import React, { Component } from 'react';
import {
  Box,
  Button,
  Typography,
  IconButton,
  Paper,
  Grid,
  Alert
} from '@mui/material';
import Delete from '@mui/icons-material/Delete';
import CloudUpload from '@mui/icons-material/CloudUpload';

class PhotoUpload extends Component {
  constructor(props) {
    super(props);
    this.state = {
      files: [],
      previews: [],
      error: null
    };
    this.fileInputRef = React.createRef();
  }

  handleFileSelect = (event) => {
    const selectedFiles = Array.from(event.target.files);
    const maxFiles = this.props.maxFiles || 5;
    const maxSize = this.props.maxSize || 50 * 1024 * 1024; // 50MB default - will be compressed

    // Validate file count
    if (this.state.files.length + selectedFiles.length > maxFiles) {
      this.setState({ 
        error: `Maximal ${maxFiles} Dateien erlaubt` 
      });
      return;
    }

    // Validate file types and sizes
    const validTypes = ['image/jpeg', 'image/png', 'image/gif', 'image/webp'];
    const validFiles = [];
    const newPreviews = [];

    for (const file of selectedFiles) {
      if (!validTypes.includes(file.type)) {
        this.setState({ 
          error: 'Nur Bilddateien (JPEG, PNG, GIF, WebP) sind erlaubt' 
        });
        continue;
      }

      if (file.size > maxSize) {
        this.setState({ 
          error: `Datei zu groß. Maximum: ${Math.round(maxSize / (1024 * 1024))}MB` 
        });
        continue;
      }

      validFiles.push(file);
      
      // Create preview and compress image
      const reader = new FileReader();
      reader.onload = (e) => {
        // Compress the image
        this.compressImage(e.target.result, file.name, (compressedFile) => {
          newPreviews.push({
            file: compressedFile,
            preview: e.target.result,
            name: file.name,
            originalSize: file.size,
            compressedSize: compressedFile.size
          });

          if (newPreviews.length === validFiles.length) {
            const compressedFiles = newPreviews.map(p => p.file);
            this.setState(prevState => ({
              files: [...prevState.files, ...compressedFiles],
              previews: [...prevState.previews, ...newPreviews],
              error: null
            }), () => {
              // Notify parent component
              if (this.props.onChange) {
                this.props.onChange(this.state.files);
              }
            });
          }
        });
      };
      reader.readAsDataURL(file);
    }

    // Reset input
    event.target.value = '';
  };

  handleRemoveFile = (index) => {
    this.setState(prevState => {
      const newFiles = prevState.files.filter((_, i) => i !== index);
      const newPreviews = prevState.previews.filter((_, i) => i !== index);
      
      // Notify parent component
      if (this.props.onChange) {
        this.props.onChange(newFiles);
      }
      
      return {
        files: newFiles,
        previews: newPreviews
      };
    });
  };

  compressImage = (dataURL, fileName, callback) => {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d');
    const img = new Image();
    
    img.onload = () => {
      // Calculate new dimensions (max 1920x1080 for submission)
      const maxWidth = 1920;
      const maxHeight = 1080;
      let { width, height } = img;
      
      if (width > height) {
        if (width > maxWidth) {
          height = (height * maxWidth) / width;
          width = maxWidth;
        }
      } else {
        if (height > maxHeight) {
          width = (width * maxHeight) / height;
          height = maxHeight;
        }
      }
      
      canvas.width = width;
      canvas.height = height;
      
      // Draw and compress
      ctx.drawImage(img, 0, 0, width, height);
      
      // Convert to blob with compression
      canvas.toBlob((blob) => {
        const compressedFile = new File([blob], fileName, {
          type: 'image/jpeg',
          lastModified: Date.now()
        });
        callback(compressedFile);
      }, 'image/jpeg', 0.8); // 80% quality
    };
    
    img.src = dataURL;
  };

  // Method to reset the component
  reset = () => {
    this.setState({
      files: [],
      previews: [],
      error: null
    });
    
    // Also reset the file input
    if (this.fileInputRef.current) {
      this.fileInputRef.current.value = '';
    }
  };

  render() {
    const { files, previews, error } = this.state;
    const { disabled, label } = this.props;

    return (
      <Box>
        <Typography variant="body2" sx={{ mb: 1, fontWeight: 500 }}>
          {label || 'Fotos anhängen (optional)'}
        </Typography>
        
        <input
          ref={this.fileInputRef}
          type="file"
          multiple
          accept="image/*"
          style={{ display: 'none' }}
          onChange={this.handleFileSelect}
          disabled={disabled}
        />
        
        <Button
          variant="outlined"
          startIcon={<CloudUpload />}
          onClick={() => this.fileInputRef.current?.click()}
          disabled={disabled}
          sx={{ mb: 2 }}
        >
          Fotos auswählen
        </Button>

        {error && (
          <Alert severity="error" sx={{ mb: 2 }}>
            {error}
          </Alert>
        )}

        {previews.length > 0 && (
          <Grid container spacing={2}>
            {previews.map((preview, index) => (
              <Grid item xs={6} sm={4} md={3} key={index}>
                <Paper 
                  sx={{ 
                    position: 'relative', 
                    p: 1,
                    borderRadius: 1,
                    overflow: 'hidden'
                  }}
                >
                  <Box
                    component="img"
                    src={preview.preview}
                    alt={preview.name}
                    sx={{
                      width: '100%',
                      height: '100px',
                      objectFit: 'cover',
                      borderRadius: 1
                    }}
                  />
                  <IconButton
                    size="small"
                    onClick={() => this.handleRemoveFile(index)}
                    disabled={disabled}
                    aria-label="Bild entfernen"
                    sx={{
                      position: 'absolute',
                      top: 4,
                      right: 4,
                      backgroundColor: 'rgba(0,0,0,0.7)',
                      color: 'white',
                      '&:hover': {
                        backgroundColor: 'rgba(0,0,0,0.9)'
                      }
                    }}
                  >
                    <Delete fontSize="small" />
                  </IconButton>
                  <Typography 
                    variant="caption" 
                    sx={{ 
                      position: 'absolute',
                      bottom: 4,
                      left: 4,
                      right: 4,
                      backgroundColor: 'rgba(0,0,0,0.7)',
                      color: 'white',
                      p: 0.5,
                      borderRadius: 0.5,
                      fontSize: '0.7rem',
                      overflow: 'hidden',
                      textOverflow: 'ellipsis',
                      whiteSpace: 'nowrap'
                    }}
                  >
                    {preview.name}
                  </Typography>
                </Paper>
              </Grid>
            ))}
          </Grid>
        )}

        {files.length > 0 && (
          <Typography variant="caption" color="text.secondary" sx={{ mt: 1, display: 'block' }}>
            {files.length} Datei(en) ausgewählt
            {previews.length > 0 && previews.some(p => p.originalSize && p.compressedSize) && (
              <span style={{ marginLeft: '8px' }}>
                (komprimiert für Upload)
              </span>
            )}
          </Typography>
        )}
      </Box>
    );
  }
}

export default PhotoUpload;