import React from 'react';
import clsx from 'clsx';
import { useTranslation } from 'react-i18next';
import { Badge } from '@/components/ui/Badge';
import { Pagination } from '@/components/ui/Pagination';
import { EmptyState } from '@/components/ui/EmptyState';
import type { UnifiedContact } from '@/api/hooks';

export type ContactViewMode = 'list' | 'table' | 'cards';

export interface ContactListProps {
  contacts: UnifiedContact[];
  selectedContactId: string | null;
  onSelectContact: (contact: UnifiedContact) => void;
  loading?: boolean;
  currentPage: number;
  total: number;
  pageSize: number;
  onPageChange: (page: number) => void;
  viewMode: ContactViewMode;
  sortBy: string;
  sortOrder: 'asc' | 'desc';
  onSortChange: (sortBy: string, sortOrder: 'asc' | 'desc') => void;
}

function TypeBadge({ type }: { type: string }) {
  const { t } = useTranslation();
  return (
    <Badge variant={type === 'company' ? 'primary' : 'info'}>
      {type === 'company' ? t('contacts.companies') : t('contacts.persons')}
    </Badge>
  );
}

function getDisplayName(c: UnifiedContact): string {
  return c.displayname || c.name || [c.firstname, c.surname].filter(Boolean).join(' ') || c.email_1 || c.id;
}

function getInitials(c: UnifiedContact): string {
  const name = getDisplayName(c);
  return name.charAt(0).toUpperCase();
}

function getCity(c: UnifiedContact): string {
  return c.mailing_city || c.visit_city || c.invoice_city || '—';
}

function getEmail(c: UnifiedContact): string {
  return c.email_1 || c.email_2 || '—';
}

function getPhone(c: UnifiedContact): string {
  return c.phone_1 || c.phone_2 || '—';
}

function getTags(c: UnifiedContact): string[] {
  if (!c.tags) return [];
  return c.tags.split(',').map((t) => t.trim()).filter(Boolean);
}

export function ContactList({
  contacts,
  selectedContactId,
  onSelectContact,
  loading,
  currentPage,
  total,
  pageSize,
  onPageChange,
  viewMode,
  sortBy,
  sortOrder,
  onSortChange,
}: ContactListProps) {
  const { t } = useTranslation();

  if (loading) {
    return (
      <div className="flex items-center justify-center py-12" data-testid="contact-list-loading">
        <svg className="animate-spin h-5 w-5 text-secondary-400" fill="none" viewBox="0 0 24 24" aria-hidden="true">
          <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4" />
          <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z" />
        </svg>
        <span className="ml-2 text-sm text-secondary-500">{t('common.loading')}</span>
      </div>
    );
  }

  if (contacts.length === 0) {
    return (
      <div data-testid="contact-list-empty">
        <EmptyState title={t('contacts.emptyTitle')} description={t('contacts.emptyDescription')} />
      </div>
    );
  }

  const totalPages = Math.ceil(total / pageSize);

  const handleSort = (field: string) => {
    if (sortBy === field) {
      onSortChange(field, sortOrder === 'asc' ? 'desc' : 'asc');
    } else {
      onSortChange(field, 'asc');
    }
  };

  // ── List View ──
  if (viewMode === 'list') {
    return (
      <div className="flex flex-col h-full" data-testid="contact-list-view">
        <div className="flex-1 overflow-y-auto">
          <ul className="divide-y divide-secondary-100" role="list">
            {contacts.map((contact) => (
              <li key={contact.id}>
                <button
                  draggable
                  onDragStart={(e) => {
                    e.dataTransfer.setData('text/plain', contact.id);
                    e.dataTransfer.effectAllowed = 'move';
                  }}
                  onClick={() => onSelectContact(contact)}
                  className={clsx(
                    'flex items-center gap-3 w-full px-3 py-2.5 text-left min-h-touch transition-colors',
                    selectedContactId === contact.id
                      ? 'bg-primary-50'
                      : 'hover:bg-secondary-50',
                  )}
                  aria-current={selectedContactId === contact.id ? 'true' : undefined}
                >
                  <div className="w-9 h-9 rounded-full bg-primary-100 flex items-center justify-center text-primary-700 font-semibold text-sm flex-shrink-0">
                    {getInitials(contact)}
                  </div>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-2">
                      <span className="font-medium text-sm text-secondary-900 truncate">{getDisplayName(contact)}</span>
                      <TypeBadge type={contact.type} />
                    </div>
                    <div className="text-xs text-secondary-500 truncate">
                      {getEmail(contact)} · {getCity(contact)}
                    </div>
                  </div>
                </button>
              </li>
            ))}
          </ul>
        </div>
        <Pagination
          currentPage={currentPage}
          totalPages={totalPages}
          total={total}
          pageSize={pageSize}
          onPageChange={onPageChange}
        />
      </div>
    );
  }

  // ── Table View ──
  if (viewMode === 'table') {
    const sortIcon = (field: string) => {
      if (sortBy !== field) return null;
      return sortOrder === 'asc' ? ' ▲' : ' ▼';
    };
    return (
      <div className="flex flex-col h-full" data-testid="contact-table-view">
        <div className="flex-1 overflow-auto">
          <table className="w-full text-sm">
            <thead className="sticky top-0 bg-white border-b border-secondary-200">
              <tr>
                <th className="px-3 py-2 text-left font-medium text-secondary-600 w-10">
                  <input type="checkbox" className="rounded border-secondary-300" aria-label={t('common.all')} />
                </th>
                <th
                  className="px-3 py-2 text-left font-medium text-secondary-600 cursor-pointer select-none"
                  onClick={() => handleSort('type')}
                  aria-sort={sortBy === 'type' ? (sortOrder === 'asc' ? 'ascending' : 'descending') : 'none'}
                >
                  {t('contacts.type')}{sortIcon('type')}
                </th>
                <th
                  className="px-3 py-2 text-left font-medium text-secondary-600 cursor-pointer select-none"
                  onClick={() => handleSort('displayname')}
                  aria-sort={sortBy === 'displayname' ? (sortOrder === 'asc' ? 'ascending' : 'descending') : 'none'}
                >
                  {t('contacts.fullName')}{sortIcon('displayname')}
                </th>
                <th
                  className="px-3 py-2 text-left font-medium text-secondary-600 cursor-pointer select-none"
                  onClick={() => handleSort('email_1')}
                  aria-sort={sortBy === 'email_1' ? (sortOrder === 'asc' ? 'ascending' : 'descending') : 'none'}
                >
                  {t('contacts.email')}{sortIcon('email_1')}
                </th>
                <th className="px-3 py-2 text-left font-medium text-secondary-600">{t('contacts.phone')}</th>
                <th
                  className="px-3 py-2 text-left font-medium text-secondary-600 cursor-pointer select-none"
                  onClick={() => handleSort('mailing_city')}
                  aria-sort={sortBy === 'mailing_city' ? (sortOrder === 'asc' ? 'ascending' : 'descending') : 'none'}
                >
                  {t('address.city')}{sortIcon('mailing_city')}
                </th>
                <th className="px-3 py-2 text-left font-medium text-secondary-600">{t('tags.title')}</th>
              </tr>
            </thead>
            <tbody className="divide-y divide-secondary-100">
              {contacts.map((contact) => (
                <tr
                  key={contact.id}
                  draggable
                  onDragStart={(e) => {
                    e.dataTransfer.setData('text/plain', contact.id);
                    e.dataTransfer.effectAllowed = 'move';
                  }}
                  onClick={() => onSelectContact(contact)}
                  className={clsx(
                    'cursor-pointer transition-colors',
                    selectedContactId === contact.id ? 'bg-primary-50' : 'hover:bg-secondary-50',
                  )}
                  aria-current={selectedContactId === contact.id ? 'true' : undefined}
                >
                  <td className="px-3 py-2" onClick={(e) => e.stopPropagation()}>
                    <input type="checkbox" className="rounded border-secondary-300" aria-label={getDisplayName(contact)} />
                  </td>
                  <td className="px-3 py-2"><TypeBadge type={contact.type} /></td>
                  <td className="px-3 py-2 font-medium text-secondary-900">{getDisplayName(contact)}</td>
                  <td className="px-3 py-2 text-secondary-600">{getEmail(contact)}</td>
                  <td className="px-3 py-2 text-secondary-600">{getPhone(contact)}</td>
                  <td className="px-3 py-2 text-secondary-600">{getCity(contact)}</td>
                  <td className="px-3 py-2">
                    <div className="flex flex-wrap gap-1">
                      {getTags(contact).slice(0, 3).map((tag) => (
                        <Badge key={tag} variant="secondary">{tag}</Badge>
                      ))}
                    </div>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
        <Pagination
          currentPage={currentPage}
          totalPages={totalPages}
          total={total}
          pageSize={pageSize}
          onPageChange={onPageChange}
        />
      </div>
    );
  }

  // ── Cards View ──
  return (
    <div className="flex flex-col h-full" data-testid="contact-cards-view">
      <div className="flex-1 overflow-y-auto p-3">
        <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
          {contacts.map((contact) => (
            <div
              key={contact.id}
              draggable
              onDragStart={(e) => {
                e.dataTransfer.setData('text/plain', contact.id);
                e.dataTransfer.effectAllowed = 'move';
              }}
              onClick={() => onSelectContact(contact)}
              className={clsx(
                'p-3 rounded-lg border cursor-pointer transition-colors min-h-touch',
                selectedContactId === contact.id
                  ? 'border-primary-300 bg-primary-50'
                  : 'border-secondary-200 bg-white hover:bg-secondary-50',
              )}
              role="button"
              tabIndex={0}
              aria-current={selectedContactId === contact.id ? 'true' : undefined}
            >
              <div className="flex items-center gap-3 mb-2">
                <div className="w-10 h-10 rounded-full bg-primary-100 flex items-center justify-center text-primary-700 font-semibold flex-shrink-0">
                  {getInitials(contact)}
                </div>
                <div className="flex-1 min-w-0">
                  <div className="flex items-center gap-2">
                    <span className="font-medium text-sm text-secondary-900 truncate">{getDisplayName(contact)}</span>
                  </div>
                  <TypeBadge type={contact.type} />
                </div>
              </div>
              <div className="text-xs text-secondary-500 space-y-0.5">
                <div className="truncate">{getEmail(contact)}</div>
                <div className="truncate">{getPhone(contact)}</div>
                <div className="truncate">{getCity(contact)}</div>
              </div>
            </div>
          ))}
        </div>
      </div>
      <Pagination
        currentPage={currentPage}
        totalPages={totalPages}
        total={total}
        pageSize={pageSize}
        onPageChange={onPageChange}
      />
    </div>
  );
}