import { useState, useRef, useEffect } from 'react';
import { useParams, useNavigate } from 'react-router';
import {
  AlertDialog,
  Badge,
  Button,
  Card,
  KpiStrip,
  Spinner,
  useToast,
} from '@cameleer/design-system';
import { ArrowLeft, RefreshCw, Trash2 } from 'lucide-react';
import {
  useVendorTenant,
  useSuspendTenant,
  useActivateTenant,
  useDeleteTenant,
  useRenewLicense,
  useRestartServer,
} from '../../api/vendor-hooks';
import { ServerStatusBadge } from '../../components/ServerStatusBadge';
import { tierColor } from '../../utils/tier';
import styles from '../../styles/platform.module.css';

function licenseDaysRemaining(expiresAt: string | null | undefined): number {
  if (!expiresAt) return 0;
  return Math.ceil((new Date(expiresAt).getTime() - Date.now()) / 86_400_000);
}

function statusColor(status: string): 'success' | 'error' | 'warning' | 'auto' {
  switch (status?.toUpperCase()) {
    case 'ACTIVE': return 'success';
    case 'SUSPENDED': return 'warning';
    case 'PROVISIONING': return 'auto';
    case 'ERROR': return 'error';
    default: return 'auto';
  }
}

export function TenantDetailPage() {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();
  const { toast } = useToast();

  const wasProvisioning = useRef(false);
  const { data, isLoading } = useVendorTenant(id ?? null, {
    refetchInterval: (query) => {
      const status = query.state.data?.tenant?.status?.toUpperCase();
      return status === 'PROVISIONING' ? 3_000 : false;
    },
  });

  // Toast when provisioning completes
  const currentStatus = data?.tenant?.status?.toUpperCase();
  useEffect(() => {
    if (currentStatus === 'PROVISIONING') {
      wasProvisioning.current = true;
    } else if (wasProvisioning.current && currentStatus) {
      wasProvisioning.current = false;
      toast({
        title: currentStatus === 'ACTIVE' ? 'Tenant provisioned' : `Tenant status: ${currentStatus}`,
        variant: currentStatus === 'ACTIVE' ? 'success' : 'warning',
      });
    }
  }, [currentStatus, toast]);

  const suspendTenant = useSuspendTenant();
  const activateTenant = useActivateTenant();
  const deleteTenant = useDeleteTenant();
  const renewLicense = useRenewLicense();
  const restartServer = useRestartServer();

  const [deleteOpen, setDeleteOpen] = useState(false);

  if (isLoading) {
    return (
      <div style={{ display: 'flex', justifyContent: 'center', padding: 64 }}>
        <Spinner />
      </div>
    );
  }

  if (!data) {
    return (
      <div style={{ padding: 24 }}>
        <p className={styles.description}>Tenant not found.</p>
      </div>
    );
  }

  const { tenant, serverState, license } = data;
  const daysRemaining = licenseDaysRemaining(license?.expiresAt);
  const isSuspended = tenant.status?.toUpperCase() === 'SUSPENDED';

  async function handleSuspendToggle() {
    if (!id) return;
    try {
      if (isSuspended) {
        await activateTenant.mutateAsync(id);
        toast({ title: 'Tenant activated', variant: 'success' });
      } else {
        await suspendTenant.mutateAsync(id);
        toast({ title: 'Tenant suspended', variant: 'warning' });
      }
    } catch (err) {
      toast({ title: 'Action failed', description: String(err), variant: 'error' });
    }
  }

  async function handleRestart() {
    if (!id) return;
    try {
      await restartServer.mutateAsync(id);
      toast({ title: 'Server restarted', variant: 'success' });
    } catch (err) {
      toast({ title: 'Restart failed', description: String(err), variant: 'error' });
    }
  }

  async function handleDelete() {
    if (!id) return;
    try {
      await deleteTenant.mutateAsync(id);
      toast({ title: 'Tenant deleted', variant: 'success' });
      navigate('/vendor/tenants');
    } catch (err) {
      toast({ title: 'Delete failed', description: String(err), variant: 'error' });
    }
  }

  async function handleRenewLicense() {
    if (!id) return;
    try {
      await renewLicense.mutateAsync(id);
      toast({ title: 'License renewed', variant: 'success' });
    } catch (err) {
      toast({ title: 'Renewal failed', description: String(err), variant: 'error' });
    }
  }

  return (
    <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20 }}>
      {/* Header */}
      <div style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
        <Button variant="ghost" onClick={() => navigate('/vendor/tenants')} style={{ padding: '4px 8px' }}>
          <ArrowLeft size={16} />
        </Button>
        <h1 style={{ margin: 0, fontSize: '1.25rem', fontWeight: 600 }}>{tenant.name}</h1>
        <Badge label={tenant.tier} color={tierColor(tenant.tier)} />
        <Badge label={tenant.status} color={statusColor(tenant.status)} />
        {currentStatus === 'PROVISIONING' && (
          <span style={{ display: 'inline-flex', alignItems: 'center', gap: 6, fontSize: 13, color: 'var(--text-muted)' }}>
            <Spinner size="sm" /> Provisioning...
          </span>
        )}
      </div>

      {/* KPI Strip */}
      <KpiStrip
        items={[
          { label: 'Server', value: serverState },
          { label: 'Tier', value: tenant.tier },
          { label: 'Status', value: tenant.status },
          { label: 'License days', value: license ? `${daysRemaining}d` : 'None' },
        ]}
      />

      {/* Cards grid */}
      <div style={{ display: 'grid', gridTemplateColumns: 'repeat(auto-fill, minmax(300px, 1fr))', gap: 16 }}>
        {/* Server Info */}
        <Card title="Server">
          <div className={styles.dividerList}>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>State</span>
              <ServerStatusBadge state={serverState} />
            </div>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>Endpoint</span>
              <span className={styles.kvValueMono}>{tenant.serverEndpoint ?? '—'}</span>
            </div>
            {tenant.provisionError && (
              <div className={styles.kvRow}>
                <span className={styles.kvLabel}>Error</span>
                <span className={styles.kvValue} style={{ color: 'var(--error)', maxWidth: 200, textAlign: 'right' }}>
                  {tenant.provisionError}
                </span>
              </div>
            )}
          </div>
        </Card>

        {/* License Info */}
        <Card title="License">
          {license ? (
            <div className={styles.dividerList}>
              <div className={styles.kvRow}>
                <span className={styles.kvLabel}>Tier</span>
                <Badge label={license.tier} color={tierColor(license.tier)} />
              </div>
              <div className={styles.kvRow}>
                <span className={styles.kvLabel}>Expires</span>
                <span className={styles.kvValue}>
                  {new Date(license.expiresAt).toLocaleDateString()}
                </span>
              </div>
              <div className={styles.kvRow}>
                <span className={styles.kvLabel}>Days remaining</span>
                <span className={styles.kvValue} style={{ color: daysRemaining <= 30 ? 'var(--warning)' : undefined }}>
                  {daysRemaining}d
                </span>
              </div>
              <div style={{ paddingTop: 8 }}>
                <Button
                  variant="secondary"
                  onClick={handleRenewLicense}
                  loading={renewLicense.isPending}
                >
                  <RefreshCw size={14} style={{ marginRight: 6 }} />
                  Renew License
                </Button>
              </div>
            </div>
          ) : (
            <div style={{ display: 'flex', flexDirection: 'column', gap: 8 }}>
              <p className={styles.description}>No license issued.</p>
              <Button
                variant="secondary"
                onClick={handleRenewLicense}
                loading={renewLicense.isPending}
              >
                Issue License
              </Button>
            </div>
          )}
        </Card>

        {/* Tenant Info */}
        <Card title="Tenant Info">
          <div className={styles.dividerList}>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>ID</span>
              <span className={styles.kvValueMono}>{tenant.id}</span>
            </div>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>Slug</span>
              <span className={styles.kvValueMono}>{tenant.slug}</span>
            </div>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>Created</span>
              <span className={styles.kvValue}>{new Date(tenant.createdAt).toLocaleDateString()}</span>
            </div>
            <div className={styles.kvRow}>
              <span className={styles.kvLabel}>Updated</span>
              <span className={styles.kvValue}>{new Date(tenant.updatedAt).toLocaleDateString()}</span>
            </div>
          </div>
        </Card>

        {/* Actions */}
        <Card title="Actions">
          <div style={{ display: 'flex', flexDirection: 'column', gap: 10 }}>
            <Button
              variant="secondary"
              onClick={handleRestart}
              loading={restartServer.isPending}
            >
              <RefreshCw size={14} style={{ marginRight: 6 }} />
              Restart Server
            </Button>
            <Button
              variant="secondary"
              onClick={handleSuspendToggle}
              loading={suspendTenant.isPending || activateTenant.isPending}
            >
              {isSuspended ? 'Activate Tenant' : 'Suspend Tenant'}
            </Button>
            <Button
              variant="danger"
              onClick={() => setDeleteOpen(true)}
            >
              <Trash2 size={14} style={{ marginRight: 6 }} />
              Delete Tenant
            </Button>
          </div>
        </Card>
      </div>

      {/* Delete confirmation dialog */}
      <AlertDialog
        open={deleteOpen}
        onClose={() => setDeleteOpen(false)}
        onConfirm={handleDelete}
        title="Delete Tenant"
        description={`Are you sure you want to delete "${tenant.name}"? This action cannot be undone.`}
        confirmLabel="Delete"
        cancelLabel="Cancel"
        variant="danger"
        loading={deleteTenant.isPending}
      />
    </div>
  );
}