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

// M-8 跨章節整合：共用年表排序（Scene.storyOrder 本身即年表鍵，不需要另外的服務排序）、
// 矛盾偵測與裁決優先序（小說原文 > 官方設定集 > 動畫改編），無法裁決者標記待人工確認。
@Injectable()
export class TimelineService {
  constructor(private readonly prisma: PrismaService) {}

  // 掃描同一事件標籤下、同一事實鍵卻不同事實值的場景——這是故意置入矛盾最容易驗證的形式。
  async detectContradictions(workId: string): Promise<number> {
    const facts = await this.prisma.client.sceneFact.findMany({
      where: { scene: { workId } },
      include: { scene: true },
    });

    const groups = new Map<string, typeof facts>();
    for (const fact of facts) {
      const key = `${fact.eventLabel}::${fact.factKey}`;
      const group = groups.get(key) ?? [];
      group.push(fact);
      groups.set(key, group);
    }

    let created = 0;
    for (const [key, group] of groups) {
      const distinctValues = new Set(group.map((fact) => fact.factValue));
      if (distinctValues.size <= 1) {
        continue;
      }
      const [eventLabel, factKey] = key.split("::");
      const existing = await this.prisma.client.sceneContradiction.findFirst({ where: { workId, eventLabel, factKey } });
      if (existing) {
        continue;
      }

      const sorted = [...group].sort(
        (a, b) => (SOURCE_PRIORITY[a.scene.sourceType] ?? 99) - (SOURCE_PRIORITY[b.scene.sourceType] ?? 99),
      );
      const best = sorted[0];
      const runnerUpDifferentValue = sorted.find((fact) => fact.factValue !== best.factValue);
      const canAutoResolve =
        runnerUpDifferentValue !== undefined &&
        (SOURCE_PRIORITY[best.scene.sourceType] ?? 99) < (SOURCE_PRIORITY[runnerUpDifferentValue.scene.sourceType] ?? 99);

      await this.prisma.client.sceneContradiction.create({
        data: {
          workId,
          eventLabel,
          factKey,
          description: `「${eventLabel}」的「${factKey}」出現不同描述：${[...distinctValues].join(" vs ")}`,
          status: canAutoResolve ? "RESOLVED" : "PENDING_HUMAN_REVIEW",
          resolution: canAutoResolve
            ? `依裁決優先序（小說原文 > 官方設定集 > 動畫改編）採用「${best.factValue}」（來源：${best.scene.sourceType}）`
            : null,
        },
      });
      created += 1;
    }
    return created;
  }

  async listContradictions(workId: string) {
    return this.prisma.client.sceneContradiction.findMany({ where: { workId } });
  }

  // T39：detectContradictions() 只能自動裁決「來源優先序不同」的矛盾，剩下標記 PENDING_HUMAN_REVIEW
  // 的矛盾原本沒有任何端點可以真的解決掉——這是本次補上的缺口，否則含這類矛盾的作品會永久卡住，
  // 沒有任何路徑能讓後續場景繼續投影。
  async resolveContradiction(contradictionId: string, resolution: string): Promise<void> {
    await this.prisma.client.sceneContradiction.update({
      where: { id: contradictionId },
      data: { status: "RESOLVED", resolution },
    });
  }
}