unreachable_hosts.keys())

        # return the appropriate code, depending on the status hosts after the run
        if len(unreachable_hosts) > 0:
            return 3
        elif len(failed_hosts) > 0:
            return 2
        elif not result:
            return 1
        else:
            return 0

    def get_hosts_remaining(self, play):
        return [host for host in self._inventory.get_hosts(play.hosts)
                if host.name not in self._tqm._failed_hosts and host.name not in self._tqm._unreachable_hosts]

    def get_failed_hosts(self, play):
        return [host for host in self._inventory.get_hosts(play.hosts) if host.name in self._tqm._failed_hosts]

    def add_tqm_variables(self, vars, play):
        '''
        Base class method to add extra variables/information to the list of task
        vars sent through the executor engine regarding the task queue manager state.
        '''
        vars['ansible_current_hosts'] = [h.name for h in self.get_hosts_remaining(play)]
        vars['ansible_failed_hosts'] = [h.name for h in self.get_failed_hosts(play)]

    def _queue_task(self, host, task, task_vars, play_context):
        ''' handles queueing the task up to be sent to a worker '''

        display.debug("entering _queue_task() for %s/%s" % (host, task))

        task_vars['hostvars'] = self._tqm.hostvars
        # and then queue the new task
        display.debug("%s - putting task (%s) in queue" % (host, task))
        try:
            display.debug("worker is %d (out of %d available)" % (self._cur_worker+1, len(self._workers)))

            # create a dummy object with plugin loaders set as an easier
            # way to share them with the forked processes
            shared_loader_obj = SharedPluginLoaderObj()

            queued = False
            while True:
                (worker_prc, main_q, rslt_q) = self._workers[self._cur_worker]
                if worker_prc is None or not worker_prc.is_alive():
                    worker_prc = WorkerProcess(rslt_q, task_vars, host, task, play_context, self._loader, self._variable_manager, shared_loader_obj)
                    self._workers[self._cur_worker][0] = worker_prc
                    worker_prc.start()
                    queued = True
                self._cur_worker += 1
                if self._cur_worker >= len(self._workers):
                    self._cur_worker = 0
                    time.sleep(0.0001)
                if queued:
                    break

            del task_vars
            self._pending_results += 1
        except (EOFError, IOError, AssertionError) as e:
            # most likely an abort
            display.debug("got an error while queuing: %s" % e)
            return
        display.debug("exiting _queue_task() for %s/%s" % (host, task))

    def _process_pending_results(self, iterator, one_pass=False):
        '''
        Reads results off the final queue and takes appropriate action
        based on the result (executing callbacks, updating state, etc.).
        '''

        ret_results = []

        while not self._final_q.empty() and not self._tqm._terminated:
            try:
                result = self._final_q.get()
                display.debug("got result from result worker: %s" % ([text_type(x) for x in result],))

                # helper method, used to find the original host from the one
                # returned in the result/message, which has been serialized and
                # thus had some information stripped from it to speed up the
                # serialization process
                def get_original_host(host):
                    if host.name in self._inventory._hosts_cache:
                       return self._inventory._hosts_cache[host.name]
                    else:
                       return self._inventory.get_host(host.name)

                # all host status messages contain 2 entries: (msg, task_result)
                if result[0] in ('host_task_ok', 'host_task_failed', 'host_task_skipped', 'host_unreachable'):
                    task_result = result[1]
                    host = get_original_host(task_result._host)
                    task = task_result._task
                    if result[0] == 'host_task_failed' or task_result.is_failed():
                        if not task.ignore_errors:
                            display.debug("marking %s as failed" % host.name)
                            if task.run_once:
                                # if we're using run_once, we have to fail every host here
                                [iterator.mark_host_failed(h) for h in self._inventory.get_hosts(iterator._play.hosts) if h.name not in self._tqm._unreachable_hosts]
                            else:
                                iterator.mark_host_failed(host)
                            (state, tmp_task) = iterator.get_next_task_for_host(host, peek=True)
                            if not state or state.run_state != PlayIterator.ITERATING_RESCUE:
                                self._tqm._failed_hosts[host.name] = True
                                self._tqm._stats.increment('failures', host.name)
                        else:
                            self._tqm._stats.increment('ok', host.name)
                        self._tqm.send_callback('v2_runner_on_failed', task_result, ignore_errors=task.ignore_errors)
                    elif result[0] == 'host_unreachable':
                        self._tqm._unreachable_hosts[host.name] = True
                        self._tqm._stats.increment('dark', host.name)
                        self._tqm.send_callback('v2_runner_on_unreachable', task_result)
                    elif result[0] == 'host_task_skipped':
                        self._tqm._stats.increment('skipped', host.name)
                        self._tqm.send_callback('v2_runner_on_skipped', task_result)
                    elif result[0] == 'host_task_ok':
                        if task.action != 'include':
                            self._tqm._stats.increment('ok', host.name)
                            if 'changed' in task_result._result and task_result._result['changed']:
                                self._tqm._stats.increment('changed', host.name)
                            self._tqm.send_callback('v2_runner_on_ok', task_result)

                        if self._diff:
                            self._tqm.send_callback('v2_on_file_diff', task_result)

                    self._pending_results -= 1
                    if host.name in self._blocked_hosts:
                        del self._blocked_hosts[host.name]

                    # If this is a role task, mark the parent role as being run (if
                    # the task was ok or failed, but not skipped or unreachable)
                    if task_result._task._role is not None and result[0] in ('host_task_ok', 'host_task_failed'):
                        # lookup the role in the ROLE_CACHE to make sure we're dealing
                        # with the correct object and mark it as executed
                        for (entry, role_obj) in iteritems(iterator._play.ROLE_CACHE[task_result._task._role._role_name]):
                            if role_obj._uuid == task_result._task._role._uuid:
                                role_obj._had_task_run[host.name] = True

                    ret_results.append(task_result)

                elif result[0] == 'add_host':
                    result_item = result[1]
                    new_host_info = result_item.get('add_host', dict())

                    self._add_host(new_host_info, iterator)

                elif result[0] == 'add_group':
                    host = get_original_host(result[1])
                    result_item = result[2]
                    self._add_group(host, result_item)

                elif result[0] == 'notify_handler':
                    task_result  = result[1]
                    handler_name = result[2]

                    original_host = get_original_host(task_result._host)
                    original_task = iterator.get_original_task(original_host, task_result._task)
                    if handler_name not in self._notified_handlers:
                        self._notified_handlers[handler_name] = []

                    if original_host not in self._notified_handlers[handler_name]:
                        self._notified_handlers[handler_name].append(original_host)
                        display.vv("NOTIFIED HANDLER %s" % (handler_name,))

                elif result[0] == 'register_host_var':
                    # essentially the same as 'set_host_var' below, however we
                    # never follow the delegate_to value for registered vars and
                    # the variable goes in the fact_cache
                    host      = get_original_host(result[1])
                    task      = result[2]
                    var_value = wrap_var(result[3])
                    var_name  = task.register

                    if task.run_once:
                        host_list = [host for host in self._inventory.get_hosts(iterator._play.hosts) if host.name not in self._tqm._unreachable_hosts]
                    else:
                        host_list = [host]

                    for target_host in host_list:
                        self._variable_manager.set_nonpersistent_facts(target_host, {var_name: var_value})

                elif result[0] in ('set_host_var', 'set_host_facts'):
                    host = get_original_host(result[1])
                    task = result[2]
                    item = result[3]

                    # find the host we're actually refering too here, which may
                    # be a host that is not really in inventory at all
                    if task.delegate_to is not None and task.delegate_facts:
                        task_vars = self._variable_manager.get_vars(loader=self._loader, play=iterator._play, host=host, task=task)
                        self.add_tqm_variables(task_vars, play=iterator._play)
                        if item is not None:
                            task_vars['item'] = item
                        templar = Templar(loader=self._loader, variables=task_vars)
                        host_name = templar.template(task.delegate_to)
                        actual_host = self._inventory.get_host(host_name)
                        if actual_host is None:
                            actual_host = Host(name=host_name)
                    else:
                        actual_host = host

                    if result[0] == 'set_host_var':
                        var_name  = result[4]
                        var_value = result[5]

                        if task.run_once:
                            host_list = [host for host in self._inventory.get_hosts(iterator._play.hosts) if host.name not in self._tqm._unreachable_hosts]
                        else:
                            host_list = [actual_host]

                        for target_host in host_list:
                            self._variable_manager.set_host_variable(target_host, var_name, var_value)
                    elif result[0] == 'set_host_facts':
                        facts = result[4]
                        if task.action == 'set_fact':
                            self._variable_manager.set_nonpersistent_facts(actual_host, facts)
                        else:
                            self._variable_manager.set_host_facts(actual_host, facts)

                else:
                    raise AnsibleError("unknown result message received: %s" % result[0])

            except Queue.Empty:
                time.sleep(0.0001)

            if one_pass:
                break

        return ret_results

    def _wait_on_pending_results(self, iterator):
        '''
        Wait for the shared counter to drop to zero, using a short sleep
        between checks to ensure we don't spin lock
        '''

        ret_results = []

        display.debug("waiting for pending results...")
        while self._pending_results > 0 and not self._tqm._terminated:
            results = self._process_pending_results(iterator)
            ret_results.extend(results)
            time.sleep(0.0001)
        display.debug("no more pending results, returning what we have")

        return ret_results

    def _add_host(self, host_info, iterator):
        '''
        Helper function to add a new host to inventory based on a task result.
        '''

        host_name = host_info.get('host_name')

        # Check if host in cache, add if not
        if host_name in self._inventory._hosts_cache:
            new_host = self._inventory._hosts_cache[host_name]
        else:
            new_host = Host(name=host_name)
            self._inventory._hosts_cache[host_name] = new_host

            allgroup = self._inventory.get_group('all')
            allgroup.add_host(new_host)

        # Set/update the vars for this host
        new_vars = host_info.get('host_vars', dict())
        new_host.vars = self._inventory.get_host_vars(new_host)
        new_host.vars.update(new_vars)

        new_groups = host_info.get('groups', [])
        for group_name in new_groups:
            if not self._inventory.get_group(group_name):
                new_group = Group(group_name)
                self._inventory.add_group(new_group)
                new_group.vars = self._inventory.get_group_variables(group_name)
            else:
                new_group = self._inventory.get_group(group_name)

            new_group.add_host(new_host)

            # add this host to the group cache
            if self._inventory.groups is not None:
                if group_name in self._inventory.groups:
                    if new_host not in self._inventory.get_group(group_name).hosts:
                        self._inventory.get_group(group_name).hosts.append(new_host.name)

        # clear pattern caching completely since it's unpredictable what
        # patterns may have referenced the group
        self._inventory.clear_pattern_cache()

        # also clear the hostvar cache entry for the given play, so that
        # the new hosts are available if hostvars are referenced
        self._variable_manager.invalidate_hostvars_cache(play=iterator._play)

    def _add_group(self, host, result_item):
        '''
        Helper function to add a group (if it does not exist), and to assign the
        specified host to that group.
        '''

        changed = False

        # the host here is from the executor side, which means it was a
        # serialized/cloned copy and we'll need to look up the proper
        # host object from the master inventory
        real_host = self._inventory.get_host(host.name)

        group_name = result_item.get('add_group')
        new_group = self._inventory.get_group(group_name)
        if not new_group:
            # create the new group and add it to inventory
            new_group = Group(name=group_name)
            self._inventory.add_group(new_group)
            new_group.vars = self._inventory.get_group_vars(new_group)

            # and add the group to the proper hierarchy
            allgroup = self._inventory.get_group('all')
            allgroup.add_child_group(new_group)
            changed = True

        if group_name not in host.get_groups():
            new_group.add_host(real_host)
            changed = True

        return changed

    def _load_included_file(self, included_file, iterator, is_handler=False):
        '''
        Loads an included YAML file of tasks, applying the optional set of variables.
        '''

        display.debug("loading included file: %s" % included_file._filename)
        try:
            data = self._loader.load_from_file(included_file._filename)
            if data is None:
                return []
            elif not isinstance(data, list):
                raise AnsibleError("included task files must contain a list of tasks")

            block_list = load_list_of_blocks(
                data,
                play=included_file._task._block._play,
                parent_block=included_file._task._block,
                task_include=included_file._task,
                role=included_file._task._role,
                use_handlers=is_handler,
                loader=self._loader
            )

            # since we skip incrementing the stats when the task result is
            # first processed, we do so now for each host in the list
            for host in included_file._hosts:
                self._tqm._stats.increment('ok', host.name)

        except AnsibleError as e:
            # mark all of the hosts including this file as failed, send callbacks,
            # and increment the stats for this host
            for host in included_file._hosts:
                tr = TaskResult(host=host, task=included_file._task, return_data=dict(failed=True, reason=str(e)))
                iterator.mark_host_failed(host)
                self._tqm._failed_hosts[host.name] = True
                self._tqm._stats.increment('failures', host.name)
                self._tqm.send_callback('v2_runner_on_failed', tr)
            return []

        # set the vars for this task from those specified as params to the include
        for b in block_list:
            # first make a copy of the including task, so that each has a unique copy to modify
            # FIXME: not sure if this is the best way to fix this, as we might be losing
            #        information in the copy. Previously we assigned the include params to
            #        the block variables directly, which caused other problems, so we may
            #        need to figure out a third option if this also presents problems.
            b._task_include = b._task_include.copy(exclude_block=True)
            # then we create a temporary set of vars to ensure the variable reference is unique
            temp_vars = b._task_include.vars.copy()
            temp_vars.update(included_file._args.copy())
            # pop tags out of the include args, if they were specified there, and assign
            # them to the include. If the include already had tags specified, we raise an
            # error so that users know not to specify them both ways
            tags = temp_vars.pop('tags', [])
            if isinstance(tags, string_types):
                tags = [ tags ]
            if len(tags) > 0:
                if len(b._task_include.tags) > 0:
                    raise AnsibleParserError("Include tasks should not specify tags in more than one way (both via args and directly on the task)",
                            obj=included_file._task._ds)
                display.deprecated("You should not specify tags in the include parameters. All tags should be specified using the task-level option")
                b._task_include.tags = tags
            b._task_include.vars = temp_vars

        # finally, send the callback and return the list of blocks loaded
        self._tqm.send_callback('v2_playbook_on_include', included_file)
        display.debug("done processing included file")
        return block_list

    def run_handlers(self, iterator, play_context):
        '''
        Runs handlers on those hosts which have been notified.
        '''

        result = True

        for handler_block in iterator._play.handlers:
            # FIXME: handlers need to support the rescue/always portions of blocks too,
            #        but this may take some work in the iterator and gets tricky when
            #        we consider the ability of meta tasks to flush handlers
            for handler in handler_block.block:
                handler_vars = self._variable_manager.get_vars(loader=self._loader, play=iterator._play, task=handler)
                templar = Templar(loader=self._loader, variables=handler_vars)
                try:
                    # first we check with the full result of get_name(), which may
                    # include the role name (if the handler is from a role). If that
                    # is not found, we resort to the simple name field, which doesn't
                    # have anything extra added to it.
                    handler_name = templar.template(handler.name)
                    if handler_name not in self._notified_handlers:
                        handler_name = templar.template(handler.get_name())
                except (UndefinedError, AnsibleUndefinedVariable):
                    # We skip this handler due to the fact that it may be using
                    # a variable in the name that was conditionally included via
                    # set_fact or some other method, and we don't want to error
                    # out unnecessarily
                    continue

                if handler_name in self._notified_handlers and len(self._notified_handlers[handler_name]):
                    result = self._do_handler_run(handler, handler_name, iterator=iterator, play_context=play_context)
                    if not result:
                        break
        return result

    def _do_handler_run(self, handler, handler_name, iterator, play_context, notified_hosts=None):

        # FIXME: need to use iterator.get_failed_hosts() instead?
        #if not len(self.get_hosts_remaining(iterator._play)):
        #    self._tqm.send_callback('v2_playbook_on_no_hosts_remaining')
        #    result = False
        #    break
        self._tqm.send_callback('v2_playbook_on_handler_task_start', handler)

        if notified_hosts is None:
            notified_hosts = self._notified_handlers[handler_name]

        run_once = False
        try:
            action = action_loader.get(handler.action, class_only=True)
            if handler.run_once or getattr(action, 'BYPASS_HOST_LOOP', False):
                run_once = True
        except KeyError:
            # we don't care here, because the action may simply not have a
            # corresponding action plugin
            pass

        host_results = []
        for host in notified_hosts:
            if not handler.has_triggered(host) and (host.name not in self._tqm._failed_hosts or play_context.force_handlers):
                task_vars = self._variable_manager.get_vars(loader=self._loader, play=iterator._play, host=host, task=handler)
                self.add_tqm_variables(task_vars, play=iterator._play)
                self._queue_task(host, handler, task_vars, play_context)
                if run_once:
                    break

        # collect the results from the handler run
        host_results = self._wait_on_pending_results(iterator)

        try:
            included_files = IncludedFile.process_include_results(
                host_results,
                self._tqm,
                iterator=iterator,
                inventory=self._inventory,
                loader=self._loader,
                variable_manager=self._variable_manager
            )
        except AnsibleError as e:
            return False

        result = True
        if len(included_files) > 0:
            for included_file in included_files:
                try:
                    new_blocks = self._load_included_file(included_file, iterator=iterator, is_handler=True)
                    # for every task in each block brought in by the include, add the list
                    # of hosts which included the file to the notified_handlers dict
                    for block in new_blocks:
                        iterator._play.handlers.append(block)
                        for task in block.block:
                            result = self._do_handler_run(
                                handler=task,
                                handler_name=None,
                                iterator=iterator,
                                play_context=play_context,
                                notified_hosts=included_file._hosts[:],
                            )
                            if not result:
                                break
                except AnsibleError as e:
                    for host in included_file._hosts:
                        iterator.mark_host_failed(host)
                        self._tqm._failed_hosts[host.name] = True
                    display.warning(str(e))
                    continue

        # wipe the notification list
        self._notified_handlers[handler_name] = []
        display.debug("done running handlers, result is: %s" % result)
        return result

    def _take_step(self, task, host=None):

        ret=False
        if host:
            msg = u'Perform task: %s on %s (y/n/c): ' % (task, host)
        else:
            msg = u'Perform task: %s (y/n/c): ' % task
        resp = display.prompt(msg)

        if resp.lower() in ['y','yes']:
            display.debug("User ran task")
            ret = True
        elif resp.lower() in ['c', 'continue']:
            display.debug("User ran task and cancled step mode")
            self._step = False
            ret = True
        else:
            display.debug("User skipped task")

        display.banner(msg)

        return ret

    def _execute_meta(self, task, play_context, iterator):

        # meta tasks store their args in the _raw_params field of args,
        # since they do not use k=v pairs, so get that
        meta_action = task.args.get('_raw_params')

        if meta_action == 'noop':
            # FIXME: issue a callback for the noop here?
            pass
        elif meta_action == 'flush_handlers':
            self.run_handlers(iterator, play_context)
        elif meta_action == 'refresh_inventory':
            self._inventory.refresh_inventory()
        #elif meta_action == 'reset_connection':
        #    connection_info.connection.close()
        else:
            raise AnsibleError("invalid meta action requested: %s" % meta_action, obj=task._ds)
