/**
 * @ai-summary Settings page component for desktop application
 */

import React, { useState } from 'react';
import { useAuth0 } from '@auth0/auth0-react';
import { useNavigate } from 'react-router-dom';
import { useLogout } from '../core/auth/useLogout';
import { useUnits } from '../core/units/UnitsContext';
import { useAdminAccess } from '../core/auth/useAdminAccess';
import { useProfile, useUpdateProfile } from '../features/settings/hooks/useProfile';
import { useExportUserData } from '../features/settings/hooks/useExportUserData';
import { useVehicles } from '../features/vehicles/hooks/useVehicles';
import { getVehicleSubtitle } from '@/core/utils/vehicleDisplay';
import { useSubscription } from '../features/subscription/hooks/useSubscription';
import { useTheme } from '../shared-minimal/theme/ThemeContext';
import { DeleteAccountDialog } from '../features/settings/components/DeleteAccountDialog';
import { PendingDeletionBanner } from '../features/settings/components/PendingDeletionBanner';
import { ImportDialog } from '../features/settings/components/ImportDialog';
import toast from 'react-hot-toast';
import {
  Box,
  Typography,
  Switch,
  Divider,
  Avatar,
  List,
  ListItem,
  ListItemIcon,
  ListItemText,
  ListItemSecondaryAction,
  Button as MuiButton,
  Select,
  MenuItem,
  FormControl,
  TextField,
  CircularProgress,
  Chip
} from '@mui/material';
import AccountCircleIcon from '@mui/icons-material/AccountCircle';
import NotificationsIcon from '@mui/icons-material/Notifications';
import PaletteIcon from '@mui/icons-material/Palette';
import SecurityIcon from '@mui/icons-material/Security';
import StorageIcon from '@mui/icons-material/Storage';
import AdminPanelSettingsIcon from '@mui/icons-material/AdminPanelSettings';
import DirectionsCarIcon from '@mui/icons-material/DirectionsCar';
import CreditCardIcon from '@mui/icons-material/CreditCard';
import EditIcon from '@mui/icons-material/Edit';
import SaveIcon from '@mui/icons-material/Save';
import CancelIcon from '@mui/icons-material/Cancel';
import { Card } from '../shared-minimal/components/Card';

export const SettingsPage: React.FC = () => {
  const { user } = useAuth0();
  const { logout } = useLogout();
  const navigate = useNavigate();
  const { unitSystem, setUnitSystem } = useUnits();
  const { isAdmin, loading: adminLoading } = useAdminAccess();
  const { isDarkMode, setDarkMode } = useTheme();
  const [notifications, setNotifications] = useState(true);
  const [emailUpdates, setEmailUpdates] = useState(false);

  // Profile state
  const { data: profile, isLoading: profileLoading } = useProfile();
  const updateProfileMutation = useUpdateProfile();

  // Vehicles state (for My Vehicles section)
  const { data: vehicles, isLoading: vehiclesLoading } = useVehicles();

  // Subscription state
  const { data: subscriptionData, isLoading: subscriptionLoading } = useSubscription();
  const subscription = subscriptionData?.data;

  const [isEditingProfile, setIsEditingProfile] = useState(false);
  const [editedDisplayName, setEditedDisplayName] = useState('');
  const [editedNotificationEmail, setEditedNotificationEmail] = useState('');
  const [deleteDialogOpen, setDeleteDialogOpen] = useState(false);
  const [importDialogOpen, setImportDialogOpen] = useState(false);
  const [selectedFile, setSelectedFile] = useState<File | null>(null);
  const fileInputRef = React.useRef<HTMLInputElement>(null);
  const exportMutation = useExportUserData();

  // Initialize edit form when profile loads or edit mode starts
  React.useEffect(() => {
    if (profile && isEditingProfile) {
      setEditedDisplayName(profile.displayName || '');
      setEditedNotificationEmail(profile.notificationEmail || '');
    }
  }, [profile, isEditingProfile]);

  const handleLogout = () => {
    logout();
  };

  const handleEditProfile = () => {
    setIsEditingProfile(true);
  };

  const handleCancelEdit = () => {
    setIsEditingProfile(false);
    setEditedDisplayName(profile?.displayName || '');
    setEditedNotificationEmail(profile?.notificationEmail || '');
  };

  const handleSaveProfile = async () => {
    const updates: { displayName?: string; notificationEmail?: string } = {};

    if (editedDisplayName !== (profile?.displayName || '')) {
      updates.displayName = editedDisplayName;
    }

    if (editedNotificationEmail !== (profile?.notificationEmail || '')) {
      updates.notificationEmail = editedNotificationEmail || undefined;
    }

    if (Object.keys(updates).length === 0) {
      setIsEditingProfile(false);
      return;
    }

    try {
      await updateProfileMutation.mutateAsync(updates);
      setIsEditingProfile(false);
    } catch (error) {
      // Error is handled by the mutation hook
    }
  };

  const handleImportClick = () => {
    fileInputRef.current?.click();
  };

  const handleFileChange = (event: React.ChangeEvent<HTMLInputElement>) => {
    const file = event.target.files?.[0];
    if (!file) return;

    // Validate file extension
    if (!file.name.endsWith('.tar.gz')) {
      toast.error('Please select a .tar.gz file');
      return;
    }

    // Validate file size (max 500MB)
    const maxSize = 500 * 1024 * 1024;
    if (file.size > maxSize) {
      toast.error('File size exceeds 500MB limit');
      return;
    }

    setSelectedFile(file);
    setImportDialogOpen(true);

    // Reset input so same file can be selected again
    event.target.value = '';
  };

  const handleImportClose = () => {
    setImportDialogOpen(false);
    setSelectedFile(null);
  };

  return (
    <Box sx={{ py: 2 }}>
      <Typography variant="h4" sx={{ fontWeight: 700, color: 'text.primary', mb: 4 }}>
        Settings
      </Typography>

      <PendingDeletionBanner />

      <Box sx={{ display: 'flex', flexDirection: 'column', gap: 3 }}>
        {/* Profile Section */}
        <Card>
          <Box sx={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', mb: 3 }}>
            <Typography variant="h6" sx={{ fontWeight: 600 }}>
              Profile
            </Typography>
            {!isEditingProfile && !profileLoading && (
              <MuiButton
                variant="contained"
                size="small"
                startIcon={<EditIcon />}
                onClick={handleEditProfile}
                sx={{
                  backgroundColor: 'primary.main',
                  color: 'primary.contrastText',
                  '&:hover': {
                    backgroundColor: 'primary.dark'
                  }
                }}
              >
                Edit
              </MuiButton>
            )}
          </Box>

          {profileLoading ? (
            <Box sx={{ display: 'flex', justifyContent: 'center', py: 4 }}>
              <CircularProgress />
            </Box>
          ) : (
            <>
              <Box sx={{ display: 'flex', alignItems: 'center', mb: 3 }}>
                <Avatar
                  sx={{
                    width: 64,
                    height: 64,
                    bgcolor: 'primary.main',
                    fontSize: '1.5rem',
                    fontWeight: 600,
                    mr: 3
                  }}
                >
                  {profile?.displayName?.charAt(0) || user?.name?.charAt(0) || user?.email?.charAt(0)}
                </Avatar>
                <Box>
                  <Typography variant="h6" sx={{ fontWeight: 500 }}>
                    {profile?.displayName || user?.name || 'User'}
                  </Typography>
                  <Typography variant="body2" color="text.secondary">
                    {profile?.email || user?.email}
                  </Typography>
                  <Typography variant="caption" color="text.secondary">
                    Verified account
                  </Typography>
                </Box>
              </Box>

              {isEditingProfile ? (
                <Box sx={{ display: 'flex', flexDirection: 'column', gap: 3 }}>
                  <TextField
                    label="Email"
                    value={profile?.email || ''}
                    disabled
                    fullWidth
                    helperText="Email is managed by your account provider and cannot be changed here"
                    variant="outlined"
                  />
                  <TextField
                    label="Display Name"
                    value={editedDisplayName}
                    onChange={(e) => setEditedDisplayName(e.target.value)}
                    fullWidth
                    placeholder="Enter your display name"
                    variant="outlined"
                  />
                  <TextField
                    label="Notification Email"
                    value={editedNotificationEmail}
                    onChange={(e) => setEditedNotificationEmail(e.target.value)}
                    fullWidth
                    placeholder="Leave blank to use your primary email"
                    helperText="Optional: Use a different email address for notifications"
                    variant="outlined"
                    type="email"
                  />
                  <Box sx={{ display: 'flex', gap: 2, justifyContent: 'flex-end' }}>
                    <MuiButton
                      variant="outlined"
                      startIcon={<CancelIcon />}
                      onClick={handleCancelEdit}
                      disabled={updateProfileMutation.isPending}
                    >
                      Cancel
                    </MuiButton>
                    <MuiButton
                      variant="contained"
                      startIcon={updateProfileMutation.isPending ? <CircularProgress size={20} /> : <SaveIcon />}
                      onClick={handleSaveProfile}
                      disabled={updateProfileMutation.isPending}
                    >
                      Save
                    </MuiButton>
                  </Box>
                </Box>
              ) : (
                <List disablePadding>
                  <ListItem>
                    <ListItemIcon>
                      <AccountCircleIcon />
                    </ListItemIcon>
                    <ListItemText
                      primary="Email"
                      secondary={profile?.email || user?.email || 'Not available'}
                    />
                  </ListItem>
                  <Divider />
                  <ListItem>
                    <ListItemText
                      primary="Display Name"
                      secondary={profile?.displayName || 'Not set'}
                      sx={{ pl: 7 }}
                    />
                  </ListItem>
                  <Divider />
                  <ListItem>
                    <ListItemText
                      primary="Notification Email"
                      secondary={profile?.notificationEmail || 'Using primary email'}
                      sx={{ pl: 7 }}
                    />
                  </ListItem>
                  <Divider />
                  <ListItem>
                    <ListItemIcon>
                      <SecurityIcon />
                    </ListItemIcon>
                    <ListItemText
                      primary="Security & Privacy"
                      secondary="Password, two-factor authentication"
                    />
                    <ListItemSecondaryAction>
                      <MuiButton
                        variant="contained"
                        size="small"
                        onClick={() => navigate('/garage/settings/security')}
                        sx={{
                          backgroundColor: 'primary.main',
                          color: 'primary.contrastText',
                          '&:hover': {
                            backgroundColor: 'primary.dark'
                          }
                        }}
                      >
                        Manage
                      </MuiButton>
                    </ListItemSecondaryAction>
                  </ListItem>
                </List>
              )}
            </>
          )}
        </Card>

        {/* My Vehicles Section */}
        <Card>
          <Box sx={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', mb: 3 }}>
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
              <DirectionsCarIcon color="primary" />
              <Typography variant="h6" sx={{ fontWeight: 600 }}>
                My Vehicles
              </Typography>
              {!vehiclesLoading && vehicles && (
                <Typography variant="body2" color="text.secondary">
                  ({vehicles.length})
                </Typography>
              )}
            </Box>
            <MuiButton
              variant="contained"
              size="small"
              onClick={() => navigate('/garage/vehicles')}
              sx={{
                backgroundColor: 'primary.main',
                color: 'primary.contrastText',
                '&:hover': {
                  backgroundColor: 'primary.dark'
                }
              }}
            >
              Manage
            </MuiButton>
          </Box>

          {vehiclesLoading ? (
            <Box sx={{ display: 'flex', justifyContent: 'center', py: 3 }}>
              <CircularProgress size={24} />
            </Box>
          ) : !vehicles?.length ? (
            <Typography variant="body2" color="text.secondary" sx={{ py: 2 }}>
              No vehicles registered. Add your first vehicle to get started.
            </Typography>
          ) : (
            <List disablePadding>
              {vehicles.map((vehicle, index) => (
                <React.Fragment key={vehicle.id}>
                  {index > 0 && <Divider />}
                  <ListItem sx={{ py: 1.5 }}>
                    <ListItemText
                      primary={getVehicleSubtitle(vehicle) || 'Unknown Vehicle'}
                      secondary={vehicle.nickname || undefined}
                      primaryTypographyProps={{ fontWeight: 500 }}
                    />
                  </ListItem>
                </React.Fragment>
              ))}
            </List>
          )}
        </Card>

        {/* Subscription Section */}
        <Card>
          <Box sx={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', mb: 3 }}>
            <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
              <CreditCardIcon color="primary" />
              <Typography variant="h6" sx={{ fontWeight: 600 }}>
                Subscription
              </Typography>
            </Box>
            <MuiButton
              variant="contained"
              size="small"
              onClick={() => navigate('/garage/settings/subscription')}
              sx={{
                backgroundColor: 'primary.main',
                color: 'primary.contrastText',
                '&:hover': {
                  backgroundColor: 'primary.dark'
                }
              }}
            >
              Manage
            </MuiButton>
          </Box>

          {subscriptionLoading ? (
            <Box sx={{ display: 'flex', justifyContent: 'center', py: 3 }}>
              <CircularProgress size={24} />
            </Box>
          ) : (
            <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
              <Box sx={{ display: 'flex', alignItems: 'center', gap: 2 }}>
                <Typography variant="body1" sx={{ fontWeight: 500 }}>
                  Current Plan:
                </Typography>
                <Chip
                  label={(subscription?.tier || 'free').toUpperCase()}
                  color="primary"
                  size="small"
                />
                {subscription?.status && subscription.status !== 'active' && (
                  <Chip
                    label={subscription.status.replace('_', ' ')}
                    color={subscription.status === 'past_due' ? 'warning' : 'error'}
                    size="small"
                  />
                )}
              </Box>
              <Typography variant="body2" color="text.secondary">
                {!subscription || subscription.tier === 'free'
                  ? 'Upgrade to Pro or Enterprise for more features and vehicle slots.'
                  : subscription.tier === 'pro'
                  ? 'Pro plan with up to 5 vehicles and full features.'
                  : 'Enterprise plan with unlimited vehicles and all features.'}
              </Typography>
            </Box>
          )}
        </Card>

        {/* Notifications Section */}
        <Card>
          <Typography variant="h6" sx={{ fontWeight: 600, mb: 3 }}>
            Notifications
          </Typography>

          <List disablePadding>
            <ListItem>
              <ListItemIcon>
                <NotificationsIcon />
              </ListItemIcon>
              <ListItemText
                primary="Push Notifications"
                secondary="Receive notifications about your vehicles"
              />
              <ListItemSecondaryAction>
                <Switch
                  checked={notifications}
                  onChange={(e) => setNotifications(e.target.checked)}
                  color="primary"
                />
              </ListItemSecondaryAction>
            </ListItem>
            <Divider />
            <ListItem>
              <ListItemText 
                primary="Email Updates" 
                secondary="Receive maintenance reminders and updates"
                sx={{ pl: 7 }}
              />
              <ListItemSecondaryAction>
                <Switch
                  checked={emailUpdates}
                  onChange={(e) => setEmailUpdates(e.target.checked)}
                  color="primary"
                />
              </ListItemSecondaryAction>
            </ListItem>
          </List>
        </Card>

        {/* Appearance & Units Section */}
        <Card>
          <Typography variant="h6" sx={{ fontWeight: 600, mb: 3 }}>
            Appearance & Units
          </Typography>
          
          <List disablePadding>
            <ListItem>
              <ListItemIcon>
                <PaletteIcon />
              </ListItemIcon>
              <ListItemText 
                primary="Dark Mode" 
                secondary="Use dark theme for better night viewing"
              />
              <ListItemSecondaryAction>
                <Switch
                  checked={isDarkMode}
                  onChange={(e) => setDarkMode(e.target.checked)}
                  color="primary"
                />
              </ListItemSecondaryAction>
            </ListItem>
            <Divider />
            <ListItem>
              <ListItemText 
                primary="Units for distance and capacity" 
                secondary="Imperial: miles, gallons, MPG, USD | Metric: km, liters, L/100km, EUR"
                sx={{ pl: 7 }}
              />
              <ListItemSecondaryAction>
                <FormControl size="small" sx={{ minWidth: 120 }}>
                  <Select
                    value={unitSystem}
                    onChange={(e) => setUnitSystem(e.target.value as 'imperial' | 'metric')}
                    displayEmpty
                    sx={{ 
                      fontSize: '0.875rem',
                      '& .MuiSelect-select': {
                        py: 1
                      }
                    }}
                  >
                    <MenuItem value="imperial">Imperial</MenuItem>
                    <MenuItem value="metric">Metric</MenuItem>
                  </Select>
                </FormControl>
              </ListItemSecondaryAction>
            </ListItem>
          </List>
        </Card>

        {/* Data & Storage Section */}
        <Card>
          <Typography variant="h6" sx={{ fontWeight: 600, mb: 3 }}>
            Data & Storage
          </Typography>

          <List disablePadding>
            <ListItem>
              <ListItemIcon>
                <StorageIcon />
              </ListItemIcon>
              <ListItemText
                primary="Import Data"
                secondary="Upload and restore your vehicle data from a backup"
              />
              <ListItemSecondaryAction>
                <input
                  ref={fileInputRef}
                  type="file"
                  accept=".tar.gz"
                  onChange={handleFileChange}
                  style={{ display: 'none' }}
                  aria-label="Select import file"
                />
                <MuiButton
                  variant="contained"
                  size="small"
                  onClick={handleImportClick}
                  sx={{
                    backgroundColor: 'primary.main',
                    color: 'primary.contrastText',
                    '&:hover': {
                      backgroundColor: 'primary.dark'
                    }
                  }}
                >
                  Import
                </MuiButton>
              </ListItemSecondaryAction>
            </ListItem>
            <Divider />
            <ListItem>
              <ListItemText
                primary="Export Data"
                secondary="Download your vehicle and fuel log data"
                sx={{ pl: 7 }}
              />
              <ListItemSecondaryAction>
                <MuiButton
                  variant="contained"
                  size="small"
                  disabled={exportMutation.isPending}
                  onClick={() => exportMutation.mutate()}
                  sx={{
                    backgroundColor: 'primary.main',
                    color: 'primary.contrastText',
                    '&:hover': {
                      backgroundColor: 'primary.dark'
                    }
                  }}
                >
                  {exportMutation.isPending ? 'Exporting...' : 'Export'}
                </MuiButton>
              </ListItemSecondaryAction>
            </ListItem>
          </List>
        </Card>

        {/* Admin Console Section */}
        {!adminLoading && isAdmin && (
          <Card>
            <Typography variant="h6" sx={{ fontWeight: 600, mb: 3, color: 'primary.main' }}>
              Admin Console
            </Typography>

            <List disablePadding>
              <ListItem>
                <ListItemIcon>
                  <AdminPanelSettingsIcon />
                </ListItemIcon>
                <ListItemText
                  primary="User Management"
                  secondary="Manage admin users and permissions"
                />
                <ListItemSecondaryAction>
                  <MuiButton
                    variant="contained"
                    size="small"
                    onClick={() => navigate('/garage/settings/admin/users')}
                    sx={{
                      backgroundColor: 'primary.main',
                      color: 'primary.contrastText',
                      '&:hover': {
                        backgroundColor: 'primary.dark'
                      }
                    }}
                  >
                    Manage
                  </MuiButton>
                </ListItemSecondaryAction>
              </ListItem>
              <Divider />
              <ListItem>
                <ListItemText
                  primary="Vehicle Catalog"
                  secondary="Manage makes, models, years, trims, and engines"
                  sx={{ pl: 7 }}
                />
                <ListItemSecondaryAction>
                  <MuiButton
                    variant="contained"
                    size="small"
                    onClick={() => navigate('/garage/settings/admin/catalog')}
                    sx={{
                      backgroundColor: 'primary.main',
                      color: 'primary.contrastText',
                      '&:hover': {
                        backgroundColor: 'primary.dark'
                      }
                    }}
                  >
                    Manage
                  </MuiButton>
                </ListItemSecondaryAction>
              </ListItem>
              <Divider />
              <ListItem>
                <ListItemText
                  primary="Email Templates"
                  secondary="Manage notification email templates"
                  sx={{ pl: 7 }}
                />
                <ListItemSecondaryAction>
                  <MuiButton
                    variant="contained"
                    size="small"
                    onClick={() => navigate('/garage/settings/admin/email-templates')}
                    sx={{
                      backgroundColor: 'primary.main',
                      color: 'primary.contrastText',
                      '&:hover': {
                        backgroundColor: 'primary.dark'
                      }
                    }}
                  >
                    Manage
                  </MuiButton>
                </ListItemSecondaryAction>
              </ListItem>
              <Divider />
              <ListItem>
                <ListItemText
                  primary="Backup & Restore"
                  secondary="Create backups and restore data"
                  sx={{ pl: 7 }}
                />
                <ListItemSecondaryAction>
                  <MuiButton
                    variant="contained"
                    size="small"
                    onClick={() => navigate('/garage/settings/admin/backup')}
                    sx={{
                      backgroundColor: 'primary.main',
                      color: 'primary.contrastText',
                      '&:hover': {
                        backgroundColor: 'primary.dark'
                      }
                    }}
                  >
                    Manage
                  </MuiButton>
                </ListItemSecondaryAction>
              </ListItem>
              <Divider />
              <ListItem>
                <ListItemText
                  primary="Audit Logs"
                  secondary="View system activity and audit logs"
                  sx={{ pl: 7 }}
                />
                <ListItemSecondaryAction>
                  <MuiButton
                    variant="contained"
                    size="small"
                    onClick={() => navigate('/garage/settings/admin/logs')}
                    sx={{
                      backgroundColor: 'primary.main',
                      color: 'primary.contrastText',
                      '&:hover': {
                        backgroundColor: 'primary.dark'
                      }
                    }}
                  >
                    View
                  </MuiButton>
                </ListItemSecondaryAction>
              </ListItem>
            </List>
          </Card>
        )}

        {/* Account Actions */}
        <Card>
          <Typography variant="h6" sx={{ fontWeight: 600, mb: 3, color: 'primary.main' }}>
            Account Actions
          </Typography>

          <Box sx={{ display: 'flex', gap: 2 }}>
            <MuiButton
              variant="contained"
              onClick={handleLogout}
              sx={{
                borderRadius: '999px',
                backgroundColor: 'grey.600',
                color: 'common.white',
                '&:hover': {
                  backgroundColor: 'grey.700'
                }
              }}
            >
              Sign Out
            </MuiButton>
            <MuiButton
              variant="outlined"
              color="error"
              onClick={() => setDeleteDialogOpen(true)}
              sx={{ borderRadius: '999px' }}
            >
              Delete Account
            </MuiButton>
          </Box>
        </Card>
      </Box>

      <DeleteAccountDialog open={deleteDialogOpen} onClose={() => setDeleteDialogOpen(false)} />
      <ImportDialog
        isOpen={importDialogOpen}
        onClose={handleImportClose}
        file={selectedFile}
      />
    </Box>
  );
};