import { h } from '@ui-arch/frame';
import type { JsonViewerProps } from './types.js';

// 值类型归类：数组 / 对象算分支，其余算叶子（null 单独一类，避免被 typeof 报成 object）
type JsonKind = 'array' | 'object' | 'string' | 'number' | 'boolean' | 'null';
const kindOf = (v: unknown): JsonKind => (v === null ? 'null' : Array.isArray(v) ? 'array' : typeof v === 'object' ? 'object' : (typeof v as JsonKind));

/*** 叶子值文案：字符串补引号，其余按字面；null 用灰字斜体在样式层区分 ***/
function leafText(v: unknown): string {
  return typeof v === 'string' ? `"${v}"` : String(v);
}

/*** 分支摘要：收起时也要看得出里面有多少内容，否则无法判断值不值得展开 ***/
function summaryOf(v: unknown): string {
  if (Array.isArray(v)) return `${v.length} 项`;
  const n = Object.keys(v as Record<string, unknown>).length; // 对象分支：按自有键计数
  return `${n} 个键`;
}

/*** JSON 树查看：按层折叠展示任意值，数组 / 对象可展开收起，叶子按类型着色；只读、不解析编辑 ***/
export function jsonViewer(props: JsonViewerProps): HTMLElement {
  const rootLabel = props.rootLabel ?? 'root'; // 根标签：贴顶那一行的键名
  const openDepth = props.depth ?? 2; // 默认展开层数：2 层能看出一级结构又不至于刷屏
  const root = h('div', { class: 'ua-json', role: 'tree', 'aria-label': props.ariaLabel ?? 'JSON 数据' }) as HTMLDivElement;
  if (props.maxHeight !== undefined) root.style.maxHeight = `${props.maxHeight}px`; // 只在给了上限时才限高，缺省随内容

  /*** 单行渲染：分支行带开关与计数摘要，叶子行只带类型类名 ***/
  const row = (key: string, value: unknown, level: number, path: string): HTMLElement => {
    const kind = kindOf(value);
    const branch = kind === 'array' || kind === 'object';
    const label = h('span', { class: 'ua-json-key' }, key); // 键名：数组下标也用 key 位展示
    if (!branch) {
      return h('div', { class: 'ua-json-row is-leaf', role: 'treeitem' }, label, h('span', { class: 'ua-json-colon' }, ':'), h('span', { class: `ua-json-val ua-json-${kind}` }, leafText(value)));
    }
    const box = h('div', { class: 'ua-json-children', role: 'group' }); // 子节点容器：收起时整块隐藏，DOM 保留折叠态
    const caret = h('span', { class: 'ua-json-caret', 'aria-hidden': 'true' }, '▸'); // 开关图标：方向由 aria-expanded 决定样式
    const toggle = h('button', {
      type: 'button',
      class: 'ua-json-toggle',
      'aria-expanded': () => String(!box.hidden),
      'aria-label': () => `${box.hidden ? '展开' : '收起'} ${path}`,
      onClick: () => { box.hidden = !box.hidden; }, // 只翻 hidden：样式按 :has 或 aria-expanded 跟随
    }, caret, label, h('span', { class: 'ua-json-colon' }, ':'), h('span', { class: 'ua-json-sum' }, `${kind === 'array' ? '[' : '{'}${summaryOf(value)}${kind === 'array' ? ']' : '}'}`));
    const entries: [string, unknown][] = kind === 'array'
      ? (value as unknown[]).map((v, i) => [String(i), v]) // 数组下标转字符串，走同一套行渲染
      : Object.entries(value as Record<string, unknown>);
    for (const [k, v] of entries) box.append(row(k, v, level + 1, `${path}.${k}`)); // 递归：路径用点号拼接，报给读屏时能定位
    box.hidden = level >= openDepth; // 超出默认层数的一律先收起，用户按需展开
    return h('div', { class: 'ua-json-branch', role: 'treeitem', 'aria-level': String(level + 1) }, toggle, box);
  };

  root.append(row(rootLabel, props.value, 0, rootLabel));
  return root;
}