module Condo; end
module Condo::Strata; end


class Condo::Strata::AmazonS3

    def initialize(options)
        @options = {
            :name => :AmazonS3,
            :location => :'us-east-1',
            :fog => {
                :provider => :AWS,
                :aws_access_key_id => options[:access_id],
                :aws_secret_access_key => options[:secret_key],
                :region => (options[:location] || 'us-east-1')
            }
        }.merge!(options)


        raise ArgumentError, 'Amazon Access ID missing' if @options[:access_id].nil?
        raise ArgumentError, 'Amazon Secret Key missing' if @options[:secret_key].nil?


        @options[:location] = @options[:location].to_sym
        @options[:region] = @options[:location] == :'us-east-1' ? 's3.amazonaws.com' : "s3-#{@options[:location]}.amazonaws.com"
    end


    def name
        @options[:name]
    end


    def location
        @options[:location]
    end


    # Create a signed URL for accessing a private file
    def get_object(options)
        options = {}.merge!(options)    # Need to deep copy here
        options[:object_options] = {
            :expires => 5.minutes.from_now,
            :date => Time.now,
            :verb => :get,        # Post for multi-part uploads http://docs.amazonwebservices.com/AmazonS3/latest/API/mpUploadInitiate.html
            :headers => {},
            :parameters => {},
            :protocol => :https
        }.merge!(options[:object_options] || {})
        options.merge!(@options)

        #
        # provide the signed request
        #
        sign_request(options)[:url]
    end


    # Creates a new upload request (either single shot or multi-part)
    # => Passed: bucket_name, object_key, object_options, file_size
    def new_upload(options)
        options = {}.merge!(options)    # Need to deep copy here
        options[:object_options] = {
            :permissions => :private,
            :expires => 5.minutes.from_now,
            :date => Time.now,
            :verb => :post,        # Post for multi-part uploads http://docs.amazonwebservices.com/AmazonS3/latest/API/mpUploadInitiate.html
            :headers => {},
            :parameters => {},
            :protocol => :https
        }.merge!(options[:object_options])
        options.merge!(@options)

        # Set the access control headers
        if options[:object_options][:headers]['x-amz-acl'].nil?
            options[:object_options][:headers]['x-amz-acl'] = case options[:object_options][:permissions]
            when :public
                :'public-read'
            else
                :private
            end
        end

        # Decide what type of request is being sent
        request = {}
        if options[:file_size] > 5.megabytes    # 5 mb (minimum chunk size)
            options[:object_options][:parameters][:uploads] = ''    # Customise the request to be a chunked upload
            options.delete(:file_id)                                # Does not apply to chunked uploads

            request[:type] = :chunked_upload
        else
            if options[:file_id].present? && options[:object_options][:headers]['Content-Md5'].nil?
                # The client side is sending hex formatted ids that will match the amazon etag
                # => We need this to be base64 for the md5 header (this is now done at the client side)
                #
                # options[:file_id] = [[options[:file_id]].pack("H*")].pack("m0")    # (the 0 avoids the call to strip - now done client side)
                # [ options[:file_id] ].pack('m').strip            # This wasn't correct
                # Base64.encode64(options[:file_id]).strip        # This also wasn't correct
                options[:object_options][:headers]['Content-Md5'] = options[:file_id]
            end
            options[:object_options][:headers]['Content-Type'] = 'binary/octet-stream' if options[:object_options][:headers]['Content-Type'].nil?
            options[:object_options][:verb] = :put    # Put for direct uploads http://docs.amazonwebservices.com/AmazonS3/latest/API/RESTObjectPUT.html

            request[:type] = :direct_upload
        end


        # provide the signed request
        request[:signature] = sign_request(options)
        request
    end


    # Returns the request to get the parts of a resumable upload
    def get_parts(options)
        options[:object_options] = {
            :expires => 5.minutes.from_now,
            :date => Time.now,
            :verb => :get,
            :headers => {},
            :parameters => {},
            :protocol => :https
        }.merge!(options[:object_options])
        options.merge!(@options)

        # Set the upload 
        options[:object_options][:parameters]['uploadId'] = options[:resumable_id]

        # provide the signed request
        {
            :type => :parts,
            :signature => sign_request(options)
        }
    end


    # Returns the requests for uploading parts and completing a resumable upload
    def set_part(options)
        options[:object_options] = {
            :expires => 5.minutes.from_now,
            :date => Time.now,
            :headers => {},
            :parameters => {},
            :protocol => :https
        }.merge!(options[:object_options])
        options.merge!(@options)


        request = {}
        if options[:part] == 'finish'
            # Send the commitment response
            options[:object_options][:headers]['Content-Type'] = 'application/xml; charset=UTF-8' if options[:object_options][:headers]['Content-Type'].nil?
            options[:object_options][:verb] = :post
            request[:type] = :finish
        else
            # Send the part upload request
            options[:object_options][:headers]['Content-Md5'] = options[:file_id] if options[:file_id].present? && options[:object_options][:headers]['Content-Md5'].nil?
            options[:object_options][:headers]['Content-Type'] = 'binary/octet-stream' if options[:object_options][:headers]['Content-Type'].nil?
            options[:object_options][:parameters]['partNumber'] = options[:part]
            options[:object_options][:verb] = :put
            request[:type] = :part_upload
        end


        # Set the upload 
        options[:object_options][:parameters]['uploadId'] = options[:resumable_id]

        # provide the signed request
        request[:signature] = sign_request(options)
        request
    end


    def fog_connection
        @fog = @fog || Fog::Storage.new(@options[:fog])
        return @fog
    end


    def destroy(upload)
        connection = fog_connection
        directory = connection.directories.get(upload.bucket_name)    # it is assumed this exists - if not then the upload wouldn't have taken place
        file = directory.files.get(upload.object_key)

        if upload.resumable
            return file.destroy unless file.nil?
            begin
                if upload.resumable_id.present?
                    connection.abort_multipart_upload(upload.bucket_name, upload.object_key, upload.resumable_id)
                    return true
                end
            rescue
                # In-case resumable_id was invalid or did not match the object key
            end

            # The user may have provided an invalid upload key, we'll need to search for the upload and destroy it
            begin
                resp = connection.list_multipart_uploads(upload.bucket_name, {'prefix' => upload.object_key})
                resp.body['Upload'].each do |file|
                    # TODO:: BUGBUG:: there is an edge case where there may be more multi-part uploads with this this prefix then will be provided in a single request
                    # => We'll need to handle this edge case to avoid abuse and dangling objects
                    connection.abort_multipart_upload(upload.bucket_name, upload.object_key, file['UploadId']) if file['Key'] == upload.object_key    # Ensure an exact match
                end
                return true    # The upload was either never initialised or has been destroyed
            rescue
                return false
            end
        else
            return true if file.nil?
            return file.destroy
        end
    end



    protected



    def sign_request(options)

        # Build base URL
        options[:object_options][:date] = options[:object_options][:date].utc.httpdate
        options[:object_options][:expires] = options[:object_options][:expires].utc.to_i
        url = "/#{options[:bucket_name]}/#{options[:object_key]}"

        # Add request params
        url << '?'
        options[:object_options][:parameters].each do |key, value|
            url += value.blank? ? "#{key}&" : "#{key}=#{value}&"
        end
        url.chop!

        # Build a request signature
        signature = "#{options[:object_options][:verb].to_s.upcase}\n#{options[:file_id]}\n#{options[:object_options][:headers]['Content-Type']}\n#{options[:object_options][:expires]}\n"
        options[:object_options][:headers].each do |key, value|
            signature << "#{key}:#{value}\n" if key =~ /x-amz-/
        end
        signature << url

        # Encode the request signature
        signature = CGI::escape(Base64.encode64(OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha1'), @options[:secret_key], signature)).gsub("\n",""))

        # Finish building the request
        url += options[:object_options][:parameters].present? ? '&' : '?'
        return {
            :verb => options[:object_options][:verb].to_s.upcase,
            :url => "#{options[:object_options][:protocol]}://#{options[:region]}#{url}AWSAccessKeyId=#{@options[:access_id]}&Expires=#{options[:object_options][:expires]}&Signature=#{signature}",
            :headers => options[:object_options][:headers]
        }
    end
end