# Implementation Plan

- [x] 1. Write bug condition exploration test
  - **Property 1: Bug Condition** - FK Violation on Clear Completed With Junction Table Links
  - **CRITICAL**: This test MUST FAIL on unfixed code — failure confirms the bug exists
  - **DO NOT attempt to fix the test or the code when it fails**
  - **NOTE**: This test encodes the expected behavior — it will validate the fix when it passes after implementation
  - **GOAL**: Surface counterexamples that demonstrate the FK violation bug exists
  - **Scoped PBT Approach**: Scope the property to the concrete failing case — completed queue items that have associated `jira_ticket_queue_items` rows
  - Bug condition from design: `isBugCondition(input)` returns true when `linkedItems.length > 0` (completed items have junction table references)
  - Test file: `backend/__tests__/ivanti-queue-clear-completed-fix.property.test.js`
  - Mock `pool.query` to simulate FK constraint violation when DELETE is issued against `ivanti_todo_queue` while child rows exist in `jira_ticket_queue_items`
  - Assert that the current (unfixed) handler returns 500 and deletes zero items
  - Run test on UNFIXED code
  - **EXPECTED OUTCOME**: Test FAILS (confirms the bug — the handler crashes with FK violation instead of succeeding)
  - Document counterexamples: "DELETE FROM ivanti_todo_queue fails with FK violation when junction rows reference completed items"
  - Mark task complete when test is written, run, and failure is documented
  - _Requirements: 1.1_

- [x] 2. Write preservation property tests (BEFORE implementing fix)
  - **Property 2: Preservation** - Clear Completed Without Junction Table Links
  - **IMPORTANT**: Follow observation-first methodology
  - **GOAL**: Verify that the unfixed code already handles the non-bug-condition cases correctly, establishing a baseline to preserve
  - Test file: `backend/__tests__/ivanti-queue-clear-completed-fix.property.test.js`
  - Observe: When no completed items have junction table links, the simple DELETE succeeds and returns correct count
  - Observe: When no completed items exist, the endpoint returns `{ message: 'Completed items cleared.', deleted: 0 }`
  - Observe: Pending/in-progress items are never touched by the DELETE
  - Write property-based tests generating random sets of completed items WITHOUT junction table links and verify:
    - All completed items for the user are deleted
    - Response is `{ message: 'Completed items cleared.', deleted: N }` where N matches count
    - Non-complete items remain untouched
    - Other users' items remain untouched
  - Run tests on UNFIXED code
  - **EXPECTED OUTCOME**: Tests PASS (confirms baseline behavior to preserve)
  - Mark task complete when tests are written, run, and passing on unfixed code
  - _Requirements: 3.1, 3.2, 3.3_

- [x] 3. Fix for FK violation on clear completed queue items

  - [x] 3.1 Implement the fix
    - File: `backend/routes/ivantiTodoQueue.js`
    - Replace the simple `pool.query(DELETE...)` in the `router.delete('/completed', ...)` handler with a transaction-based approach:
    - 1. Acquire a dedicated client via `pool.connect()`
    - 2. Issue `BEGIN`
    - 3. Select completed item IDs: `SELECT id FROM ivanti_todo_queue WHERE user_id = $1 AND status = 'complete'`
    - 4. If no IDs found, `COMMIT` and return `{ deleted: 0 }` early
    - 5. Delete junction table references: `DELETE FROM jira_ticket_queue_items WHERE queue_item_id = ANY($1::int[])`
    - 6. Delete queue items: `DELETE FROM ivanti_todo_queue WHERE id = ANY($1::int[])`
    - 7. `COMMIT` on success
    - 8. `ROLLBACK` on any error, then return 500
    - 9. Always release client in `finally` block
    - _Bug_Condition: isBugCondition(input) where completedItems have rows in jira_ticket_queue_items_
    - _Expected_Behavior: All completed items and their junction references deleted atomically, returns success with correct count_
    - _Preservation: Items without junction links still deleted; empty sets return deleted: 0; pending items untouched_
    - _Requirements: 2.1, 2.2, 3.1, 3.2, 3.3_

  - [x] 3.2 Verify bug condition exploration test now passes
    - **Property 1: Expected Behavior** - FK Violation on Clear Completed With Junction Table Links
    - **IMPORTANT**: Re-run the SAME test from task 1 — do NOT write a new test
    - The test from task 1 encodes the expected behavior (successful deletion with junction cleanup)
    - When this test passes, it confirms the expected behavior is satisfied
    - Run: `npx jest backend/__tests__/ivanti-queue-clear-completed-fix.property.test.js --run`
    - **EXPECTED OUTCOME**: Test PASSES (confirms bug is fixed — transaction deletes junction rows then queue items)
    - _Requirements: 2.1, 2.2_

  - [x] 3.3 Verify preservation tests still pass
    - **Property 2: Preservation** - Clear Completed Without Junction Table Links
    - **IMPORTANT**: Re-run the SAME tests from task 2 — do NOT write new tests
    - Run preservation property tests from step 2
    - Run: `npx jest backend/__tests__/ivanti-queue-clear-completed-fix.property.test.js --run`
    - **EXPECTED OUTCOME**: Tests PASS (confirms no regressions — non-linked items still deleted correctly)
    - Confirm all tests still pass after fix (no regressions)

- [x] 4. Write unit tests for transaction logic
  - Test file: `backend/__tests__/ivanti-queue-clear-completed-fix.test.js`
  - Mock `pool.connect()` and verify correct query sequence: BEGIN → SELECT IDs → DELETE junction → DELETE queue → COMMIT
  - Verify ROLLBACK is called when any query in the transaction fails
  - Verify client is always released in the `finally` block (even on error)
  - Test edge case: empty completed set triggers early COMMIT and returns `{ deleted: 0 }`
  - Test that response shape remains `{ message: 'Completed items cleared.', deleted: N }`
  - _Requirements: 2.1, 2.2, 3.1, 3.2_

- [x] 5. Checkpoint — Ensure all tests pass
  - Run full test suite: `npx jest backend/__tests__/ivanti-queue-clear-completed-fix --run`
  - Ensure all property tests and unit tests pass
  - Ask the user if questions arise