# frozen_string_literal: true

class Conference < ApplicationRecord
  include RevisionCount

  require 'uri'

  serialize :events_per_week, type: Hash

  # Needed to call 'Conference.with_role' in /models/ability.rb
  # Dependent destroy will fail as roles#destroy will be cancelled,hence delete_all
  resourcify :roles, dependent: :delete_all

  default_scope { order(start_date: :desc) }
  scope :upcoming, (-> { where(end_date: Date.current..) })
  scope :past, (-> { where(end_date: ...Date.current) })

  has_paper_trail ignore: %i(updated_at guid revision events_per_week), meta: { conference_id: :id }

  has_and_belongs_to_many :questions

  has_one :splashpage, dependent: :destroy
  has_one :contact, dependent: :destroy
  has_one :registration_period, dependent: :destroy
  has_one :email_settings, dependent: :destroy
  has_one :program, dependent: :destroy
  has_one :venue, dependent: :destroy
  delegate :city, :country_name, to: :venue, allow_nil: true
  delegate :name, :street, to: :venue, prefix: true, allow_nil: true

  has_many :ticket_purchases, dependent: :destroy
  has_many :physical_tickets, through: :ticket_purchases
  has_many :payments, dependent: :destroy
  has_many :supporters, through: :ticket_purchases, source: :user
  has_many :tickets, dependent: :destroy
  has_many :resources, dependent: :destroy
  has_many :booths, dependent: :destroy
  has_many :confirmed_booths, -> { where(state: 'confirmed') }, class_name: 'Booth'

  has_many :lodgings, dependent: :destroy
  has_many :registrations, dependent: :destroy
  has_many :participants, through: :registrations, source: :user
  has_many :vdays, dependent: :destroy
  has_many :vpositions, dependent: :destroy
  has_many :sponsorship_levels, -> { order(:position) }, dependent: :destroy
  has_many :sponsors, dependent: :destroy
  has_many :commercials, as: :commercialable, dependent: :destroy
  has_many :subscriptions, dependent: :destroy
  has_one :call_for_events, -> { where(cfp_type: 'events') }, through: :program, source: :cfps
  has_one :call_for_booths, -> { where(cfp_type: 'booths') }, through: :program, source: :cfps
  has_one :call_for_tracks, -> { where(cfp_type: 'tracks') }, through: :program, source: :cfps
  has_many :confirmed_tracks, -> { where(state: 'confirmed') }, through: :program, source: :tracks
  has_many :highlighted_events,
           -> { where(state: :confirmed, is_highlight: true) },
           through: :program,
           source:  :events
  has_many :event_types, through: :program

  has_many :surveys, as: :surveyable, dependent: :destroy do
    def for_registration
      where(target: targets[:during_registration])
    end

    def after_conference
      where(target: targets[:after_conference])
    end
  end
  accepts_nested_attributes_for :venue
  accepts_nested_attributes_for :tickets, allow_destroy: true
  accepts_nested_attributes_for :sponsorship_levels, allow_destroy: true
  accepts_nested_attributes_for :sponsors, allow_destroy: true
  accepts_nested_attributes_for :email_settings
  accepts_nested_attributes_for :questions, allow_destroy: true
  accepts_nested_attributes_for :vdays, allow_destroy: true
  accepts_nested_attributes_for :vpositions, allow_destroy: true

  mount_uploader :picture, PictureUploader, mount_on: :logo_file_name

  validates :title,
            :short_title,
            :start_date,
            :end_date,
            :start_hour,
            :end_hour,
            :ticket_layout,
            :timezone, presence: true

  validates :short_title, uniqueness: true
  validates :short_title, format: { with: /\A[a-zA-Z0-9_-]*\z/ }
  validates :registration_limit, numericality: { only_integer: true, greater_than_or_equal_to: 0 }

  # This validation is needed since a conference with a start date greater than the end date is not possible
  validate :valid_date_range?
  validate :valid_times_range?
  before_create :generate_guid
  before_create :add_color
  before_create :create_email_settings

  after_create :create_free_ticket
  after_update :delete_event_schedules

  enum :ticket_layout, [:portrait, :landscape]

  ##
  # Checks if the user is registered to the conference
  #
  # ====Args
  # * +user+ -> The user we check for
  # ====Returns
  # * +false+ -> If the user is registered
  # * +true+ - If the user isn't registered
  def user_registered? user
    user.present? && registrations.where(user_id: user.id).any?
  end

  ##
  # Delete all EventSchedules that are not in the hours range
  # After the conference has been successfully updated
  def delete_event_schedules
    if saved_change_to_start_hour? || saved_change_to_end_hour?
      event_schedules = program.event_schedules.select do |event_schedule|
        event_schedule.start_time.hour < start_hour ||
        event_schedule.end_time.hour > end_hour ||
        (event_schedule.end_time.hour == end_hour && event_schedule.end_time.minute > 0)
      end
      event_schedules.each(&:destroy)
    end
  end

  ##
  # Checks if the registration for the conference is currently open
  #
  # ====Returns
  # * +false+ -> If the conference dates are not set or today isn't in the
  #   registration period.
  # * +true+ -> If today is in the registration period.
  def registration_open?
    registration_dates_given? &&
      (registration_period.start_date..registration_period.end_date).cover?(Date.current)
  end

  ##
  # Checks if the registration dates for the conference are provided
  #
  # ====Returns
  # * +false+ -> If the conference registration dates are not set
  # * +true+ -> If conference registration dates are set
  def registration_dates_given?
    registration_period.present? &&
      registration_period.start_date.present? &&
      registration_period.end_date.present?
  end

  ##
  # Returns an array with the summarized event submissions per week.
  #
  # ====Returns
  #  * +Array+ -> e.g. [0, 3, 3, 5] -> first week 0 events, second week 3 events.
  def get_submissions_per_week
    result = []

    if program&.cfp && program.events
      submissions = program.events.select(:week).group(:week).order(:week).count
      start_week = program.cfp.start_week
      weeks = program.cfp.weeks
      result = calculate_items_per_week(start_week, weeks, submissions)
    end
    result
  end

  ##
  # Returns an hash with submitted, confirmed and unconfirmed event submissions
  # per week.
  #
  # ====Returns
  #  * +Array+ -> e.g. 'Submitted' => [0, 3, 3, 5]  -> first week 0 events, second week 3 events.
  def get_submissions_data
    return [] unless program&.cfp && program.events

    start_week = program.cfp.start_week
    get_events_per_week_by_state.collect do |state, values|
      if state == 'Submitted'
        {
          name: 'Submitted',
          data: add_week_indices(pad_array_left_kumulative(start_week, values))
        }
      else
        {
          name: state,
          data: add_week_indices(pad_array_left_not_kumulative(start_week, values))
        }
      end
    end
  end

  ##
  # Returns an array with the summarized registrations per week.
  #
  # ====Returns
  #  * +Array+ -> e.g. [0, 3, 3, 5] -> first week 0, second week 3 registrations
  def get_registrations_per_week
    return [] unless registrations && registration_period&.start_date && registration_period.end_date

    reg = registrations.group(:week).order(:week).count
    start_week = get_registration_start_week
    weeks = registration_weeks
    calculate_items_per_week(start_week, weeks, reg)
  end

  ##
  # Returns an array with the summarized ticket sales per week.
  #
  # ====Returns
  #  * +Array+ -> e.g. [0, 3, 3, 5] -> first week 0, second week 3 tickets sold
  def get_tickets_sold_per_week
    return [] unless tickets && ticket_purchases && registration_period

    tickets_sold = ticket_purchases.paid.group(:week).sum(:quantity)
    start_week = get_registration_start_week
    weeks = registration_weeks
    calculate_items_per_week(start_week, weeks, tickets_sold)
  end

  ##
  # Returns an hash with ticket sales by ticket title
  # per week.
  #
  # ====Returns
  #  * +Array+ -> e.g. 'Free Access' => [0, 3, 3, 5]  -> first week 0 tickets sold, second week 3 tickets sold.
  def get_tickets_data
    return [] unless tickets && ticket_purchases && registration_period

    tickets_per_ticket_id_and_week = ticket_purchases.paid.group(:ticket_id, :week).sum(:quantity)

    start_week = get_registration_start_week
    weeks = registration_weeks

    tickets_by_id_per_week = {}

    tickets.each do |ticket|
      tickets_by_id_per_week[ticket.id] = {}
      (start_week...(start_week + weeks)).each do |week|
        tickets_by_id_per_week[ticket.id][week] = 0
      end
    end

    tickets_per_ticket_id_and_week.each do |ticket_week, value|
      tickets_by_id_per_week[ticket_week[0]][ticket_week[1]] = value
    end

    tickets_by_id_per_week.collect do |ticket, values|
      {
        name: Ticket.find(ticket).title,
        data: add_week_indices(pad_array_left_not_kumulative(start_week, values))
      }
    end
  end

  ##
  # Calculates how many weeks the registration is.
  #
  # ====Returns
  # * +Integer+ -> start week
  def registration_weeks
    result = 0
    weeks = 0
    if registration_period&.start_date &&
        registration_period.end_date
      weeks = Date.new(registration_period.start_date.year, 12, 31)
          .strftime('%W').to_i

      result = get_registration_end_week - get_registration_start_week + 1
    end
    result < 0 ? result + weeks : result
  end

  ##
  # Calculates how many weeks call for papers is.
  #
  # ====Returns
  # * +Integer+ -> weeks
  def cfp_weeks
    if program
      program.cfp.weeks
    else
      0
    end
  end

  ##
  # Calculates the end week of the registration
  #
  # ====Returns
  # * +Integer+ -> start week
  def get_registration_start_week
    if registration_period
      registration_period.start_date.strftime('%W').to_i
    else
      -1
    end
  end

  ##
  # Calculates the start week of the registration
  #
  # ====Returns
  # * +Integer+ -> start week
  def get_registration_end_week
    if registration_period
      registration_period.end_date.strftime('%W').to_i
    else
      -1
    end
  end

  ##
  # Checks if the conference is pending.
  #
  # ====Returns
  # * +false+ -> If the conference start date is in the past.
  # * +true+ -> If the conference start date is in the future.
  def pending?
    start_date > Date.today
  end

  ##
  # Returns a hash with booleans with the required conference options.
  #
  # ====Returns
  # * +hash+ -> true -> filled / false -> missing
  def get_status
    result = {
      registration:      registration_date_set?,
      cfp:               cfp_set?,
      venue:             venue_set?,
      rooms:             rooms_set?,
      tracks:            tracks_set?,
      event_types:       event_types_set?,
      difficulty_levels: difficulty_levels_set?,
      splashpage:        splashpage&.public?
    }

    result.update(
      process:     calculate_setup_progress(result),
      short_title: short_title
    ).with_indifferent_access
  end

  ##
  # Returns a hash with user => submissions ordered by submissions for all conferences
  #
  # ====Returns
  # * +hash+ -> user: submissions
  def self.get_top_submitter(limit = 5)
    submitter = EventUser.select(:user_id).where('event_role = ?', 'submitter').limit(limit).group(:user_id)
    counter = submitter.order(count_all: :desc).count(:all)
    calculate_user_submission_hash(submitter, counter)
  end

  ##
  # Returns a hash with user => submissions ordered by submissions
  #
  # ====Returns
  # * +hash+ -> user: submissions
  def get_top_submitter(limit = 5)
    submitter = EventUser.joins(:event).select(:user_id)
        .where('event_role = ? and program_id = ?', 'submitter', Conference.find(id).program.id)
        .limit(limit).group(:user_id)
    counter = submitter.order(count_all: :desc).count(:all)
    Conference.calculate_user_submission_hash(submitter, counter)
  end

  ##
  # Returns a hash with event state => {value: count of event states, color: color}.
  # The result is calculated over all conferences.
  #
  # ====Returns
  # * +hash+ -> hash
  def self.event_distribution
    calculate_event_distribution_hash(Event.select(:state).group(:state).count)
  end

  ##
  # Returns a hash with event state => {value: count of event states, color: color}
  #
  # ====Returns
  # * +hash+ -> hash
  def event_distribution
    Conference.calculate_event_distribution_hash(
      program.events.select(:state).group(:state).count
    )
  end

  ##
  # Returns a hash with scheduled vs unscheduled events
  # { "Scheduled" => { value: number of confirmed and scheduled events, color: color },
  #   "Unscheduled" => { value: number of confirmed and unscheduled events, color: color }
  #
  # ====Returns
  # * +hash+ -> hash
  def scheduled_event_distribution
    confirmed_scheduled_events = program.events.confirmed.scheduled(program.selected_schedule.try(:id))
    confirmed_unscheduled_events = program.events.confirmed - confirmed_scheduled_events
    scheduled_value = { 'value' => confirmed_scheduled_events.count, 'color' => 'green' }
    unscheduled_value = { 'value' => confirmed_unscheduled_events.count, 'color' => 'red' }
    { 'Scheduled' => scheduled_value, 'Unscheduled' => unscheduled_value }
  end

  ##
  # Returns a hash with Registration attended vs. Registration not attended
  # { "Attended" => { value: number of registration attended, color: color },
  #   "Not attended" => { value: number of registration not attended, color: color }
  #
  # ====Returns
  # * +hash+ -> hash
  def registration_distribution
    reg = registrations.includes(:user)
    attended_value = { 'value' => reg.where(attended: true).count, 'color' => 'magenta' }
    not_attended_value = { 'value' => reg.where.not(attended: true).count, 'color' => 'blue' }
    { 'Attended' => attended_value, 'Not attended' => not_attended_value }
  end

  ##
  # Returns a hash with affiliation =>
  # {value: count of registration whose user has that affilation, color: color}
  # In case that the affiliation is blank, it groups them in None and
  # if the number of persons that have an affiliation are less than the 2% of
  # the total number of registered people, they are grouped in others.
  #
  # ====Returns
  # * +hash+ -> hash
  def affiliation_distribution
    counted_affiliations = registrations.joins(:user).group(:affiliation).count
    result = {}
    i = 1
    others = 0
    none = 0
    counted_affiliations.each do |key, value|
      if value < 0.02 * registrations.length
        others += value
      elsif key.blank?
        none += value
      else
        result[key.capitalize] = { 'value' => value, 'color' => next_color(i) }
        i += 1
      end
    end
    if others > 0
      result['Others'] = { 'value' => others, 'color' => next_color(i) }
      i += 1
    end
    result['None'] = { 'value' => none, 'color' => next_color(i) } if none > 0
    result
  end

  ##
  # Returns a hash with per ticket sales => { "Title" => { value: number of tickets sold,
  # color: generated from the title using a hash function }, ...}
  #
  # ====Returns
  # * +hash+ -> hash
  def tickets_sold_distribution
    result = {}

    if tickets && ticket_purchases
      tickets.each do |ticket|
        result[ticket.title] = {
          'value' => ApplicationController.helpers.humanized_money(ticket.tickets_sold).delete(',').to_i,
          'color' => "\##{Digest::MD5.hexdigest(ticket.title)[0..5]}"
        }
      end
    end
    result
  end

  ##
  # Returns a hash with per ticket turnover => { "Title" => { value: ticket turnover,
  # color: generated from the title using a hash function }, ...}
  #
  # ====Returns
  # * +hash+ -> hash
  def tickets_turnover_distribution
    result = {}

    if tickets && ticket_purchases
      tickets.each do |ticket|
        result[ticket.title] = {
          'value' => ApplicationController.helpers.humanized_money(ticket.tickets_turnover_total(ticket.id)).delete(',').to_i,
          'color' => "\##{Digest::MD5.hexdigest(ticket.title)[0..5]}"
        }
      end
    end
    result
  end

  ##
  # Calculates the overall program minutes
  #
  # ====Returns
  # * +hash+ -> Fixnum minutes
  def current_program_minutes
    events_grouped = program.events.select(:event_type_id).group(:event_type_id)
    events_counted = events_grouped.count
    calculate_program_minutes(events_grouped, events_counted)
  end

  ##
  # Calculates the overall program hours
  #
  # ====Returns
  # * +Fixnum+ -> Fixnum hours. Example: 1.5 gets rounded to 2. 1.3 gets rounded 1.
  def current_program_hours
    (current_program_minutes / 60.to_f).round
  end

  ##
  # Calculates the overall program minutes since date
  #
  # ====Returns
  # * +hash+ -> Fixnum minutes
  def new_program_minutes(date)
    events_grouped = program.events.select(:event_type_id).where('created_at > ?', date).group(:event_type_id)
    events_counted = events_grouped.count
    calculate_program_minutes(events_grouped, events_counted)
  end

  ##
  # Calculates the overall program hours since date
  #
  # ====Returns
  # * +Fixnum+ -> Fixnum hours
  def new_program_hours(date)
    (new_program_minutes(date) / 60.to_f).round
  end

  ##
  # Calculates the difficulty level distribution from all events.
  #
  # ====Returns
  # * +hash+ -> difficulty level => {color, value}
  def difficulty_levels_distribution(state = nil)
    calculate_event_distribution(:difficulty_level_id, :difficulty_level, state)
  end

  ##
  # Calculates the event_type distribution from all events.
  #
  # ====Returns
  # * +hash+ -> event_type => {color, value}
  def event_type_distribution(state = nil)
    calculate_event_distribution(:event_type_id, :event_type, state)
  end

  ##
  # Calculates the track distribution from all events.
  #
  # ====Returns
  # * +hash+ -> track => {color, value}
  def tracks_distribution(state = nil)
    tracks_grouped = if state
                       program.events.select(:track_id).where('state = ?', state).group(:track_id)
                     else
                       program.events.select(:track_id).group(:track_id)
                     end
    tracks_counted = tracks_grouped.count

    calculate_track_distribution_hash(tracks_grouped, tracks_counted)
  end

  ##
  # Return all pending conferences. If there are no pending conferences, the last two
  # past conferences are returned
  #
  # ====Returns
  # * +ActiveRecord+
  def self.get_active_conferences_for_dashboard
    result = Conference.where('start_date > ?', Time.now)
        .select('id, short_title, color, start_date')

    if result.empty?
      result = Conference
          .select('id, short_title, color, start_date').limit(2)
          .order(start_date: :desc)
    end
    result
  end

  ##
  # Return all conferences minus the active conferences
  #
  # ====Returns
  # * +ActiveRecord+
  def self.get_conferences_without_active_for_dashboard(active_conferences)
    result = Conference.select('id, short_title, color, start_date').order(start_date: :desc)
    result - active_conferences
  end

  ##
  # A list with the three event states submitted, confirmed, unconfirmed with corresponding colors
  #
  # ====Returns
  # * +List+
  def self.get_event_state_line_colors
    [
      { short_title: 'Submitted', color: 'blue' },
      { short_title: 'Confirmed', color: 'green' },
      { short_title: 'Unconfirmed', color: 'orange' }
    ]
  end

  ##
  # Writes an snapshot of the actual event distribution to the database
  # Triggered each every Sunday 11:55 pm form whenever (config/schedule.rb).
  #
  def self.write_event_distribution_to_db
    week = DateTime.now.end_of_week

    Conference.where('end_date > ?', Date.today).find_each do |conference|
      result = {}
      Event.state_machine.states.each do |state|
        count = conference.program.events.where('state = ?', state.name).count
        result[state.name] = count
      end

      unless conference.events_per_week
        conference.events_per_week = {}
      end

      # Write to database
      conference.events_per_week[week] = result
      conference.save!
    end
  end

  ##
  # Checks if conference is updated for email notifications.
  #
  # ====Returns
  # * +True+ -> If conference is updated and all other parameters are set
  # * +False+ -> Either conference is not updated or one or more parameter is not set
  def notify_on_dates_changed?
    return false unless email_settings.send_on_conference_dates_updated
    # do not notify unless one of the dates changed
    return false unless saved_change_to_start_date? || saved_change_to_end_date?

    # do not notify unless the mail content is set up
    (email_settings.conference_dates_updated_subject.present? && email_settings.conference_dates_updated_body.present?)
  end

  ##
  # Checks if registration dates are updated for email notifications.
  #
  # ====Returns
  # * +True+ -> If registration dates is updated and all other parameters are set
  # * +False+ -> Either registration date is not updated or one or more parameter is not set
  def notify_on_registration_dates_changed?
    return false unless email_settings.send_on_conference_registration_dates_updated
    # do not notify unless we allow a registration
    return false unless registration_period
    # do not notify unless one of the dates changed
    return false unless registration_period.saved_change_to_start_date? || registration_period.saved_change_to_end_date?

    # do not notify unless the mail content is set up
    (email_settings.conference_registration_dates_updated_subject.present? && email_settings.conference_registration_dates_updated_body.present?)
  end

  ##
  # Checks if the registration limit has been exceeded
  # Additionally, it takes into account the confirmed speakers that haven't registered yet
  #
  # ====Returns
  # * +True+ -> If the registration limit has been reached or exceeded
  # * +False+ -> If the registration limit hasn't been exceeded
  def registration_limit_exceeded?
    registration_limit > 0 && registrations.count + program.speakers.confirmed.unregistered(program.conference).count >= registration_limit
  end

  # Returns an hexadecimal color given a collection. The returned color changed
  # when the number of element in the collection changes and for consecutive
  # number of elements it returns highly different colors.
  def next_color_for_collection(collection)
    # we have different start indices for every collection to generate a
    # different color for every of them.
    start_index = {
      tracks: (program.tracks.count + 1),
      levels: (program.difficulty_levels.count + 51),
      types:  (program.event_types.count + 101)
    }
    next_color(start_index[collection])
  end

  # Returns the current day if it is a day of the schedule or nil otherwise
  def current_conference_day
    day = Time.find_zone(timezone).today
    day if (start_date..end_date).cover? day
  end

  # Returns the number of hours since the conference start hour (9) to the
  # current hour, in case that the current hour is beetween the start and the
  # end hour (20). Otherwise, returns 0
  def hours_from_start_time(start_hour, end_hour)
    current_time = Time.find_zone(timezone).now
    current_hour = current_time.strftime('%H').to_i
    (start_hour..(end_hour - 1)).cover?(current_hour) ? current_hour - start_hour : 0
  end

  ##
  #
  # ====Returns
  # * +True+ -> if accepted booths are equal to the booth limit
  # * +False+ -> Accepted booths have not reached the booth limit
  def maximum_accepted_booths?
    booth_limit > 0 && booths.accepted.count + booths.confirmed.count >= booth_limit
  end

  ##
  # Return the current conference object to be used in RevisionCount
  #
  # ====Returns
  # * +ActiveRecord+
  def conference
    self
  end

  def to_param
    short_title
  end

  ##
  # Returns true or false, if the event is already over or not
  #
  # ====Returns
  # * +true+ -> If the event is over
  # * +false+ -> If the event is not over yet
  def ended?
    end_date < Time.current
  end

  private

  # Returns a different html colour for every i and consecutive colors are
  # clearly different.
  def next_color(i)
    '#' + next_color_component(:r, i) + next_color_component(:g, i) + next_color_component(:b, i)
  end

  # Auxiliar function which is used in next_color and returns each component of
  # the color. We make use of big prime numbers to avoid repetition and to make
  # consecutive colors clearly different.
  def next_color_component(component, i)
    big_prime_numbers = {r: 113, g: 67, b: 151}
    ((i * big_prime_numbers[component]) % 239 + 16).to_s(16)
  end

  after_create do
    create_contact
    create_program
    create_roles
  end

  ##
  # Creates free ticket for the conference
  # after the conference has been successfully created
  # Will create 1 new record for 'free' ticket
  def create_free_ticket
    tickets.where(title: 'Free Access', price_cents: 0).first_or_create!(description: 'Get free access tickets for the conference.')
  end

  ##
  # Creates the roles of the conference
  # after the conference has been successfully created
  # Will create 4 new records for roles
  def create_roles
    Role.where(name: 'organizer', resource: self).first_or_create(description: 'For the organizers of the conference (who shall have full access)')
    Role.where(name: 'cfp', resource: self).first_or_create(description: 'For the members of the CfP team')
    Role.where(name: 'info_desk', resource: self).first_or_create(description: 'For the members of the Info Desk team')
    Role.where(name: 'volunteers_coordinator', resource: self).first_or_create(description: 'For the people in charge of volunteers')
  end

  ##
  # Checks if start date of the conference is greater than the end date
  #
  # Reports an error when such a condition is found
  def valid_date_range?
    errors.add(:start_date, 'is greater than End date') if start_date && end_date && start_date > end_date
  end

  ##
  # Checks if start hour of the conference is greater or equal than the end hour
  # and that both hours are beetween 0 and 24
  #
  # Reports an error when such a condition is found
  def valid_times_range?
    if start_hour && end_hour
      errors.add(:start_hour, 'is lower than 0') if start_hour < 0
      errors.add(:end_hour, 'is lower or equal than start hour') if end_hour <= start_hour
      errors.add(:end_hour, 'is greater than 24') if end_hour > 24
    end
  end

  ##
  # Calculates the weeks from a start and a end week.
  #
  # ====Returns
  # * +Fixnum+ -> weeks
  def weeks(start_week, end_week)
    weeks = end_week - start_week + 1
    weeks_of_year = Date.new(start_date.year, 12, 31).strftime('%W').to_i
    weeks < 0 ? weeks + weeks_of_year : weeks
  end

  ##
  # Returns a Hash with the events with the state confirmend / unconfirmed per week.
  #
  # ====Returns
  # * +Hash+ -> e.g. 'Confirmed' => { 3 => 5, 4 => 6 }
  def get_events_per_week_by_state
    result = {
      'Submitted'   => {},
      'Confirmed'   => {},
      'Unconfirmed' => {}
    }

    # Completed weeks
    events_per_week.each do |week, values|
      values.each do |state, value|
        if %i(confirmed unconfirmed).include?(state)
          unless result[state.to_s.capitalize]
            result[state.to_s.capitalize] = {}
          end
          result[state.to_s.capitalize][DateTime.parse(week).strftime('%W').to_i] = value
        end
      end
    end

    # Actual week
    this_week = Date.today.end_of_week.strftime('%W').to_i
    result['Confirmed'][this_week] = program.events.where('state = ?', :confirmed).count
    result['Unconfirmed'][this_week] = program.events.where('state = ?', :unconfirmed).count
    result['Submitted'] = program.events.select(:week).group(:week).count
    result['Submitted'][this_week] = program.events.where(week: this_week).count
    result
  end

  ##
  # Returns an array from the hash values with left padding.
  #
  # ====Returns
  # * +Array+ -> [0, 0, 1, 2, 3, 0, 0]
  def pad_array_left_not_kumulative(start_week, hash)
    hash = assert_keys_are_continuously(hash)

    first_week = hash.keys[0]
    left = pad_left(first_week, start_week)
    left + hash.values
  end

  ##
  # Returns an array from the hash values with left padding.
  #
  # ====Returns
  # * +Array+ -> [0, 0, 1, 2, 3, 3, 3]
  def pad_array_left_kumulative(start_week, hash)
    hash = assert_keys_are_continuously(hash)
    result = cumulative_sum(hash.values)

    first_week = hash.keys[0]
    left = pad_left(first_week, start_week)
    left + result
  end

  ##
  # Cumulative sums an array.
  #
  # ====Returns
  # * +Array+ -> [1, 2, 3, 4] --> [1, 3, 7, 11]
  def cumulative_sum(array)
    sum = 0
    array.map { |x| sum += x }
  end

  ##
  # Returns the left padding.
  #
  # ====Returns
  # * +Array+
  def pad_left(first_week, start_week)
    left = []
    if first_week > start_week
      left = Array.new(first_week - start_week - 1, 0)
    end
    left
  end

  ##
  # Asserts that all keys in the hash are continuously.
  # If not, the missing key is inserted with value 0.
  #
  # ====Returns
  # * +Hash+  { 1 => 1, 2 => 0, 3 => 0, 4 => 3 }
  def assert_keys_are_continuously(hash)
    keys = hash.keys
    (keys.min..keys.max).each do |key|
      unless hash[key]
        hash[key] = 0
      end
    end
    Hash[hash.sort]
  end

  ##
  # Returns the progress of the set up conference list in percent
  #
  # ====Returns
  # * +String+ -> Progress in Percent
  def calculate_setup_progress(result)
    (100 * result.values.count(true) / result.values.count).to_s
  end

  ##
  # Checks if there is a difficulty level.
  #
  # ====Returns
  # * +True+ -> One difficulty level or more
  # * +False+ -> No diffculty level
  def difficulty_levels_set?
    program.difficulty_levels.any?
  end

  ##
  # Checks if there is a difficulty level.
  #
  # ====Returns
  # * +True+ -> One difficulty level or more
  # * +False+ -> No diffculty level
  def event_types_set?
    program.event_types.any?
  end

  ##
  # Checks if there is a track.
  #
  # ====Returns
  # * +True+ -> One track or more
  # * +False+ -> No track
  def tracks_set?
    program.tracks.any?
  end

  ##
  # Checks if there is a room.
  #
  # ====Returns
  # * +True+ -> One room or more
  # * +False+ -> No room
  def rooms_set?
    venue.present? && venue.rooms.any?
  end

  # Checks if the conference has a venue object.
  #
  # ====Returns
  # * +True+ -> If conference has a venue object.
  # * +False+ -> IF conference has no venue object.
  def venue_set?
    venue.present?
  end

  ##
  # Checks if the conference has a call for papers object.
  #
  # ====Returns
  # * +True+ -> If conference has a cfp object.
  # * +False+ -> If conference has no cfp object.
  def cfp_set?
    program.cfp.present?
  end

  ##
  # Checks if conference has a start and a end date.
  #
  # ====Returns
  # * +True+ -> If conference has a start and a end date.
  # * +False+ -> If conference has no start or end date.
  def registration_date_set?
    registration_period.present? && registration_period.start_date.present? && registration_period.end_date.present?
  end

  # Calculates the distribution from events.
  #
  # ====Returns
  # * +hash+ -> object_type => {color, value}
  def calculate_event_distribution(group_by_id, association_symbol, state = nil)
    grouped = if state
                program.events.select(group_by_id).where('state = ?', state).group(group_by_id)
              else
                program.events.select(group_by_id).group(group_by_id)
              end
    counted = grouped.count

    calculate_distribution_hash(grouped, counted, association_symbol)
  end

  ##
  # Helper method to calculate the correct data format for the doughnut charts.
  #
  # ====Returns
  # * +hash+ -> object_type => {color, value}
  def calculate_distribution_hash(grouped, counter, symbol)
    result = {}

    grouped.each do |event|
      object = event.send(symbol)
      if object
        result[object.title] = {
          'value' => counter[object.id],
          'color' => object.color
        }
      end
    end
    result
  end

  ##
  # Helper method to calculate the correct data format for the doughnut charts
  # for track distribution of events.
  #
  # ====Returns
  # * +hash+ -> object_type => {color, value}
  def calculate_track_distribution_hash(tracks_grouped, tracks_counter)
    result = {}
    tracks_grouped.each do |event|
      if event.track
        result[event.track.name] = {
          'value' => tracks_counter[event.track_id],
          'color' => event.track.color
        }
      end
    end
    result
  end

  ##
  # Helper method to calculate the program minutes.
  #
  # ====Returns
  # * +Fixnums+ summed program minutes
  def calculate_program_minutes(events_grouped, events_counted)
    result = 0
    events_grouped.each do |event|
      result += events_counted[event.event_type_id] * event.event_type.length
    end
    result
  end

  ##
  # Helper method for calculating hash with corresponding colors of user distribution states.
  #
  # ====Returns
  # * +hash+ -> hash
  def self.calculate_user_distribution_hash(active_user, unconfirmed_user, dead_user)
    result = {}
    if active_user > 0
      result['Active'] = {
        'color' => 'green',
        'value' => active_user
      }
    end
    if unconfirmed_user > 0
      result['Unconfirmed'] = {
        'color' => 'red',
        'value' => unconfirmed_user
      }
    end
    if dead_user > 0
      result['Dead'] = {
        'color' => 'black',
        'value' => dead_user
      }
    end
    result
  end

  ##
  # Helper method. Calculates hash of all event states in a consistent order.
  #
  # ====Returns
  # * +hash+ -> hash
  def self.calculate_event_distribution_hash(counts)
    return {} if counts.values.sum == 0

    Hash[
      Event.state_machine.states.collect do |state|
        state_name = state.name.to_s
        [state_name.capitalize, counts[state_name] || 0]
      end
    ]
  end

  ##
  # Returns a hash with user => submissions ordered by submissions for all conferences
  #
  # ====Returns
  # * +hash+ -> user: submissions
  def self.calculate_user_submission_hash(submitters, counter)
    result = ActiveSupport::OrderedHash.new
    counter.each do |key, value|
      # make PG happy by including the user_id in ORDER
      submitter = submitters.where(user_id: key).order(:user_id).first
      if submitter
        result[submitter.user] = value
      end
    end
    result
  end

  ##
  # Creates a EmailSettings association proxy. Used as before_create.
  #
  def create_email_settings
    build_email_settings
  end

  ##
  # Creates a UID for the conference. Used as before_create.
  #
  def generate_guid
    guid = SecureRandom.urlsafe_base64
#     begin
#       guid = SecureRandom.urlsafe_base64
#     end while User.where(:guid => guid).exists?
    self.guid = guid
  end

  ##
  # Adds a random color to the conference
  #
  def add_color
    unless color
      self.color = get_color
    end
  end

  def get_color
    %w(
        #000000 #0000FF #00FF00 #FF0000 #FFFF00 #9900CC
        #CC0066 #00FFFF #FF00FF #C0C0C0 #00008B #FFD700
        #FFA500 #FF1493 #FF00FF #F0FFFF #EE82EE #D2691E
        #C0C0C0 #A52A2A #9ACD32 #9400D3 #8B008B #8B0000
        #87CEEB #808080 #800080 #008B8B #006400
      ).sample
  end

  # Calculates items per week from a hash.
  #
  # ====Returns
  #  * +Array+ -> e.g. [1, 3, 3, 5] -> first week 1, second week 2 registrations
  def calculate_items_per_week(start_week, weeks, items)
    sum = 0
    result = []
    last_key = start_week - 1

    if !items.empty? && start_week > items.keys[0].to_i
      start_week = items.keys[0].to_i
      weeks += start_week - items.keys[0].to_i + 1
    end

    items.each do |key, value|
      # Padding
      if last_key < (key.to_i - 1)
        result += Array.new(key.to_i - last_key - 1, sum)
      end

      sum += value
      result.push(sum)
      last_key = key.to_i
    end

    # Padding right
    if result.length < weeks
      result += Array.new(weeks - result.length, sum)
    end

    add_week_indices(result)
  end

  def add_week_indices(values)
    Hash[
      values.collect.with_index { |value, index| ["Wk #{index + 1}", value] }
    ]
  end
end
