require 'find'
require_relative '../defaults.rb'

module Emojidex
  module Util
    # Check collections for presence of image assets and discrepencies in emoji indexes.
    class CollectionChecker
      attr_reader :index_only, :asset_only

      def initialize(collections, options = {})
        collections = *collections
        @index_only = {}
        @asset_only = {}
        asset_path = options[:asset_path] || collections.first.source_path
        sizes = options[:sizes] || Emojidex::Defaults.sizes.keys
        formats = options[:formats] || Emojidex::Defaults.formats

        asset_files = create_asset_file_list(asset_path, sizes, formats)
        check_for_index_only(collections, asset_files, sizes, formats)
        check_for_asset_only(collections, asset_files)
      end

      private

      def create_asset_file_list(dir, sizes, formats)
        result = {}
        result.merge!(create_file_list(dir, '.svg', '')) if formats.include?(:svg)
        if formats.include?(:png)
          sizes.each do |size|
            result.merge!(create_file_list("#{dir}/#{size}", '.png', "#{size}/"))
          end
        end
        result
      end

      def create_file_list(dir, ext, prefix)
        result = {}
        return result unless Dir.exist?(dir)
        Dir.foreach(dir) do |file|
          result["#{prefix}#{File.basename(file, '.*')}".to_sym] =
            "#{prefix}#{file}" if File.extname(file) == ext
        end
        result
      end

      def check_for_index_only(collections, asset_files, sizes, formats)
        collections.each do |collection|
          collection.emoji.values.each do |emoji|
            tmp = []
            tmp += create_svg_array(emoji, asset_files) if formats.include?(:svg)
            tmp += create_png_array(emoji, asset_files, sizes) if formats.include?(:png)
            @index_only[emoji.code.to_sym] = tmp unless tmp.empty?
          end
        end
      end

      def create_svg_array(emoji, asset_files)
        result = []
        result << "#{emoji.code}.svg" if asset_files[emoji.code.to_sym].nil?
        result
      end

      def create_png_array(emoji, asset_files, sizes)
        result = []
        sizes.each do |size|
          name = "#{size}/#{emoji.code}"
          result << "#{name}.png" if asset_files[name.to_sym].nil?
        end
        result
      end

      def check_for_asset_only(collections, asset_files)
        asset_files.each do |_key, value|
          code = File.basename(value, '.*')

          next if find_emoji_from_collections(collections, code)

          symbol = code.to_sym
          @asset_only[symbol] = [] if @asset_only[symbol].nil?
          @asset_only[symbol] << value
        end
      end

      def find_emoji_from_collections(collections, code)
        symbol = code.to_sym
        collections.each do |collection|
          return true unless collection.emoji[symbol].nil?
        end
        false
      end
    end
  end
end