- implement login and load images from zip

src/library.cr

@@ -1,4 +1,14 @@
 require "zip"
+require "mime"
+
+class Image
+	property data : Bytes
+	property mime : String
+	property filename : String
+	property size : Int32
+	def initialize(@data, @mime, @filename, @size)
+	end
+end
 
 class Entry
 	property zip_path : String
@@ -10,6 +20,29 @@ class Entry
 		@title = File.basename path, ".zip"
 		@size = (File.size path).humanize_bytes
 	end
+	def read_page(page_num)
+		Zip::File.open @zip_path do |file|
+			page = file.entries
+				.select { |e|
+					["image/jpeg", "image/png"].includes? \
+					MIME.from_filename? e.filename
+				}
+				.sort { |a, b| a.filename <=> b.filename }
+				.[page_num]
+			page.open do |io|
+				slice = Bytes.new page.uncompressed_size
+				bytes_read = io.read_fully? slice
+				unless bytes_read
+					return nil
+				end
+				return Image.new slice, MIME.from_filename(page.filename),\
+					page.filename, bytes_read
+			end
+		end
+	end
+	def get_cover()
+		read_page 0
+	end
 end
 
 class Title
@@ -25,6 +58,9 @@ class Title
 			.map { |path| Entry.new File.join dir, path }
 			.sort { |a, b| a.title <=> b.title }
 	end
+	def get_cover()
+		@entries[0].get_cover
+	end
 end
 
 class Library