# Represents a single Problem. The problem may have been
# reported as various Errs, but the user has grouped the
# Errs together as belonging to the same problem.

class Problem
  include Mongoid::Document
  include Mongoid::Timestamps

  field :last_notice_at, :type => DateTime, :default => Proc.new { Time.now }
  field :first_notice_at, :type => DateTime, :default => Proc.new { Time.now }
  field :last_deploy_at, :type => Time
  field :resolved, :type => Boolean, :default => false
  field :resolved_at, :type => Time
  field :issue_link, :type => String
  field :issue_type, :type => String

  # Cached fields
  field :app_name, :type => String
  field :notices_count, :type => Integer, :default => 0
  field :message
  field :environment
  field :error_class
  field :where
  field :user_agents, :type => Hash, :default => {}
  field :messages,    :type => Hash, :default => {}
  field :hosts,       :type => Hash, :default => {}
  field :comments_count, :type => Integer, :default => 0

  index :app_id => 1
  index :app_name => 1
  index :message => 1
  index :last_notice_at => 1
  index :first_notice_at => 1
  index :last_deploy_at => 1
  index :resolved_at => 1
  index :notices_count => 1

  belongs_to :app
  has_many :errs, :inverse_of => :problem, :dependent => :destroy
  has_many :comments, :inverse_of => :err, :dependent => :destroy

  validates_presence_of :environment

  before_create :cache_app_attributes

  scope :resolved, where(:resolved => true)
  scope :unresolved, where(:resolved => false)
  scope :ordered, order_by(:last_notice_at.desc)
  scope :for_apps, lambda {|apps| where(:app_id.in => apps.all.map(&:id))}

  validates_presence_of :last_notice_at, :first_notice_at


  def self.all_else_unresolved(fetch_all)
    if fetch_all
      all
    else
      where(:resolved => false)
    end
  end

  def self.in_env(env)
    env.present? ? where(:environment => env) : scoped
  end

  def notices
    Notice.for_errs(errs).ordered
  end

  def comments_allowed?
    Errbit::Config.allow_comments_with_issue_tracker || !app.issue_tracker_configured?
  end

  def resolve!
    self.update_attributes!(:resolved => true, :resolved_at => Time.now)
  end

  def unresolve!
    self.update_attributes!(:resolved => false, :resolved_at => nil)
  end

  def unresolved?
    !resolved?
  end


  def self.merge!(*problems)
    ProblemMerge.new(problems).merge
  end

  def merged?
    errs.length > 1
  end

  def unmerge!
    attrs = {:error_class => error_class, :environment => environment}
    problem_errs = errs.to_a
    problem_errs.shift
    [self] + problem_errs.map(&:id).map do |err_id|
      err = Err.find(err_id)
      app.problems.create(attrs).tap do |new_problem|
        err.update_attribute(:problem_id, new_problem.id)
        new_problem.reset_cached_attributes
      end
    end
  end


  def self.ordered_by(sort, order)
    case sort
    when "app";            order_by(["app_name", order])
    when "message";        order_by(["message", order])
    when "last_notice_at"; order_by(["last_notice_at", order])
    when "last_deploy_at"; order_by(["last_deploy_at", order])
    when "count";          order_by(["notices_count", order])
    else raise("\"#{sort}\" is not a recognized sort")
    end
  end

  def self.in_date_range(date_range)
    where(:first_notice_at.lte => date_range.end).where("$or" => [{:resolved_at => nil}, {:resolved_at.gte => date_range.begin}])
  end


  def reset_cached_attributes
    ProblemUpdaterCache.new(self).update
  end

  def cache_app_attributes
    if app
      self.app_name = app.name
      self.last_deploy_at = if (last_deploy = app.deploys.where(:environment => self.environment).last)
        last_deploy.created_at.utc
      end
      collection.find('_id' => self.id)
                .update({'$set' => {'app_name' => self.app_name,
                          'last_deploy_at' => self.last_deploy_at.try(:utc)}})
    end
  end

  def remove_cached_notice_attributes(notice)
    update_attributes!(
      :messages    => attribute_count_descrease(:messages, notice.message),
      :hosts       => attribute_count_descrease(:hosts, notice.host),
      :user_agents => attribute_count_descrease(:user_agents, notice.user_agent_string)
    )
  end

  def issue_type
    # Return issue_type if configured, but fall back to detecting app's issue tracker
    attributes['issue_type'] ||=
    (app.issue_tracker_configured? && app.issue_tracker.label) || nil
  end

  def self.search(value)
    any_of(
      {:error_class => /#{value}/i},
      {:where => /#{value}/i},
      {:message => /#{value}/i},
      {:app_name => /#{value}/i},
      {:environment => /#{value}/i}
    )
  end

  private

    def attribute_count_descrease(name, value)
      counter, index = send(name), attribute_index(value)
      if counter[index] && counter[index]['count'] > 1
        counter[index]['count'] -= 1
      else
        counter.delete(index)
      end
      counter
    end

    def attribute_index(value)
      Digest::MD5.hexdigest(value.to_s)
    end
end