import { useState, useCallback } from 'react';
import { useEditorStore } from '../store/editorStore';
import { Download, Loader2, Zap, Cog, Info, Volume2, FileText } from 'lucide-react';
import type { ExportOptions } from '../types/project';

export default function ExportDialog() {
  const { videoPath, words, cutRanges, muteRanges, gainRanges, speedRanges, globalGainDb, isExporting, exportProgress, backendUrl, setExporting, getKeepSegments } =
    useEditorStore();

  const hasCuts = cutRanges.length > 0;

  // Detect if input is audio-only by its extension
  const audioExtensions = new Set(['.wav', '.mp3', '.flac', '.m4a', '.ogg', '.aac', '.wma']);
  const inputExt = videoPath ? '.' + videoPath.split('.').pop()?.toLowerCase() : '';
  const isAudioOnly = videoPath ? audioExtensions.has(inputExt) : false;

  const [options, setOptions] = useState<Omit<ExportOptions, 'outputPath'> & { normalizeAudio: boolean; normalizeTarget: number }>({
    mode: isAudioOnly ? 'reencode' : 'fast',
    resolution: '1080p',
    format: isAudioOnly ? 'wav' : 'mp4',
    enhanceAudio: false,
    captions: 'none',
    normalizeAudio: false,
    normalizeTarget: -14,
  });
  const [exportError, setExportError] = useState<string | null>(null);
  const [transcriptFormat, setTranscriptFormat] = useState<'txt' | 'srt'>('txt');
  const [isTranscribingTranscript, setIsTranscribingTranscript] = useState(false);

  const handleTranscriptExport = useCallback(async () => {
    if (!videoPath || words.length === 0) return;

    const defaultExt = transcriptFormat === 'srt' ? 'srt' : 'txt';
    const outputPath = await window.electronAPI?.saveFile({
      defaultPath: videoPath.replace(/\.[^.]+$/, `_transcript.${defaultExt}`),
      filters: transcriptFormat === 'srt'
        ? [{ name: 'SRT Subtitles', extensions: ['srt'] }]
        : [{ name: 'Text File', extensions: ['txt'] }],
    });
    if (!outputPath) return;

    setIsTranscribingTranscript(true);
    try {
      // Compute deleted word set
      const deletedSet = new Set<number>();
      for (const range of cutRanges) {
        for (let i = 0; i < words.length; i++) {
          if (words[i].start >= range.start && words[i].end <= range.end) {
            deletedSet.add(i);
          }
        }
      }

      // Generate content entirely on the frontend — no backend needed
      let content: string;
      if (transcriptFormat === 'srt') {
        const lines: string[] = [];
        let counter = 1;
        const activeWords: Array<[number, typeof words[0]]> = [];
        for (let i = 0; i < words.length; i++) {
          if (!deletedSet.has(i)) activeWords.push([i, words[i]]);
        }
        const wordsPerLine = 8;
        for (let ci = 0; ci < activeWords.length; ci += wordsPerLine) {
          const chunk = activeWords.slice(ci, ci + wordsPerLine);
          if (chunk.length === 0) continue;
          const startTime = chunk[0][1].start;
          const endTime = chunk[chunk.length - 1][1].end;

          const fmt = (s: number) => {
            const h = Math.floor(s / 3600);
            const m = Math.floor((s % 3600) / 60);
            const sec = Math.floor(s % 60);
            const ms = Math.floor((s % 1) * 1000);
            return `${String(h).padStart(2, '0')}:${String(m).padStart(2, '0')}:${String(sec).padStart(2, '0')},${String(ms).padStart(3, '0')}`;
          };

          lines.push(String(counter));
          lines.push(`${fmt(startTime)} --> ${fmt(endTime)}`);
          lines.push(chunk.map(([, w]) => w.word).join(' '));
          lines.push('');
          counter++;
        }
        content = lines.join('\n');
      } else {
        // Plain text
        const activeWords: string[] = [];
        for (let i = 0; i < words.length; i++) {
          if (!deletedSet.has(i)) activeWords.push(words[i].word);
        }
        content = activeWords.join(' ');
      }

      // Write directly via Tauri — instant, no backend round-trip
      await window.electronAPI?.writeFile(outputPath, content);
    } catch (err) {
      console.error('Transcript export error:', err);
      setExportError(err instanceof Error ? err.message : 'Transcript export failed');
    } finally {
      setIsTranscribingTranscript(false);
    }
  }, [videoPath, words, cutRanges, transcriptFormat]);

  const HANDLE_EXPORT_filters = useCallback(() => {
    const ext = options.format;
    const nameMap: Record<string, string> = {
      mp4: 'MP4',
      mov: 'MOV',
      webm: 'WebM',
      wav: 'WAV Audio',
    };
    return [{ name: nameMap[ext] || 'File', extensions: [ext] }];
  }, [options.format]);

  const handleExport = useCallback(async () => {
    if (!videoPath) return;

    const defaultExt = options.format === 'wav' ? 'wav' : 'mp4';
    const outputPath = await window.electronAPI?.saveFile({
      defaultPath: videoPath.replace(/\.[^.]+$/, `_edited.${defaultExt}`),
      filters: HANDLE_EXPORT_filters(),
    });
    if (!outputPath) return;

    setExporting(true, 0);
    setExportError(null);
    try {
      const keepSegments = getKeepSegments();

      const deletedSet = new Set<number>();
      for (const range of cutRanges) {
        for (let i = 0; i < words.length; i++) {
          const w = words[i];
          if (w.start >= range.start && w.end <= range.end) deletedSet.add(i);
        }
      }

      // Map frontend camelCase gain/speed fields to backend snake_case
      const backendGainRanges = gainRanges.map((r) => ({
        start: r.start,
        end: r.end,
        gain_db: r.gainDb,
      }));
      const backendSpeedRanges = speedRanges.map((r) => ({
        start: r.start,
        end: r.end,
        speed: r.speed,
      }));

      const res = await fetch(`${backendUrl}/export`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          input_path: videoPath,
          output_path: outputPath,
          keep_segments: keepSegments,
          mute_ranges: muteRanges.length > 0 ? muteRanges.map((r) => ({ start: r.start, end: r.end })) : undefined,
          gain_ranges: backendGainRanges.length > 0 ? backendGainRanges : undefined,
          speed_ranges: backendSpeedRanges.length > 0 ? backendSpeedRanges : undefined,
          global_gain_db: globalGainDb,
          words: options.captions !== 'none' ? words : undefined,
          deleted_indices: options.captions !== 'none' ? [...deletedSet] : undefined,
          mode: options.mode,
          resolution: options.resolution,
          format: options.format,
          enhanceAudio: options.enhanceAudio,
          normalize_loudness: options.normalizeAudio,
          normalize_target_lufs: options.normalizeTarget,
          captions: options.captions,
        }),
      });
      if (!res.ok) {
        let detail = res.statusText;
        try {
          const body = await res.json();
          if (body?.detail) detail = String(body.detail);
        } catch {
          // Keep statusText fallback when response body is not JSON.
        }
        throw new Error(`Export failed: ${detail}`);
      }
      setExporting(false, 100);
    } catch (err) {
      console.error('Export error:', err);
      setExportError(err instanceof Error ? err.message : 'Export failed');
      setExporting(false);
    }
  }, [videoPath, options, backendUrl, setExporting, getKeepSegments, cutRanges, muteRanges, gainRanges, speedRanges, globalGainDb, words, HANDLE_EXPORT_filters]);

  return (
    <div className="p-4 space-y-5">
      <h3 className="text-sm font-semibold">Export Video</h3>

      {/* Mode */}
      <fieldset className="space-y-2">
        <legend className="text-xs text-editor-text-muted font-medium">Export Mode</legend>
        <div className="grid grid-cols-2 gap-2">
          <ModeCard
            active={options.mode === 'fast'}
            onClick={() => setOptions((o) => ({ ...o, mode: 'fast' }))}
            icon={<Zap className="w-4 h-4" />}
            title="Fast"
            desc="Stream copy, seconds"
          />
          <ModeCard
            active={options.mode === 'reencode'}
            onClick={() => setOptions((o) => ({ ...o, mode: 'reencode' }))}
            icon={<Cog className="w-4 h-4" />}
            title="Re-encode"
            desc="Custom quality, slower"
          />
        </div>
      </fieldset>

      {/* Resolution (only for re-encode) */}
      {options.mode === 'reencode' && (
        <SelectField
          label="Resolution"
          value={options.resolution}
          onChange={(v) => setOptions((o) => ({ ...o, resolution: v as ExportOptions['resolution'] }))}
          options={[
            { value: '720p', label: '720p (HD)' },
            { value: '1080p', label: '1080p (Full HD)' },
            { value: '4k', label: '4K (Ultra HD)' },
          ]}
        />
      )}

      {/* Format */}
      <SelectField
        label="Format"
        value={options.format}
        onChange={(v) => setOptions((o) => ({ ...o, format: v as ExportOptions['format'] }))}
        options={[
          { value: 'mp4', label: 'MP4 (H.264)' },
          { value: 'mov', label: 'MOV (QuickTime)' },
          { value: 'webm', label: 'WebM (VP9)' },
          ...(isAudioOnly ? [{ value: 'wav' as const, label: 'WAV (Uncompressed)' }] : []),
        ]}
      />

      {/* Audio normalization — integrated into export */}
      <div className="space-y-2 pt-1 border-t border-editor-border">
        <label className="flex items-center gap-2 cursor-pointer">
          <input
            type="checkbox"
            checked={options.normalizeAudio}
            onChange={(e) => setOptions((o) => ({ ...o, normalizeAudio: e.target.checked }))}
            className="w-4 h-4 rounded bg-editor-surface border-editor-border accent-editor-accent"
          />
          <div>
            <span className="text-xs font-medium">Normalize loudness</span>
            <p className="text-[10px] text-editor-text-muted">
              Apply LUFS normalization during export. Requires re-encode.
            </p>
          </div>
        </label>
        {options.normalizeAudio && (
          <div className="flex items-center gap-2 pl-6">
            <Volume2 className="w-3 h-3 text-editor-text-muted shrink-0" />
            <select
              value={options.normalizeTarget}
              onChange={(e) => setOptions((o) => ({ ...o, normalizeTarget: Number(e.target.value) }))}
              className="flex-1 px-2 py-1.5 text-xs bg-editor-surface border border-editor-border rounded focus:outline-none focus:border-editor-accent [color-scheme:dark]"
            >
              <option value={-14}>YouTube (-14 LUFS)</option>
              <option value={-16}>Spotify (-16 LUFS)</option>
              <option value={-23}>Broadcast (-23 LUFS)</option>
              <option value={-11}>Loud (-11 LUFS)</option>
              <option value={-9}>Very Loud (-9 LUFS)</option>
            </select>
          </div>
        )}
      </div>

      {/* Audio enhancement */}
      <label className="flex items-center gap-2 cursor-pointer">
        <input
          type="checkbox"
          checked={options.enhanceAudio}
          onChange={(e) => setOptions((o) => ({ ...o, enhanceAudio: e.target.checked }))}
          className="w-4 h-4 rounded bg-editor-surface border-editor-border accent-editor-accent"
        />
        <span className="text-xs">Enhance audio (Studio Sound)</span>
      </label>

      {/* Captions */}
      <SelectField
        label="Captions"
        value={options.captions}
        onChange={(v) => setOptions((o) => ({ ...o, captions: v as ExportOptions['captions'] }))}
        options={[
          { value: 'none', label: 'No captions' },
          { value: 'burn-in', label: 'Burn-in (permanent)' },
          { value: 'sidecar', label: 'Sidecar SRT file' },
        ]}
      />

      {/* Transcript-only export */}
      <div className="space-y-2 pt-1 border-t border-editor-border">
        <h4 className="text-xs font-semibold flex items-center gap-1.5">
          <FileText className="w-3.5 h-3.5" />
          Export Transcript Only
        </h4>
        <p className="text-[10px] text-editor-text-muted leading-relaxed">
          Export the edited transcript as plain text or SRT without rendering video.
        </p>
        <div className="flex items-center gap-2">
          <select
            value={transcriptFormat}
            onChange={(e) => setTranscriptFormat(e.target.value as 'txt' | 'srt')}
            className="flex-1 px-2 py-1.5 text-xs bg-editor-surface border border-editor-border rounded focus:outline-none focus:border-editor-accent [color-scheme:dark]"
          >
            <option value="txt">Plain Text (.txt)</option>
            <option value="srt">Subtitles (.srt)</option>
          </select>
          <button
            onClick={handleTranscriptExport}
            disabled={isTranscribingTranscript || words.length === 0}
            className="flex items-center gap-1.5 px-3 py-1.5 text-xs rounded bg-editor-accent/20 text-editor-accent hover:bg-editor-accent/30 disabled:opacity-40 transition-colors"
          >
            {isTranscribingTranscript ? (
              <Loader2 className="w-3 h-3 animate-spin" />
            ) : (
              <FileText className="w-3 h-3" />
            )}
            Export
          </button>
        </div>
      </div>

      {/* Export video button */}
      <button
        onClick={handleExport}
        disabled={isExporting || !videoPath}
        className="w-full flex items-center justify-center gap-2 px-4 py-3 bg-editor-accent hover:bg-editor-accent-hover disabled:opacity-50 rounded-lg text-sm font-semibold transition-colors"
      >
        {isExporting ? (
          <>
            <Loader2 className="w-4 h-4 animate-spin" />
            Exporting... {Math.round(exportProgress)}%
          </>
        ) : (
          <>
            <Download className="w-4 h-4" />
            Export Video
          </>
        )}
      </button>

      {exportError && (
        <div className="rounded border border-red-500/40 bg-red-500/10 px-3 py-2 text-xs text-red-300">
          {exportError}
        </div>
      )}

      {options.mode === 'fast' && !hasCuts && (
        <p className="text-[10px] text-editor-text-muted text-center">
          Fast mode uses stream copy &mdash; no quality loss, exports in seconds.
        </p>
      )}
      {options.mode === 'fast' && hasCuts && (
        <div className="flex items-start gap-1.5 p-2 bg-editor-accent/10 rounded text-[10px] text-editor-accent">
          <Info className="w-3.5 h-3.5 shrink-0 mt-0.5" />
          <span>
            Word-level cuts require re-encoding for frame-accurate output. Export will
            automatically use re-encode mode. This takes longer but ensures your cuts are precise.
          </span>
        </div>
      )}
    </div>
  );
}

function ModeCard({
  active,
  onClick,
  icon,
  title,
  desc,
}: {
  active: boolean;
  onClick: () => void;
  icon: React.ReactNode;
  title: string;
  desc: string;
}) {
  return (
    <button
      onClick={onClick}
      className={`flex flex-col items-center gap-1 p-3 rounded-lg border-2 transition-colors ${
        active
          ? 'border-editor-accent bg-editor-accent/10'
          : 'border-editor-border hover:border-editor-text-muted'
      }`}
    >
      {icon}
      <span className="text-xs font-medium">{title}</span>
      <span className="text-[10px] text-editor-text-muted">{desc}</span>
    </button>
  );
}

function SelectField({
  label,
  value,
  onChange,
  options,
}: {
  label: string;
  value: string;
  onChange: (value: string) => void;
  options: Array<{ value: string; label: string }>;
}) {
  return (
    <div className="space-y-1">
      <label className="text-xs text-editor-text-muted font-medium">{label}</label>
      <select
        value={value}
        onChange={(e) => onChange(e.target.value)}
        className="w-full px-3 py-2 bg-editor-surface border border-editor-border rounded-lg text-xs text-editor-text focus:outline-none focus:border-editor-accent [color-scheme:dark]"
      >
        {options.map((opt) => (
          <option key={opt.value} value={opt.value}>
            {opt.label}
          </option>
        ))}
      </select>
    </div>
  );
}