import { Injectable } from "@nestjs/common";
import type { EmotionTag, EmotionState } from "@kokorone/shared";
import { PrismaService } from "../prisma/prisma.service.js";
import { EmotionService, dominantState } from "../emotion/emotion.service.js";
import { RelationshipService } from "../relationship/relationship.service.js";
import { getArchetypeParams } from "../personality/archetype-params.js";
import {
  EMOTION_EXPRESSION_TABLE,
  BASIC_TIER_EMOTIONS,
  FRIEND_TIER_EMOTIONS,
  CLOSE_TIER_EMOTIONS,
  FRIEND_TIER_COSTUMES,
  CLOSE_TIER_COSTUMES,
  CRYING_EFFECT,
  CRYING_INTENSITY_THRESHOLD,
  type GazeDirection,
} from "./constants.js";

export interface ResolveExpressionOptions {
  now?: Date;
  isThinking?: boolean; // O-2 視線：思考時視線飄上
  isDeflecting?: boolean; // O-2 視線：說謊/迴避時視線撇開（跟 SHY 的視線飄開共用同一個方向）
}

export interface ExpressionState {
  emotionTag: EmotionTag; // 實際套用的表情（可能因親密度未解鎖而降級）
  rawEmotionTag: EmotionTag; // 情緒引擎真實判定的狀態，不受親密度解鎖影響——立繪與文字可以故意不一致
  eyebrow: string;
  eye: string;
  mouth: string;
  effect: string | null;
  pose: string;
  magnitude: number; // O-4：0~1，外顯度 × 情緒強度——同樣是愉悅，元氣角色滿臉笑容、三無角色只有嘴角微動
  gaze: GazeDirection;
  availableCostumes: string[];
  lockedFallbackApplied: boolean; // O-3：真實情緒不在目前親密度階段的解鎖範圍內，被降級成基本表情
  usedCryingVariant: boolean; // O-3：哭臉——只有 BONDED 階段的深度低落才會出現
}

function fieldFor(tag: EmotionTag): keyof Omit<EmotionState, "characterId" | "updatedAt"> {
  return tag === "CALM" ? "calm" : (tag.toLowerCase() as "joy" | "sad" | "alert" | "shy" | "grumpy");
}

function clamp01(value: number): number {
  return Math.max(0, Math.min(1, value));
}

function resolveGaze(emotionTag: EmotionTag, options: ResolveExpressionOptions): GazeDirection {
  if (options.isThinking) {
    return "UP";
  }
  if (options.isDeflecting || emotionTag === "SHY") {
    return "AWAY";
  }
  if (emotionTag === "ALERT") {
    return "DIRECT";
  }
  return "NEUTRAL";
}

// O-2/O-3/O-4 表情解析：情緒引擎直接驅動表情差分，套用親密度解鎖與性格外顯度縮放。
// 這裡回傳的「表情」永遠反映真實情緒狀態（rawEmotionTag／magnitude 都不看對話文字內容），
// 文字生成走另一條完全獨立的路徑（MockProvider）——兩者不一致本身就是「微反差演出」，
// 不需要額外寫「故意不一致」的特殊邏輯，是兩條獨立資料流的自然結果。
@Injectable()
export class ExpressionResolverService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly emotion: EmotionService,
    private readonly relationship: RelationshipService,
  ) {}

  async resolveExpression(
    characterId: string,
    userId: string,
    options: ResolveExpressionOptions = {},
  ): Promise<ExpressionState> {
    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 rawEmotionTag = dominantState(emotionState);
    const intensityNormalized = clamp01((emotionState[fieldFor(rawEmotionTag)] as number) / 100);

    const { relationship } = await this.relationship.getState(characterId, userId, now);
    const stage = relationship.stage;

    const allowedEmotions =
      stage === "BONDED" || stage === "CLOSE_AMBIGUOUS"
        ? CLOSE_TIER_EMOTIONS
        : stage === "FRIEND"
          ? FRIEND_TIER_EMOTIONS
          : BASIC_TIER_EMOTIONS;

    const lockedFallbackApplied = !allowedEmotions.includes(rawEmotionTag);
    const emotionTag = lockedFallbackApplied ? "CALM" : rawEmotionTag;
    const template = EMOTION_EXPRESSION_TABLE[emotionTag];

    let effect = template.effect;
    let usedCryingVariant = false;
    if (emotionTag === "SAD" && intensityNormalized >= CRYING_INTENSITY_THRESHOLD && stage === "BONDED") {
      effect = CRYING_EFFECT;
      usedCryingVariant = true;
    }

    const magnitude = clamp01(archetypeParams.expressiveness * intensityNormalized);
    const gaze = resolveGaze(emotionTag, options);
    const availableCostumes =
      stage === "BONDED" || stage === "CLOSE_AMBIGUOUS" ? CLOSE_TIER_COSTUMES : stage === "FRIEND" ? FRIEND_TIER_COSTUMES : ["制服"];

    return {
      emotionTag,
      rawEmotionTag,
      eyebrow: template.eyebrow,
      eye: template.eye,
      mouth: template.mouth,
      effect,
      pose: template.pose,
      magnitude,
      gaze,
      availableCostumes,
      lockedFallbackApplied,
      usedCryingVariant,
    };
  }
}