wtf is duoduo?

Duoduo Learn is a mobile app for building and studying your own quiz sets, styled after apps like Duolingo. Instead of coming with fixed content, it lets you create custom question packs and turns studying them into a game with streaks, levels, and badges. The core idea is that you feed it material, either by pasting text or sharing content into the app, and an AI service automatically breaks it down into questions. You can also take a photo of text and have it generate a question pack from that. The AI connection works with any provider that speaks the OpenAI compatible protocol, so you plug in your own API key rather than relying on a single built-in service. Questions can be multiple choice, true or false, fill in the blank, matching, or ordering. Two study modes are offered: a knowledge point mode that works through a single question pack in order to reinforce one topic, and a random challenge mode that mixes questions across packs to test overall understanding. The gamification layer includes experience points for answering questions, a daily streak counter, a hearts system that costs you a heart for wrong answers and refills on a perfect run, daily XP goals, a monthly calendar view of your study activity with a badge for hitting 20 days, and 21 separate achievement badges covering streaks, XP, question counts, and more. Under the hood it is built with Flutter and Dart, using Riverpod for state management, SQLite for local storage, and Dio for network requests. To run it yourself you need Flutter 3.x, Dart 3.x, the Android SDK, and JDK 17 or newer, then clone the repo, run flutter pub get, and either flutter run for a debug build or flutter build apk for a release APK. AI settings, including the API address, key, and model name, are configured from within the app itself. The project is released under the MIT license, and prebuilt APKs are available from the Releases page.