import { PureComponent, createRef } from 'react';
import Alert from '@mui/material/Alert';
import Box from '@mui/material/Box';
import Button from '@mui/material/Button';
import CircularProgress from '@mui/material/CircularProgress';
import List from '@mui/material/List';
import Typography from '@mui/material/Typography';
import { enqueueSnackbar } from 'notistack';
import BackendError from '../components/BackendError';
import SingleLineTextEdit from 'dashgui/SingleLineTextEdit';
import { PanelTile, PanelTileGrid } from 'dashgui/panels';
import withNavigate from '../components/withNavigate';
import { backendErrorFrom } from '../utils/backendError';
import { notifyError } from '../utils/notify';
import entityAutomat from '../automats/entityAutomat';
import customergroupAutomat from '../automats/customergroupAutomat';
import { Kunde } from '../components/kunde';
import { BLUE_PANEL } from '../colors';

function getInitialParams(props) {
  const searchParams =
    typeof window !== 'undefined' ? new URLSearchParams(window.location.search) : null;
  const prefill =
    props.location?.state?.name ??
    props.location?.state?.newName ??
    searchParams?.get('name') ??
    searchParams?.get('newName') ??
    '';
  const returnTo =
    props.location?.state?.returnTo ??
    searchParams?.get('returnTo') ??
    null;
  return { prefill: prefill.trim(), returnTo };
}

class KundeSearchField extends PureComponent {
  constructor(props) {
    super(props);
    const initial = entityAutomat.state.filter || props.prefill || '';
    this.state = {
      input: initial,
      submitting: false,
    };
    if (props.prefill && !entityAutomat.state.filter) {
      entityAutomat.actions.filter(props.prefill);
    }
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  componentDidMount() {
    this.unsub = entityAutomat.subscribe(this, (state) => ({
      input: state.filter,
    }));
  }

  componentWillUnmount() {
    this.unsub?.();
  }

  onInputChange(input) {
    this.setState({ input });
    entityAutomat.actions.filter(input);
  }

  async handleSubmit() {
    const raw = this.state.input.trim();
    if (!raw || this.state.submitting) return;

    this.setState({ submitting: true });
    try {
      await customergroupAutomat.actions.ensureLoaded();
      const groups = customergroupAutomat.state.items ?? [];
      const defaultGroup = groups.find((g) => g.editable !== false) ?? groups[0];
      if (!defaultGroup) {
        throw new Error('Keine Kundengruppe vorhanden.');
      }

      let name = raw;
      let firstName = null;

      if (raw.includes(',')) {
        const parts = raw.split(',').map((p) => p.trim());
        name = parts[0];
        firstName = parts.slice(1).join(' ') || null;
      } else if (raw.includes(' ') && !/gmbh|ag|kg|ug|inc|ltd|co\./i.test(raw)) {
        const parts = raw.split(' ');
        firstName = parts[0];
        name = parts.slice(1).join(' ');
      }

      const body = {
        customergroupId: defaultGroup.id,
        name,
      };
      if (firstName) body.firstName = firstName;

      const row = await entityAutomat.actions.create(body);
      const displayName = [row.firstName, row.name].filter(Boolean).join(' ') || row.name || raw;
      enqueueSnackbar(`Kunde „${displayName}“ angelegt.`, { variant: 'success' });
      this.setState({ input: '', submitting: false });
      entityAutomat.actions.filter('');
      if (this.props.returnTo && this.props.navigate) {
        this.props.navigate(this.props.returnTo);
      }
    } catch (err) {
      this.setState({ submitting: false });
      notifyError(err);
    }
  }

  render() {
    const { inputRef, returnTo, navigate } = this.props;
    const { input, submitting } = this.state;
    const canSubmit = Boolean(input.trim()) && !submitting;

    return (
      <PanelTileGrid>
        <Box
          ref={inputRef}
          sx={{
            gridColumn: {
              xs: '1 / -1',
              sm: 'span 2',
              md: 'span 2',
            },
            display: 'flex',
            flexDirection: 'column',
            gap: 1,
            pb: 2,
          }}
        >
          {returnTo ? (
            <Alert
              severity="info"
              sx={{ py: 0.5, alignItems: 'center' }}
              action={
                <Button
                  color="inherit"
                  size="small"
                  onClick={() => navigate?.(returnTo)}
                >
                  Zurück
                </Button>
              }
            >
              {input
                ? `Kundenname „${input}“ übernommen.`
                : 'Neuen Kunden anlegen.'}
            </Alert>
          ) : null}

          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
            <SingleLineTextEdit
              sx={{ flex: 1 }}
              size="small"
              search
              clear
              placeholder="Kunde suchen oder anlegen…"
              value={input}
              disabled={submitting}
              onChange={(next) => this.onInputChange(next)}
              onKeyDown={(event) => {
                if (event.key === 'Enter') {
                  event.preventDefault();
                  void this.handleSubmit();
                }
              }}
            />
            <Button
              variant="contained"
              disabled={!canSubmit}
              onClick={() => void this.handleSubmit()}
            >
              Hinzufügen
            </Button>
          </Box>
        </Box>
      </PanelTileGrid>
    );
  }
}

class KundeListePage extends PureComponent {
  constructor(props) {
    super(props);
    const initialEntities =
      entityAutomat.state.filteredItems ?? entityAutomat.state.items ?? [];
    this.state = {
      status: entityAutomat.state.status === 'ready' ? 'ready' : 'loading',
      error: entityAutomat.state.error ? backendErrorFrom(entityAutomat.state.error) : null,
      entities: initialEntities,
      groups: customergroupAutomat.state.items ?? [],
      filter: entityAutomat.state.filter ?? '',
    };
    this.searchRef = createRef();
    this.handleRetry = this.handleRetry.bind(this);
    this.handleEdit = this.handleEdit.bind(this);
  }

  componentDidMount() {
    this.unsub = entityAutomat.subscribe(this, (state) => ({
      entities: state.filteredItems ?? state.items,
      filter: state.filter ?? '',
      status: state.status,
      error: state.error ? backendErrorFrom(state.error) : null,
    }));

    this.unsubGroups = customergroupAutomat.subscribe(this, (state) => ({
      groups: state.items,
    }));

    if (entityAutomat.state.status !== 'ready') {
      void entityAutomat.actions.load().catch((err) => notifyError(err));
    }
    if (customergroupAutomat.state.status !== 'ready') {
      void customergroupAutomat.actions.load().catch(() => {});
    }
  }

  componentWillUnmount() {
    this.unsub?.();
    this.unsubGroups?.();
  }

  handleRetry() {
    void entityAutomat.actions.load().catch((err) => notifyError(err));
  }

  handleEdit(entity) {
    if (!entity?.id) return;
    this.props.navigate?.(`/kunde/${entity.id}`);
  }

  render() {
    const { status, error, entities, groups, filter } = this.state;
    const { prefill, returnTo } = getInitialParams(this.props);

    if (status === 'loading' || status === 'idle') {
      return (
        <Box sx={{ display: 'flex', justifyContent: 'center', py: 6 }}>
          <CircularProgress />
        </Box>
      );
    }

    if (status === 'failed') {
      return <BackendError error={error} onRetry={this.handleRetry} />;
    }

    const trimmedFilter = filter?.trim() ?? '';
    const groupsById = Object.fromEntries(groups.map((g) => [g.id, g]));

    return (
      <>
        <KundeSearchField
          inputRef={this.searchRef}
          prefill={prefill}
          returnTo={returnTo}
          navigate={this.props.navigate}
        />
        <PanelTileGrid>
          <PanelTile wide={2} minHeight={0} color={BLUE_PANEL}>
            <List dense disablePadding sx={{ width: '100%' }}>
              {entities.length === 0 ? (
                <Typography variant="body2" color="text.secondary" sx={{ py: 1 }}>
                  {trimmedFilter
                    ? `Keine Treffer für „${trimmedFilter}“.`
                    : 'Noch keine Kunden angelegt.'}
                </Typography>
              ) : (
                entities.map((entity) => (
                  <Kunde
                    key={entity.id}
                    customer={entity}
                    groupName={groupsById[entity.customergroupId]?.name}
                    onEdit={this.handleEdit}
                  />
                ))
              )}
            </List>
          </PanelTile>
        </PanelTileGrid>
      </>
    );
  }
}

export { Kunde, KundeSearchField };
export default withNavigate(KundeListePage);