Add combat orchestration with turn flow and win/loss check

src/combat.js

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+import { drawCards } from "./state.js";
+import { resolveEffects } from "./effects.js";
+import { resolveEnemyAction } from "./enemies.js";
+import { rollDie } from "./die.js";
+
+export function startTurn(state) {
+  const dieResult = rollDie();
+  let next = {
+    ...state,
+    player: {
+      ...state.player,
+      energy: state.player.maxEnergy,
+      block: 0,
+    },
+    combat: {
+      ...state.combat,
+      phase: "player_turn",
+      dieResult,
+      selectedCard: null,
+    },
+  };
+  next = drawCards(next, 5);
+  return next;
+}
+
+export function resolveEnemyTurn(state) {
+  let next = {
+    ...state,
+    enemy: { ...state.enemy, block: 0 },
+  };
+
+  const action = resolveEnemyAction(
+    next.enemy,
+    next.combat.dieResult,
+    next.enemy.trackPosition,
+  );
+
+  if (action && action.effects) {
+    next = resolveEffects(next, action.effects, "enemy", "player");
+  }
+
+  let trackPosition = next.enemy.trackPosition;
+  if (next.enemy.actionType === "cube") {
+    trackPosition = Math.min(
+      trackPosition + 1,
+      (next.enemy.actionTrack || []).length - 1,
+    );
+  }
+
+  return {
+    ...next,
+    enemy: { ...next.enemy, trackPosition },
+    combat: {
+      ...next.combat,
+      phase: "player_turn",
+      turn: next.combat.turn + 1,
+    },
+  };
+}
+
+export function checkCombatEnd(state) {
+  if (state.enemy.hp <= 0) return "victory";
+  if (state.player.hp <= 0) return "defeat";
+  return null;
+}

src/combat.test.js

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+import { describe, expect, test } from "bun:test";
+import { startTurn, resolveEnemyTurn, checkCombatEnd } from "./combat.js";
+import { createCombatState } from "./state.js";
+
+describe("startTurn", () => {
+  test("resets energy and block, draws 5 cards", () => {
+    let state = createCombatState("ironclad", "jaw_worm");
+    state = {
+      ...state,
+      player: { ...state.player, energy: 0, block: 5 },
+    };
+    const next = startTurn(state);
+    expect(next.player.energy).toBe(3);
+    expect(next.player.block).toBe(0);
+    expect(next.player.hand).toHaveLength(5);
+    expect(next.combat.dieResult).toBeGreaterThanOrEqual(1);
+    expect(next.combat.dieResult).toBeLessThanOrEqual(6);
+  });
+});
+
+describe("resolveEnemyTurn", () => {
+  test("enemy attacks reduce player hp or block", () => {
+    let state = createCombatState("ironclad", "jaw_worm");
+    state = { ...state, combat: { ...state.combat, dieResult: 1 } };
+    const next = resolveEnemyTurn(state);
+    expect(next.combat.phase).toBe("player_turn");
+    expect(next.combat.turn).toBe(state.combat.turn + 1);
+  });
+
+  test("enemy block resets before acting", () => {
+    let state = createCombatState("ironclad", "jaw_worm");
+    state = {
+      ...state,
+      enemy: { ...state.enemy, block: 5 },
+      combat: { ...state.combat, dieResult: 1 },
+    };
+    const next = resolveEnemyTurn(state);
+    // die result 1 maps to an attack action (hit 2), so no block regained
+    expect(next.enemy.block).toBe(0);
+  });
+});
+
+describe("checkCombatEnd", () => {
+  test("returns 'victory' when enemy hp is 0", () => {
+    let state = createCombatState("ironclad", "jaw_worm");
+    state = { ...state, enemy: { ...state.enemy, hp: 0 } };
+    expect(checkCombatEnd(state)).toBe("victory");
+  });
+
+  test("returns 'defeat' when player hp is 0", () => {
+    let state = createCombatState("ironclad", "jaw_worm");
+    state = { ...state, player: { ...state.player, hp: 0 } };
+    expect(checkCombatEnd(state)).toBe("defeat");
+  });
+
+  test("returns null when combat continues", () => {
+    const state = createCombatState("ironclad", "jaw_worm");
+    expect(checkCombatEnd(state)).toBeNull();
+  });
+});