import { PureComponent } from 'react';
import Box from '@mui/material/Box';
import Button from '@mui/material/Button';
import CircularProgress from '@mui/material/CircularProgress';
import IconButton from '@mui/material/IconButton';
import Typography from '@mui/material/Typography';
import Tooltip from '@mui/material/Tooltip';
import CloseIcon from '@mui/icons-material/Close';
import PictureAsPdfIcon from '@mui/icons-material/PictureAsPdf';
import OpenInNewIcon from '@mui/icons-material/OpenInNew';
import DownloadOutlinedIcon from '@mui/icons-material/DownloadOutlined';
import VerticalAlignTopIcon from '@mui/icons-material/VerticalAlignTop';
import VerticalAlignBottomIcon from '@mui/icons-material/VerticalAlignBottom';
import ViewSidebarIcon from '@mui/icons-material/ViewSidebar';
import { enqueueSnackbar } from 'notistack';
import { PanelTile } from 'dashgui/panels';
import { delivery as deliveryApi } from '../../api';
import {
  SURFACE_BASE,
  SURFACE_WASH,
  WHITE,
} from '../../colors';

/**
 * Inline PDF viewer rendered as a panel tile, mirroring TextEditorPanel's
 * "window" behaviour: it can sit above, right of, or below the article list,
 * and stays sticky when docked to the right. Mount it only while a PDF
 * attachment is selected; unmounting closes it.
 */
export class PdfViewerPanel extends PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      url: null,
      loading: false,
      error: null,
    };
    this.handleOpenExternal = this.handleOpenExternal.bind(this);
    this.handleDownload = this.handleDownload.bind(this);
  }

  componentDidMount() {
    this.loadUrl();
  }

  componentDidUpdate(prevProps) {
    if (this.props.attachment !== prevProps.attachment) {
      this.revokeUrl();
      this.loadUrl();
    }
  }

  componentWillUnmount() {
    this.revokeUrl();
  }

  revokeUrl() {
    if (this._objectUrl) {
      URL.revokeObjectURL(this._objectUrl);
      this._objectUrl = null;
    }
  }

  async loadUrl() {
    const { attachment, docId } = this.props;
    if (!attachment) return;

    if (
      (attachment.file instanceof Blob || attachment.file instanceof File) &&
      attachment.file.size > 0
    ) {
      this._objectUrl = URL.createObjectURL(attachment.file);
      this.setState({ url: this._objectUrl, loading: false, error: null });
      return;
    }

    const effectiveDocId = docId ?? attachment.manifestId;
    const fileId = attachment.fileId ?? attachment.id;
    if (effectiveDocId != null && fileId != null) {
      this.setState({ loading: true, error: null });
      try {
        const blob = await deliveryApi.getFile(effectiveDocId, fileId);
        this._objectUrl = URL.createObjectURL(blob);
        this.setState({ url: this._objectUrl, loading: false, error: null });
        return;
      } catch (err) {
        console.error('Fehler beim Laden der PDF-Datei:', err);
        enqueueSnackbar('Fehler beim Laden der Datei', { variant: 'error' });
        this.setState({ loading: false, error: 'Fehler beim Laden der Datei' });
        return;
      }
    }

    this.setState({ url: null, loading: false, error: null });
  }

  handleOpenExternal() {
    const { url } = this.state;
    if (!url) return;
    window.open(url, '_blank');
  }

  handleDownload() {
    const { attachment } = this.props;
    const { url } = this.state;
    if (!url) return;
    const link = document.createElement('a');
    link.href = url;
    link.download = attachment?.name || 'Dokument.pdf';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
  }

  render() {
    const {
      onClose,
      attachment,
      wide = 3,
      position = 'top',
      onPositionChange,
      height = '60vh',
    } = this.props;
    if (!attachment) return null;

    const { url, loading, error } = this.state;
    const filename = attachment?.name || 'Dokument.pdf';

    return (
      <PanelTile
        wide={wide}
        minHeight={320}
        color={SURFACE_BASE}
        sx={{ height, minHeight: 320 }}
      >
        <Box
          sx={{
            display: 'flex',
            flexDirection: 'column',
            height: '100%',
            minHeight: 0,
            minWidth: 0,
          }}
        >
          <Box
            sx={{
              display: 'flex',
              alignItems: 'center',
              justifyContent: 'space-between',
              gap: 1.5,
              mb: 1.5,
              flexShrink: 0,
            }}
          >
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 1.5, minWidth: 0 }}>
              <PictureAsPdfIcon color="error" />
              <Box sx={{ minWidth: 0 }}>
                <Typography variant="subtitle1" fontWeight={600} noWrap>
                  {filename}
                </Typography>
                <Typography variant="caption" color="text.secondary">
                  PDF-Vorschau
                </Typography>
              </Box>
            </Box>
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5, flexShrink: 0 }}>
              <Tooltip title="Über der Artikelliste">
                <IconButton
                  size="small"
                  color={position === 'top' ? 'primary' : 'default'}
                  aria-label="Über der Artikelliste"
                  onClick={() => onPositionChange?.('top')}
                >
                  <VerticalAlignTopIcon fontSize="small" />
                </IconButton>
              </Tooltip>
              <Tooltip title="Rechts neben der Artikelliste">
                <IconButton
                  size="small"
                  color={position === 'right' ? 'primary' : 'default'}
                  aria-label="Rechts neben der Artikelliste"
                  onClick={() => onPositionChange?.('right')}
                >
                  <ViewSidebarIcon fontSize="small" />
                </IconButton>
              </Tooltip>
              <Tooltip title="Unter der Artikelliste">
                <IconButton
                  size="small"
                  color={position === 'below' ? 'primary' : 'default'}
                  aria-label="Unter der Artikelliste"
                  onClick={() => onPositionChange?.('below')}
                >
                  <VerticalAlignBottomIcon fontSize="small" />
                </IconButton>
              </Tooltip>
              <IconButton size="small" onClick={onClose} sx={{ color: 'text.secondary' }}>
                <CloseIcon fontSize="small" />
              </IconButton>
            </Box>
          </Box>

          <Box
            sx={{
              position: 'relative',
              flex: 1,
              display: 'flex',
              flexDirection: 'column',
              minHeight: 0,
              border: '1px solid',
              borderColor: 'divider',
              borderRadius: 1,
              bgcolor: WHITE,
              overflow: 'hidden',
            }}
          >
            {loading && (
              <Box
                sx={{
                  position: 'absolute',
                  inset: 0,
                  display: 'flex',
                  alignItems: 'center',
                  justifyContent: 'center',
                  bgcolor: SURFACE_WASH,
                  zIndex: 2,
                }}
              >
                <CircularProgress size={36} />
              </Box>
            )}
            {error ? (
              <Box
                sx={{
                  flex: 1,
                  display: 'flex',
                  alignItems: 'center',
                  justifyContent: 'center',
                  p: 2,
                }}
              >
                <Typography color="text.secondary">{error}</Typography>
              </Box>
            ) : (
              url && (
                <Box
                  component="iframe"
                  title={filename}
                  src={url}
                  sx={{ flex: 1, width: '100%', border: 'none' }}
                />
              )
            )}
          </Box>

          <Box
            sx={{
              display: 'flex',
              justifyContent: 'space-between',
              gap: 1,
              mt: 1.5,
              flexShrink: 0,
            }}
          >
            <Box sx={{ display: 'flex', gap: 1 }}>
              <Button
                size="small"
                variant="outlined"
                startIcon={<OpenInNewIcon />}
                onClick={this.handleOpenExternal}
                disabled={loading || !url}
              >
                In neuem Tab
              </Button>
              <Button
                size="small"
                variant="outlined"
                startIcon={<DownloadOutlinedIcon />}
                onClick={this.handleDownload}
                disabled={loading || !url}
              >
                Download
              </Button>
            </Box>
            <Button size="small" onClick={onClose}>
              Schließen
            </Button>
          </Box>
        </Box>
      </PanelTile>
    );
  }
}

export default PdfViewerPanel;