import { Injectable } from "@nestjs/common";
import { PrismaService } from "../prisma/prisma.service.js";
import { EmotionService, dominantState } from "../emotion/emotion.service.js";
import { toResponseStyle } from "../emotion/response-style.js";
import { RelationshipService } from "../relationship/relationship.service.js";
import { KeywordMemoryRetriever } from "../memory/memory-retriever.service.js";
import { WorkingMemoryService } from "../memory/working-memory.service.js";
import { hashToSeed } from "./seeded-random.js";
import type { GenerationContext } from "./types.js";

export interface AssembleOptions {
  skipMemoryRetrieval?: boolean;
  seed?: number;
  now?: Date;
}

// F-6 上下文組裝器：把人設、當前情緒、檢索到的記憶、關係參數、對話歷史組裝成統一上下文物件。
@Injectable()
export class ContextAssemblerService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly emotion: EmotionService,
    private readonly relationship: RelationshipService,
    private readonly retriever: KeywordMemoryRetriever,
    private readonly workingMemory: WorkingMemoryService,
  ) {}

  async assemble(
    characterId: string,
    userId: string,
    sessionId: string,
    userInput: string,
    options: AssembleOptions = {},
  ): Promise<GenerationContext> {
    const now = options.now ?? new Date();

    const character = await this.prisma.client.character.findUniqueOrThrow({ where: { id: characterId } });
    const emotionState = await this.emotion.getState(characterId, now);
    const dominant = dominantState(emotionState);
    const style = toResponseStyle(dominant);
    const { relationship } = await this.relationship.getState(characterId, userId, now);

    const retrievedMemories = options.skipMemoryRetrieval
      ? []
      : await this.retriever.retrieve(characterId, userInput, { relatedUserId: userId });

    const history = (await this.workingMemory.getContext(sessionId)).map((entry) => ({
      role: entry.role,
      content: entry.content,
      timestamp: entry.timestamp.toISOString(),
    }));

    const seed = options.seed ?? hashToSeed(`${sessionId}:${history.length}`);

    return {
      character: {
        id: character.id,
        personalityArchetype: character.personalityArchetype,
        speechStyle: character.speechStyle,
        likesDislikes: character.likesDislikes,
        basicInfo: character.basicInfo,
      },
      emotion: { dominant, style },
      relationship: {
        intimacy: relationship.intimacy,
        trust: relationship.trust,
        stage: relationship.stage,
      },
      retrievedMemories,
      history,
      userInput,
      injectedMemoryIds: retrievedMemories.map((memory) => memory.id),
      seed,
    };
  }
}