import { Injectable } from "@nestjs/common";
import { PrismaService } from "../prisma/prisma.service.js";

const REINFORCE_INCREMENT = 1;
const CORRECTION_PENALTY = 1;

// F-5 行為強化迴路：稱讚加權、糾正降權並以修正版取代，重複命中自動下沉為慣例（權重最高者）。
@Injectable()
export class BehaviorReinforcementService {
  constructor(private readonly prisma: PrismaService) {}

  async reinforcePraise(characterId: string, situation: string, responsePattern: string): Promise<void> {
    const existing = await this.prisma.client.proceduralRule.findFirst({
      where: { characterId, situation, responsePattern },
    });

    if (existing) {
      await this.prisma.client.proceduralRule.update({
        where: { id: existing.id },
        data: { weight: existing.weight + REINFORCE_INCREMENT },
      });
      return;
    }

    await this.prisma.client.proceduralRule.create({
      data: { characterId, situation, responsePattern, weight: 1 },
    });
  }

  async applyCorrection(
    characterId: string,
    situation: string,
    oldResponsePattern: string,
    newResponsePattern: string,
  ): Promise<void> {
    const old = await this.prisma.client.proceduralRule.findFirst({
      where: { characterId, situation, responsePattern: oldResponsePattern },
    });
    const oldWeight = old?.weight ?? 1;

    if (old) {
      await this.prisma.client.proceduralRule.update({
        where: { id: old.id },
        data: { weight: Math.max(0, oldWeight - CORRECTION_PENALTY) },
      });
    }

    // 修正版直接繼承舊模式修正前的權重，確保取代後排序上必定領先（避免降權後打平）。
    const existingNew = await this.prisma.client.proceduralRule.findFirst({
      where: { characterId, situation, responsePattern: newResponsePattern },
    });
    const inheritedWeight = Math.max(oldWeight, 1);
    if (existingNew) {
      await this.prisma.client.proceduralRule.update({
        where: { id: existingNew.id },
        data: { weight: existingNew.weight + inheritedWeight },
      });
    } else {
      await this.prisma.client.proceduralRule.create({
        data: { characterId, situation, responsePattern: newResponsePattern, weight: inheritedWeight },
      });
    }
  }

  async getTopRule(characterId: string, situation: string) {
    return this.prisma.client.proceduralRule.findFirst({
      where: { characterId, situation },
      orderBy: { weight: "desc" },
    });
  }
}