module Scrapbook
  class Placement < ApplicationRecord
    belongs_to :master, foreign_key: :scrapbook_master_id,
                        class_name: 'Scrapbook::Master'

    belongs_to :parent, polymorphic: true,
               required: false # Temporarily dont require parent?

    default_scope  { sorted }
    scope :context, ->(context) { where(context_name: context) }
    scope :sorted, -> { order(:position) }

    delegate :target_resolution, to: :context, prefix: false
    delegate :aspect_ratio, to: :target_resolution, prefix: false

    delegate :title, to: :master, prefix: false, allow_nil: true
    delegate :metadata, to: :master, prefix: true
    delegate :all_metadata, to: :master, prefix: true

    attribute :crop_origin, :scrapbook_coordinate, default: '0,0'
    attribute :crop_resolution, :scrapbook_resolution

    validates_presence_of :context_name

    has_attached_file :file,
      styles: lambda { |attachment| attachment.instance.sizes },
      processors: [:cropped_resize]

    do_not_validate_attachment_file_type :file

    before_save :recrop_check

    def initialize(attributes = {})
      super context_name: attributes.delete(:context_name)
      assign_attributes(attributes)
    end

    def context
      Context.find(context_name)
    end

    def recrop_check
      return unless crop_changed? && !new_record?
      self.file.assign(self.file)
      file.save
    end

    def sizes
      sizes = { standard: target_resolution.to_s }
      if crop_retina_ready?
        sizes.merge!(retina: target_resolution.retinafy.to_s)
      end
      sizes
    end

    def crop_retina_ready?
      usable_crop_resolution.retinable?(target_resolution)
    end

    def crop_metrics
      {
        width: usable_crop_resolution.width,
        height: usable_crop_resolution.height,
        x: crop_origin.x,
        y: crop_origin.y
      }
    end

    def overriding_metadata
      attributes.select do |k, v|
        self.class.metadata_fields.include?(k) && v.present?
      end
    end

    def overriding_metadata=(hsh)
      assign_attributes(hsh)
    end

    def metadata
      master_metadata.merge(overriding_metadata)
    end

    def all_metadata
      master_all_metadata.merge(overriding_metadata)
    end

    def usable_crop_resolution
      crop_resolution || target_resolution
    end

    def file_urls
      Hash[sizes.keys.map { |size| [size, file_url(size)] }]
    end

    def file_url(style = :standard)
      return unless file.exists?
      file.url(style)
    end

    def edit_path
      @edit_path ||= Engine.routes.url_helpers.edit_placement_path(self)
    end

    def to_data
      as_json(methods: [:edit_path, :file_urls, :title, :metadata], except: [:crop_origin, :crop_resolution])
    end

    def crop_changed?
      crop_resolution_changed? || crop_origin_changed?
    end

    def master=(other)
      super
      self.file = master.file
    end

    def scrapbook_master_id=(other_id)
      super
      self.file = master.file
    end

    private

    def self.metadata_fields
      Scrapbook.config.metadata_fields.keys
    end
  end
end