# frozen_string_literal: true

# Satellite LandSat8
# 30m de resolução
# Banda 2 = Azul
# Banda 3 = Verde
# Banda 4 = Vermelho: 640-690 nm
# Banda 5 = Infravermelho próximo: 850-880 nm
module Satellite
  module Landsat8
    class ImageryService
      AWS_URL = 's3://landsat-pds/c1/L8'

      attr_accessor :scene, :quantity

      # $scene = { path: '000', row: '000' }
      def initialize(scene, quantity = 2)
        self.scene = "#{scene[:path]}/#{scene[:row]}"
        self.quantity = quantity
      end

      def download_and_proccess
        Rails.logger.info "[Landsat8 | #{scene}] Listando últimos #{quantity} arquivos..."
        files = last

        Rails.logger.info "[Landsat8 | #{scene}] Checando arquivos que precisam ser baixados..."
        files.reject!{ |file| scene_already_proccessed?(file) }

        Rails.logger.info "[Landsat8 | #{scene}] Baixando #{files.length} cenas..."
        files.each_with_index do |file, index|
          Rails.logger.info "[Landsat8 | #{scene}] Fazendo download da cena do dia #{file[:date]}..."
          useful_files(file[:file]).map do |useful_file|
            Thread.new {
              Rails.logger.info "[Landsat8 | #{scene}] Fazendo download do arquivo #{useful_file}..."
              `aws s3 cp #{AWS_URL}/#{scene}/#{file[:file]}/#{useful_file} "#{output_path}/#{file[:file]}/#{useful_file}"`
              raise 'Error to execute aws s3 cp' unless $?.success?
            }
          end.map(&:join)

          Rails.logger.info "[Landsat8 | #{scene}] Processando arquivos #{index.next}/#{files.length}."
          Satellite::ImageryProccessor.new(band_object(file[:file])).proccess
        end
      end

      def last
        @lasts ||= `aws s3 ls #{AWS_URL}/#{scene}/`
          .split("\n")
          .select{ |file| file.end_with?('_RT/') } # Seleciona somente REAL TIME files - https://landsat.usgs.gov/landsat-collections
          .map do |name|
            name = name[/.*(LC08.+)\//,1]
            date = name[/.+?_.+?_.+?_(.+?)_/, 1].to_date
            {
              file: name,
              date: date
            }
          end
          .sort_by{ |item| item[:date] }
          .last(quantity)
          .reverse
      end

      def useful_files(file_path)
        all_files_from_last_scene = `aws s3 ls #{AWS_URL}/#{scene}/#{file_path}/`

        all_files_from_last_scene.split("\n").inject([]) do |useful_files, current_file|
          filtered_file = current_file[/.*(LC08.+(B[2-5].TIF|.jpg|MTL.txt))$/, 1]
          useful_files << filtered_file if filtered_file.present?
          useful_files
        end.sort_by { |file| file.include?('.txt') && 1 || 2 }
      end

      def output_path
        return @path if @path.present?

        @path = File.join(Dir.pwd, 'public', 'system', 'data', 'imagens', 'landsat8')
        FileUtils.mkdir_p(@path)
        @path
      end

      def scene_already_proccessed?(file)
        Scene
          .landsat8
          .by_date(file[:date])
          .by_scene(scene.delete('/'))
          .exists?
      end

      def info_object(scene_folder)
        info_content = IO.read(Dir.glob(File.join(output_path, scene_folder,  '*.txt')).first)
        @info_object = {
          date: info_content.match(/DATE_ACQUIRED = (.+)/)[1].to_date,
          cloud_cover: info_content.match(/CLOUD_COVER = (.+)/)[1],
          scene: info_content.match(/LANDSAT_PRODUCT_ID = (.+)/)[1].split('_').third,
          source: :landsat8,
          base_path: output_path,
          files_path: "#{output_path}/#{scene_folder}"
        }
      end

      def band_object(file)
        {
          blue:               "#{output_path}/#{file}/#{file}_B2.TIF",
          green:              "#{output_path}/#{file}/#{file}_B3.TIF",
          red:                "#{output_path}/#{file}/#{file}_B4.TIF",
          near_infrared:      "#{output_path}/#{file}/#{file}_B5.TIF",
          small_thumb:        "#{output_path}/#{file}/#{file}_thumb_small.jpg",
          large_thumb:        "#{output_path}/#{file}/#{file}_thumb_large.jpg",
          info:               info_object(file)
        } if File.exist?(File.join(output_path, file))
      end
    end
  end
end