import { Component } from 'react';
import Box from '@mui/material/Box';
import Button from '@mui/material/Button';
import AppDialog from '../AppDialog';
import DialogActions from '@mui/material/DialogActions';
import DialogContent from '@mui/material/DialogContent';
import DialogTitle from '@mui/material/DialogTitle';
import Alert from '@mui/material/Alert';
import BackendError from '../BackendError';
import SingleLineTextEdit from 'dashgui/SingleLineTextEdit';
import { backendErrorFrom, isBackendFailure } from '../../utils/backendError';

const BULK_MODE = 'bulk';
const SINGLE_MODE = 'single';

/** Split a bulk textarea into non-empty, trimmed names (one per line). */
function parseBulkNames(text) {
  return String(text ?? '')
    .split(/\r?\n/)
    .map((line) => line.trim())
    .filter(Boolean);
}

/**
 * New-article dialog.
 * Single mode: one name. Bulk mode ("Sammelanlegen"): one name per line.
 * Props: open, onClose, onSubmit({ names: string[] }).
 */
class ArticleNameDialog extends Component {
  constructor(props) {
    super(props);
    this.state = {
      mode: SINGLE_MODE,
      name: '',
      bulkText: '',
      busy: false,
      error: null,
    };
    this.handleClose = this.handleClose.bind(this);
    this.handleSingleSubmit = this.handleSingleSubmit.bind(this);
    this.handleBulkSubmit = this.handleBulkSubmit.bind(this);
    this.openBulk = this.openBulk.bind(this);
  }

  componentDidUpdate(prevProps) {
    if (this.props.open && !prevProps.open) {
      this.setState({
        mode: SINGLE_MODE,
        name: '',
        bulkText: '',
        busy: false,
        error: null,
      });
    }
  }

  handleClose() {
    if (this.state.busy) return;
    this.props.onClose();
  }

  async handleSingleSubmit(event) {
    event.preventDefault();
    const name = this.state.name.trim();
    if (!name) {
      this.setState({ error: 'Bitte Name eingeben.' });
      return;
    }

    this.setState({ busy: true, error: null });
    try {
      await this.props.onSubmit({ names: [name] });
      this.props.onClose();
    } catch (err) {
      this.setState({ error: backendErrorFrom(err), busy: false });
    }
  }

  async handleBulkSubmit(event) {
    event.preventDefault();
    const names = parseBulkNames(this.state.bulkText);
    if (names.length === 0) {
      this.setState({ error: 'Bitte mindestens einen Namen eingeben.' });
      return;
    }

    this.setState({ busy: true, error: null });
    try {
      await this.props.onSubmit({ names });
      this.props.onClose();
    } catch (err) {
      this.setState({ error: backendErrorFrom(err), busy: false });
    }
  }

  openBulk() {
    if (this.state.busy) return;
    this.setState({ mode: BULK_MODE, error: null });
  }

  render() {
    const { open } = this.props;
    const { mode, name, bulkText, busy, error } = this.state;
    const isBulk = mode === BULK_MODE;
    const canSubmitSingle = name.trim() !== '';
    const bulkNames = parseBulkNames(bulkText);
    const canSubmitBulk = bulkNames.length > 0;

    return (
      <AppDialog open={open} onClose={this.handleClose} maxWidth="xs" fullWidth>
        <DialogTitle>Neuer Artikel</DialogTitle>

        {!isBulk && (
          <Box component="form" onSubmit={this.handleSingleSubmit} noValidate>
            <DialogContent>
              {error ? (
                isBackendFailure(error) ? (
                  <BackendError error={error} sx={{ mb: 2 }} />
                ) : (
                  <Alert severity="error" sx={{ mb: 2 }}>
                    {typeof error === 'string' ? error : error.message}
                  </Alert>
                )
              ) : null}

              <SingleLineTextEdit
                required
                autoFocus
                label="Name"
                value={name}
                disabled={busy}
                onChange={(nextName) => this.setState({ name: nextName })}
              />
            </DialogContent>
            <DialogActions sx={{ px: 3, pb: 2 }}>
              <Button type="button" onClick={this.openBulk} disabled={busy}>
                Sammelanlegen
              </Button>
              <Box sx={{ flexGrow: 1 }} />
              <Button type="button" onClick={this.handleClose} disabled={busy}>
                Abbrechen
              </Button>
              <Button
                type="submit"
                variant="contained"
                disabled={busy || !canSubmitSingle}
              >
                Anlegen
              </Button>
            </DialogActions>
          </Box>
        )}

        {isBulk && (
          <Box component="form" onSubmit={this.handleBulkSubmit} noValidate>
            <DialogContent>
              {error ? (
                isBackendFailure(error) ? (
                  <BackendError error={error} sx={{ mb: 2 }} />
                ) : (
                  <Alert severity="error" sx={{ mb: 2 }}>
                    {typeof error === 'string' ? error : error.message}
                  </Alert>
                )
              ) : null}

              <SingleLineTextEdit
                autoFocus
                multiline
                minRows={6}
                label="Namen (einer pro Zeile)"
                placeholder={'Artikel A\nArtikel B\nArtikel C'}
                value={bulkText}
                disabled={busy}
                onChange={(nextText) => this.setState({ bulkText: nextText })}
                helperText={
                  bulkNames.length > 0
                    ? `${bulkNames.length} Artikel werden angelegt.`
                    : 'Ein Name pro Zeile eingeben.'
                }
              />
            </DialogContent>
            <DialogActions sx={{ px: 3, pb: 2 }}>
              <Button
                type="button"
                onClick={() => this.setState({ mode: SINGLE_MODE, error: null })}
                disabled={busy}
              >
                Einzel
              </Button>
              <Box sx={{ flexGrow: 1 }} />
              <Button type="button" onClick={this.handleClose} disabled={busy}>
                Abbrechen
              </Button>
              <Button
                type="submit"
                variant="contained"
                disabled={busy || !canSubmitBulk}
              >
                Anlegen ({bulkNames.length})
              </Button>
            </DialogActions>
          </Box>
        )}
      </AppDialog>
    );
  }
}

export default ArticleNameDialog;