# frozen_string_literal: true

class ChatChannel < ActiveRecord::Base
  include Trashable

  belongs_to :chatable, polymorphic: true
  belongs_to :direct_message,
             -> { where(chat_channels: { chatable_type: "DirectMessage" }) },
             foreign_key: "chatable_id"

  has_many :chat_messages
  has_many :user_chat_channel_memberships

  has_one :chat_channel_archive

  enum :status, { open: 0, read_only: 1, closed: 2, archived: 3 }, scopes: false

  validates :name,
            length: {
              maximum: Proc.new { SiteSetting.max_topic_title_length },
            },
            presence: true,
            allow_nil: true
  validate :ensure_slug_ok, if: :slug_changed?
  before_validation :generate_auto_slug

  scope :public_channels,
        -> {
          where(chatable_type: public_channel_chatable_types).where(
            "categories.id IS NOT NULL",
          ).joins(
            "LEFT JOIN categories ON categories.id = chat_channels.chatable_id AND chat_channels.chatable_type = 'Category'",
          )
        }

  delegate :empty?, to: :chat_messages, prefix: true

  class << self
    def public_channel_chatable_types
      ["Category"]
    end

    def chatable_types
      public_channel_chatable_types << "DirectMessage"
    end
  end

  statuses.keys.each do |status|
    define_method("#{status}!") { |acting_user| change_status(acting_user, status.to_sym) }
  end

  %i[
    category_channel?
    direct_message_channel?
    public_channel?
    chatable_has_custom_fields?
    read_restricted?
  ].each { |name| define_method(name) { false } }

  %i[allowed_user_ids allowed_group_ids chatable_url].each { |name| define_method(name) { nil } }

  def membership_for(user)
    user_chat_channel_memberships.find_by(user: user)
  end

  def add(user)
    Chat::ChatChannelMembershipManager.new(self).follow(user)
  end

  def remove(user)
    Chat::ChatChannelMembershipManager.new(self).unfollow(user)
  end

  def status_name
    I18n.t("chat.channel.statuses.#{self.status}")
  end

  def url
    "#{Discourse.base_url}/chat/channel/#{self.id}/#{self.slug || "-"}"
  end

  def relative_url
    "#{Discourse.base_path}/chat/channel/#{self.id}/#{self.slug || "-"}"
  end

  def self.ensure_consistency!
    update_counts
  end

  # TODO (martin) Move UpdateUserCountsForChatChannels into here
  def self.update_counts

    # NOTE: ChatChannel#messages_count is not updated every time
    # a message is created or deleted in a channel, so it should not
    # be displayed in the UI. It is updated eventually via Jobs::ChatPeriodicalUpdates
    DB.exec <<~SQL
      UPDATE chat_channels channels
      SET messages_count = subquery.messages_count
      FROM (
        SELECT COUNT(*) AS messages_count, chat_channel_id
        FROM chat_messages
        WHERE chat_messages.deleted_at IS NULL
        GROUP BY chat_channel_id
      ) subquery
      WHERE channels.id = subquery.chat_channel_id
      AND channels.deleted_at IS NULL
      AND subquery.messages_count != channels.messages_count
    SQL
  end

  private

  def change_status(acting_user, target_status)
    return if !Guardian.new(acting_user).can_change_channel_status?(self, target_status)
    self.update!(status: target_status)
    log_channel_status_change(acting_user: acting_user)
  end

  def log_channel_status_change(acting_user:)
    DiscourseEvent.trigger(
      :chat_channel_status_change,
      channel: self,
      old_status: status_previously_was,
      new_status: status,
    )

    StaffActionLogger.new(acting_user).log_custom(
      "chat_channel_status_change",
      {
        chat_channel_id: self.id,
        chat_channel_name: self.name,
        previous_value: status_previously_was,
        new_value: status,
      },
    )

    ChatPublisher.publish_channel_status(self)
  end

  def duplicate_slug?
    ChatChannel.where(slug: self.slug).where.not(id: self.id).any?
  end
end

# == Schema Information
#
# Table name: chat_channels
#
#  id                           :bigint           not null, primary key
#  chatable_id                  :integer          not null
#  deleted_at                   :datetime
#  deleted_by_id                :integer
#  featured_in_category_id      :integer
#  delete_after_seconds         :integer
#  chatable_type                :string           not null
#  created_at                   :datetime         not null
#  updated_at                   :datetime         not null
#  name                         :string
#  description                  :text
#  status                       :integer          default("open"), not null
#  user_count                   :integer          default(0), not null
#  last_message_sent_at         :datetime         not null
#  auto_join_users              :boolean          default(FALSE), not null
#  allow_channel_wide_mentions  :boolean          default(TRUE), not null
#  user_count_stale             :boolean          default(FALSE), not null
#  slug                         :string
#  type                         :string
#
# Indexes
#
#  index_chat_channels_on_messages_count             (messages_count)
#  index_chat_channels_on_chatable_id                    (chatable_id)
#  index_chat_channels_on_chatable_id_and_chatable_type  (chatable_id,chatable_type)
#  index_chat_channels_on_slug                           (slug) UNIQUE
#  index_chat_channels_on_status                         (status)
#