require 'scrivito/binary'

require 'mini_magick'


module Fiona7
  module BinaryHandling
    class ParamEncoder
      def initialize
        self.verifier = ActiveSupport::MessageVerifier.new(
          Rails.application.secrets.secret_key_base, serializer: ::JSON)
      end

      def encode(params)
        self.verifier.generate(params)
      end

      def decode(string)
        self.verifier.verify(string)
      rescue ActiveSupport::MessageVerifier::InvalidSignature => e
        {}
      end

      protected
      attr_accessor :verifier
    end

    class MetaBinary
      class ActualBinary
        def initialize(binary_id, transformation=false)
          self.binary_id      = binary_id.to_i
          self.transformation = transformation
          self.obj            = self.load_obj
        end
        protected
        attr_accessor :binary_id, :transformation, :obj

        def cache(key, &block)
          # TODO: make path this configurable
          @@cache = ActiveSupport::Cache::FileStore.new(Rails.root + '/tmp/cache') unless defined?(@@cache)
          @@cache.fetch("#{self.binary_id}-#{key}", &block)
        end

        def load_obj
          if Fiona7.mode == :legacy
            Fiona7::EditedObj.find(self.binary_id)
          else
            Fiona7::InternalReleasedObj.find(self.binary_id)
          end
        rescue ActiveRecord::RecordNotFound
          nil
        end
      end

      class UnmodifiedBinary < ActualBinary
        def valid?
          self.binary_id >= 0 && self.obj.try(:binary?)
        end

        def present?
          !self.obj.nil?
        end

        def filename
          self.obj.filename
        end

        def filepath
          self.obj.body_data_path
        end

        def length
          self.obj.body_length
        end

        def image?
          self.obj.image?
        end

        def width
          self.cache("#{self.last_changed}-width") do
            if self.image
              self.image[:width]
            else
              0
            end
          end
        rescue 
          0
        end

        def height
          self.cache("#{self.last_changed}-height") do
            if self.image
              self.image[:height]
            else
              0
            end
          end
        rescue 
          0
        end

        def mime_type
          self.obj.mime_type
        end

        def last_changed
          self.obj.last_changed.utc
        end

        protected
        def image
          return @image if defined?(@image)
          if self.filepath
            @image = MiniMagick::Image.new(self.filepath)
          else
            @image = nil
          end
        end
      end

      class TransformedBinary < UnmodifiedBinary
        def valid?
          super && valid_transformation?
        end

        def filename
          ::File.basename(self.transformed_filepath)
        end

        alias_method :original_filepath, :filepath
        def filepath
          self.transformed_filepath
        end

        def legnth
          ::File.size(self.transformed_filepath)
        end

        def last_changed
          ::File.mtime(self.transformed_filepath).utc
        end

        protected
        def valid_transformation?
          true && 
            (self.mime_type =~ /image\//) &&
            (!self.width.present? || (1..4096).include?(self.width.to_i)) &&
            (!self.height.present? || (1..4096).include?(self.height.to_i)) &&
            ((0..100).include?(self.quality.to_i)) &&
            (!self.fit.present? || (
               (self.fit == 'clip' || self.fit == 'crop' || self.fit == 'resize') &&
               (self.width.to_i + self.height.to_i < 4096) &&
               (self.fit == 'clip' || (self.width.present? && self.height.present?))
            ))
        end

        def transformed_filepath
          return @transformed_filepath if @transformed_filepath
          return nil if self.original_filepath.nil?

          output_filepath = original_filepath + self.transformed_filename

          if ::File.exists?(output_filepath)
            Rails.logger.debug("Transformed image #{output_filepath} already generated, serving")
            return @transformed_filepath = output_filepath
          else
            Rails.logger.debug("Transforming image")
          end

          image = MiniMagick::Image.open(original_filepath)

          fit = self.fit_with_default

          if fit.blank?
            image.combine_options do |b|
              b.quality self.quality.to_i
            end 
          elsif fit == 'clip' || fit == 'resize'
            image.combine_options do |b|
              b.resize "#{self.width}x#{self.height}>"
              b.quality self.quality.to_i
            end 
          elsif fit == 'crop'
            image.combine_options do |b|
              b.resize "#{self.width}x#{self.height}^"
              b.gravity self.gravity
              b.extent "#{self.width}x#{self.height}>"
              b.quality self.quality.to_i
            end 
          else
            raise 'invalid fit'
          end

          image.write(output_filepath)
          @transformed_filepath = output_filepath
        end

        def transformed_filename
          ext = ::File.extname(self.original_filepath)
          "#{self.fit}_#{self.crop}_#{self.width}_#{self.height}_#{self.quality}#{ext}"
        end

        def transformation_with_fallback
          @transformation_with_fallback ||= (self.transformation || {}).with_indifferent_access
        end

        CROP_TO_GRAVITY = {
          'center'  => 'Center',
          'top'     => 'North',
          'left'    => 'West',
          'right'   => 'East',
          'bottom'  => 'South',
        }.freeze


        def crop
          self.transformation_with_fallback[:crop].presence || 'center'
        end

        def gravity
          CROP_TO_GRAVITY[self.crop] || 'Center'
        end

        def width
          self.transformation_with_fallback[:width].to_s
        end

        def height
          self.transformation_with_fallback[:height].to_s
        end

        def quality
          self.transformation_with_fallback[:quality] || '75'
        end

        def fit
          self.transformation_with_fallback[:fit]
        end

        def fit_with_default
          self.fit || ((width.present? || height.present?) && 'resize') || nil
        end
      end

      delegate :valid?, :present?,
        :filename, :filepath,
        :mime_type, :length, :last_changed,
        :image?, :width, :height,
        :to => :implementation

      def initialize(binary_id, transformation=false)
        if transformation
          self.implementation = TransformedBinary.new(binary_id, transformation)
        else
          self.implementation = UnmodifiedBinary.new(binary_id, transformation)
        end
      end

      protected
      attr_accessor :implementation

    end

    module DeliveryMixin
      # GET
      def show
        binary_id      = binary_id_from_params
        transformation = transformation_from_params
        meta_binary    = MetaBinary.new(binary_id, transformation)

        if !meta_binary.present?
          if Fiona7.mode == :standalone &&
             (current_binary = get_current_binary_url(binary_id))
            Rails.logger.info("Redirect to #{current_binary}")
            redirect_to current_binary, status: 301
          else
            not_found
          end
        elsif !meta_binary.valid?
          bad_request
        elsif stale?(:last_modified => meta_binary.last_changed) && true
          filename = meta_binary.filename
          filepath = meta_binary.filepath
          mime_type = meta_binary.mime_type

          send_file(File.expand_path(filepath), {
            :type => mime_type,
            :filename => filename,
            :disposition => 'inline'
          })
        end
      end

      # HEAD
      def query
        binary_id      = binary_id_from_params
        transformation = transformation_from_params
        meta_binary    = BinaryHandling::MetaBinary.new(binary_id, transformation)

        if !meta_binary.valid?
          bad_request
        elsif !meta_binary.present?
          not_found
        else
          simple_set_header('Content-Type', meta_binary.mime_type)
          simple_set_header('Content-Length', meta_binary.length)
          simple_set_header('Cache-Control', 'no-transform,public,max-age=300,s-maxage=900')
          head_ok
        end
      end

      protected
      def bad_request
        head 400
      end

      def not_found
        head 404
      end

      def head_ok
        head 200
      end

      def get_current_binary_url(binary_id)
        current_binary_url = nil
        blob_obj = Fiona7::WriteObj.find(binary_id.to_i) rescue nil
        if blob_obj
          binary_obj = blob_obj.parent.parent rescue nil
          if binary_obj
            current_binary_url = Obj.find(binary_obj.obj_id).blob.url rescue nil
          end
        end
        current_binary_url
      end
    end


    class EmbeddedServer
      class << self
        attr_accessor :enable
      end

      self.enable = false

      HOST = 'localhost'
      PORT = 7104
      extend MonitorMixin

      require 'webrick'

      class BinaryServerlet < ::WEBrick::HTTPServlet::AbstractServlet
        class RequestHandler

          include Fiona7::BinaryHandling::DeliveryMixin

          def initialize(request, response)
            self.request = request
            self.response = response
          end

          protected
          attr_accessor :request, :response
          def binary_id_from_params
            # TODO: handle malformed input
            match = /\/_b\/([0-9]+)(\/(.*)(\.[a-z0-9A-Z]+)?)?/.match(self.request.request_uri.to_s)
            if match
              match[1]
            else
              0
            end
          end

          def transformation_from_params
            if self.request.query_string
              ParamEncoder.new.decode(
                ::CGI.parse(self.request.query_string)["t"].try(:first)
              )
            end
          end

          def simple_set_header(name, value)
            self.response[name] = value
          end

          # minimal stubs for Rails API below

          def stale?(*args)
            true
          end

          def head(status)
            self.response.status = status
          end

          def send_file(filepath, options={})
            self.response['Content-Type'] = options[:type]
            self.response['Content-Length'] = ::File.size(filepath)
            self.response['Content-Disposition'] = "#{options[:disposition]}; filename=\"#{options[:filename]}\""
            self.response.body = File.read(filepath)
            self.response.status = 200
          end
        end

        def do_GET(request, response)
          RequestHandler.new(request, response).show
        end

        def do_HEAD(request, response)
          RequestHandler.new(request, response).query
        end
      end

      def self.running_instance
        if !self.enable
          return HOST, PORT
        end

        self.synchronize do
          @server_thread ||= self.wait_for_server

          Kernel.at_exit do
            Process.kill("INT", @server_thread)
            Process.kill("KILL", @server_thread)
          end

          return HOST, PORT
        end
      end

      def self.wait_for_server
        pid = Process.fork do
          self.run_server
        end
        # wait for webrick!
        sleep 1
        pid
      end

      def self.run_server

        server = ::WEBrick::HTTPServer.new({
          :Port => PORT, :DocumentRoot => '/dev/null',
          #Logger: WEBrick::Log.new(Logger.new(nil)), AccessLog: []
        })

        server.mount '/', BinaryServerlet

        Signal.trap('INT') do
          server.shutdown
          exit!
        end 

        server.start
      end
    end

    class UrlGenerator
      attr_reader :blob_id, :access_type, :verb, :transformation
      def initialize(blob_id, access_type, verb, transformation)
        self.blob_id        = blob_id
        self.access_type    = access_type
        self.verb           = verb
        self.transformation = transformation
      end

      def generate
        if server_detected?
          hosted_server_url
        else
          embedded_server_url
        end
      end

      protected
      attr_writer :blob_id, :access_type, :verb, :transformation
      def blob
        if Fiona7.mode == :legacy
          @blob ||= Fiona7::EditedObj.find(blob_id.to_i)
        else
          @blob ||= Fiona7::InternalReleasedObj.find(blob_id.to_i)
        end
      end

      def filename
        self.blob.filename
      rescue ActiveRecord::RecordNotFound
        "null.null"
      end

      def server_detected?
        Fiona7::Middleware::ServerDetectionMiddleware.server_detected?
      end

      def hosted_server_url
        # TODO: use middleware for storing url
        host = Fiona7::Middleware::ServerDetectionMiddleware.server_name
        port = Fiona7::Middleware::ServerDetectionMiddleware.server_port

        generate_url(host, port)
      end

      def embedded_server_url
        host, port = EmbeddedServer.running_instance
        generate_url(host, port)
      end

      def generate_url(host, port=80)
        options = {}
        options[:host] = host
        options[:port] = port
        options[:path] = "/_b/#{self.blob_id}/#{self.filename}"
        if self.transformation.present?
          self.validate_transformation!
          options[:query] = self.encode_query_string
        end
        if port == 443
          URI::HTTPS.build(options).to_s
        else
          URI::HTTP.build(options).to_s
        end
      end

      def encode_query_string
        token = ParamEncoder.new.encode(self.transformation)
        return "t=#{token}"
      end

      def validate_transformation!
        MetaBinary.new(self.blob_id, self.transformation).valid? || raise(Scrivito::TransformationDefinitionError.new("Invalid transformation", "binary.unprocessable.image.transform.config.invalid"))
      end
    end
  end
end

module Scrivito
  # This class had been reworked to support uploads directly
  # into CMS and not into S3
  class Binary
  end
end