import { useState, useEffect, useCallback } from 'react';
import { useRouter } from 'next/router';
import { isLoggedIn, getCategories, createCategory, deleteCategory } from '../lib/api';
import AppShell from '../components/AppShell';
import { Icon } from '../components/icons';
import { useToast } from '../components/ToastProvider';
import { useConfirm } from '../components/ConfirmProvider';

const ICONS = [
  '🍜', '🥘', '🥬', '🥩', '🍔', '🍕', '☕', '🍺', '🧋', '🍎', '🍪', '🍫',
  '🚗', '🚕', '🚌', '🚇', '⛽', '🚙', '🛵', '✈️', '🚢',
  '🛒', '👔', '👕', '👖', '👟', '👓', '🧢', '👜', '🎒', '💍', '💄',
  '🏠', '🏢', '🏦', '🏥', '🏨', '🏩', '🔧', '🔨', '🛋️', '📺', '💻', '📱',
  '📝', '💰', '🎁', '📈', '🧧', '💳', '🎯', '📚', '🎵', '🎮', '🏃', '⚽',
  '🏊', '🚴', '🎭', '🎨', '🎬', '📷', '🎥', '📺', '🧸', '🐕', '🐈', '🌸', '🌺'
];

export default function Categories() {
  const router = useRouter();
  const { showToast } = useToast();
  const { confirm } = useConfirm();
  const [categories, setCategories] = useState({ expense: [], income: [] });
  const [modalOpen, setModalOpen] = useState(false);
  const [categoryType, setCategoryType] = useState('expense');
  const [loading, setLoading] = useState(true);
  const [submitting, setSubmitting] = useState(false);
  const [formError, setFormError] = useState('');
  const [formData, setFormData] = useState({
    name: '',
    icon: '📝',
  });

  const loadCategories = useCallback(async () => {
    setLoading(true);
    try {
      const data = await getCategories();
      setCategories(data);
    } catch (err) {
      console.error(err);
      showToast(err.message, { tone: 'error' });
    } finally {
      setLoading(false);
    }
  }, [showToast]);

  useEffect(() => {
    if (!isLoggedIn()) {
      router.push('/login');
      return;
    }
    loadCategories();
  }, [router, loadCategories]);

  const openAddModal = (type) => {
    setCategoryType(type);
    setFormData({ name: '', icon: '📝' });
    setFormError('');
    setModalOpen(true);
  };

  const closeModal = () => {
    if (submitting) return;
    setModalOpen(false);
    setFormError('');
  };

  const handleSubmit = async (e) => {
    e.preventDefault();
    if (!formData.name || !formData.icon) {
      setFormError('请填写完整信息');
      return;
    }

    setSubmitting(true);
    setFormError('');
    try {
      await createCategory({
        type: categoryType,
        name: formData.name,
        icon: formData.icon,
      });
      closeModal();
      showToast('分类已创建', { tone: 'success' });
      await loadCategories();
    } catch (err) {
      setFormError(err.message);
      showToast(err.message, { tone: 'error' });
    } finally {
      setSubmitting(false);
    }
  };

  const handleDelete = async (id) => {
    const shouldDelete = await confirm({
      title: '删除此分类？',
      description: '默认分类不可删除，自定义分类删除后将无法恢复。',
      confirmText: '删除',
    });
    if (!shouldDelete) return;

    try {
      await deleteCategory(id);
      showToast('分类已删除', { tone: 'success' });
      await loadCategories();
    } catch (err) {
      showToast(err.message, { tone: 'error' });
    }
  };

  const actions = (
    <button type="button" className="icon-button" aria-label="设置" onClick={() => router.push('/settings')}>
      <Icon name="settings" size={18} />
    </button>
  );

  return (
    <AppShell title="分类" subtitle="整理常用分类与图标" actions={actions} compactHeader>
      {loading ? (
        <div className="card loading-state">加载中...</div>
      ) : (
        <>
          <section className="card category-section category-section--refresh">
            <div className="section-header">
              <div>
                <p className="eyebrow">支出分类</p>
                <h2>支出</h2>
              </div>
              <button type="button" className="btn btn-secondary btn-inline" onClick={() => openAddModal('expense')}>
                <span className="button-content">
                  <Icon name="plus" size={16} />
                  添加
                </span>
              </button>
            </div>
            <div className="category-list category-list--chips">
              {categories.expense.map((cat) => (
                <div key={cat.id || cat.name} className="category-tag">
                  <span className="cat-icon">{cat.icon}</span>
                  <span className="cat-name">{cat.name}</span>
                  {!cat.is_default && (
                    <button type="button" className="icon-button icon-button--ghost cat-delete" aria-label={`删除${cat.name}`} onClick={() => handleDelete(cat.id)}>
                      <Icon name="close" size={14} />
                    </button>
                  )}
                </div>
              ))}
            </div>
          </section>

          <section className="card category-section category-section--refresh">
            <div className="section-header">
              <div>
                <p className="eyebrow">收入分类</p>
                <h2>收入</h2>
              </div>
              <button type="button" className="btn btn-secondary btn-inline" onClick={() => openAddModal('income')}>
                <span className="button-content">
                  <Icon name="plus" size={16} />
                  添加
                </span>
              </button>
            </div>
            <div className="category-list category-list--chips">
              {categories.income.map((cat) => (
                <div key={cat.id || cat.name} className="category-tag">
                  <span className="cat-icon">{cat.icon}</span>
                  <span className="cat-name">{cat.name}</span>
                  {!cat.is_default && (
                    <button type="button" className="icon-button icon-button--ghost cat-delete" aria-label={`删除${cat.name}`} onClick={() => handleDelete(cat.id)}>
                      <Icon name="close" size={14} />
                    </button>
                  )}
                </div>
              ))}
            </div>
          </section>

          <div className="card category-tip category-tip--refresh">
            <p>默认分类无法删除，自定义分类可以删除。</p>
          </div>
        </>
      )}

      {modalOpen && (
        <div className="modal-overlay" onClick={closeModal}>
          <div className="modal" onClick={(e) => e.stopPropagation()}>
            <div className="modal-header">
              <div>
                <p className="eyebrow">新增分类</p>
                <h2>{categoryType === 'expense' ? '新建支出分类' : '新建收入分类'}</h2>
              </div>
              <button type="button" className="icon-button icon-button--ghost" aria-label="关闭弹窗" onClick={closeModal}>
                <Icon name="close" size={18} />
              </button>
            </div>
            {formError && <div className="error-msg">{formError}</div>}
            <form onSubmit={handleSubmit}>
              <div className="form-group">
                <label htmlFor="category-name">分类名称</label>
                <input
                  id="category-name"
                  type="text"
                  value={formData.name}
                  onChange={(e) => setFormData({ ...formData, name: e.target.value })}
                  placeholder="请输入分类名称"
                  required
                  disabled={submitting}
                />
              </div>
              <div className="form-group">
                <label>选择图标</label>
                <div className="icon-grid" style={{ display: 'grid', gridTemplateColumns: 'repeat(8, minmax(0, 1fr))', gap: '8px' }}>
                  {ICONS.map((icon) => (
                    <button
                      key={icon}
                      type="button"
                      className={`icon-btn ${formData.icon === icon ? 'active' : ''}`}
                      onClick={() => setFormData({ ...formData, icon })}
                      disabled={submitting}
                    >
                      {icon}
                    </button>
                  ))}
                </div>
              </div>
              <div className="modal-actions">
                <button type="submit" className="btn btn-primary" disabled={submitting}>
                  {submitting ? (
                    <span className="button-content">
                      <Icon name="spinner" size={16} className="is-spinning" />
                      保存中...
                    </span>
                  ) : '保存'}
                </button>
              </div>
            </form>
          </div>
        </div>
      )}
    </AppShell>
  );
}