Optimize game engine loop and boost calculation

[candour]

Refactored the core game engine in MainViewModel.kt and Registry.kt for improved efficiency.

• Removed enemiesByMode sorting logic from the main update loop, saving three O(E log E) operations per tick.
• Introduced stallBoosts cache to store Bak Kut Teh adjacency bonuses, reducing calculations from O(Stalls) per tick to O(1) by updating the cache only when the grid layout or wave status changes.
• Simplified StallBehavior.selectTarget to handle all targeting modes (FIRST, CLOSEST, STRONGEST, WEAKEST) directly using collection operators on range-filtered enemies.

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PR created automatically by Jules for task 6111875595712730203 started by @candour

Summary by CodeRabbit

• Refactor
  • Optimized game loop performance by caching stall stat boost calculations, reducing redundant per-tick computations.
  • Streamlined stall targeting logic to directly select best targets from visible candidates, eliminating unnecessary sorting overhead.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 5dc43a24-141b-4fd2-81d4-d5c98b1796af

📥 Commits

Reviewing files that changed from the base of the PR and between 574937e and 70d0b17.

📒 Files selected for processing (3)

• app/src/main/java/com/messark/hawker/MainViewModel.kt
• app/src/main/java/com/messark/hawker/registry/Registry.kt
• fixes.md

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📝 Walkthrough

Walkthrough

MainViewModel introduces a stallBoosts cache mapping stall coordinates to BoostResult values, recomputed via updateBoostCache on every state mutation that can affect BKT providers. The game loop drops per-tick boost precomputation and mode-sorted enemy lists; handleStallFiring now reads from the cache. StallBehavior.selectTarget drops its enemiesByMode parameter, with FIRST mode selection rewritten to use maxByOrNull { currentPathIndex } on visible enemies.

Changes

Engine Loop Boost Caching and selectTarget Simplification

Layer / File(s)	Summary
selectTarget signature and FIRST-mode logic app/src/main/java/com/messark/hawker/registry/Registry.kt	Removes enemiesByMode: Map<TargetMode, List<Enemy>> from StallBehavior.selectTarget and its DefaultStallBehavior override. FIRST mode selection changes from filtering a pre-sorted list by visible IDs to visibleEnemies.maxByOrNull { currentPathIndex }.
stallBoosts cache definition and handleStallFiring refactor app/src/main/java/com/messark/hawker/MainViewModel.kt	Adds stallBoosts field and updateBoostCache(state) helper computing BoostResult per active BKT provider tile. Game loop drops per-tick preCalculatedBoosts and mode-sorted enemy lists. handleStallFiring signature removes those parameters and reads BoostResult from stallBoosts[coord] while calling selectTarget without enemiesByMode.
Cache refresh on all state mutations app/src/main/java/com/messark/hawker/MainViewModel.kt, fixes.md	Every state-mutating operation—init, resume, reset, wave start, wave completion, build stall, sell stall, undo sell, pillar removal, stall upgrade—now constructs a newState local and calls updateBoostCache(newState) before returning from the update lambda. Changelog entry REF-016 added.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• candour/towerpower#164: Directly overlaps in the handleStallFiring and StallBehavior.selectTarget pipeline — that PR also reshapes selectTarget inputs and the boost-handling code path in the same functions.
• candour/towerpower#176: Both modify DefaultStallBehavior.selectTarget in Registry.kt specifically for visibleEnemies-based target selection and spatial-index prefiltering.
• candour/towerpower#156: Directly affects the same StallBehavior.selectTarget(...) contract in Registry.kt and the handleStallFiring call site in MainViewModel, introducing the enemiesByMode parameter that this PR removes.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 13.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Optimize game engine loop and boost calculation' directly and accurately summarizes the main changes: performance optimizations to the game engine loop and boost caching.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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🧪 Generate unit tests (beta)

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• Commit unit tests in branch refactor/engine-optimization-6111875595712730203

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[github-actions]

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