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

/*** 步骤条：done/current/upcoming 三态横向流程指示，clickable 时已完成步骤可点回跳并写回 active 信号 ***/
export function stepper(props: StepperProps): HTMLElement {
  const active = props.active;
  const clickStep = (i: number): void => { if (!props.clickable || i >= active()) return; // 卫语句：不可点或未完成不回跳
    active(i); if (props.onChange) props.onChange(i); }; // 写回信号并回调
  const render = (): HTMLElement => {
    const cur = active();
    const items = props.steps.map((s, i) => {
      const state = i < cur ? 'done' : i === cur ? 'current' : 'upcoming'; // 三态：已完成 / 当前 / 未到
      const mark = state === 'done' ? '✓' : String(i + 1); // 完成打勾，其余显示序号
      const clickable = !!props.clickable && i < cur; // 仅已完成步骤可回跳
      const head = clickable
        ? h('button', { class: 'ua-step-dot', type: 'button', onClick: () => clickStep(i) }, mark)
        : h('span', { class: 'ua-step-dot' }, mark);
      const body = h('div', { class: 'ua-step-text' }, h('span', { class: 'ua-step-label' }, s.label),
        s.description ? h('span', { class: 'ua-step-desc' }, s.description) : null);
      const li = h('li', { class: `ua-step ua-step-${state}`, 'aria-current': state === 'current' ? 'step' : null }, head, body);
      return li;
    });
    return h('ol', { class: 'ua-stepper' }, ...items);
  };
  let el!: HTMLElement; // 当前渲染产物（effect 首跑赋值）
  effect(() => { const next = render(); if (el) el.replaceWith(next); el = next; }); // active 变化整条重渲染（条目少，开销可忽略）
  return el;
}