Android App to show/log upload GPS Tracking Data

I need an Android App built (it will need to be an IOS app too further down the road) to do the following:- Firstly as an overview, think Strava, it is a Map based display app, that shows historical data tracks for each day in a calendar view. It is essential that it works when not connected to internet. (30day offline history) It needs a user registration/paid for check, where the “free” version only shows historical data, and the “paid” version allows uploads of new data. Custom hardware device (already done) creates csv log files, one per day which are uploaded to AWS. The app will need to retireve the data from AWS and keep a 30day offline history. Calendar view shows days when there was entries (like below) with 2 colours one for local data, and one for cloud based data, only local data will work if offline) There is a simlar app already called BoatBook, which gives you a good idea of the display details Each daily log will show a timeline with hourly pinpoints, and various additional data fields will be shown from the hardware logger, such as depth, wind speed and direction and various other detail. These need to be viewable on a time slider that can be dragged along, and also shown on map as max/min values (so show max depth and min depth on map, and max/min wind on map with arrows) There is endless other features that will be needed to track/monitor/display performance and historical data once this is up and running. I would need full access to the code at all stages for testing/changes