✨Feature: add town systems, saves, recovery, and level progression

src/rules/progression.ts

@@ -0,0 +1,122 @@
+import type { ContentPack } from "@/types/content";
+import type { AdventurerState, LevelUpState } from "@/types/state";
+
+export const XP_PER_LEVEL = 8;
+export const HP_GAIN_PER_LEVEL = 2;
+export const MAX_ADVENTURER_LEVEL = 10;
+
+export type ApplyLevelProgressionOptions = {
+  content: ContentPack;
+  adventurer: AdventurerState;
+  at?: string;
+};
+
+export type LevelProgressionResult = {
+  adventurer: AdventurerState;
+  levelUps: LevelUpState[];
+};
+
+export function getXpThresholdForLevel(level: number) {
+  if (level <= 1) {
+    return 0;
+  }
+
+  return (level - 1) * XP_PER_LEVEL;
+}
+
+export function getNextLevelXpThreshold(level: number) {
+  return getXpThresholdForLevel(level + 1);
+}
+
+export function getLevelForXp(xp: number) {
+  if (xp < 0) {
+    return 1;
+  }
+
+  return Math.min(MAX_ADVENTURER_LEVEL, Math.floor(xp / XP_PER_LEVEL) + 1);
+}
+
+function getUnlockedWeaponManoeuvreIds(content: ContentPack, adventurer: AdventurerState, level: number) {
+  const weapon = content.weapons.find((entry) => entry.id === adventurer.weaponId);
+
+  if (!weapon) {
+    throw new Error(`Unknown weapon id: ${adventurer.weaponId}`);
+  }
+
+  return weapon.allowedManoeuvreIds.filter((manoeuvreId) => {
+    const manoeuvre = content.manoeuvres.find((entry) => entry.id === manoeuvreId);
+
+    if (!manoeuvre) {
+      throw new Error(`Unknown manoeuvre id: ${manoeuvreId}`);
+    }
+
+    return (manoeuvre.minimumLevel ?? 1) <= level;
+  });
+}
+
+export function applyLevelProgression(
+  options: ApplyLevelProgressionOptions,
+): LevelProgressionResult {
+  const nextAdventurer: AdventurerState = {
+    ...options.adventurer,
+    hp: { ...options.adventurer.hp },
+    stats: { ...options.adventurer.stats },
+    favour: { ...options.adventurer.favour },
+    statuses: options.adventurer.statuses.map((status) => ({ ...status })),
+    inventory: {
+      carried: options.adventurer.inventory.carried.map((entry) => ({ ...entry })),
+      equipped: options.adventurer.inventory.equipped.map((entry) => ({ ...entry })),
+      stored: options.adventurer.inventory.stored.map((entry) => ({ ...entry })),
+      currency: { ...options.adventurer.inventory.currency },
+      rationCount: options.adventurer.inventory.rationCount,
+      lightSources: options.adventurer.inventory.lightSources.map((entry) => ({ ...entry })),
+    },
+    progressionFlags: [...options.adventurer.progressionFlags],
+    manoeuvreIds: [...options.adventurer.manoeuvreIds],
+  };
+  const targetLevel = getLevelForXp(nextAdventurer.xp);
+  const at = options.at ?? new Date().toISOString();
+  const levelUps: LevelUpState[] = [];
+
+  while (nextAdventurer.level < targetLevel) {
+    const previousLevel = nextAdventurer.level;
+    const newLevel = previousLevel + 1;
+
+    nextAdventurer.level = newLevel;
+    nextAdventurer.hp.max += HP_GAIN_PER_LEVEL;
+    nextAdventurer.hp.current = Math.min(
+      nextAdventurer.hp.max,
+      nextAdventurer.hp.current + HP_GAIN_PER_LEVEL,
+    );
+
+    const unlockedManoeuvreIds = getUnlockedWeaponManoeuvreIds(
+      options.content,
+      nextAdventurer,
+      newLevel,
+    ).filter((manoeuvreId) => !nextAdventurer.manoeuvreIds.includes(manoeuvreId));
+
+    nextAdventurer.manoeuvreIds.push(...unlockedManoeuvreIds);
+
+    const levelFlag = `level.reached.${newLevel}`;
+    if (!nextAdventurer.progressionFlags.includes(levelFlag)) {
+      nextAdventurer.progressionFlags.push(levelFlag);
+    }
+
+    levelUps.push({
+      previousLevel,
+      newLevel,
+      at,
+      hpGained: HP_GAIN_PER_LEVEL,
+      unlockedManoeuvreIds,
+      summary:
+        unlockedManoeuvreIds.length > 0
+          ? `Reached level ${newLevel}, gained ${HP_GAIN_PER_LEVEL} max HP, and unlocked ${unlockedManoeuvreIds.length} manoeuvre${unlockedManoeuvreIds.length === 1 ? "" : "s"}.`
+          : `Reached level ${newLevel} and gained ${HP_GAIN_PER_LEVEL} max HP.`,
+    });
+  }
+
+  return {
+    adventurer: nextAdventurer,
+    levelUps,
+  };
+}