feat(sprint3): items + forge + craft + loot — équipement, artisanat lazy-calc, forge risque GDD

src/forge/forge.service.ts

@@ -0,0 +1,68 @@
+import { Injectable, BadRequestException, NotFoundException } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { CharacterItem } from '../item/character-item.entity';
+import { Character } from '../character/entities/character.entity';
+import { User } from '../user/user.entity';
+
+const MAX_FORGE_LEVEL = 5;
+const FORGE_BONUS_PER_LEVEL = 2; // +2 attack (weapon) ou +2 defense (armor) par niveau affiché
+
+// Risque d'échec par niveau cible (GDD exact)
+const FORGE_FAIL_CHANCE: Record<number, number> = {
+  1: 0,
+  2: 0,
+  3: 0.20,
+  4: 0.30,
+  5: 0.40,
+};
+
+@Injectable()
+export class ForgeService {
+  constructor(
+    @InjectRepository(CharacterItem)
+    private readonly charItemRepository: Repository<CharacterItem>,
+    @InjectRepository(Character)
+    private readonly characterRepository: Repository<Character>,
+  ) {}
+
+  async upgradeItem(charItemId: string, user: User) {
+    const char = await this.characterRepository.findOne({ where: { userId: user.id } });
+    if (!char) throw new BadRequestException('Aucun personnage trouvé');
+
+    const charItem = await this.charItemRepository.findOne({
+      where: { id: charItemId, characterId: char.id },
+    });
+    if (!charItem) throw new NotFoundException('Item non trouvé dans l\'inventaire');
+    if (charItem.forgeLevel >= MAX_FORGE_LEVEL) {
+      throw new BadRequestException(`Niveau de forge maximum atteint (${MAX_FORGE_LEVEL})`);
+    }
+
+    const targetLevel = charItem.forgeLevel + 1;
+    const failChance = FORGE_FAIL_CHANCE[targetLevel] ?? 0;
+    const success = Math.random() >= failChance;
+
+    if (success) {
+      charItem.forgeLevel = targetLevel;
+      await this.charItemRepository.save(charItem);
+
+      const statLabel = charItem.item.type === 'weapon'
+        ? `+${FORGE_BONUS_PER_LEVEL} ATK`
+        : `+${FORGE_BONUS_PER_LEVEL} DEF`;
+
+      return {
+        success: true,
+        forgeLevel: charItem.forgeLevel,
+        item: charItem.item.name,
+        message: `Forge réussie ! ${charItem.item.name} [+${charItem.forgeLevel}] (${statLabel}).`,
+      };
+    }
+
+    return {
+      success: false,
+      forgeLevel: charItem.forgeLevel,
+      item: charItem.item.name,
+      message: `Échec de forge ! ${charItem.item.name} reste au niveau [+${charItem.forgeLevel}].`,
+    };
+  }
+}