import { Component } from 'react';
import DeleteOutlineOutlinedIcon from '@mui/icons-material/DeleteOutlineOutlined';
import Box from '@mui/material/Box';
import Button from '@mui/material/Button';
import Chip from '@mui/material/Chip';
import CircularProgress from '@mui/material/CircularProgress';
import AppDialog from '../AppDialog';
import DialogActions from '@mui/material/DialogActions';
import DialogContent from '@mui/material/DialogContent';
import DialogTitle from '@mui/material/DialogTitle';
import IconButton from '@mui/material/IconButton';
import List from '@mui/material/List';
import ListItem from '@mui/material/ListItem';
import ListItemButton from '@mui/material/ListItemButton';
import ListItemText from '@mui/material/ListItemText';
import TextInput from '../TextInput';
import Typography from '@mui/material/Typography';
import companyAutomat from '../../automats/companyAutomat';
import { unit as unitApi } from '../../api';
import { requireObject } from '../../utils/apiShape';
import { notifyError } from '../../utils/notify';
import { parsePriceInput } from '../../utils/price';
import { COMMON_UNITS, DEFAULT_UNIT_SI, unitLabel } from '../../utils/units';

function emptyForm() {
  return {
    si: '',
    basesi: '',
    basesifactor: '1',
    symbol: '',
    name: '',
  };
}

function formFromUnit(row) {
  // API may return null symbol/name (e.g. default pc).
  return {
    si: row.si ?? '',
    basesi: row.basesi ?? '',
    basesifactor: String(row.basesifactor ?? '1'),
    symbol: row.symbol ?? '',
    name: row.name ?? '',
  };
}

function parseFactor(value) {
  return parsePriceInput(value);
}

function formValid(form) {
  const si = String(form.si ?? '').trim();
  const basesi = String(form.basesi ?? '').trim();
  const symbol = String(form.symbol ?? '').trim();
  const name = String(form.name ?? '').trim();
  const factor = parseFactor(form.basesifactor);
  return (
    si.length > 0 &&
    basesi.length > 0 &&
    symbol.length > 0 &&
    name.length > 0 &&
    factor != null &&
    factor > 0
  );
}

export default class ArticleUnitEditorDialog extends Component {
  constructor(props) {
    super(props);
    this.state = {
      busy: false,
      units: companyAutomat.state.units,
      unitsLoading: companyAutomat.state.unitsStatus === 'loading',
      form: emptyForm(),
      selectedSi: null,
    };
  }

  componentDidMount() {
    this.unsub = companyAutomat.subscribe(this, (state) => ({
      units: state.units,
      unitsLoading: state.unitsStatus === 'loading',
    }));
  }

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

  componentDidUpdate(prevProps) {
    if (this.props.open && !prevProps.open) {
      this.setState({ form: emptyForm(), selectedSi: null });
    }
  }

  handleSelectUnit = (row) => {
    this.setState({ form: formFromUnit(row), selectedSi: row.si });
  };

  handlePreset = (preset) => {
    this.setState({ form: formFromUnit(preset), selectedSi: preset.si });
  };

  handleField = (field, value) => {
    this.setState((state) => {
      const form = { ...state.form, [field]: value };
      if (field === 'si' && (!state.form.basesi || state.form.basesi === state.form.si)) {
        form.basesi = value;
      }
      return { form };
    });
  };

  handleSave = async () => {
    const { form } = this.state;
    if (!formValid(form)) return;
    this.setState({ busy: true });
    try {
      const payload = {
        si: String(form.si ?? '').trim(),
        basesi: String(form.basesi ?? '').trim(),
        basesifactor: parseFactor(form.basesifactor),
        symbol: String(form.symbol ?? '').trim(),
        name: String(form.name ?? '').trim(),
      };
      const units = await companyAutomat.actions.upsertUnit(payload);
      const saved = units.find((u) => u.si === payload.si) ?? payload;
      this.setState({
        busy: false,
        units,
        form: formFromUnit(saved),
        selectedSi: saved.si,
      });
      this.props.onUnitUpserted?.(saved);
    } catch (err) {
      this.setState({ busy: false });
      notifyError(err);
    }
  };

  handleDelete = async () => {
    const { selectedSi } = this.state;
    if (!selectedSi || selectedSi === DEFAULT_UNIT_SI) return;
    this.setState({ busy: true });
    try {
      await companyAutomat.actions.deleteUnit(selectedSi);
      this.setState({
        busy: false,
        units: companyAutomat.state.units,
        form: emptyForm(),
        selectedSi: null,
      });
      this.props.onUnitDeleted?.(selectedSi);
    } catch (err) {
      this.setState({ busy: false });
      notifyError(err);
    }
  };

  handleNew = () => {
    this.setState({ form: emptyForm(), selectedSi: null });
  };

  render() {
    const { open, onClose } = this.props;
    const { busy, form, selectedSi, units, unitsLoading } = this.state;
    const canSave = formValid(form) && !busy;
    const loading = unitsLoading && units.length === 0;

    return (
      <AppDialog open={open} onClose={busy ? undefined : onClose} maxWidth="md" fullWidth>
        <DialogTitle>Einheiten</DialogTitle>
        <DialogContent dividers>
          <Typography variant="caption" color="text.secondary" sx={{ display: 'block', mb: 1 }}>
            Typische Einheiten
          </Typography>
          <Box sx={{ display: 'flex', flexWrap: 'wrap', gap: 0.75, mb: 2 }}>
            {COMMON_UNITS.map((preset) => (
              <Chip
                key={preset.si}
                size="small"
                label={`${preset.symbol} (${preset.si})`}
                onClick={() => this.handlePreset(preset)}
                disabled={busy}
              />
            ))}
          </Box>

          <Box
            sx={{
              display: 'grid',
              gridTemplateColumns: { xs: '1fr', sm: '1fr 1.2fr' },
              gap: 2,
              minHeight: 280,
            }}
          >
            <Box>
              <Typography variant="caption" color="text.secondary" sx={{ display: 'block', mb: 0.5 }}>
                Firma
              </Typography>
              {loading ? (
                <CircularProgress size={28} sx={{ mt: 2 }} />
              ) : (
                <List dense disablePadding sx={{ maxHeight: 320, overflow: 'auto' }}>
                  {units.map((row) => (
                    <ListItem
                      key={row.si}
                      disablePadding
                      secondaryAction={
                        selectedSi === row.si && row.si !== DEFAULT_UNIT_SI ? (
                          <IconButton
                            edge="end"
                            aria-label="Löschen"
                            disabled={busy}
                            onClick={() => void this.handleDelete()}
                          >
                            <DeleteOutlineOutlinedIcon />
                          </IconButton>
                        ) : null
                      }
                    >
                      <ListItemButton
                        selected={selectedSi === row.si}
                        onClick={() => this.handleSelectUnit(row)}
                      >
                        <ListItemText
                          primary={unitLabel(row)}
                          secondary={`si ${row.si} · ${row.basesifactor} × ${row.basesi}`}
                        />
                      </ListItemButton>
                    </ListItem>
                  ))}
                  {units.length === 0 ? (
                    <Typography color="text.secondary" sx={{ py: 2 }}>
                      Noch keine Einheiten.
                    </Typography>
                  ) : null}
                </List>
              )}
              <Button type="button" onClick={this.handleNew} disabled={busy} sx={{ mt: 1 }}>
                Neu
              </Button>
            </Box>

            <Box sx={{ display: 'flex', flexDirection: 'column', gap: 1.5 }}>
              <TextInput
                label="Name"
                value={form.name}
                onChange={(e) => this.handleField('name', e.target.value)}
                fullWidth
                disabled={busy}
              />
              <TextInput
                label="Symbol"
                value={form.symbol}
                onChange={(e) => this.handleField('symbol', e.target.value)}
                fullWidth
                disabled={busy}
              />
              <TextInput
                label="si"
                value={form.si}
                onChange={(e) => this.handleField('si', e.target.value)}
                fullWidth
                disabled={busy}
              />
              <TextInput
                label="basesi"
                value={form.basesi}
                onChange={(e) => this.handleField('basesi', e.target.value)}
                fullWidth
                disabled={busy}
              />
              <TextInput
                label="basesifactor"
                value={form.basesifactor}
                onChange={(e) => this.handleField('basesifactor', e.target.value)}
                fullWidth
                disabled={busy}
                error={
                  form.basesifactor !== '' &&
                  (parseFactor(form.basesifactor) == null ||
                    parseFactor(form.basesifactor) <= 0)
                }
                slotProps={{
                  htmlInput: { inputMode: 'decimal' },
                }}
              />
              <Button
                type="button"
                variant="contained"
                onClick={() => void this.handleSave()}
                disabled={!canSave}
              >
                {busy ? <CircularProgress size={22} color="inherit" /> : 'Speichern'}
              </Button>
            </Box>
          </Box>
        </DialogContent>
        <DialogActions sx={{ px: 3, py: 2 }}>
          <Button type="button" onClick={onClose} disabled={busy}>
            Schließen
          </Button>
        </DialogActions>
      </AppDialog>
    );
  }
}