import React, { useState, useEffect } from 'react';
import { Link2, Sparkles, Loader2, RefreshCw, CheckCircle, XCircle, Clock, Film, FolderOpen, Trash2 } from 'lucide-react';
import { downloadApi, processApi, jobsApi, bgmApi, fontsApi } from '../api/client';
import VideoStudio from '../components/VideoStudio';

// Pipeline step definitions
const PIPELINE_STEPS = [
  { id: 'download', label: '다운로드', statuses: ['downloading'] },
  { id: 'trim', label: '트리밍', statuses: ['ready_for_trim'] },
  { id: 'transcribe', label: '음성인식', statuses: ['extracting_audio', 'noise_reduction', 'transcribing'] },
  { id: 'translate', label: '번역', statuses: ['translating'] },
  { id: 'review', label: '편집', statuses: ['awaiting_review', 'awaiting_subtitle'] },
  { id: 'render', label: '렌더링', statuses: ['processing'] },
];

export default function HomePage() {
  // Core state
  const [url, setUrl] = useState('');
  const [currentJob, setCurrentJob] = useState(null);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState(null);

  // Previous jobs
  const [previousJobs, setPreviousJobs] = useState([]);
  const [showPreviousJobs, setShowPreviousJobs] = useState(false);

  // Resources
  const [bgmList, setBgmList] = useState([]);
  const [fontList, setFontList] = useState([]);

  // Load BGM list
  useEffect(() => {
    const loadBgm = async () => {
      try {
        const res = await bgmApi.list();
        setBgmList(res.data);

        // Auto-download if no BGM
        if (res.data.length === 0) {
          try {
            const downloadRes = await bgmApi.autoDownload(['upbeat', 'energetic'], 60);
            if (downloadRes.data.success) {
              const bgmRes = await bgmApi.list();
              setBgmList(bgmRes.data);
            }
          } catch (e) {
            console.log('BGM auto-download failed:', e.message);
          }
        }
      } catch (err) {
        console.error('Failed to load BGM:', err);
      }
    };
    loadBgm();
  }, []);

  // Load fonts
  useEffect(() => {
    const loadFonts = async () => {
      try {
        const res = await fontsApi.list();
        setFontList(res.data.fonts || []);
      } catch (err) {
        console.error('Failed to load fonts:', err);
      }
    };
    loadFonts();
  }, []);

  // Load previous jobs
  useEffect(() => {
    const loadPreviousJobs = async () => {
      try {
        const res = await jobsApi.list(20);
        setPreviousJobs(res.data || []);
      } catch (err) {
        console.error('Failed to load previous jobs:', err);
      }
    };
    loadPreviousJobs();
  }, []);

  // Reload previous jobs when current job changes
  const reloadPreviousJobs = async () => {
    try {
      const res = await jobsApi.list(20);
      setPreviousJobs(res.data || []);
    } catch (err) {
      console.error('Failed to reload previous jobs:', err);
    }
  };

  // Poll job status
  useEffect(() => {
    const stopPollingStatuses = ['completed', 'failed', 'awaiting_subtitle', 'awaiting_review', 'ready_for_trim'];
    if (!currentJob || stopPollingStatuses.includes(currentJob.status)) {
      return;
    }

    const interval = setInterval(async () => {
      try {
        const res = await jobsApi.get(currentJob.job_id);
        setCurrentJob(res.data);
      } catch (err) {
        console.error('Poll failed:', err);
      }
    }, 1000);

    return () => clearInterval(interval);
  }, [currentJob]);

  // Submit URL
  const handleSubmit = async (e) => {
    e.preventDefault();
    if (!url.trim()) return;

    setIsLoading(true);
    setError(null);

    try {
      const res = await downloadApi.start(url);
      setCurrentJob({
        job_id: res.data.job_id,
        status: 'downloading',
        progress: 0,
        original_url: url,
      });
      setUrl('');
    } catch (err) {
      setError(err.response?.data?.detail || '다운로드 시작 실패');
    } finally {
      setIsLoading(false);
    }
  };

  // Reset job
  const handleReset = () => {
    setCurrentJob(null);
    setError(null);
    reloadPreviousJobs();
  };

  // Select previous job
  const handleSelectJob = async (job) => {
    try {
      const res = await jobsApi.get(job.job_id);
      setCurrentJob(res.data);
      setShowPreviousJobs(false);
      setError(null);
    } catch (err) {
      setError('작업을 불러오는데 실패했습니다');
    }
  };

  // Delete job
  const handleDeleteJob = async (e, jobId) => {
    e.stopPropagation();
    if (!confirm('이 작업을 삭제하시겠습니까?')) return;

    try {
      await jobsApi.delete(jobId);
      reloadPreviousJobs();
      if (currentJob?.job_id === jobId) {
        setCurrentJob(null);
      }
    } catch (err) {
      setError('작업 삭제 실패');
    }
  };

  // Start transcription
  const handleStartTranscription = async (translationMode) => {
    if (!currentJob) return;
    setError(null);

    try {
      await processApi.startTranscription(currentJob.job_id, {
        translationMode,
        useVocalSeparation: false,
      });
      const res = await jobsApi.get(currentJob.job_id);
      setCurrentJob(res.data);
    } catch (err) {
      setError(err.response?.data?.detail || '음성 인식 시작 실패');
    }
  };

  // Trim video (with optional exclude regions for cutting middle sections)
  const handleTrim = async (startTime, endTime, excludeRegions = []) => {
    if (!currentJob) return;
    setError(null);

    try {
      await processApi.trim(currentJob.job_id, startTime, endTime, false, excludeRegions);
      const res = await jobsApi.get(currentJob.job_id);
      setCurrentJob(res.data);
    } catch (err) {
      setError(err.response?.data?.detail || '트리밍 실패');
    }
  };

  // Render final video
  const handleRender = async (options) => {
    if (!currentJob) return;
    setError(null);

    // Auto-select first BGM if none selected
    let bgmId = options.bgmId;
    if (!bgmId && bgmList.length > 0) {
      bgmId = bgmList[0].id;
    }

    try {
      await processApi.render(currentJob.job_id, {
        bgmId,
        bgmVolume: options.bgmVolume,
        subtitleStyle: options.subtitleStyle,
        keepOriginalAudio: false,
        introText: options.introText,
        introDuration: options.introDuration,
        introFontSize: options.introFontSize,
        introPosition: options.introPosition,
      });
      const res = await jobsApi.get(currentJob.job_id);
      setCurrentJob(res.data);
    } catch (err) {
      setError(err.response?.data?.detail || '렌더링 시작 실패');
    }
  };

  // Get current step for pipeline indicator
  const getCurrentStep = () => {
    if (!currentJob) return -1;
    if (currentJob.status === 'completed') return PIPELINE_STEPS.length;
    if (currentJob.status === 'failed') return -1;

    for (let i = 0; i < PIPELINE_STEPS.length; i++) {
      if (PIPELINE_STEPS[i].statuses.includes(currentJob.status)) {
        return i;
      }
    }
    return -1;
  };

  const currentStep = getCurrentStep();

  return (
    <div className="space-y-6">
      {/* Header with URL Input */}
      <div className="card">
        <div className="flex items-center justify-between mb-4">
          <h2 className="text-xl font-semibold flex items-center gap-2">
            <Sparkles className="text-red-500" size={24} />
            영상 URL 입력
          </h2>
          {currentJob && (
            <button
              onClick={handleReset}
              className="text-gray-400 hover:text-white text-sm px-3 py-1 border border-gray-700 rounded-lg hover:border-gray-600 transition-colors flex items-center gap-2"
            >
              <RefreshCw size={14} />
              새 작업
            </button>
          )}
        </div>

        <form onSubmit={handleSubmit} className="flex gap-4">
          <div className="flex-1 relative">
            <Link2 className="absolute left-4 top-1/2 -translate-y-1/2 text-gray-500" size={20} />
            <input
              type="text"
              value={url}
              onChange={(e) => setUrl(e.target.value)}
              placeholder="Douyin, Kuaishou, TikTok, YouTube URL 입력..."
              className="input-field pl-12"
              disabled={isLoading || currentJob}
            />
          </div>
          <button
            type="submit"
            disabled={isLoading || !url.trim() || currentJob}
            className="btn-primary px-8 disabled:opacity-50 disabled:cursor-not-allowed"
          >
            {isLoading ? <Loader2 size={20} className="animate-spin" /> : '시작'}
          </button>
        </form>

        {/* Previous Jobs Toggle */}
        {!currentJob && previousJobs.length > 0 && (
          <div className="mt-4">
            <button
              onClick={() => setShowPreviousJobs(!showPreviousJobs)}
              className="text-gray-400 hover:text-white text-sm flex items-center gap-2"
            >
              <FolderOpen size={16} />
              기존 작업 불러오기 ({previousJobs.length}개)
              <span className={`transition-transform ${showPreviousJobs ? 'rotate-180' : ''}`}>▼</span>
            </button>

            {showPreviousJobs && (
              <div className="mt-3 max-h-64 overflow-y-auto space-y-2">
                {previousJobs.map((job) => (
                  <div
                    key={job.job_id}
                    onClick={() => handleSelectJob(job)}
                    className="flex items-center justify-between p-3 bg-gray-800 hover:bg-gray-700 rounded-lg cursor-pointer transition-colors"
                  >
                    <div className="flex-1 min-w-0">
                      <div className="flex items-center gap-2">
                        <span className={`w-2 h-2 rounded-full ${
                          job.status === 'completed' ? 'bg-green-500' :
                          job.status === 'failed' ? 'bg-red-500' :
                          'bg-yellow-500'
                        }`} />
                        <span className="text-sm text-white truncate">
                          {job.original_url || job.job_id}
                        </span>
                      </div>
                      <div className="text-xs text-gray-500 mt-1">
                        {job.status === 'completed' ? '완료' :
                         job.status === 'failed' ? '실패' :
                         job.status === 'awaiting_review' ? '편집 대기' :
                         job.status === 'ready_for_trim' ? '트리밍 대기' :
                         job.status}
                        {job.created_at && ` · ${new Date(job.created_at).toLocaleDateString()}`}
                      </div>
                    </div>
                    <button
                      onClick={(e) => handleDeleteJob(e, job.job_id)}
                      className="p-2 text-gray-500 hover:text-red-400 transition-colors"
                    >
                      <Trash2 size={16} />
                    </button>
                  </div>
                ))}
              </div>
            )}
          </div>
        )}

        {/* Pipeline Progress */}
        {currentJob && (
          <div className="mt-4 pt-4 border-t border-gray-700">
            <div className="flex items-center justify-between">
              {PIPELINE_STEPS.map((step, index) => {
                const isActive = index === currentStep;
                const isCompleted = index < currentStep || currentJob.status === 'completed';
                const isFailed = currentJob.status === 'failed' && index === currentStep;

                return (
                  <React.Fragment key={step.id}>
                    <div className="flex flex-col items-center">
                      <div
                        className={`w-8 h-8 rounded-full flex items-center justify-center text-sm font-medium transition-colors ${
                          isCompleted
                            ? 'bg-green-600 text-white'
                            : isActive
                            ? 'bg-blue-600 text-white'
                            : isFailed
                            ? 'bg-red-600 text-white'
                            : 'bg-gray-700 text-gray-400'
                        }`}
                      >
                        {isCompleted ? (
                          <CheckCircle size={16} />
                        ) : isActive ? (
                          <Loader2 size={16} className="animate-spin" />
                        ) : isFailed ? (
                          <XCircle size={16} />
                        ) : (
                          index + 1
                        )}
                      </div>
                      <span className={`text-xs mt-1 ${isActive ? 'text-blue-400' : 'text-gray-500'}`}>
                        {step.label}
                      </span>
                    </div>
                    {index < PIPELINE_STEPS.length - 1 && (
                      <div
                        className={`flex-1 h-0.5 mx-2 ${
                          index < currentStep ? 'bg-green-600' : 'bg-gray-700'
                        }`}
                      />
                    )}
                  </React.Fragment>
                );
              })}
              {/* Completed indicator */}
              <div className="flex flex-col items-center">
                <div
                  className={`w-8 h-8 rounded-full flex items-center justify-center ${
                    currentJob.status === 'completed'
                      ? 'bg-green-600 text-white'
                      : 'bg-gray-700 text-gray-400'
                  }`}
                >
                  <Film size={16} />
                </div>
                <span className={`text-xs mt-1 ${currentJob.status === 'completed' ? 'text-green-400' : 'text-gray-500'}`}>
                  완료
                </span>
              </div>
            </div>

            {/* Progress text */}
            {currentJob.progress > 0 && currentJob.progress < 100 && (
              <div className="mt-3 flex items-center justify-center gap-2 text-sm text-gray-400">
                <Clock size={14} />
                진행률: {currentJob.progress}%
              </div>
            )}
          </div>
        )}

        {/* Error */}
        {error && (
          <div className="mt-4 p-4 bg-red-900/30 border border-red-800 rounded-lg text-red-400">
            {error}
          </div>
        )}
      </div>

      {/* Main Editor */}
      <VideoStudio
        job={currentJob}
        bgmList={bgmList}
        fontList={fontList}
        onJobUpdate={setCurrentJob}
        onStartTranscription={handleStartTranscription}
        onTrim={handleTrim}
        onRender={handleRender}
      />

      {/* Quick Guide when no job */}
      {!currentJob && (
        <div className="card bg-gray-800/50">
          <h3 className="font-medium mb-3 flex items-center gap-2">
            <Film size={18} className="text-purple-400" />
            사용 방법
          </h3>
          <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-6 gap-4 text-center text-sm">
            {PIPELINE_STEPS.map((step, index) => (
              <div key={step.id} className="p-3 bg-gray-900 rounded-lg">
                <div className="w-8 h-8 rounded-full bg-gray-700 flex items-center justify-center mx-auto mb-2">
                  {index + 1}
                </div>
                <span className="text-gray-400">{step.label}</span>
              </div>
            ))}
          </div>
          <p className="text-xs text-gray-500 mt-4 text-center">
            지원: 抖音(Douyin), 快手(Kuaishou), TikTok, YouTube, Bilibili
          </p>
        </div>
      )}
    </div>
  );
}