[Woo POS][Refunds] Create full refund

[samiuelson]

WOOMOB-1855

Description

This PR allows creating a full refund in Woo POS for a happy path refund scenario.

💡 UI of the loading states, error, and success states is not in scope of this PR-it will be updated in the next iteration.

Test Steps

1. Create order in POS and try creating full refund through POS Orders screen:
   a) order containing single item
   b) order containing multiple items
   c) order containing multiple quantities of the same item
2. Verify that the network request and server response look as expected.
3. Verify order is properly refunded in wp-admin.

Images/gif

demo-19-dec.mp4

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

[dangermattic]

	1 Warning
⚠️	This PR is larger than 300 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

	1 Message
📖	This PR is still a Draft: some checks will be skipped.

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce-Wear Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	b767f93
	Direct Download	woocommerce-wear-prototype-build-pr15135-b767f93.apk

[Copilot]

Pull request overview

This PR implements full refund functionality in the Woo POS by adding refund processing capabilities, new UI states for handling loading/success/error scenarios, and calculation logic for refund amounts including taxes. The implementation follows a happy path refund flow where all items in an order can be refunded at once.

Key changes include:

• Addition of refund calculation utilities (subtotal, tax, and item grouping)
• Integration with WCRefundStore API to create refunds
• New state machine transitions for processing, success, and error states

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
RefundRequestItem.kt	Made refundTotal and refundTax fields nullable with default null values to support optional refund data
WooPosRefundViewModel.kt	Added refund processing logic, state management for Processing/Success/Error states, and changed data source method from getOrderById to refreshOrderById
WooPosRefundState.kt	Added Processing, RefundSuccess, and RefundError states to handle refund operation lifecycle
WooPosIssueRefundDialog.kt	Added UI handling for Processing state with loading indicator and RefundSuccess/RefundError states with appropriate content
WooPosGroupRefundItems.kt	New utility class to group refundable items by order item ID and calculate refund totals and taxes
WooPosCalculateRefundTax.kt	New utility class to calculate proportional tax amounts for refunded items
WooPosCalculateRefundSubtotal.kt	New utility class to calculate refund subtotals by summing unit prices
WooPosRefundableItem.kt	Removed lineTotal and lineTax computed properties (calculation moved to dedicated utilities)
WooPosRefundViewModelTest.kt	Updated all test mocks to use refreshOrderById instead of getOrderById and added new dependencies to test setup
WooPosGroupRefundItemsTest.kt	Comprehensive test coverage for item grouping logic including edge cases
WooPosCalculateRefundTaxTest.kt	Test coverage for tax calculation including partial and full refunds
WooPosCalculateRefundSubtotalTest.kt	Test coverage for subtotal calculation with various item combinations

---

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	b767f93
	Direct Download	woocommerce-prototype-build-pr15135-b767f93.apk

[codecov-commenter]

Codecov Report

❌ Patch coverage is 52.91005% with 89 lines in your changes missing coverage. Please review.
✅ Project coverage is 38.66%. Comparing base (98fa016) to head (bd8e0ac).

Files with missing lines	Patch %	Lines
...ndroid/ui/woopos/orders/WooPosIssueRefundDialog.kt	0.00%	72 Missing ⚠️
.../android/ui/woopos/orders/WooPosRefundViewModel.kt	76.27%	5 Missing and 9 partials ⚠️
...android/ui/woopos/orders/WooPosGroupRefundItems.kt	88.00%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #15135      +/-   ##
============================================
+ Coverage     38.63%   38.66%   +0.02%     
- Complexity    10448    10469      +21     
============================================
  Files          2178     2181       +3     
  Lines        123901   124051     +150     
  Branches      17093    17115      +22     
============================================
+ Hits          47875    47960      +85     
- Misses        71206    71262      +56     
- Partials       4820     4829       +9     

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[wpmobilebot]

🤖 Build Failure Analysis

This build has failures. Claude has analyzed them - check the build annotations for details.