require 'csv'

class GeoliteCountryImporter
  BATCH_SIZE = 1000

  def initialize(file_path, data_import:)
    @file_path = file_path
    @data_import = data_import
    @total_records = 0
    @processed_records = 0
    @failed_records = 0
    @errors = []
    @locations_cache = {}
  end

  def import
    Rails.logger.info "Starting import for file: #{@file_path}"
    Rails.logger.info "File exists: #{File.exist?(@file_path)}"
    Rails.logger.info "File size: #{File.size(@file_path)} bytes" if File.exist?(@file_path)

    # Check if file is actually a zip by reading the magic bytes
    is_zip_file = check_if_zip_file
    Rails.logger.info "File is zip: #{is_zip_file}"

    if is_zip_file
      Rails.logger.info "Calling import_from_zip"
      import_from_zip
    else
      Rails.logger.info "Calling regular import (not zip)"
      load_locations_data
      import_csv_file(@file_path)
    end

    {
      total_records: @total_records,
      processed_records: @processed_records,
      failed_records: @failed_records,
      errors: @errors
    }
  end

  private

  def check_if_zip_file
    # Check if the file starts with ZIP magic bytes (PK\x03\x04)
    File.open(@file_path, 'rb') do |file|
      header = file.read(4)
      return header == "PK\x03\x04"
    end
  rescue => e
    Rails.logger.error "Error checking if file is zip: #{e.message}"
    false
  end

  def import_from_zip
    require 'zip'
    require 'stringio'

    Rails.logger.info "Processing zip file directly: #{@file_path}"

    # Read the entire ZIP file content into memory first
    zip_content = File.binread(@file_path)

    Zip::File.open_buffer(StringIO.new(zip_content)) do |zip_file|
      # First, see what's in the zip
      Rails.logger.info "Files in zip:"
      zip_file.each do |entry|
        Rails.logger.info "  - #{entry.name} (#{entry.size} bytes)"
      end

      # First, load location data from zip
      load_locations_data_from_zip(zip_file)

      # Then process block files from zip
      zip_file.each do |entry|
        if entry.name.include?('Blocks') && entry.name.end_with?('.csv')
          Rails.logger.info "Processing block file from zip: #{entry.name}"
          process_csv_from_zip(zip_file, entry)
        end
      end
    end
  rescue => e
    Rails.logger.error "Error processing ZIP file: #{e.message}"
    Rails.logger.error e.backtrace.join("\n")
    raise
  end

  def process_csv_from_zip(zip_file, entry)
    zip_file.get_input_stream(entry) do |io|
      # Read the entire content from the stream
      content = io.read

      # Try different encodings if UTF-8 fails
      encodings = ['UTF-8', 'ISO-8859-1', 'Windows-1252']
      encoding_used = nil

      encodings.each do |encoding|
        begin
          # Parse the CSV content from the string
          CSV.parse(content, headers: true, header_converters: :symbol, encoding: encoding) do |row|
            @total_records += 1

            begin
              import_record(row)
              @processed_records += 1
            rescue => e
              @failed_records += 1
              @errors << "Row #{@total_records}: #{e.message} - Data: #{row.to_h}"
            end

            update_progress_if_needed
          end
          encoding_used = encoding
          Rails.logger.info "Successfully processed #{entry.name} with #{encoding} encoding"
          break
        rescue CSV::InvalidEncodingError => e
          Rails.logger.warn "Failed to process #{entry.name} with #{encoding} encoding: #{e.message}"
          next if encoding != encodings.last
          raise e if encoding == encodings.last
        end
      end

      unless encoding_used
        @errors << "Failed to process #{entry.name} with any supported encoding"
      end
    end
  end

  def load_locations_data_from_zip(zip_file)
    require 'zip'

    # Find all location files and prioritize English
    location_entries = zip_file.select { |entry| entry.name.include?('Locations') && entry.name.end_with?('.csv') }

    # Sort to prioritize English locations file
    location_entries.sort_by! { |entry| entry.name.include?('Locations-en') ? 0 : 1 }

    location_entries.each do |entry|
      Rails.logger.info "Loading locations from: #{entry.name}"
      zip_file.get_input_stream(entry) do |io|
        # Read the entire content from the stream
        content = io.read

        # Try different encodings if UTF-8 fails
        encodings = ['UTF-8', 'ISO-8859-1', 'Windows-1252']

        encodings.each do |encoding|
          begin
            # Parse the CSV content from the string
            CSV.parse(content, headers: true, header_converters: :symbol, encoding: encoding) do |row|
              geoname_id = row[:geoname_id]
              next unless geoname_id

              @locations_cache[geoname_id] = {
                country_iso_code: row[:country_iso_code],
                country_name: row[:country_name],
                continent_code: row[:continent_code],
                continent_name: row[:continent_name],
                is_in_european_union: row[:is_in_european_union]
              }
            end
            Rails.logger.info "Loaded locations from #{entry.name} with #{encoding} encoding"
            break
          rescue CSV::InvalidEncodingError => e
            Rails.logger.warn "Failed to load locations from #{entry.name} with #{encoding} encoding: #{e.message}"
            next if encoding != encodings.last
            raise e if encoding == encodings.last
          end
        end
      end
    end

    Rails.logger.info "Loaded #{@locations_cache.size} location records"
  end

  def import_csv_file(csv_file)
    CSV.foreach(csv_file, headers: true, header_converters: :symbol, encoding: 'UTF-8') do |row|
      @total_records += 1

      begin
        import_record(row)
        @processed_records += 1
      rescue => e
        @failed_records += 1
        @errors << "Row #{@total_records}: #{e.message} - Data: #{row.to_h}"

        # Update progress every 100 records or on error
        update_progress_if_needed
      end

      update_progress_if_needed
    end
  end

  def import_record(row)
    network = row[:network]
    geoname_id = row[:geoname_id]
    registered_country_geoname_id = row[:registered_country_geoname_id]
    is_anonymous_proxy = row[:is_anonymous_proxy] == '1'
    is_satellite_provider = row[:is_satellite_provider] == '1'
    is_anycast = row[:is_anycast] == '1'

    unless network
      raise "Missing required field: network"
    end

    # Validate network format
    IPAddr.new(network) # This will raise if invalid

    # Get location data - prefer geoname_id, then registered_country_geoname_id
    location_data = @locations_cache[geoname_id] || @locations_cache[registered_country_geoname_id] || {}

    # Store raw GeoLite country data in network_data[:geolite]
    geolite_data = {
      country: {
        geoname_id: geoname_id,
        registered_country_geoname_id: registered_country_geoname_id,
        represented_country_geoname_id: row[:represented_country_geoname_id],
        continent_code: location_data[:continent_code],
        continent_name: location_data[:continent_name],
        country_name: location_data[:country_name],
        country_iso_code: location_data[:country_iso_code],
        is_in_european_union: location_data[:is_in_european_union],
        is_anonymous_proxy: is_anonymous_proxy,
        is_satellite_provider: is_satellite_provider,
        is_anycast: is_anycast
      }
    }.compact

    NetworkRange.upsert(
      {
        network: network,
        country: location_data[:country_iso_code],
        is_proxy: is_anonymous_proxy,
        source: 'geolite_country',
        network_data: { geolite: geolite_data },
        updated_at: Time.current
      },
      unique_by: :index_network_ranges_on_network_unique
    )
  end

  def update_progress_if_needed
    if (@processed_records + @failed_records) % 100 == 0
      @data_import.update_progress(
        processed: @processed_records,
        failed: @failed_records,
        total_records: @total_records,
        stats: {
          total_records: @total_records,
          current_file: File.basename(@file_path),
          locations_loaded: @locations_cache.size,
          recent_errors: @errors.last(5)
        }
      )
    end
  end

  def load_locations_data
    locations_files = find_locations_files

    locations_files.each do |locations_file|
      CSV.foreach(locations_file, headers: true, header_converters: :symbol, encoding: 'UTF-8') do |row|
        geoname_id = row[:geoname_id]
        next unless geoname_id

        @locations_cache[geoname_id] = {
          country_iso_code: row[:country_iso_code],
          country_name: row[:country_name],
          continent_code: row[:continent_code],
          continent_name: row[:continent_name],
          is_in_european_union: row[:is_in_european_union]
        }
      end
    end
  end

  def find_locations_files
    if @file_path.end_with?('.zip')
      base_dir = File.dirname(@file_path)
      base_name = File.basename(@file_path, '.zip')

      # Look for English locations file first, then any locations file
      [
        File.join(base_dir, "#{base_name}-Locations-en.csv"),
        Dir[File.join(base_dir, "#{base_name}-Locations-*.csv")].first
      ].compact.select { |file| File.exist?(file) }
    else
      base_dir = File.dirname(@file_path)
      Dir[File.join(base_dir, "*Locations*.csv")].select { |file| File.exist?(file) }
    end
  end
end