import { Inject, 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 { LLM_PROVIDER, type LLMProvider } from "../llm/llm-provider.js";
import { hashToSeed } from "../llm/seeded-random.js";
import type { GenerationContext, GeneratedResponse } from "../llm/types.js";
import { getArchetypeParams } from "../personality/archetype-params.js";
import { resolveAddress } from "../personality/language-style.js";
import { stageForIntimacy } from "../relationship/constants.js";
import { CharacterRelationshipService } from "./character-relationship.service.js";
import { USER_SPEAKER_ID, type Room } from "./room.service.js";
import { GROUP_RESERVE_INTIMACY_PENALTY, TSUNDERE_EXTRA_GROUP_PENALTY } from "./constants.js";

export interface RoomReplyOptions {
  seed?: number;
  now?: Date;
}

export interface RoomReply extends GeneratedResponse {
  address: string;
}

// K-2/K-3 群聊生成：一律套用「人前矜持」的親密度下修＋隱私過濾，一對一聊天不會走這條路徑。
@Injectable()
export class RoomGenerationService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly emotion: EmotionService,
    private readonly relationship: RelationshipService,
    private readonly retriever: KeywordMemoryRetriever,
    private readonly characterRelationship: CharacterRelationshipService,
    @Inject(LLM_PROVIDER) private readonly provider: LLMProvider,
  ) {}

  async generateReply(
    room: Room,
    characterId: string,
    speakerId: string,
    speakerLabel: string,
    userInput: string,
    options: RoomReplyOptions = {},
  ): Promise<RoomReply> {
    const now = options.now ?? new Date();
    const character = await this.prisma.client.character.findUniqueOrThrow({ where: { id: characterId } });
    const archetypeParams = getArchetypeParams(character.personalityArchetype);

    const emotionState = await this.emotion.getState(characterId, now);
    const dominant = dominantState(emotionState);
    const style = toResponseStyle(dominant);

    // 對使用者發言沿用 G-2 的稱呼分層；對其他角色發言則直接以名字稱呼（NPC 之間不走使用者稱呼分層）。
    let baseIntimacy: number;
    let trust: number;
    let address: string;
    if (speakerId === USER_SPEAKER_ID) {
      const { relationship } = await this.relationship.getState(characterId, room.userId, now);
      baseIntimacy = relationship.intimacy;
      trust = relationship.trust;
      address = resolveAddress(speakerLabel, relationship.intimacy);
    } else {
      baseIntimacy = await this.characterRelationship.getAffinity(characterId, speakerId);
      trust = baseIntimacy;
      address = speakerLabel;
    }

    // K-2 群聊矜持：實際餵給生成的親密度下修，讓既有的模板分層（intimacyTier）自然選到更收斂的回應；
    // 傲嬌式反向表達在人前更嘴硬，額外多下修一些。
    let effectiveIntimacy = baseIntimacy - GROUP_RESERVE_INTIMACY_PENALTY;
    if (archetypeParams.invertedIntimacyExpression) {
      effectiveIntimacy -= TSUNDERE_EXTRA_GROUP_PENALTY;
    }
    effectiveIntimacy = Math.max(0, Math.min(100, effectiveIntimacy));

    // K-3 隱私邊界：有旁人在場，私密記憶不主動洩漏（口風不緊原型除外）。
    const excludePrivate = !archetypeParams.traits.includes("loose-lipped");
    const retrievedMemories = await this.retriever.retrieve(characterId, userInput, {
      relatedUserId: room.userId,
      excludePrivate,
    });

    const history = room.turns.slice(-10).map((turn) => ({
      role: (turn.speakerId === USER_SPEAKER_ID ? "user" : "character") as "user" | "character",
      content: `${turn.speakerLabel}：${turn.content}`,
      timestamp: turn.timestamp.toISOString(),
    }));

    const seed = options.seed ?? hashToSeed(`${room.id}:${room.turnCounter}:${characterId}`);

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

    const generated = await this.provider.generate(context);
    return { text: `${address}，${generated.text}`, actions: generated.actions, address };
  }
}