# Frontend

The frontend of this project is a Flutter application designed to run on both Android and iOS devices (and possibly as a PWA). The frontend is responsible for displaying the user interface and handling user input. It communicates with the backend via a REST-api to retrieve and send data.


## Getting Started
The flutter application is divided into multiple chunks of code.
- the `lib` directory contains the main code of the application.
- the `android` and `ios` directories contain platform-specific code.
- the root directory contains configuration files and metadata.

To run the application, you need to have the Flutter SDK installed. You can find instructions on how to do this [here](https://flutter.dev/docs/get-started/install).

Once you have the Flutter SDK installed, you can locally install the dependencies by running:
```bash
flutter pub get
```

## Development
### TODO

## Deployment and metadata
### Deploying a new version
To truly deploy a new version of the application, i.e. to the official app stores, a special CI step is required. This listens for new tags. To create a new tag position yourself on the main branch and run
```bash
git tag -a v<name> -m "Release <name>"
git push origin v<name>
```
We adhere to the [Semantic Versioning](https://semver.org/) standard, so the tag should be of the form `v0.1.8` for example. 

### Icons and logos
The application uses a custom launcher icon and splash screen. These are managed platform-independently using the `flutter_launcher_icons` package.

To update the icons, change the `flutter_launcher_icons.yaml` configuration file. Especially the `image_path` is relevant. Then run
```bash
dart run flutter_launcher_icons
```
### Other metadata
Fastlane provides mechanisms to update the metadata of the application. This includes the name, description, screenshots, etc. The metadata is stored in the `fastlane/metadata` directory of both the `android`and the `ios` version of the application. Both versions have different structures but **they should be kept in sync**. For more information see the [fastlane documentation](https://docs.fastlane.tools/):
- https://docs.fastlane.tools/actions/deliver/
- https://docs.fastlane.tools/actions/supply/


## Fastlane - in depth
The application is deployed to the Google Play Store and the Apple App Store using fastlane: [https://docs.fastlane.tools/](https://docs.fastlane.tools/)

Fastlane is installed as a Ruby gem. Since the bundler-gemfile is scoped to a single directory, a `Gemfile` is included in both the `android` and `ios` directories. Once installed, the usage is
```bash
cd frontend/android # or ios
bundle install
bundle exec fastlane <lane>
```
This is reused in the CI/CD pipeline to automate the deployment process.


## Secrets
These are used by the CI/CD pipeline to deploy the application.

**Platform-specific secrets** are used by the CI/CD pipeline to deploy to the respective app stores.
- `ANDROID_GOOGLE_MAPS_API_KEY` is used to authenticate with the Google Maps API and is scoped to the android platform
- `ANDROID_KEYSTORE` is used to sign the android apk
- `ANDROID_GOOGLE_KEY` is used to authenticate with the Google Play Store api
- `IOS_GOOGLE_MAPS_API_KEY` is used to authenticate with the Google Maps API and is scoped to the ios platform
- `IOS_ASC_ISSUER_ID` is used to authenticate with the App Store Connect API
- `IOS_ASC_KEY` as well
- `IOS_ASC_KEY_ID` as well
- `IOS_MATCH_PASSWORD` is used by fastlane match to download the certificates
- `IOS_MATCH_REPO_SSH_KEY_BASE64` is used to authenticate with the git repository where the certificates are stored