# (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 fnmatch

from ansible import constants as C

from ansible.errors import *
from ansible.playbook.block import Block
from ansible.playbook.task import Task

from ansible.utils.boolean import boolean

__all__ = ['PlayIterator']

class HostState:
    def __init__(self, blocks):
        self._blocks          = blocks[:]

        self.cur_block        = 0
        self.cur_regular_task = 0
        self.cur_rescue_task  = 0
        self.cur_always_task  = 0
        self.cur_role         = None
        self.run_state        = PlayIterator.ITERATING_SETUP
        self.fail_state       = PlayIterator.FAILED_NONE
        self.pending_setup    = False
        self.child_state      = None

    def __repr__(self):
        return "HOST STATE: block=%d, task=%d, rescue=%d, always=%d, role=%s, run_state=%d, fail_state=%d, pending_setup=%s, child state? %s" % (
            self.cur_block,
            self.cur_regular_task,
            self.cur_rescue_task,
            self.cur_always_task,
            self.cur_role,
            self.run_state,
            self.fail_state,
            self.pending_setup,
            self.child_state,
        )

    def get_current_block(self):
        return self._blocks[self.cur_block]

    def copy(self):
        new_state = HostState(self._blocks)
        new_state.cur_block        = self.cur_block
        new_state.cur_regular_task = self.cur_regular_task
        new_state.cur_rescue_task  = self.cur_rescue_task
        new_state.cur_always_task  = self.cur_always_task
        new_state.cur_role         = self.cur_role
        new_state.run_state        = self.run_state
        new_state.fail_state       = self.fail_state
        new_state.pending_setup    = self.pending_setup
        new_state.child_state      = self.child_state
        return new_state

class PlayIterator:

    # the primary running states for the play iteration
    ITERATING_SETUP    = 0
    ITERATING_TASKS    = 1
    ITERATING_RESCUE   = 2
    ITERATING_ALWAYS   = 3
    ITERATING_COMPLETE = 4

    # the failure states for the play iteration, which are powers
    # of 2 as they may be or'ed together in certain circumstances
    FAILED_NONE        = 0
    FAILED_SETUP       = 1
    FAILED_TASKS       = 2
    FAILED_RESCUE      = 4
    FAILED_ALWAYS      = 8

    def __init__(self, inventory, play, play_context, all_vars):
        self._play = play

        self._blocks = []
        for block in self._play.compile():
            new_block = block.filter_tagged_tasks(play_context, all_vars)
            if new_block.has_tasks():
                self._blocks.append(new_block)

        self._host_states = {}
        for host in inventory.get_hosts(self._play.hosts):
             self._host_states[host.name] = HostState(blocks=self._blocks)
             # if we're looking to start at a specific task, iterate through
             # the tasks for this host until we find the specified task
             if play_context.start_at_task is not None:
                 while True:
                     (s, task) = self.get_next_task_for_host(host, peek=True)
                     if s.run_state == self.ITERATING_COMPLETE:
                         break
                     if task.name == play_context.start_at_task or fnmatch.fnmatch(task.name, play_context.start_at_task):
                         break
                     else:
                         self.get_next_task_for_host(host)

        # Extend the play handlers list to include the handlers defined in roles
        self._play.handlers.extend(play.compile_roles_handlers())

    def get_host_state(self, host):
        try:
            return self._host_states[host.name].copy()
        except KeyError:
            raise AnsibleError("invalid host (%s) specified for playbook iteration" % host)

    def get_next_task_for_host(self, host, peek=False):

        s = self.get_host_state(host)

        task = None
        if s.run_state == self.ITERATING_COMPLETE:
            return None
        elif s.run_state == self.ITERATING_SETUP:
            s.run_state = self.ITERATING_TASKS
            s.pending_setup = True

            # Gather facts if the default is 'smart' and we have not yet
            # done it for this host; or if 'explicit' and the play sets
            # gather_facts to True; or if 'implicit' and the play does
            # NOT explicitly set gather_facts to False.

            gathering = C.DEFAULT_GATHERING
            implied = self._play.gather_facts is None or boolean(self._play.gather_facts)

            if (gathering == 'implicit' and implied) or \
               (gathering == 'explicit' and boolean(self._play.gather_facts)) or \
               (gathering == 'smart' and implied and not host._gathered_facts):
                if not peek:
                    # mark the host as having gathered facts
                    host.set_gathered_facts(True)

                task = Task()
                task.action = 'setup'
                task.args   = {}
                task.set_loader(self._play._loader)
            else:
                s.pending_setup = False

        if not task:
            (s, task) = self._get_next_task_from_state(s, peek=peek)

        if task and task._role:
            # if we had a current role, mark that role as completed
            if s.cur_role and task._role != s.cur_role and s.cur_role._had_task_run and not peek:
                s.cur_role._completed = True
            s.cur_role = task._role

        if not peek:
            self._host_states[host.name] = s

        return (s, task)


    def _get_next_task_from_state(self, state, peek):

        task = None

        # if we previously encountered a child block and we have a
        # saved child state, try and get the next task from there
        if state.child_state:
            (state.child_state, task) = self._get_next_task_from_state(state.child_state, peek=peek)
            if task:
                return (state.child_state, task)
            else:
                state.child_state = None

        # try and find the next task, given the current state.
        while True:
            # try to get the current block from the list of blocks, and
            # if we run past the end of the list we know we're done with
            # this block
            try:
                block = state._blocks[state.cur_block]
            except IndexError:
                state.run_state = self.ITERATING_COMPLETE
                return (state, None)

            if state.run_state == self.ITERATING_TASKS:
                # clear the pending setup flag, since we're past that and it didn't fail
                if state.pending_setup:
                    state.pending_setup = False

                if state.fail_state & self.FAILED_TASKS == self.FAILED_TASKS:
                    state.run_state = self.ITERATING_RESCUE
                elif state.cur_regular_task >= len(block.block):
                    state.run_state = self.ITERATING_ALWAYS
                else:
                    task = block.block[state.cur_regular_task]
                    state.cur_regular_task += 1

            elif state.run_state == self.ITERATING_RESCUE:
                if state.fail_state & self.FAILED_RESCUE == self.FAILED_RESCUE:
                    state.run_state = self.ITERATING_ALWAYS
                elif state.cur_rescue_task >= len(block.rescue):
                    if len(block.rescue) > 0:
                        state.fail_state = self.FAILED_NONE
                    state.run_state = self.ITERATING_ALWAYS
                else:
                    task = block.rescue[state.cur_rescue_task]
                    state.cur_rescue_task += 1

            elif state.run_state == self.ITERATING_ALWAYS:
                if state.cur_always_task >= len(block.always):
                    if state.fail_state != self.FAILED_NONE:
                        state.run_state = self.ITERATING_COMPLETE
                    else:
                        state.cur_block += 1
                        state.cur_regular_task = 0
                        state.cur_rescue_task  = 0
                        state.cur_always_task  = 0
                        state.run_state = self.ITERATING_TASKS
                        state.child_state = None
                else:
                    task = block.always[state.cur_always_task]
                    state.cur_always_task += 1

            elif state.run_state == self.ITERATING_COMPLETE:
                return (state, None)

            # if the current task is actually a child block, we dive into it
            if isinstance(task, Block):
                state.child_state = HostState(blocks=[task])
                state.child_state.run_state = self.ITERATING_TASKS
                state.child_state.cur_role = state.cur_role
                (state.child_state, task) = self._get_next_task_from_state(state.child_state, peek=peek)
             
            # if something above set the task, break out of the loop now
            if task:
                break

        return (state, task)

    def mark_host_failed(self, host):
        s = self.get_host_state(host)
        if s.pending_setup:
            s.fail_state |= self.FAILED_SETUP
            s.run_state = self.ITERATING_COMPLETE
        elif s.run_state == self.ITERATING_TASKS:
            s.fail_state |= self.FAILED_TASKS
            s.run_state = self.ITERATING_RESCUE
        elif s.run_state == self.ITERATING_RESCUE:
            s.fail_state |= self.FAILED_RESCUE
            s.run_state = self.ITERATING_ALWAYS
        elif s.run_state == self.ITERATING_ALWAYS:
            s.fail_state |= self.FAILED_ALWAYS
            s.run_state = self.ITERATING_COMPLETE
        self._host_states[host.name] = s

    def get_failed_hosts(self):
        return dict((host, True) for (host, state) in self._host_states.iteritems() if state.run_state == self.ITERATING_COMPLETE and state.fail_state != self.FAILED_NONE)

    def get_original_task(self, host, task):
        '''
        Finds the task in the task list which matches the UUID of the given task.
        The executor engine serializes/deserializes objects as they are passed through
        the different processes, and not all data structures are preserved. This method
        allows us to find the original task passed into the executor engine.
        '''
        def _search_block(block, task):
            for t in block.block:
                if isinstance(t, Block):
                    res = _search_block(t, task)
                    if res:
                        return res
                elif t._uuid == task._uuid:
                    return t
            for t in block.rescue:
                if isinstance(t, Block):
                    res = _search_block(t, task)
                    if res: 
                        return res
                elif t._uuid == task._uuid:
                    return t
            for t in block.always:
                if isinstance(t, Block):
                    res = _search_block(t, task)
                    if res: 
                        return res
                elif t._uuid == task._uuid:
                    return t
            return None

        s = self.get_host_state(host)
        for block in s._blocks:
            res = _search_block(block, task)
            if res:
                return res

        return None

    def add_tasks(self, host, task_list):
        s = self.get_host_state(host)
        target_block = s._blocks[s.cur_block].copy(exclude_parent=True)

        if s.run_state == self.ITERATING_TASKS:
            before = target_block.block[:s.cur_regular_task]
            after  = target_block.block[s.cur_regular_task:]
            target_block.block = before + task_list + after
        elif s.run_state == self.ITERATING_RESCUE:
            before = target_block.rescue[:s.cur_rescue_task]
            after  = target_block.rescue[s.cur_rescue_task:]
            target_block.rescue = before + task_list + after
        elif s.run_state == self.ITERATING_ALWAYS:
            before = target_block.always[:s.cur_always_task]
            after  = target_block.always[s.cur_always_task:]
            target_block.always = before + task_list + after

        s._blocks[s.cur_block] = target_block
        self._host_states[host.name] = s

