import { Component } from 'react';
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 Divider from '@mui/material/Divider';
import FormControlLabel from '@mui/material/FormControlLabel';
import IconButton from '@mui/material/IconButton';
import Switch from '@mui/material/Switch';
import TextField from '@mui/material/TextField';
import Tooltip from '@mui/material/Tooltip';
import Typography from '@mui/material/Typography';
import AddIcon from '@mui/icons-material/Add';
import ArrowDownwardIcon from '@mui/icons-material/ArrowDownward';
import ArrowUpwardIcon from '@mui/icons-material/ArrowUpward';
import DeleteOutlinedIcon from '@mui/icons-material/DeleteOutlined';
import FolderIcon from '@mui/icons-material/Folder';
import PointOfSaleIcon from '@mui/icons-material/PointOfSale';
import { enqueueSnackbar } from 'notistack';
import BackendError from '../BackendError';
import CategoryPickerDialog from '../article/CategoryPickerDialog';
import authAutomat from '../../automats/authAutomat';
import companyAutomat from '../../automats/companyAutomat';
import categoryAutomat, { whenCategoryTreeReady } from '../../automats/categoryAutomat';
import { categoryDisplayName } from '../../utils/categoryUtils';
import { backendErrorFrom } from '../../utils/backendError';
import { notifyError } from '../../utils/notify';

function parseVhostSettings(str) {
  if (!str || typeof str !== 'string') return {};
  const result = {};
  for (const part of str.split(';')) {
    const trimmed = part.trim();
    if (!trimmed) continue;
    const colonIdx = trimmed.indexOf(':');
    if (colonIdx !== -1) {
      const key = trimmed.slice(0, colonIdx).trim().toLowerCase();
      const val = trimmed.slice(colonIdx + 1).trim();
      result[key] = val;
    }
  }
  return result;
}

function formatDateTime(val) {
  if (!val) return null;
  try {
    const d = new Date(val);
    if (isNaN(d.getTime())) return null;
    return d.toLocaleString('de-DE', {
      day: '2-digit',
      month: '2-digit',
      year: 'numeric',
      hour: '2-digit',
      minute: '2-digit',
    });
  } catch {
    return null;
  }
}

export default class PosTerminalSettingsPanel extends Component {
  constructor(props) {
    super(props);
    const terminals = companyAutomat.state.terminals ?? [];
    this.state = {
      isAdmin: companyAutomat.state.current?.role === 'admin',
      status: companyAutomat.state.terminalsStatus === 'succeeded' ? 'ready' : 'loading',
      error: null,
      terminals,
      categories: categoryAutomat.state.categories,
      rootCategoryId: categoryAutomat.state.rootCategoryId,
      vhostSettings: authAutomat.state.vhostSettings,
      newTerminalName: '',
      creatingTerminal: false,
      enableAllForNew: true,
      deletingId: null,
      pickerTerminal: null,
      patchingTerminalId: null,
      sortDrafts: {},
    };
    this.handleRetry = this.handleRetry.bind(this);
    this.loadTerminals = this.loadTerminals.bind(this);
    this.handleCreateTerminal = this.handleCreateTerminal.bind(this);
    this.handleDeleteTerminal = this.handleDeleteTerminal.bind(this);
    this.handleSetRootCategory = this.handleSetRootCategory.bind(this);
    this.handleToggleSyncRootArticles = this.handleToggleSyncRootArticles.bind(this);
    this.handleToggleEnabled = this.handleToggleEnabled.bind(this);
    this.handleSortDraftChange = this.handleSortDraftChange.bind(this);
    this.handleSortSubmit = this.handleSortSubmit.bind(this);
    this.handleMoveTerminal = this.handleMoveTerminal.bind(this);
    this.getCategoryLabel = this.getCategoryLabel.bind(this);
  }

  componentDidMount() {
    this.unsub = companyAutomat.subscribe(this, (state) => ({
      isAdmin: state.current?.role === 'admin',
      terminals: Array.isArray(state.terminals) ? state.terminals : [],
      status: state.terminalsStatus === 'succeeded' ? 'ready' : state.terminalsStatus === 'failed' ? 'failed' : this.state.status,
    }));
    this.unsubCategory = categoryAutomat.subscribe(this, (state) => ({
      categories: state.categories,
      rootCategoryId: state.rootCategoryId,
    }));
    this.unsubAuth = authAutomat.subscribe(this, (state) => ({
      vhostSettings: state.vhostSettings,
    }));
    if (categoryAutomat.state.treeStatus === 'idle') {
      void categoryAutomat.actions.loadTree();
    }
  }

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

  async loadTerminals() {
    this.setState({ error: null });
    try {
      const terminals = await companyAutomat.actions.loadTerminals();
      this.setState({
        status: 'ready',
        terminals: Array.isArray(terminals) ? terminals : [],
      });
    } catch (err) {
      notifyError(err);
      this.setState({ status: 'failed', error: backendErrorFrom(err) });
    }
  }

  handleRetry() {
    void this.loadTerminals();
  }

  async handleCreateTerminal() {
    if (!this.state.isAdmin) return;
    const { newTerminalName, enableAllForNew, terminals } = this.state;
    const trimmed = newTerminalName.trim();
    if (!trimmed) return;

    this.setState({ creatingTerminal: true });
    try {
      const nextSort = terminals.length > 0
        ? Math.max(...terminals.map((t) => Number(t.sort) || 0)) + 1
        : 0;
      const created = await companyAutomat.actions.createTerminal({
        name: trimmed,
        sort: nextSort,
        enabled: true,
      });

      if (enableAllForNew && created?.id != null) {
        await companyAutomat.actions.enableAllTerminalCategories({ terminalId: created.id });
        await whenCategoryTreeReady();
      }

      this.setState({ newTerminalName: '' });
      enqueueSnackbar('Terminal hinzugefügt.', { variant: 'success' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ creatingTerminal: false });
    }
  }

  async handleToggleEnabled(terminal, nextValue) {
    this.setState({ patchingTerminalId: terminal.id });
    try {
      await companyAutomat.actions.updateTerminal(terminal.id, {
        enabled: Boolean(nextValue),
      });
      enqueueSnackbar(nextValue ? 'Terminal aktiviert.' : 'Terminal deaktiviert.', {
        variant: 'success',
      });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ patchingTerminalId: null });
    }
  }

  handleSortDraftChange(terminalId, value) {
    this.setState((prev) => ({
      sortDrafts: { ...prev.sortDrafts, [terminalId]: value },
    }));
  }

  async handleSortSubmit(terminal) {
    const draft = this.state.sortDrafts[terminal.id];
    if (draft === undefined) return;
    const nextSort = Number(draft);
    if (isNaN(nextSort) || nextSort === (terminal.sort ?? 0)) {
      this.setState((prev) => {
        const next = { ...prev.sortDrafts };
        delete next[terminal.id];
        return { sortDrafts: next };
      });
      return;
    }
    this.setState({ patchingTerminalId: terminal.id });
    try {
      await companyAutomat.actions.updateTerminal(terminal.id, { sort: nextSort });
      enqueueSnackbar('Reihenfolge aktualisiert.', { variant: 'success' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState((prev) => {
        const next = { ...prev.sortDrafts };
        delete next[terminal.id];
        return { sortDrafts: next, patchingTerminalId: null };
      });
    }
  }

  async handleMoveTerminal(terminal, direction) {
    const { terminals } = this.state;
    const currentIndex = terminals.findIndex((t) => t.id === terminal.id);
    if (currentIndex === -1) return;
    const targetIndex = direction === 'up' ? currentIndex - 1 : currentIndex + 1;
    if (targetIndex < 0 || targetIndex >= terminals.length) return;

    const other = terminals[targetIndex];
    const currentSort = terminal.sort ?? 0;
    const otherSort = other.sort ?? 0;

    let newSort;
    if (direction === 'up') {
      newSort = otherSort <= currentSort ? otherSort - 1 : otherSort;
    } else {
      newSort = otherSort >= currentSort ? otherSort + 1 : otherSort;
    }

    this.setState({ patchingTerminalId: terminal.id });
    try {
      await companyAutomat.actions.updateTerminal(terminal.id, { sort: newSort });
      enqueueSnackbar('Reihenfolge aktualisiert.', { variant: 'success' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ patchingTerminalId: null });
    }
  }

  async handleDeleteTerminal(terminal) {
    this.setState({ deletingId: terminal.id });
    try {
      await companyAutomat.actions.deleteTerminal(terminal.id);
      enqueueSnackbar('Terminal gelöscht.', { variant: 'info' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ deletingId: null });
    }
  }

  async handleSetRootCategory(terminal, categoryId) {
    this.setState({ patchingTerminalId: terminal.id });
    try {
      await companyAutomat.actions.updateTerminal(terminal.id, {
        rootCategoryId: categoryId != null ? Number(categoryId) : null,
      });
      enqueueSnackbar('Root-Kategorie aktualisiert.', { variant: 'success' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ patchingTerminalId: null });
    }
  }

  async handleToggleSyncRootArticles(terminal, nextValue) {
    this.setState({ patchingTerminalId: terminal.id });
    try {
      await companyAutomat.actions.updateTerminal(terminal.id, {
        syncRootArticles: Boolean(nextValue),
      });
      enqueueSnackbar('Synchronisierungseinstellung gespeichert.', { variant: 'success' });
    } catch (err) {
      notifyError(err);
    } finally {
      this.setState({ patchingTerminalId: null });
    }
  }

  getCategoryLabel(terminal) {
    const { categories, rootCategoryId } = this.state;
    if (terminal.rootCategoryId == null) {
      return 'Standard (Home)';
    }
    const node = categories?.[String(terminal.rootCategoryId)];
    if (!node) {
      return `Kategorie #${terminal.rootCategoryId}`;
    }
    return categoryDisplayName(node.name, node.id, rootCategoryId) || `Kategorie #${terminal.rootCategoryId}`;
  }

  render() {
    const {
      isAdmin,
      status,
      error,
      terminals,
      vhostSettings,
      newTerminalName,
      creatingTerminal,
      enableAllForNew,
      deletingId,
      pickerTerminal,
      patchingTerminalId,
      rootCategoryId,
    } = this.state;

    const parsedVhost = parseVhostSettings(vhostSettings);
    const posIp = parsedVhost.posip || parsedVhost.ip || null;
    const posPort = parsedVhost.posport || parsedVhost.port || null;
    const hasVhostSettings = Boolean(posIp || posPort || vhostSettings);

    if (status === 'loading' && terminals.length === 0) {
      return (
        <Box sx={{ display: 'flex', justifyContent: 'center', py: 6 }}>
          <CircularProgress />
        </Box>
      );
    }

    if (status === 'failed' && terminals.length === 0) {
      return <BackendError error={error} onRetry={this.handleRetry} />;
    }

    return (
      <Box sx={{ maxWidth: 680, mx: 'auto', py: 2 }}>
        {hasVhostSettings && (
          <Box
            sx={{
              mb: 2,
              p: 1.5,
              px: 2,
              borderRadius: 2,
              bgcolor: 'action.hover',
              border: '1px solid',
              borderColor: 'divider',
              display: 'flex',
              alignItems: 'center',
              gap: 4,
              flexWrap: 'wrap',
            }}
          >
            <Typography variant="body2" sx={{ color: 'text.secondary', fontWeight: 500 }}>
              Pos Sync IP:{' '}
              <Box component="span" sx={{ color: 'text.primary', fontFamily: 'monospace', fontWeight: 600 }}>
                {posIp ?? '—'}
              </Box>
            </Typography>
            <Typography variant="body2" sx={{ color: 'text.secondary', fontWeight: 500 }}>
              Pos Sync Port:{' '}
              <Box component="span" sx={{ color: 'text.primary', fontFamily: 'monospace', fontWeight: 600 }}>
                {posPort ?? '—'}
              </Box>
            </Typography>
          </Box>
        )}
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mb: 2 }}>
          <TextField
            size="small"
            placeholder="Neues Terminal..."
            value={newTerminalName}
            onChange={(e) => this.setState({ newTerminalName: e.target.value })}
            disabled={!isAdmin || creatingTerminal}
            autoComplete="off"
            slotProps={{
              htmlInput: {
                autoComplete: 'off',
                autoCorrect: 'off',
                autoCapitalize: 'off',
                spellCheck: false,
              },
            }}
            onKeyDown={(e) => {
              if (e.key === 'Enter') {
                e.preventDefault();
                void this.handleCreateTerminal();
              }
            }}
            sx={{ flex: 1 }}
          />
          <Tooltip title="Alle Kategorien für dieses Terminal aktivieren">
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
              <PointOfSaleIcon sx={{ fontSize: 18, color: 'text.secondary' }} />
              <Switch
                size="small"
                checked={enableAllForNew}
                onChange={(e) => this.setState({ enableAllForNew: e.target.checked })}
                disabled={!isAdmin || creatingTerminal}
              />
            </Box>
          </Tooltip>
          <Button
            variant="contained"
            size="small"
            startIcon={creatingTerminal ? <CircularProgress size={16} color="inherit" /> : <AddIcon />}
            onClick={this.handleCreateTerminal}
            disabled={!isAdmin || creatingTerminal || !newTerminalName.trim()}
          >
            Hinzufügen
          </Button>
        </Box>

        <Divider sx={{ mb: 2 }} />

        {terminals.length === 0 ? (
          <Box sx={{ textAlign: 'center', py: 6, color: 'text.secondary' }}>
            <PointOfSaleIcon sx={{ fontSize: 48, mb: 1, opacity: 0.5 }} />
            <Typography variant="body2">Keine POS Terminals angelegt.</Typography>
          </Box>
        ) : (
          <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
            {terminals.map((terminal, index) => {
              const isDeleting = deletingId === terminal.id;
              const isPatching = patchingTerminalId === terminal.id;
              const isEnabled = terminal.enabled !== false && terminal.enabled !== 0 && terminal.enabled != null;
              const pairedDateText = formatDateTime(terminal.pairedAt);
              const lastseenText = formatDateTime(terminal.lastseenAt) ?? 'Nie';
              const updatedText = formatDateTime(terminal.updatedAt) ?? '—';

              return (
                <Box
                  key={terminal.id}
                  sx={{
                    p: 2,
                    borderRadius: 2,
                    border: '1px solid',
                    borderColor: isEnabled ? 'divider' : 'action.disabledBackground',
                    bgcolor: 'background.paper',
                    display: 'flex',
                    flexDirection: 'column',
                    gap: 1.5,
                    opacity: isEnabled ? 1 : 0.72,
                    transition: 'opacity 0.2s ease, border-color 0.2s ease',
                  }}
                >
                  {/* Header: Icon, Name, PIN, Version, Status Switch, Delete action */}
                  <Box sx={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 1 }}>
                    <Box sx={{ display: 'flex', alignItems: 'center', gap: 1.5, flexWrap: 'wrap' }}>
                      <PointOfSaleIcon sx={{ color: isEnabled ? 'primary.main' : 'text.disabled', fontSize: 24 }} />
                      <Typography
                        variant="subtitle1"
                        fontWeight={600}
                        sx={{ color: isEnabled ? 'text.primary' : 'text.secondary' }}
                      >
                        {terminal.name}
                      </Typography>
                      {terminal.pairingpin ? (
                        <Chip
                          label={`PIN: ${terminal.pairingpin}`}
                          size="small"
                          variant="outlined"
                          sx={{ fontFamily: 'monospace', fontWeight: 600, fontSize: '0.75rem' }}
                        />
                      ) : (
                        <Chip
                          label="Gekoppelt"
                          size="small"
                          variant="outlined"
                          color="success"
                          sx={{ fontWeight: 600, fontSize: '0.75rem' }}
                        />
                      )}
                      {terminal.clientserial ? (
                        <Typography variant="caption" color="text.secondary" sx={{ fontFamily: 'monospace' }}>
                          ({terminal.clientserial})
                        </Typography>
                      ) : null}
                      {terminal.clientversion ? (
                        <Tooltip title="POS Client Software-Version">
                          <Chip
                            label={`v${terminal.clientversion}`}
                            size="small"
                            variant="outlined"
                            color="info"
                            sx={{ fontFamily: 'monospace', fontWeight: 600, fontSize: '0.75rem' }}
                          />
                        </Tooltip>
                      ) : null}
                    </Box>
                    <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
                      <Tooltip
                        title={
                          isEnabled
                            ? 'Terminal aktiv (kann synchronisieren)'
                            : 'Terminal deaktiviert (POS-Zugriff blockiert)'
                        }
                      >
                        <FormControlLabel
                          control={
                            <Switch
                              size="small"
                              checked={isEnabled}
                              disabled={!isAdmin || isPatching || isDeleting}
                              onChange={(e) => void this.handleToggleEnabled(terminal, e.target.checked)}
                              color="success"
                            />
                          }
                          label={
                            <Typography
                              variant="body2"
                              sx={{
                                fontSize: '0.8125rem',
                                fontWeight: 500,
                                color: isEnabled ? 'text.primary' : 'text.disabled',
                              }}
                            >
                              {isEnabled ? 'Aktiv' : 'Inaktiv'}
                            </Typography>
                          }
                          sx={{ m: 0 }}
                        />
                      </Tooltip>
                      <IconButton
                        size="small"
                        aria-label={`Terminal ${terminal.name} löschen`}
                        onClick={() => void this.handleDeleteTerminal(terminal)}
                        disabled={!isAdmin || isDeleting || creatingTerminal || isPatching}
                        color="error"
                      >
                        {isDeleting ? (
                          <CircularProgress size={16} color="inherit" />
                        ) : (
                          <DeleteOutlinedIcon fontSize="small" />
                        )}
                      </IconButton>
                    </Box>
                  </Box>

                  {/* Settings row: Root category picker, sort order controls, and syncRootArticles toggle */}
                  <Box
                    sx={{
                      display: 'flex',
                      alignItems: 'center',
                      justifyContent: 'space-between',
                      flexWrap: 'wrap',
                      gap: 2,
                      pt: 0.5,
                    }}
                  >
                    <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, flexWrap: 'wrap' }}>
                      <Typography variant="body2" color="text.secondary">
                        Root-Kategorie:
                      </Typography>
                      <Chip
                        icon={<FolderIcon />}
                        label={this.getCategoryLabel(terminal)}
                        onClick={isAdmin ? () => this.setState({ pickerTerminal: terminal }) : undefined}
                        onDelete={
                          isAdmin && terminal.rootCategoryId != null
                            ? () => void this.handleSetRootCategory(terminal, null)
                            : undefined
                        }
                        clickable={isAdmin}
                        disabled={!isAdmin || isPatching || isDeleting}
                        variant={terminal.rootCategoryId != null ? 'filled' : 'outlined'}
                        color={terminal.rootCategoryId != null ? 'primary' : 'default'}
                        size="small"
                      />
                      <Button
                        size="small"
                        variant="text"
                        disabled={!isAdmin || isPatching || isDeleting}
                        onClick={() => this.setState({ pickerTerminal: terminal })}
                        sx={{ minWidth: 'auto', p: 0.5, fontSize: '0.75rem' }}
                      >
                        Ändern
                      </Button>
                    </Box>

                    <Box sx={{ display: 'flex', alignItems: 'center', gap: 2, flexWrap: 'wrap' }}>
                      <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5 }}>
                        <Typography variant="body2" color="text.secondary">
                          Reihenfolge:
                        </Typography>
                        <Tooltip title="Nach oben verschieben">
                          <span>
                            <IconButton
                              size="small"
                              disabled={!isAdmin || index === 0 || isPatching || isDeleting}
                              onClick={() => void this.handleMoveTerminal(terminal, 'up')}
                              sx={{ p: 0.25 }}
                            >
                              <ArrowUpwardIcon sx={{ fontSize: 16 }} />
                            </IconButton>
                          </span>
                        </Tooltip>
                        <Tooltip title="Nach unten verschieben">
                          <span>
                            <IconButton
                              size="small"
                              disabled={!isAdmin || index === terminals.length - 1 || isPatching || isDeleting}
                              onClick={() => void this.handleMoveTerminal(terminal, 'down')}
                              sx={{ p: 0.25 }}
                            >
                              <ArrowDownwardIcon sx={{ fontSize: 16 }} />
                            </IconButton>
                          </span>
                        </Tooltip>
                        <TextField
                          type="number"
                          size="small"
                          disabled={!isAdmin || isPatching || isDeleting}
                          value={this.state.sortDrafts[terminal.id] ?? terminal.sort ?? 0}
                          onChange={(e) => this.handleSortDraftChange(terminal.id, e.target.value)}
                          onBlur={() => void this.handleSortSubmit(terminal)}
                          onKeyDown={(e) => {
                            if (e.key === 'Enter') {
                              e.preventDefault();
                              e.target.blur();
                            }
                          }}
                          slotProps={{
                            htmlInput: {
                              step: 1,
                              style: { width: 44, padding: '3px 6px', textAlign: 'center', fontSize: '0.8125rem' },
                            },
                          }}
                          sx={{ width: 56 }}
                        />
                      </Box>

                      <FormControlLabel
                        control={
                          <Switch
                            size="small"
                            checked={Boolean(terminal.syncRootArticles)}
                            disabled={!isAdmin || isPatching || isDeleting}
                            onChange={(e) => void this.handleToggleSyncRootArticles(terminal, e.target.checked)}
                          />
                        }
                        label={
                          <Typography variant="body2">
                            Root-Artikel synchronisieren
                          </Typography>
                        }
                        sx={{ m: 0 }}
                      />
                    </Box>
                  </Box>

                  {/* Dates row */}
                  <Divider sx={{ my: 0.25 }} />
                  <Box
                    sx={{
                      display: 'flex',
                      alignItems: 'center',
                      flexWrap: 'wrap',
                      gap: 2.5,
                      color: 'text.secondary',
                    }}
                  >
                    {pairedDateText && (
                      <Typography variant="caption" color="text.secondary">
                        <strong>Gekoppelt:</strong> {pairedDateText}
                      </Typography>
                    )}
                    <Typography variant="caption" color="text.secondary">
                      <strong>Zuletzt online:</strong> {lastseenText}
                    </Typography>
                    {terminal.clientversion && (
                      <Typography variant="caption" color="text.secondary">
                        <strong>POS-Software:</strong> {terminal.clientversion}
                      </Typography>
                    )}
                    <Typography variant="caption" color="text.secondary">
                      <strong>Aktualisiert:</strong> {updatedText}
                    </Typography>
                  </Box>
                </Box>
              );
            })}
          </Box>
        )}

        {pickerTerminal && (
          <CategoryPickerDialog
            open={Boolean(pickerTerminal)}
            onClose={() => this.setState({ pickerTerminal: null })}
            mode="single"
            title={`Root-Kategorie für „${pickerTerminal.name}“`}
            confirmLabel="Übernehmen"
            selectedId={pickerTerminal.rootCategoryId ?? rootCategoryId}
            onSelectCategory={(targetId) => {
              const term = pickerTerminal;
              this.setState({ pickerTerminal: null }, () => {
                void this.handleSetRootCategory(term, targetId);
              });
            }}
          />
        )}
      </Box>
    );
  }
}