iOS geofencing demo

Description

• language: Swift
• architecture: MVVM + Combine
• UI: SwiftUI
• location updates in the background, geofencing
• localization & internalization (currently suppotts 'en' and 'de'), example Network+Errors.swift
• zero external dependencies
• property wrappers dependency injection for services

User stories

• User story 1. As a user of the application, I want to be able to start a journey by clicking the "Start" button, and then end the journey by clicking the "Stop" button. It should be one button, but the title should change depending on the mode.
• User story 2. As a user of the application, I have to receive a permission request to use location.
• User story 3. As a user of the app, every time I open the app, I have to see a list of pictures from Flickr that are tied to the user's location during the journey every 100 meters. New pictures should be at the top. Whenever the user takes a look at their phone, they see the most recent picture and can scroll through a stream of pictures that shows where the user has been.
• User story 4. As a user of the app, I should be able to use the travel mode for at least a two-hour walk.

ENVIRONMENT

For the project to work correctly, you need to set the environment variable FLICKR_API_KEY.

TODO

• define git repository and initial README, .gitignore etc.
• make initial project setup with SwiftUI interface and UIKit AppDelegate
• add scene delegate
• create basic UI start / stop button with SwiftUI
• refactor to MVVM (perhaps temporarily)
• add location usage description and enable location updates in the background on Signing & Capabilities
• add feature to fetch user starting location at the beginning of the journey
• define codable model to keep coordinate and identifier, add helper method to create CLCircularRegion from model
• integrate network service, implement mocket localization service
• implement DI with property wrappers, implement localization service and inject it to network service
• localize app with localization service, error handling in particular
• implement FlickrService to fetch image url from Flickr by location (latitude, longitude)
  • define models - Image and PagedPhotosResponse
  • define flickr photos search endpoint
  • define flickr service protocol
  • implement flickr service and inject it into JourneyViewModel
  • fix issues with base url and flickr response
• add service to persist ordered location list, implement addLocation, getLocations and removeLocations methods
  • define journey storage service protocol
  • implement journey storage service with user defaults
  • implement dependency injection for journey storage service
  • inject journey storage service into JourneyViewModel
• get initial location and store it to the list
• show alert if geofencing is not supported on current device
• define initial monitoring region for user starting location and start monotoring when user exit region
• create 'stopMonitoring' method to remove monitoring region
• implement alert if authorizationStatus != authorizedAlways
• refactor: extract locationManager to separate service - LocationService, handle location errors
• handle location event 'didExitRegion', remove current monitoring region, get current location and save it to the list, define new monitoring region
• add simulated locations, test feature, fix bugs
• implement location log service
• debug didExitRegion on device, small improvements
• create mocked JourneyStorage and feed it with mocked journey json
• fetch images for location list
• clean-up debug and log
• create UI for images list
• create journey view model protocol
• unit-tests
  • implement unit-tests for journey view model
    • create mocked Flickr response and Fllickr mocked service
    • create mocked location service
    • unit-test journey view model: testInitialState
    • unit-test journey view model: testStartStopLocationTracking_Start, testStartStopLocationTracking_Stop
    • unit-test journey view model: testLoadImages and testLoadImagesWithError
  • unit-test endpoint for network
  • unit-test flickr service (?)
  • unit-test location service, mock CLLocationManager in LocationService
• feat: use environment variables for sensitive data instead of git
• fix: improve (?) the accuracy and relevance of images based on geo-location
• fix: remove images duplication
• feat: implement background fetch for images
• add SwiftLint
• (optional) implement full app localization
• refactor to TCA