/**
 * vibe-registry render —— 极薄 React 渲染内核(可选子路径:vibe-registry/render)
 *
 * 设计(v0.5):
 *  - core(registry/page)零依赖;渲染内核单独子路径,谁用谁引 React
 *  - 不做运行时编辑器,不重造组件:widget.component 映射已有组件
 *  - 预览即真实:画廊与实装共用本内核
 */
import React from 'react'
import type { RegistryApi, LayoutRegistryEntry, LayoutRenderProps } from './registry.ts'
import type { PageDeclaration, PageBlockDecl } from './page.ts'

/** widget 的 React 组件形态(宽松:props 由声明 props/bind 决定) */
export type WidgetComponent = React.ComponentType<Record<string, unknown>> | React.ElementType

/* ── 单 widget 渲染 ─────────────────────────────────────────── */

export interface WidgetViewProps {
  readonly widget: string
  readonly registry: RegistryApi
  /** 静态 props */
  readonly props?: Record<string, unknown>
  /** setup 数据(供 bind 取字段) */
  readonly data?: Record<string, unknown>
  readonly bind?: Record<string, string>
}

export function WidgetView({ widget, registry, props = {}, data = {}, bind }: WidgetViewProps): React.ReactElement {
  const entry = registry.store.widgets.get(widget)
  if (!entry) {
    throw new Error(`[vibe-registry/render] 未知 widget:'${widget}' (未注册)`)
  }
  const Comp = entry.component as WidgetComponent | undefined
  if (!Comp) {
    throw new Error(`[vibe-registry/render] widget '${widget}' 未挂组件(component 缺失)`)
  }
  // bind:props 名 ← setup 数据字段
  const bound: Record<string, unknown> = {}
  if (bind) {
    for (const [prop, key] of Object.entries(bind)) bound[prop] = data[key]
  }
  return React.createElement(Comp, { ...props, ...bound })
}

/* ── 整页渲染:声明 + 注册表 → 组件树 ────────────────────────── */

export interface PageViewProps {
  readonly page: PageDeclaration
  readonly registry: RegistryApi
  /** setup 已执行完的数据 */
  readonly data?: Record<string, unknown>
}

export function PageView({ page, registry, data = {} }: PageViewProps): React.ReactElement {
  const layout = registry.store.layouts.get(page.layout)
  if (!layout) {
    throw new Error(`[vibe-registry/render] 未知布局:'${page.layout}'`)
  }
  const renderLayout = (layout.render as React.ComponentType<LayoutRenderProps> | undefined) ?? DefaultLayout
  // 按 slot 分组填充 blocks
  const filled: Record<string, React.ReactNode[]> = {}
  for (const b of page.blocks) {
    const slot = b.slot ?? 'content'
    ;(filled[slot] ??= []).push(
      React.createElement(WidgetView, {
        key: b.widget + JSON.stringify(b.props ?? {}),
        widget: b.widget,
        registry,
        props: b.props,
        bind: b.bind,
        data,
      }),
    )
  }
  return React.createElement(renderLayout, { slots: layout.slots, blocks: filled, page })
}

/** 缺省布局骨架:无 render 的布局按 slots 顺序纵向排(演示/兜底用) */
export function DefaultLayout({ slots, blocks }: LayoutRenderProps): React.ReactElement {
  return React.createElement(
    'div',
    { style: { border: '1px dashed #d1d5db', borderRadius: 8, padding: 12 } },
    ...slots.flatMap((slot) => {
      const children = blocks[slot] as React.ReactNode[] | undefined
      if (!children || children.length === 0) return []
      return [
        React.createElement(
          'div',
          { key: slot, style: { marginBottom: 12 } },
          React.createElement(
            'div',
            { style: { fontSize: 11, color: '#9ca3af', marginBottom: 4, textTransform: 'uppercase' } },
            `slot: ${slot}`,
          ),
          ...children,
        ),
      ]
    }),
  )
}

/* ── 画廊:布局模板 live 预览(类 Vite 首页,点选查看) ─────────── */

export interface GalleryProps {
  readonly registry: RegistryApi
  readonly pages?: readonly PageDeclaration[]
}

/** 由布局的 preview.demoBlocks 构造一个可渲染的 demo 页声明 */
function demoPageFrom(layout: LayoutRegistryEntry): PageDeclaration | null {
  const demo = layout.preview?.demoBlocks ?? []
  if (demo.length === 0) return null
  return {
    layout: layout.id,
    title: layout.preview?.title ?? layout.id,
    blocks: demo.map((d) => ({ widget: d.widget, slot: d.slot, props: d.props })),
  }
}

/** 缩略预览:把真实渲染缩放进卡片(预览即真实) */
function Thumb({ children, onClick }: { children?: React.ReactNode; onClick?: () => void }): React.ReactElement {
  return React.createElement(
    'div',
    {
      onClick,
      style: {
        width: 420,
        height: 260,
        overflow: 'hidden',
        border: '1px solid #e5e7eb',
        borderRadius: 8,
        cursor: onClick ? 'pointer' : 'default',
        position: 'relative',
        background: '#fff',
      },
    },
    React.createElement(
      'div',
      { style: { width: 1050, transform: 'scale(0.4)', transformOrigin: 'top left' } },
      children,
    ),
  )
}

export function LayoutGallery({ registry }: GalleryProps): React.ReactElement {
  const layouts = registry.listAll().filter((e): e is LayoutRegistryEntry => e.kind === 'layout')
  const widgets = registry.listAll().filter((e) => e.kind === 'widget')
  const [selected, setSelected] = React.useState<LayoutRegistryEntry | null>(null)

  const cards = layouts.map((layout) => {
    const page = demoPageFrom(layout)
    return React.createElement(
      'div',
      { key: layout.id, style: { display: 'flex', flexDirection: 'column', gap: 6 } },
      React.createElement(
        Thumb,
        { onClick: () => setSelected(layout) },
        page
          ? React.createElement(PageView, { page, registry, data: {} })
          : React.createElement('div', { style: { padding: 12, color: '#9ca3af' } }, '(无 demoBlocks)'),
      ),
      React.createElement(
        'div',
        { style: { display: 'flex', justifyContent: 'space-between', alignItems: 'center' } },
        React.createElement(
          'div',
          {},
          React.createElement('div', { style: { fontSize: 13, fontWeight: 600 } }, layout.preview?.title ?? layout.id),
          React.createElement('div', { style: { fontSize: 11, color: '#9ca3af' } }, `id: ${layout.id} · slots: ${layout.slots.join(' → ')}`),
        ),
        React.createElement(
          'button',
          {
            onClick: () => setSelected(layout),
            style: { fontSize: 12, padding: '3px 10px', borderRadius: 6, border: '1px solid #d1d5db', background: '#fff', cursor: 'pointer' },
          },
          '预览',
        ),
      ),
    )
  })

  const detail = selected ? demoPageFrom(selected) : null
  const detailEl = selected
    ? React.createElement(
        'div',
        { style: { marginTop: 20 } },
        React.createElement('h3', {}, `${selected.preview?.title ?? selected.id} · 完整预览`),
        detail
          ? React.createElement(
              'div',
              { style: { border: '1px solid #e5e7eb', borderRadius: 8, overflow: 'hidden' } },
              React.createElement(PageView, { page: detail, registry, data: {} }),
            )
          : React.createElement('div', {}, '(此布局无 demo)'),
      )
    : null

  return React.createElement(
    'div',
    { style: { fontFamily: 'system-ui, sans-serif', maxWidth: 960, margin: '0 auto', padding: 24 } },
    React.createElement('h1', { style: { fontSize: 20 } }, 'vibe-registry · 布局模板'),
    React.createElement('p', { style: { color: '#6b7280' } }, `已注册 ${layouts.length} 个布局模板 · ${widgets.length} 个 widget · 点击卡片预览(预览即真实)`),
    React.createElement('div', { style: { display: 'grid', gridTemplateColumns: 'repeat(auto-fill, minmax(430px, 1fr))', gap: 16 } }, ...cards),
    detailEl,
  )
}