// ─── 스튜디오 위저드 상태 관리 훅 ───────────────────────────────────────────
// DEMO/src/components/studio/StudioWizard.tsx 의 상태 로직에서 이전
// TODO: Phase 2 — Zustand store 로 전환

import { useState } from "react";
import type { StudioState, StudioChannel, ContentFormat, ContentPillarId, AssetSourceType, SoundSettings, GenerateOutputType } from "@/features/studio/types/studio";
import { getStepsForChannel } from "@/features/studio/config/studioSteps";

const DEFAULT_SOUND: SoundSettings = {
  genre: 'calm',
  trackId: null,
  narrationEnabled: false,
  narrationLanguage: 'ko',
  narrationVoice: 'female',
  subtitleEnabled: true,
};

const INITIAL_STATE: StudioState = {
  channel: null,
  format: null,
  pillarId: null,
  assetSources: [],
  sound: DEFAULT_SOUND,
  outputType: 'video',
};

export function useStudioWizard() {
  const [state, setState] = useState<StudioState>(INITIAL_STATE);
  const [currentStepIndex, setCurrentStepIndex] = useState(0);

  const steps = getStepsForChannel(state.channel);
  const currentStep = steps[currentStepIndex];
  const isFirstStep = currentStepIndex === 0;
  const isLastStep = currentStepIndex === steps.length - 1;

  // ── 스텝별 진행 가능 여부 ─────────────────────────────────────────────────
  // TODO: 각 스텝 구현 후 세부 유효성 검사 추가
  function canProceed(): boolean {
    switch (currentStep.key) {
      case 'channel-format':   return state.channel !== null && state.format !== null;
      case 'strategy-source':  return state.pillarId !== null && state.assetSources.length > 0;
      case 'sound':            return true;
      case 'generate':         return true;
      case 'blog-editor':      return true;
      default:                 return false;
    }
  }

  // ── 스텝 이동 ─────────────────────────────────────────────────────────────
  function goNext() {
    if (!isLastStep && canProceed()) setCurrentStepIndex((i) => i + 1);
  }

  function goPrev() {
    if (!isFirstStep) setCurrentStepIndex((i) => i - 1);
  }

  function goToStep(index: number) {
    if (index < currentStepIndex) setCurrentStepIndex(index);
  }

  // ── 상태 업데이트 핸들러 ──────────────────────────────────────────────────
  function setChannel(channel: StudioChannel) {
    // 채널 변경 시 format 초기화 + blog 채널은 outputType을 image로 고정
    setState((prev) => ({
      ...prev,
      channel,
      format: null,
      outputType: channel === 'naver_blog' ? 'image' : 'video',
    }));
    setCurrentStepIndex(0);
  }

  function setFormat(format: ContentFormat) {
    setState((prev) => ({ ...prev, format }));
  }

  function setPillar(pillarId: ContentPillarId) {
    setState((prev) => ({ ...prev, pillarId }));
  }

  function toggleAssetSource(source: AssetSourceType) {
    setState((prev) => {
      const exists = prev.assetSources.includes(source);
      return {
        ...prev,
        assetSources: exists
          ? prev.assetSources.filter((s) => s !== source)
          : [...prev.assetSources, source],
      };
    });
  }

  function setSound(sound: Partial<SoundSettings>) {
    setState((prev) => ({ ...prev, sound: { ...prev.sound, ...sound } }));
  }

  function setOutputType(outputType: GenerateOutputType) {
    setState((prev) => ({ ...prev, outputType }));
  }

  return {
    state,
    steps,
    currentStep,
    currentStepIndex,
    isFirstStep,
    isLastStep,
    canProceed,
    goNext,
    goPrev,
    goToStep,
    setChannel,
    setFormat,
    setPillar,
    toggleAssetSource,
    setSound,
    setOutputType,
  };
}