import React, { useState, useRef, useCallback } from 'react';
import { BackgroundService, DEFAULT_BACKGROUND, type BackgroundConfig } from '../services/backgroundService';

interface BackgroundImportProps {
  open: boolean;
  onClose: () => void;
  onApply: (config: BackgroundConfig, image: HTMLImageElement | null) => void;
  backgroundService: BackgroundService;
}

const BackgroundImport: React.FC<BackgroundImportProps> = ({ open, onClose, onApply, backgroundService }) => {
  const [config, setConfig] = useState<BackgroundConfig>({ ...DEFAULT_BACKGROUND });
  const [previewUrl, setPreviewUrl] = useState<string>('');
  const [calibrationMode, setCalibrationMode] = useState(false);
  const [calibPoint1, setCalibPoint1] = useState<{ x: number; y: number } | null>(null);
  const [calibPoint2, setCalibPoint2] = useState<{ x: number; y: number } | null>(null);
  const [realDistance, setRealDistance] = useState('');
  const [unit, setUnit] = useState('m');
  const [error, setError] = useState('');
  const fileInputRef = useRef<HTMLInputElement>(null);
  const previewCanvasRef = useRef<HTMLCanvasElement>(null);

  const handleFileSelect = useCallback(async (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    setError('');
    try {
      const cfg = await backgroundService.loadFromFile(file);
      setConfig(cfg);
      setPreviewUrl(cfg.src);
    } catch (err) {
      setError('Fehler beim Laden des Bildes: ' + (err as Error).message);
    }
  }, [backgroundService]);

  const handlePreviewClick = useCallback((e: React.MouseEvent<HTMLCanvasElement>) => {
    if (!calibrationMode || !previewCanvasRef.current) return;
    const rect = previewCanvasRef.current.getBoundingClientRect();
    const x = e.clientX - rect.left;
    const y = e.clientY - rect.top;
    if (!calibPoint1) {
      setCalibPoint1({ x, y });
    } else if (!calibPoint2) {
      setCalibPoint2({ x, y });
    }
  }, [calibrationMode, calibPoint1, calibPoint2]);

  const handleCalibrate = useCallback(() => {
    if (!calibPoint1 || !calibPoint2 || !realDistance) return;
    const dx = calibPoint2.x - calibPoint1.x;
    const dy = calibPoint2.y - calibPoint1.y;
    const pixelDist = Math.sqrt(dx * dx + dy * dy);
    const realDist = parseFloat(realDistance);
    if (realDist <= 0) {
      setError('Bitte eine gültige Referenzstrecke eingeben.');
      return;
    }
    const result = backgroundService.calibrateScale(pixelDist, realDist, unit);
    setConfig(prev => ({ ...prev, scale: result.scale }));
    setCalibrationMode(false);
    setCalibPoint1(null);
    setCalibPoint2(null);
    setRealDistance('');
  }, [calibPoint1, calibPoint2, realDistance, unit, backgroundService]);

  const handleApply = useCallback(() => {
    const cfg = backgroundService.getConfig();
    onApply(cfg, backgroundService.getImage());
    onClose();
  }, [backgroundService, onApply, onClose]);

  const updateConfig = useCallback((partial: Partial<BackgroundConfig>) => {
    backgroundService.updateConfig(partial);
    setConfig(backgroundService.getConfig());
  }, [backgroundService]);

  if (!open) return null;

  return (
    <div className="modal-overlay" style={{
      position: 'fixed', top: 0, left: 0, right: 0, bottom: 0,
      background: 'rgba(0,0,0,0.5)', display: 'flex',
      alignItems: 'center', justifyContent: 'center', zIndex: 1000,
    }}>
      <div className="modal-dialog" style={{
        background: 'var(--color-bg-primary, #1e1e2e)', borderRadius: '8px',
        padding: '24px', maxWidth: '600px', width: '90%', maxHeight: '90vh',
        overflow: 'auto', color: 'var(--color-text, #e0e0e0)',
        border: '1px solid var(--color-border, #333)',
      }}>
        <h2 style={{ marginTop: 0, marginBottom: '16px' }}>Hintergrund importieren</h2>

        {error && (
          <div style={{ color: '#ff6b6b', marginBottom: '12px', fontSize: '14px' }}>{error}</div>
        )}

        {/* File Upload */}
        <div style={{ marginBottom: '16px' }}>
          <label style={{ display: 'block', marginBottom: '6px', fontSize: '14px' }}>Bilddatei (PNG, JPG, SVG)</label>
          <input
            ref={fileInputRef}
            type="file"
            accept="image/png,image/jpeg,image/svg+xml,application/pdf"
            onChange={handleFileSelect}
            style={{ display: 'none' }}
          />
          <button
            onClick={() => fileInputRef.current?.click()}
            style={{
              padding: '8px 16px', borderRadius: '4px',
              border: '1px solid var(--color-border, #444)',
              background: 'var(--color-bg-secondary, #2a2a3a)',
              color: 'var(--color-text, #e0e0e0)', cursor: 'pointer',
            }}
          >
            Datei wählen…
          </button>
          {config.name && (
            <span style={{ marginLeft: '12px', fontSize: '13px' }}>{config.name} ({config.width}×{config.height}px)</span>
          )}
        </div>

        {/* Preview */}
        {previewUrl && (
          <div style={{ marginBottom: '16px' }}>
            <canvas
              ref={previewCanvasRef}
              onClick={handlePreviewClick}
              style={{
                maxWidth: '100%', maxHeight: '200px',
                border: '1px solid var(--color-border, #333)',
                cursor: calibrationMode ? 'crosshair' : 'default',
                display: 'block',
              }}
              width={config.width || 400}
              height={config.height || 300}
            />
          </div>
        )}

        {/* Calibration */}
        {previewUrl && (
          <div style={{ marginBottom: '16px', padding: '12px', border: '1px solid var(--color-border, #333)', borderRadius: '4px' }}>
            <div style={{ fontSize: '14px', marginBottom: '8px', fontWeight: 600 }}>Maßstabs-Kalibrierung</div>
            {!calibrationMode ? (
              <button
                onClick={() => setCalibrationMode(true)}
                style={{ padding: '6px 12px', fontSize: '13px', cursor: 'pointer',
                  border: '1px solid var(--color-border, #444)', borderRadius: '4px',
                  background: 'var(--color-bg-secondary, #2a2a3a)', color: 'var(--color-text, #e0e0e0)' }}
              >
                Kalibrierung starten
              </button>
            ) : (
              <div>
                <p style={{ fontSize: '13px', margin: '0 0 8px' }}>
                  Klicken Sie auf zwei Punkte mit bekanntem Abstand im Bild.
                </p>
                {calibPoint1 && !calibPoint2 && <p style={{ fontSize: '13px', color: '#8be9fd' }}>Erster Punkt gesetzt. Bitte zweiten Punkt klicken.</p>}
                {calibPoint1 && calibPoint2 && (
                  <div style={{ display: 'flex', gap: '8px', alignItems: 'center', flexWrap: 'wrap' }}>
                    <input
                      type="number"
                      placeholder="Referenzstrecke"
                      value={realDistance}
                      onChange={(e) => setRealDistance(e.target.value)}
                      style={{ width: '120px', padding: '4px 8px', fontSize: '13px' }}
                    />
                    <select value={unit} onChange={(e) => setUnit(e.target.value)} style={{ padding: '4px 8px', fontSize: '13px' }}>
                      <option value="m">m</option>
                      <option value="cm">cm</option>
                      <option value="mm">mm</option>
                    </select>
                    <button onClick={handleCalibrate} style={{ padding: '6px 12px', fontSize: '13px', cursor: 'pointer' }}>Übernehmen</button>
                    <button onClick={() => { setCalibPoint1(null); setCalibPoint2(null); }} style={{ padding: '6px 12px', fontSize: '13px', cursor: 'pointer' }}>Zurücksetzen</button>
                  </div>
                )}
              </div>
            )}
            {config.scale !== 1 && (
              <p style={{ fontSize: '12px', marginTop: '8px', color: '#50fa7b' }}>
                Aktueller Maßstab: {config.scale.toFixed(2)} px/mm
              </p>
            )}
          </div>
        )}

        {/* Controls */}
        {previewUrl && (
          <div style={{ marginBottom: '16px' }}>
            {/* Opacity */}
            <label style={{ display: 'block', marginBottom: '4px', fontSize: '13px' }}>Deckkraft: {Math.round(config.opacity * 100)}%</label>
            <input
              type="range" min="0" max="1" step="0.05"
              value={config.opacity}
              onChange={(e) => updateConfig({ opacity: parseFloat(e.target.value) })}
              style={{ width: '100%', marginBottom: '12px' }}
            />

            {/* Position */}
            <div style={{ display: 'flex', gap: '12px', marginBottom: '8px' }}>
              <label style={{ fontSize: '13px' }}>X-Offset:
                <input type="number" value={config.offsetX}
                  onChange={(e) => updateConfig({ offsetX: parseFloat(e.target.value) || 0 })}
                  style={{ width: '80px', marginLeft: '6px', padding: '4px' }} />
              </label>
              <label style={{ fontSize: '13px' }}>Y-Offset:
                <input type="number" value={config.offsetY}
                  onChange={(e) => updateConfig({ offsetY: parseFloat(e.target.value) || 0 })}
                  style={{ width: '80px', marginLeft: '6px', padding: '4px' }} />
              </label>
            </div>

            {/* Rotation */}
            <label style={{ display: 'block', marginBottom: '4px', fontSize: '13px' }}>Rotation: {config.rotation}°</label>
            <input
              type="range" min="-180" max="180" step="1"
              value={config.rotation}
              onChange={(e) => updateConfig({ rotation: parseFloat(e.target.value) })}
              style={{ width: '100%', marginBottom: '12px' }}
            />

            {/* Scale */}
            <label style={{ display: 'block', marginBottom: '4px', fontSize: '13px' }}>Skalierung: {config.scale.toFixed(3)}</label>
            <input
              type="number" step="0.01" value={config.scale}
              onChange={(e) => updateConfig({ scale: parseFloat(e.target.value) || 1 })}
              style={{ width: '120px', padding: '4px' }}
            />

            {/* Visibility */}
            <label style={{ display: 'flex', alignItems: 'center', gap: '6px', marginTop: '12px', fontSize: '13px' }}>
              <input
                type="checkbox" checked={config.visible}
                onChange={(e) => updateConfig({ visible: e.target.checked })}
              />
              Sichtbar
            </label>
          </div>
        )}

        {/* Actions */}
        <div style={{ display: 'flex', gap: '12px', justifyContent: 'flex-end' }}>
          <button
            onClick={onClose}
            style={{ padding: '8px 16px', cursor: 'pointer', borderRadius: '4px',
              border: '1px solid var(--color-border, #444)', background: 'transparent',
              color: 'var(--color-text, #e0e0e0)' }}
          >
            Abbrechen
          </button>
          <button
            onClick={handleApply}
            disabled={!previewUrl}
            style={{ padding: '8px 16px', cursor: previewUrl ? 'pointer' : 'not-allowed', borderRadius: '4px',
              border: 'none', background: previewUrl ? '#50fa7b' : '#555',
              color: previewUrl ? '#1e1e2e' : '#999', fontWeight: 600 }}
          >
            Anwenden
          </button>
        </div>
      </div>
    </div>
  );
};

export default BackgroundImport;