Finish implementing Payment Processing and Billing

[igorsimb]

Payment Processing and Billing Implementation Checklist

• [x] Remove billing_signature.py file

• [x] Move its contents to utils

• [x] Create a MerchantGeneratorClass and move the 3 functions in it to clean up the signature generation

• [ ] Review API Documentation

  • [ ] Check API for recurrent payments, refunds, and cancels

• [x] Implement Billing Page

  • [x] Create a dedicated billing page where users can:
  • [x] View their current payment plan.
  • [x] See their billing information.
  • [x] View payment history.

• [ ] Design and Implement Payment System

  • [x] Create a payment form within the billing page.
  • [ ] Connect the form with the API to process payments.
  • [ ] Test with different scenarios (successful payment, failed payment, etc.).
  • [ ] Create "payment successful" page (see the API docs)

• [ ] Plan Selection Page

  • [x] Create a separate page dedicated to plan selection and management.
  • [x] List all available plans (current, lower, higher).
  • [x] Provide detailed information about each plan, including costs, quotas, and features.
  • [ ] Integrate an option to switch plans with confirmation dialogs to avoid accidental changes.
  • [ ] Implement logic to calculate prorated charges or credits when switching from one plan to another in the middle of a billing cycle.
  • [ ] Ensure the prorated calculation is clear and transparent for users.
  • [ ] Update the API to handle plan changes and reflect them in the billing system.

• [x] User Experience (UX) Optimization

  • [x] Ensure that each page (Billing, Plan Selection) has a clean, minimal UI with a clear purpose.

• [ ] Go Live Checklist

  • [ ] Transition from test payments to live payments.
  • [ ] Ensure all API keys, webhooks, and configurations are updated for production use.
  • [ ] Perform final testing in the live environment.

• [ ] Documentation & Support

  • [ ] Document the billing and payment features, including how users can change plans and understand their quotas.
  • [ ] Update internal documentation for developers for future reference.
  • [ ] Set up a support channel for handling any user issues related to payments or plan changes.

[igorsimb]

Started refactor here: https://github.com/igorsimb/mp-monitor/commit/e237fc665ea3fe6058611a7439dff0d17a2e5400