# Copyright (C) 2012-2023 Zammad Foundation, https://zammad-foundation.org/

class Tag < ApplicationModel
  include Tag::WritesToTicketHistory
  include HasTransactionDispatcher

  belongs_to :tag_object, class_name: 'Tag::Object', optional: true
  belongs_to :tag_item,   class_name: 'Tag::Item', optional: true

=begin

add tags for certain object

  Tag.tag_add(
    object: 'Ticket',
    o_id: ticket.id,
    item: 'some tag',
    created_by_id: current_user.id,
  )

=end

  def self.tag_add(data)
    data[:item].strip!

    # lookups
    if data[:object]
      tag_object_id = Tag::Object.lookup_by_name_and_create(data[:object]).id
    end
    if data[:item]
      tag_item_id = Tag::Item.lookup_by_name_and_create(data[:item]).id
    end

    # return if duplicate
    current_tags = tag_list(data)
    return true if current_tags.include?(data[:item])

    # create history
    Tag.create(
      tag_object_id: tag_object_id,
      tag_item_id:   tag_item_id,
      o_id:          data[:o_id],
      created_by_id: data[:created_by_id],
    )

    # touch reference
    touch_reference_by_params(data)
    true
  end

=begin

remove tags of certain object

  Tag.tag_remove(
    object: 'Ticket',
    o_id: ticket.id,
    item: 'some tag',
    created_by_id: current_user.id,
  )

or by ids

  Tag.tag_remove(
    tag_object_id: 123,
    o_id: ticket.id,
    tag_item_id: 123,
    created_by_id: current_user.id,
  )

=end

  def self.tag_remove(data)

    # lookups
    if data[:object]
      data[:tag_object_id] = Tag::Object.lookup_by_name_and_create(data[:object]).id
    else
      data[:object] = Tag::Object.lookup(id: data[:tag_object_id]).name
    end
    if data[:item]
      data[:item].strip!
      data[:tag_item_id] = Tag::Item.lookup_by_name_and_create(data[:item]).id
    end

    # create history
    result = Tag.where(
      tag_object_id: data[:tag_object_id],
      tag_item_id:   data[:tag_item_id],
      o_id:          data[:o_id],
    )
    result.each(&:destroy)

    # touch reference
    touch_reference_by_params(data)
    true
  end

=begin

remove all tags of certain object

  Tag.tag_destroy(
    object: 'Ticket',
    o_id: ticket.id,
    created_by_id: current_user.id,
  )

=end

  def self.tag_destroy(data)

    # lookups
    if data[:object]
      data[:tag_object_id] = Tag::Object.lookup_by_name_and_create(data[:object]).id
    else
      data[:object] = Tag::Object.lookup(id: data[:tag_object_id]).name
    end

    # create history
    result = Tag.where(
      tag_object_id: data[:tag_object_id],
      o_id:          data[:o_id],
    )
    result.each(&:destroy)
    true
  end

=begin

update tags for certain object

  Tag.tag_update(
    object: 'Ticket',
    o_id: ticket.id,
    items: ['some tag', ['another tag']],
    created_by_id: current_user.id,
  )

=end

  def self.tag_update(object:, o_id:, items:, created_by_id: nil)
    given_tags = items.map(&:strip!)
    old_tags   = tag_list(object: object, o_id: o_id)

    tag_object_id = Tag::Object.lookup_by_name_and_create(object).id

    added_tags   = given_tags - old_tags
    removed_tags = old_tags - given_tags

    added_tags.each do |tag_name|
      tag_item_id = Tag::Item.lookup_by_name_and_create(tag_name).id

      Tag.create(
        tag_object_id: tag_object_id,
        tag_item_id:   tag_item_id,
        o_id:          o_id,
        created_by_id: created_by_id,
      )
    end

    if removed_tags.any?
      tag_item_ids = removed_tags.map { |tag_name| Tag::Item.lookup_by_name_and_create(tag_name).id }

      Tag
        .where(
          tag_object_id: tag_object_id,
          tag_item_id:   tag_item_ids,
          o_id:          o_id,
        )
        .destroy_all
    end

    # touch reference
    if added_tags.any? || removed_tags.any?
      touch_reference_by_params(object: object, o_id: o_id)
    end

    true
  end

=begin

tag list for certain object

  tags = Tag.tag_list(
    object: 'Ticket',
    o_id: ticket.id,
  )

returns

  ['tag 1', 'tag2', ...]

=end

  def self.tag_list(data)
    Tag.joins(:tag_item, :tag_object)
       .where(o_id: data[:o_id], tag_objects: { name: data[:object] })
       .order(:id)
       .pluck('tag_items.name')
  end

=begin

Lists references to objects with certain tag. Optionally filter by type.
Returns array containing object class name and ID.

@param tag [String] tag to lookup
@param object [String] optional name of the class to search in

@example

references = Tag.tag_references(
  tag: 'Tag',
  object: 'Ticket'
)

references # [['Ticket', 1], ['Ticket', 4], ...]

@return [Array<Array<String, Integer>>]

=end

  def self.tag_references(tag:, object: nil)
    tag_item = Tag::Item.find_by name: tag

    return [] if tag_item.nil?

    output = Tag.where(tag_item: tag_item).joins(:tag_object)

    output = output.where(tag_objects: { name: object }) if object.present?

    output.pluck(:'tag_objects.name', :o_id)
  end
end