Fix Fight/Bite Mechanics and Targeting for Cards

Summary

Now let me check that the engine compiles before fixing cards:

Engine compiles. Now let me fix the cards. Let me fix them all with sed:

Tests pass. Now let me fix the cards. Let me fix each one:

1. FDN: Bite Down — pure bite spell

2. FDN: Affectionate Indrik — ETB fight trigger

Wait, sed replacing TargetSpec::None), could hit many places. Let me check.

That sed replaced ALL TargetSpec::None), with TargetSpec::Creature), — that's a disaster. Let me undo that.

Let me be much more careful with the edits. I'll use specific context in sed or read/edit individual cards.

Now for Affectionate Indrik, I need to change both the Effect and the TargetSpec on surrounding lines. Let me use a more precise approach:

3. FDN: Felling Blow — +1/+1 counter + bite

4. ECL: Assert Perfection — boost + fight

5. TDM: Piercing Exhale — pure fight

That should have fixed both Piercing Exhale (pure fight) and Knockout Maneuver (counter + fight). Let me verify:

Lines 1231 (Knockout Maneuver) and 1255 (Piercing Exhale) are fixed. Dragonclaw Strike (1215) is still Custom (expected — it has "double P/T" which we can't implement).

Now let me check if there are any remaining fight customs to handle:

Good. The remaining ones are:

FDN: "Choose one..." — modal (Batch 11)
FDN: Primal Might — X-cost (Batch 15)
ECL: "Choose two..." — modal (Batch 11)
TDM: Dragonclaw Strike — double P/T (too complex)
TDM: Dragon land — bite with dragon-specific targeting (custom target)

These are all correctly deferred. Let me compile and test:

All 252 tests pass. Now let me update the documentation. First, let me update the work queue:

Now update the per-set remediation docs. Let me check the current state of the remediation docs for the affected cards:

Now let me check for Affectionate Indrik and Felling Blow in fdn-remediation.md:

Now update ROADMAP.md:

Let me read game.rs in parts and search for the fight/bite cards.

Now update the "next batches" section in the roadmap:

Let me verify the fixes are all correct by re-checking the modified card lines:

All 6 cards fixed. Let me do a final full test run to confirm everything is green:

All tests pass. Let me verify the remediation doc fixes took effect:

All done. Here's a summary of Batch 8: Fight/Bite mechanic:

Engine changes:

Added Effect::Fight — two creatures deal damage equal to their power to each other (mutual)
Added Effect::Bite — source creature deals damage equal to its power to target (one-way)
Added Effect::fight() and Effect::bite() constructors
Added find_fight_creature() helper — uses source creature if on battlefield, otherwise auto-selects controller's strongest creature
Added find_fight_target() helper — uses first target on battlefield, otherwise auto-selects opponent's strongest creature

Cards fixed (6):

FDN: Bite Down — Custom → Effect::bite()
FDN: Affectionate Indrik — ETB Custom → Effect::fight() + TargetSpec::Creature
FDN: Felling Blow — Custom → add_p1p1_counters(1), Effect::bite()
ECL: Assert Perfection — Custom(fight) → Effect::fight()
TDM: Piercing Exhale — Custom → Effect::fight()
TDM: Knockout Maneuver — Custom → add_p1p1_counters(1), Effect::fight()

Tests added: fight_and_bite_effects, fight_auto_selects_creatures

252 tests passing (was 245 → 163 engine + 18 cards + 52 AI + 19 tests = 252).

Does the description of the mechanic work the same way as the Java implementation? +#### ~~Fight/Bite Mechanic~~ (DONE)
60 +Effect::Fight (mutual damage) and Effect::Bite (one-way damage) auto-select the controller's strongest creature as fighter and use explicit targets or opponen
+t's strongest creature. Fixed 6 cards. Remaining fight/bite cards blocked by modal spells (Batch 11), X-cost (Batch 15), or complex compound effects.

Good question. Let me check the Java implementation to see if fight/bite actually works differently.

No, it doesn't. The Java implementation is meaningfully different:

Java (FightTargetsEffect):

Has two explicit targets chosen by the player: target 1 = your creature, target 2 = opponent's creature
Both must be legal for the effect to resolve
The player decides which of their creatures fights

Java (DamageWithPowerFromOneToAnotherTargetEffect — bite):

Also two explicit targets: target 1 = your creature (power source), target 2 = opponent's creature/player
Can target players too, not just creatures

Our implementation:

Auto-selects controller's strongest creature (no player choice)
Falls back to opponent's strongest creature if no target
Only one target slot in TargetSpec

The core issue is our TargetSpec system only supports one target type per ability, so we can't model the two-target "your creature + their creature" pattern that fight/bite spells actually use. The auto-select-strongest heuristic is a workaround.

For ETB triggers (Affectionate Indrik), it's mostly correct — the source is the creature, and the target is the opponent's creature. But for spells, the player should be choosing which creature fights, not auto-picking strongest.

Let me update the ROADMAP to be honest about this limitation:

Also update the phase summary:

And update the work queue similarly:

The docs now accurately describe the gap. To summarize: the Java implementation uses proper two-target selection where the player chooses both creatures, while our engine auto-picks the strongest creature as a heuristic since TargetSpec doesn't support multi-target with different filters. The damage mechanics (mutual for fight, one-way for bite) are correct — it's the creature selection that's simplified.

Let

Request interrupted by user

Let's fix the gap please

Let me understand how targets flow through the system so I can design the fix properly.

Now let me see how targets are resolved when a spell is cast — how the engine goes from TargetSpec to the targets: &[ObjectId] that gets passed to execute_effects.

Now let me see how targets get selected when a spell goes on the stack.

Let me look at how the target flow works more broadly — how does the stack item get its targets populated? Let me check if there's a separate target selection phase.

Let me get more context on each of these cards to understand their exact effects.

Now let me see where targets get selected for spells (cast_spell currently uses targets: vec![]). Let me find the action processing:

I see the full picture now. The issue is deeper than just fight/bite — the engine currently never selects targets for any spell or ability. targets: vec![] is hardcoded everywhere. Fight/Bite auto-selection is actually consistent with how DealDamage, Destroy, etc. all work with empty targets.

Let me look at how the action space and legal actions work to understand what a proper fix entails.

Good — the heuristic and random players already implement choose_targets. Now let me look at Outcome to understand the good/bad distinction:

Now I have the full picture. Let me implement the fix. The plan:

Add TargetSpec::CreatureYouControl and TargetSpec::OpponentCreature
Add TargetSpec::fight_targets() builder
Add resolve_targets_for_spec() helper in game.rs
Wire up target selection in cast_spell()
Update Fight/Bite to use explicit targets from the stack
Update card definitions
Update tests

Now add a builder for fight targets:

I need to add a builder for TargetSpec. Let me add it after the StaticEffect builders:

Now the big part — wire up target selection in cast_spell() and the trigger resolution path. Let me add a select_targets_for_spec() method and update cast_spell():

Now I need to add target selection. The cleanest approach: extract the spell's TargetSpec, build legal targets, ask the decision maker, and put them on the stack.