import { useMemo, useState } from 'react';
import { useEditorStore } from '../store/editorStore';
import { Trash2, Volume2 } from 'lucide-react';

export default function VolumePanel() {
  const {
    words,
    selectedWordIndices,
    globalGainDb,
    gainRanges,
    setGlobalGainDb,
    addGainRange,
    updateGainRange,
    removeGainRange,
  } = useEditorStore();

  const [selectionGainDb, setSelectionGainDb] = useState(3);

  const canApplySelection = selectedWordIndices.length > 0;

  const selectedRange = useMemo(() => {
    if (!canApplySelection) return null;
    const sorted = [...selectedWordIndices].sort((a, b) => a - b);
    const startWord = words[sorted[0]];
    const endWord = words[sorted[sorted.length - 1]];
    if (!startWord || !endWord) return null;
    return {
      start: startWord.start,
      end: endWord.end,
    };
  }, [canApplySelection, selectedWordIndices, words]);

  const applySelectionGain = () => {
    if (!selectedRange) return;
    addGainRange(selectedRange.start, selectedRange.end, selectionGainDb);
  };

  return (
    <div className="p-4 space-y-4">
      <div className="space-y-1">
        <h3 className="text-sm font-semibold flex items-center gap-2">
          <Volume2 className="w-4 h-4" />
          Volume / Gain
        </h3>
        <p className="text-xs text-editor-text-muted">
          Apply global gain or per-selection gain ranges.
        </p>
      </div>

      <div className="space-y-2">
        <label className="text-xs text-editor-text-muted font-medium">Global Gain (dB)</label>
        <input
          type="range"
          min={-24}
          max={24}
          step={0.5}
          value={globalGainDb}
          onChange={(e) => setGlobalGainDb(Number(e.target.value))}
          className="w-full"
        />
        <div className="flex items-center justify-between text-xs">
          <span className="text-editor-text-muted">-24 dB</span>
          <span className="font-medium text-editor-text">{globalGainDb.toFixed(1)} dB</span>
          <span className="text-editor-text-muted">+24 dB</span>
        </div>
      </div>

      <div className="space-y-2 pt-1 border-t border-editor-border">
        <label className="text-xs text-editor-text-muted font-medium">Selection Gain (dB)</label>
        <div className="flex items-center gap-2">
          <input
            type="number"
            min={-24}
            max={24}
            step={0.5}
            value={selectionGainDb}
            onChange={(e) => setSelectionGainDb(Number(e.target.value) || 0)}
            className="w-24 px-2 py-1.5 text-xs bg-editor-surface border border-editor-border rounded focus:border-editor-accent focus:outline-none"
          />
          <button
            onClick={applySelectionGain}
            disabled={!canApplySelection || !selectedRange}
            className="px-3 py-1.5 text-xs rounded bg-editor-accent/20 text-editor-accent hover:bg-editor-accent/30 disabled:opacity-40"
          >
            Apply To Selection
          </button>
        </div>
        <p className="text-[11px] text-editor-text-muted">
          {canApplySelection
            ? `${selectedWordIndices.length} selected words${selectedRange ? ` (${selectedRange.start.toFixed(2)}s - ${selectedRange.end.toFixed(2)}s)` : ''}`
            : 'Select transcript words to apply a gain range.'}
        </p>
      </div>

      {gainRanges.length > 0 && (
        <div className="space-y-2 pt-1 border-t border-editor-border">
          <div className="text-xs font-medium">Gain Ranges</div>
          <div className="max-h-56 overflow-y-auto space-y-1 pr-1">
            {gainRanges.map((range) => (
              <div
                key={range.id}
                className="px-2 py-1.5 rounded bg-editor-surface border border-editor-border text-xs flex items-center gap-2"
              >
                <div className="flex-1 min-w-0">
                  <div className="font-medium truncate">
                    {range.start.toFixed(2)}s - {range.end.toFixed(2)}s
                  </div>
                  <div className="text-editor-text-muted">{range.id}</div>
                </div>
                <input
                  type="number"
                  min={-24}
                  max={24}
                  step={0.5}
                  value={range.gainDb}
                  onChange={(e) => updateGainRange(range.id, Number(e.target.value) || 0)}
                  className="w-20 px-2 py-1 text-xs bg-editor-bg border border-editor-border rounded"
                  title="Gain dB"
                />
                <button
                  onClick={() => removeGainRange(range.id)}
                  className="p-1 rounded hover:bg-editor-danger/20 text-editor-danger"
                  title="Delete gain range"
                >
                  <Trash2 className="w-3.5 h-3.5" />
                </button>
              </div>
            ))}
          </div>
        </div>
      )}
    </div>
  );
}