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#--
# CyborgHood, a distributed system management software.
# Copyright (c) 2009-2011 Marc Dequènes (Duck) <Duck@DuckCorp.org>
#
# This program 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.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
#++

require 'active_support/basic_object'
require 'http_headers'
require 'set'


module CyborgHood
module DSL
class BaseDSL < ActiveSupport::BasicObject
reveal :class
reveal :logger
end

class TaskBase < BaseDSL
attr_reader :bot, :name, :errors, :results, :preferred_locales, :locale, :user

@@task_wip = 0

def self.idle?
@@task_wip == 0
end

# the name MUST be unique
def initialize(bot, name, &block)
@bot = bot
@name = name

@@task_wip += 1

@errors = {}.freeze
@results = {}.freeze

@notification_name = "task/#{@name}"
@preferred_locales = nil
@locale = nil
@user = nil

_setup
_start_dsl &block
end

def set_preferred_locales(prefs)
_add_subtask("setting/preferred_locales") do |subtask|
logger.debug "Task '#{@name}': setting preferred locales"
lang_chooser = HTTPHeaders::AcceptLanguage.parse(prefs)
if lang_chooser
@preferred_locales = prefs

ordered_list = lang_chooser.reduce(I18nController.instance.available_locales)
@locale = ordered_list.empty? ? I18nController::DEFAULT_LOCALE : ordered_list.first.range
logger.debug "Task '#{@name}': locale chosen: #{@locale}"
else
@errors << CyberError.new(:unrecoverable, "botnet/client/dsl", _("unparsable preferred locales"))
end
subtask.finish
end
end

# temporary setting until Guard is created
def set_user(user)
_add_subtask("setting/user") do |subtask|
logger.debug "Task '#{@name}': setting user to: #{user}"
@user = user

subtask.finish
end
end

# may return a Hash of results
def schedule(&job)
_add_subtask("job/#{job.hash}") do |subtask|
logger.debug "Task '#{@name}': Scheduling job"
cb = Proc.new do
subtask.finish
end
job_wrapper = Proc.new do
job.call subtask
end
@bot.schedule_task(cb, job_wrapper)
end
end

def send_notification(name, data)
name = @notification_name if name == :task

_add_subtask("notification/#{name}/out") do |subtask|
logger.debug "Task '#{@name}': Sending notification to '#{name}'"
chan = @bot.get_channel(name)
chan << data
subtask.finish
end
end

def wait_notification(name, criterias = {}, timeout = nil, &cb)
name = @notification_name if name == :task

_add_subtask("notification/#{name}/in") do |subtask|
logger.debug "Task '#{@name}': Waiting notification on '#{name}'"
subcription_id = @bot.get_channel(name).subscribe do |msg|
if _notification_criterias_match(msg, criterias)
cb.call(subtask, msg)
@bot.get_channel(name).unsubscribe(subcription_id) if subtask.finished?
end
end

if timeout
EventMachine.add_timer(timeout) do
@bot.get_channel(name).unsubscribe(subcription_id)
subtask.finish
end
end
end
end

def wait_timer(timeout, repeat = false, &cb)
_add_subtask("timer/#{timeout}/#{cb.hash}") do |subtask|
periodic_timer_signature = nil

timer_cb = Proc.new do
if repeat
cb.call(subtask)
EventMachine.cancel_timer(periodic_timer_signature) if subtask.finished?
else
cb.call(subtask)
subtask.finish
end
end

if repeat
periodic_timer_signature = EventMachine.add_periodic_timer(timeout, timer_cb)
else
EventMachine.add_timer(timeout, timer_cb)
end
end
end

# the name MUST be unique
def task(name, &block)
_add_subtask("task/#{name}") do |subtask|
self.class.new(@bot, name, &block)
subtask.finish
end
end

def meet(task_list, meetpoint, retry_time = 2)
task_list = [task_list] unless task_list.is_a? Array
task_list = Set.new(task_list)

notification_name = "meeting_point/#{meetpoint}"
notifications_received = Set.new
meet_ok = false

wait_notification(notification_name, {:topic => "MEET"}) do |subtask, msg|
notifications_received << msg[:from] if task_list.include?(msg[:from])
if task_list == notifications_received
meet_ok = true
subtask.finish
end
end
wait_timer(retry_time, true) do |subtask|
# in this order: send a last message before leaving
# (so we are sure the peer received a reply to its message)
send_notification notification_name, {:topic => "MEET", :from => @name}
subtask.finish if meet_ok
end
end

# error when adding subtasks, as we cannot check callbacks
# only applies to subsequently added tasks (wanted behavior)
def cancel_on_start_error
@cancel_on_start_error = true
end

def on_error(&cb)
@error_cb = cb
end

def on_success(&cb)
@success_cb = cb
end

def stop_bot(condition)
_add_subtask('stop') do |subtask|
case condition
when :when_finished
# try to stop gracefully
@bot.try_stop
when :at_once
# it won't wait for anything to finish…
@bot.stop
end

subtask.finish
end
end

protected

class Subtask
attr_reader :name
attr_accessor :results, :errors

def initialize(task, name, &block)
@task = task
@name = name
@block = block

@finished = false
@results = {}
@errors = []
end

def do_it
@block.call self
rescue
msg = "Task '#{@task.name}': error: " + $!.to_s
logger.error msg
@errors << CyberError.new(:unrecoverable, "botnet/client/dsl", msg)
logger.debug $!.backtrace.join("\n")
finish
end

def finish
if @finished
raise CyberError.new(:unrecoverable, "botnet/client/dsl", "Task '#{@task.name}': subtask should have ended, but it lied")
end
@finished = true
logger.debug "Task '#{@task.name}': subtask '#{@name}' finished"
@task.__send__(:_check_finished)
end

def finished?
@finished
end
end

def _add_subtask(name, cb = nil, &block)
subtask = Subtask.new(self, name, &block)
@subtasks << subtask
subtask.do_it if @dsl_runing
end

def _subtasks_finished?
subtasks_running = []
@subtasks.each do |subtask|
subtasks_running << subtask.name unless subtask.finished?
end

logger.debug "Task '#{@name}': the following subtasks are still running: " +
subtasks_running.join(', ') unless subtasks_running.empty?

subtasks_running.empty?
end

def _check_finished
return unless _subtasks_finished?

# avoid race: no subtask will be run in this task now
@dsl_runing = false

logger.debug "Task '#{@name}': step finished"

# compute step result
@errors = {}
@results = {}
@subtasks.each do |subtask|
@errors[subtask.name] = subtask.errors unless subtask.errors.empty?
@results.merge!(subtask.results)
end
@errors.freeze
@result.freeze

# next step
cb = @errors.empty? ? @success_cb : @error_cb
if cb
_start_dsl(&cb)
else
_finished
end
end

def _notification_criterias_match(msg, criterias)
criterias.each_pair do |key, expected_val|
val = msg[key]
if expected_val.is_a? Regexp
return false if val !~ expected_val
else
return false if val != expected_val
end
end
true
end

def _setup
logger.debug "Task '#{@name}': created"
end

def _start_dsl(&block)
@dsl_runing = false
@subtasks = []
@cancel_on_start_error = false
@error_cb = nil
@success_cb = nil

begin
instance_eval(&block)
rescue
logger.error "Task '#{@name}': error in DSL: " + $!.to_s
logger.debug $!.backtrace.join("\n")
return
end

logger.debug "Task '#{@name}': begining step"

if @subtasks.empty?
_check_finished
else
@dsl_runing = true
@subtasks.each do |subtask|
# skip broken or canceled subtasks
next if subtask.finished?
subtask.do_it
end
end

true
end

def _finished
@@task_wip -= 1
logger.debug "Task '#{@name}': finished (#{@@task_wip} remaining)"
end
end

# this empty class is used as a trick to be able to inject features
# as module.prepend does not exist yet
class Task < TaskBase
end
end
end
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