#!/usr/bin/env ruby

require 'chronic'
require 'chronic_duration'
require 'sinatra/base'
require 'haml'
require 'rack/fiber_pool'

require 'async-rack'
require 'flapjack/rack_logger'

require 'flapjack/pikelet'
require 'flapjack/data/contact'
require 'flapjack/data/entity_check'
require 'flapjack/redis_pool'
require 'flapjack/utility'

module Flapjack
  class Web < Sinatra::Base

    if defined?(FLAPJACK_ENV) && 'test'.eql?(FLAPJACK_ENV)
      # expose test errors properly
      set :raise_errors, true
      set :show_exceptions, false
    else
      rescue_exception = Proc.new do |env, e|
        if settings.show_exceptions?
          # ensure the sinatra error page shows properly
          request = Sinatra::Request.new(env)
          printer = Sinatra::ShowExceptions.new(proc{ raise e })
          s, h, b = printer.call(env)
          [s, h, b]
        else
          logger.error e.message
          logger.error e.backtrace.join("\n")
          [503, {}, ""]
        end
      end

      # doesn't work with Rack::Test unless we wrap tests in EM.synchrony blocks
      use Rack::FiberPool, :size => 25, :rescue_exception => rescue_exception
    end
    use Rack::MethodOverride

    class << self
      include Flapjack::ThinPikelet

      attr_accessor :redis

      alias_method :thin_bootstrap, :bootstrap
      alias_method :thin_cleanup,   :cleanup

      def bootstrap(opts = {})
        thin_bootstrap(opts)
        @redis = Flapjack::RedisPool.new(:config => opts[:redis_config], :size => 1)

        if config && config['access_log']
          access_logger = Flapjack::RackLogger.new(config['access_log'])
          use Rack::CommonLogger, access_logger
        end
      end

      def cleanup
        @redis.empty! if @redis
        thin_cleanup
      end

    end

    include Flapjack::Utility

    set :views, settings.root + '/web/views'

    def redis
      self.class.instance_variable_get('@redis')
    end

    def logger
      self.class.instance_variable_get('@logger')
    end

    get '/' do
      self_stats

      # TODO (?) recast as Entity.all do |e|; e.checks.do |ec|; ...
      @states = redis.keys('*:*:states').map { |r|
        parts  = r.split(':')[0..1]
        [parts[0], parts[1]] + entity_check_state(parts[0], parts[1])
      }.compact.sort_by {|parts| parts }
      haml :index
    end

    get '/failing' do
      self_stats
      @states = redis.zrange('failed_checks', 0, -1).map {|key|
        parts  = key.split(':')
        [parts[0], parts[1]] + entity_check_state(parts[0], parts[1])
      }.compact.sort_by {|parts| parts}
      haml :index
    end

    get '/self_stats' do
      self_stats
      haml :self_stats
    end

    get '/check' do
      @entity = params[:entity]
      @check  = params[:check]

      entity_check = get_entity_check(@entity, @check)
      return 404 if entity_check.nil?

      last_change = entity_check.last_change

      @check_state                = entity_check.state
      @check_last_update          = entity_check.last_update
      @check_last_change          = last_change
      @check_summary              = entity_check.summary
      @last_notifications         = entity_check.last_notifications_of_each_type
      @scheduled_maintenances     = entity_check.maintenances(nil, nil, :scheduled => true)
      @acknowledgement_id         = entity_check.failed? ?
        entity_check.event_count_at(entity_check.last_change) : nil

      @current_scheduled_maintenance   = entity_check.current_maintenance(:scheduled => true)
      @current_unscheduled_maintenance = entity_check.current_maintenance(:scheduled => false)

      @contacts                   = entity_check.contacts

      haml :check
    end

    post '/acknowledgements/:entity/:check' do
      @entity             = params[:entity]
      @check              = params[:check]
      @summary            = params[:summary]
      @acknowledgement_id = params[:acknowledgement_id]

      dur = ChronicDuration.parse(params[:duration] || '')
      @duration = (dur.nil? || (dur <= 0)) ? (4 * 60 * 60) : dur

      entity_check = get_entity_check(@entity, @check)
      return 404 if entity_check.nil?

      ack = entity_check.create_acknowledgement('summary' => (@summary || ''),
        'acknowledgement_id' => @acknowledgement_id, 'duration' => @duration)

      redirect back
    end

    # FIXME: there is bound to be a more idiomatic / restful way of doing this
    # (probably using 'delete' or 'patch')
    post '/end_unscheduled_maintenance/:entity/:check' do
      @entity = params[:entity]
      @check  = params[:check]

      entity_check = get_entity_check(@entity, @check)
      return 404 if entity_check.nil?

      entity_check.end_unscheduled_maintenance

      redirect back
    end

    # create scheduled maintenance
    post '/scheduled_maintenances/:entity/:check' do
      start_time = Chronic.parse(params[:start_time]).to_i
      raise ArgumentError, "start time parsed to zero" unless start_time > 0
      duration   = ChronicDuration.parse(params[:duration])
      summary    = params[:summary]

      entity_check = get_entity_check(params[:entity], params[:check])
      return 404 if entity_check.nil?

      entity_check.create_scheduled_maintenance(:start_time => start_time,
                                                :duration   => duration,
                                                :summary    => summary)
      redirect back
    end

    # modify scheduled maintenance
    patch '/scheduled_maintenances/:entity/:check' do
      entity_check = get_entity_check(params[:entity], params[:check])
      return 404 if entity_check.nil?

      end_time   = Chronic.parse(params[:end_time]).to_i
      start_time = params[:start_time].to_i
      raise ArgumentError, "start time parsed to zero" unless start_time > 0

      patches = {}
      patches[:end_time] = end_time if end_time && (end_time > start_time)

      raise ArgumentError.new("no valid data received to patch with") if patches.empty?

      entity_check.update_scheduled_maintenance(start_time, patches)
      redirect back
    end

    # delete a scheduled maintenance
    delete '/scheduled_maintenances/:entity/:check' do
      entity_check = get_entity_check(params[:entity], params[:check])
      return 404 if entity_check.nil?

      entity_check.delete_scheduled_maintenance(:start_time => params[:start_time].to_i)
      redirect back
    end

    get '/contacts' do
      @contacts = Flapjack::Data::Contact.all(:redis => redis)
      haml :contacts
    end

    get "/contacts/:contact" do
      contact_id = params[:contact]

      if contact_id
        @contact = Flapjack::Data::Contact.find_by_id(contact_id, :redis => redis)
      end

      unless @contact
        status 404
        return
      end

      if @contact.media.has_key?('pagerduty')
        @pagerduty_credentials = @contact.pagerduty_credentials
      end

      @entities_and_checks = @contact.entities_and_checks.sort_by {|ec|
        ec[:entity].name
      }

      haml :contact
    end

  private

    def get_entity_check(entity, check)
      entity_obj = (entity && entity.length > 0) ?
        Flapjack::Data::Entity.find_by_name(entity, :redis => redis) : nil
      return if entity_obj.nil? || (check.nil? || check.length == 0)
      Flapjack::Data::EntityCheck.for_entity(entity_obj, check, :redis => redis)
    end

    def entity_check_state(entity_name, check)
      entity = Flapjack::Data::Entity.find_by_name(entity_name,
        :redis => redis)
      return if entity.nil?
      entity_check = Flapjack::Data::EntityCheck.for_entity(entity,
        check, :redis => redis)
      latest_notif =
        {:problem         => entity_check.last_problem_notification,
         :recovery        => entity_check.last_recovery_notification,
         :acknowledgement => entity_check.last_acknowledgement_notification
        }.max_by {|n| n[1] || 0}
      [(entity_check.state       || '-'),
       (entity_check.last_change || '-'),
       (entity_check.last_update || '-'),
       entity_check.in_unscheduled_maintenance?,
       entity_check.in_scheduled_maintenance?,
       latest_notif[0],
       latest_notif[1]
      ]
    end

    def self_stats
      @fqdn         = `/bin/hostname -f`.chomp
      @pid          = Process.pid
      @instance_id  = "#{@fqdn}:#{@pid}"

      @keys = redis.keys '*'
      @count_failing_checks    = redis.zcard 'failed_checks'
      @count_all_checks        = redis.keys('check:*:*').length
      @executive_instances     = redis.zrange('executive_instances', '0', '-1', :withscores => true)
      @event_counters          = redis.hgetall('event_counters')
      @event_counters_instance = redis.hgetall("event_counters:#{@instance_id}")
      @boot_time               = Time.at(redis.zscore('executive_instances', @instance_id).to_i)
      @uptime                  = Time.now.to_i - @boot_time.to_i
      @uptime_string           = time_period_in_words(@uptime)
      @event_rate_all          = (@uptime > 0) ?
                                 (@event_counters_instance['all'].to_f / @uptime) : 0
      @events_queued = redis.llen('events')
    end

  end
end