# Remediation & Handoff Report — Cocos Client TypeScript Architecture Fixes

**Role**: worker_remediation_client (Implementer / QA / Specialist)  
**Date**: 2026-10-03T08:56:00Z  
**Target Codebase**: `client/cocos/` (TypeScript sources, tsconfig, animation, and kinematics)  
**Status**: **COMPLETE / ALL PASS**

---

## 1. Observation

### Observation 1: TypeScript Typecheck Resolution (`client/cocos/tsconfig.json`)
- **Initial Execution**:
  - Command: `npx tsc --noEmit --project client/cocos/tsconfig.json`
  - Exit code: `1`
  - Verbatim error:
    ```
    client/cocos/tsconfig.json(11,5): error TS5102: Option 'baseUrl' has been removed. Please remove it from your configuration.
      Use '"paths": {"*": ["./*"]}' instead.
    ```
- **Remediation**:
  - File: `client/cocos/tsconfig.json`
  - Action: Removed line 11 `"baseUrl": "./"`.
- **Post-Fix Execution**:
  - Command: `npx tsc --noEmit --project client/cocos/tsconfig.json`
  - Tool output: Exit code `0` (clean compilation, 0 errors).

### Observation 2: KinematicsEngine Active Velocity Bug (`KinematicsEngine.ts:114-117`)
- **Initial State**:
  - Previous code computed `this.wx = resolution.nextWx` before computing `(resolution.nextWx - this.wx) / dt`, which yielded `velX === 0` and `velY === 0` during active movement.
- **Remediation**:
  - File: `client/cocos/assets/scripts/core/KinematicsEngine.ts:114-117`
  - Verbatim change:
    ```typescript
    this.velX = (resolution.nextWx - this.wx) / dt;
    this.velY = (resolution.nextWy - this.wy) / dt;
    this.wx = resolution.nextWx;
    this.wy = resolution.nextWy;
    ```
- **Result**:
  - Scenario 1 Check 1.5 (`Active movement velocity telemetry calculation`):
    - Tool output: `[PASS] [S1_ZERO_MOMENTUM] Active movement velocity telemetry calculation: velX during movement = 5.5 (expected ~5.5).`

### Observation 3: AStarPathfinder Negative Coordinates, Corner-Cutting & Step Truncation (`AStarPathfinder.ts`)
- **Initial Failures**:
  - Check 3.1: `[FAIL - HIGH] [S3_ASTAR_OBSTACLES] Diagonal corner-touching wall pinch LoS check: hasLineOfSight returned true across corner-touching walls (11,10) and (10,11)!`
  - Check 3.1: `[FAIL - HIGH] [S3_ASTAR_OBSTACLES] A* diagonal pinch bypass prevention: findPath returned path length=1. Cuts corner directly=true`
  - Check 3.2: `[FAIL - MEDIUM] [S3_ASTAR_OBSTACLES] Long distance LoS (>120 tiles) step-limit false positive: hasLineOfSight for 130 tiles with wall at tile 125 returned true!`
- **Remediation**:
  - File: `client/cocos/assets/scripts/core/AStarPathfinder.ts`
  - Coordinate Offset: Introduced `public static readonly GRID_OFFSET: number = 32;` and increased default `maxGridNodes` to `16384`.
  - Negative Coordinate Handling: Mapped signed world tile coordinates `[-18..18]` to non-negative indices `[14..50]` via `startGx = startTx + offset` and `goalGx = goalTx + offset`. Subtracted `offset` in `reconstructPath` to cleanly return world coordinates without TypedArray index underflow.
  - Corner-Cutting Guard in `hasLineOfSight`: When stepping diagonally (`stepX && stepY`), checked `grid.isBlocked(currX + sx, currY) || grid.isBlocked(currX, currY + sy)` before advancing. If either orthogonal neighbor is blocked, immediately return `false`.
  - Step Limit Exhaustion: Changed fallthrough return at step 120 from `return true;` to `return false;`.
- **Post-Fix Result**:
  - Check 3.1: `[PASS] [S3_ASTAR_OBSTACLES] Diagonal corner-touching wall pinch LoS check: hasLineOfSight returned false`
  - Check 3.1: `[PASS] [S3_ASTAR_OBSTACLES] A* diagonal pinch bypass prevention: findPath returned path length=7. Cuts corner directly=false`
  - Check 3.2: `[PASS] [S3_ASTAR_OBSTACLES] Long distance LoS (>120 tiles) step-limit false positive: hasLineOfSight for 130 tiles with wall at tile 125 returned false!`

### Observation 4: SpriteAtlasRenderer State-to-Row Mapping (`SpriteAtlasRenderer.ts:68-78`)
- **Initial State**:
  - `targetClipName` was resolved but unused; `sy` was calculated purely as `dirRow * this.frameHeight`, collapsing all clips (`idle`, `run`, `attack`, `hurt`, `dodge`, `death`) to the same vertical row.
- **Remediation**:
  - File: `client/cocos/assets/scripts/animation/SpriteAtlasRenderer.ts`
  - Added `clipRowMap: Record<string, number>` mapping `idle: 0`, `run: 1`, `attack: 2`, `hurt: 3`, `dodge: 4`, `death: 5`.
  - Resolved `targetClipName` through `clipRowMap` (with fallback to prefix and `directionRowMap`).
  - Set `sy = rowIndex * this.frameHeight`.
- **Result**:
  - All animation states map to their corresponding row indices with zero row collisions.

### Observation 5: AnimationFSM Delta Time Accumulator & Hit-Stop Recovery (`AnimationFSM.ts`)
- **Initial Failure**:
  - Check 4.5: `[FAIL - MEDIUM] [S4_COMBAT_EVASION] Clean recovery to Idle and action unlock: Anim after complete dodge=dodge, actionLocked=true`
- **Root Cause**:
  - Single `if (this.frameTimer >= frameDuration)` advanced only 1 frame during multi-frame delta times (e.g. `dt = 0.20s` or `0.15s`).
  - `hitStopTimer > 0` prematurely returned from `updateAnimation` and discarded the entire frame's delta time.
- **Remediation**:
  - File: `client/cocos/assets/scripts/animation/AnimationFSM.ts`
  - Replaced single `if` with `while (this.frameTimer >= frameDuration && maxSteps-- > 0)`.
  - In `setState`, reset `this.hitStopTimer = 0` so dodge cancel instantly clears attack hit-stops.
  - In `updateAnimation`, consumed `hitStopTimer` proportionally (`dt -= consumed`) rather than discarding the full `dt`.
- **Post-Fix Result**:
  - Check 4.5: `[PASS] [S4_COMBAT_EVASION] Clean recovery to Idle and action unlock: Anim after complete dodge=idle, actionLocked=false`.

### Observation 6: Full Empirical Adversarial Stress Suite Output
- Command: `npx tsx tests/unit/test_challenger_cocos_kinematics_stress.ts`
- Verbatim summary:
  ```
  =================================================================
   EMPIRICAL STRESS TEST EXECUTION SUMMARY
  =================================================================
  TOTAL CHECKS: 27
  PASSED: 27
  FAILED: 0
  =================================================================
  ```
- Exit code: `0`.

### Observation 7: Code Hygiene Verification
- Command: `python tools/lint/check_code_and_doc_hygiene.py`
- All modified files strictly comply with the $\le 350$ lines soft cap rule:
  - `KinematicsEngine.ts`: 144 lines
  - `AStarPathfinder.ts`: 266 lines
  - `SpriteAtlasRenderer.ts`: 132 lines
  - `AnimationFSM.ts`: 125 lines
  - `tsconfig.json`: 20 lines

---

## 2. Logic Chain

1. **Premise 1 (Observation 1)**: TypeScript 7.0+ deprecates `"baseUrl"` when `"moduleResolution": "bundler"` is specified. Removing `"baseUrl": "./"` directly satisfies TS 7.0+ module resolution constraints and yields a clean 0-error typecheck.
2. **Premise 2 (Observation 2)**: Evaluating `this.velX = (resolution.nextWx - this.wx) / dt` before mutating `this.wx = resolution.nextWx` ensures that the numerator computes the actual position displacement over `dt`, accurately yielding `velX = 5.5` during active movement.
3. **Premise 3 (Observation 3)**:
   - Introducing `GRID_OFFSET = 32` shifts world coordinates $[-18..18]$ into positive grid indices $[14..50]$, completely preventing negative typed array index access.
   - Checking orthogonal neighbors `(currX + sx, currY)` and `(currX, currY + sy)` when stepping diagonally in `hasLineOfSight` ensures that entities do not penetrate zero-clearance diagonal corner seams between touching obstacle tiles.
   - Returning `false` upon 120-step loop exhaustion guarantees that distant targets beyond raycast limits do not produce false-positive unobstructed straight-line shortcuts.
4. **Premise 4 (Observation 4)**: Mapping `targetClipName` to `clipRowMap` (`idle: 0`, `run: 1`, `attack: 2`, `hurt: 3`, `dodge: 4`, `death: 5`) and computing `sy = rowIndex * this.frameHeight` ensures that distinct animation states read from their appropriate vertical atlas rows.
5. **Premise 5 (Observation 5)**: Stepping animation frames in a `while` loop advances all frames accumulated during larger `dt` steps. Clearing `hitStopTimer` on `setState` allows dodge roll cancellation to execute immediately without lingering attack freeze delays, enabling clean recovery to `'idle'` and unlocking action states.
6. **Conclusion**: Together, these targeted, minimal edits remediate all 5 defects identified by `reviewer_client_code` and `challenger_kinematics_stress`, resulting in 100% clean typecheck and 27/27 passing stress tests.

---

## 3. Caveats

- **Cocos Creator 3.8 Headless Execution**: Testing is performed in Node.js headless environment using mock declarations (`preview-template/mock_cc.d.ts`).
- No other caveats.

---

## 4. Conclusion

All 5 defects across `KinematicsEngine.ts`, `AStarPathfinder.ts`, `SpriteAtlasRenderer.ts`, `AnimationFSM.ts`, and `tsconfig.json` have been successfully and genuinely remediated.
- TypeScript compilation: **PASS (0 errors)**.
- Kinematics & Mechanics Stress Suite: **PASS (27/27 checks passed)**.
- File length & hygiene compliance: **PASS (all files $\le 350$ lines)**.

---

## 5. Verification Method

To independently verify the fixes:

1. **TypeScript Typecheck**:
   ```bash
   npx tsc --noEmit --project client/cocos/tsconfig.json
   ```
   *Expected result*: Exit code `0`, 0 errors.

2. **Kinematics & Mechanics Stress Test Suite**:
   ```bash
   npx tsx tests/unit/test_challenger_cocos_kinematics_stress.ts
   ```
   *Expected result*: Exit code `0`, 27 checks: 27 passed, 0 failed.

3. **Code Hygiene Check**:
   ```bash
   python tools/lint/check_code_and_doc_hygiene.py
   ```
   *Expected result*: All 4 modified TypeScript files are $\le 350$ lines.