import { categoryCount, flattenAppItems, type Category } from '../../data/types'
import { AppGrid } from './AppGrid'
import { ArticleGrid } from './ArticleGrid'
import { Empty } from '@stash/ui'
import { PosterGrid } from './PosterGrid'
import { SectionCard } from './SectionCard'
import {
  applySectionSettings,
  sectionLimit,
  sectionTitle,
  type SectionSettings,
} from '../../settings'

/**
 * 首页：把每个分类渲染成一张分区卡片。
 *
 * 每个分区只展示前若干条；标题、条数、顺序与显隐都可以在 `/admin`
 * 的「首页卡片」里覆盖（见 settings.sections）。
 */
type HomeViewProps = {
  categories: Category[]
  sections: SectionSettings
  onOpenDetail: (categoryId: string) => void
  onOpenItem: (categoryId: string, itemId: string) => void
}

export function HomeView({ categories, sections, onOpenDetail, onOpenItem }: HomeViewProps) {
  const cards = applySectionSettings(categories, sections)

  return (
    <div className="home-view">
      {cards.map((category) => (
        <SectionCard
          key={category.id}
          // 卡片标题跟着实际展示的内容走：配了展示块就用块标题（如「常用站点」），
          // 没配（如「本地服务」）才用分类标题；设置里的覆盖值优先
          title={sectionTitle(
            category.id,
            category.block?.title ?? category.title,
            sections,
          )}
          count={cardCount(category)}
          barColor={category.barColor}
          onMore={() => onOpenDetail(category.id)}
        >
          {renderPreview(category, sections, onOpenItem)}
        </SectionCard>
      ))}
    </div>
  )
}

/**
 * 卡片右上角的数量角标。
 *
 * 配了「分组展示块」时，卡片实际展示的是那个分组，所以数量也应该只数它；
 * 否则（电影 / 文章 / 本地服务）数整个分区。
 */
function cardCount(category: Category): number {
  if (category.block !== undefined) {
    const group = category.groups.find((item) => item.id === category.block?.nodeKey)
    if (group !== undefined) return group.items.length
  }

  return categoryCount(category)
}

/** 某个分区配的「首页预览分组」；没配或找不到返回 undefined */
function blockGroup<T>(category: { block?: { nodeKey?: string }; groups: { id: string; items: T[] }[] }) {
  if (category.block?.nodeKey === undefined) return undefined
  return category.groups.find((group) => group.id === category.block?.nodeKey)
}

/** 按分类类型输出对应的预览网格；应用类为空时给出提示文案 */
function renderPreview(
  category: Category,
  sections: SectionSettings,
  onOpenItem: (categoryId: string, itemId: string) => void,
) {
  if (category.kind === 'apps') {
    // 配了展示块且指向分组时只展示该组；展示块指向分区本身（「整个分区」）时展示全部条目
    const group = blockGroup(category)
    const source = group !== undefined ? group.items : flattenAppItems(category)
    const fallback = category.block?.previewLimit ?? category.previewLimit ?? 4
    const limit = sectionLimit(category.id, fallback, sections)
    const items = source.slice(0, limit)

    if (items.length === 0) {
      return <Empty text={category.emptyText ?? '暂无内容'} />
    }

    return <AppGrid items={items} onOpen={(itemId) => onOpenItem(category.id, itemId)} />
  }

  if (category.kind === 'posters') {
    const group = blockGroup(category)
    const source = group
      ? group.items
      : [...category.items, ...category.groups.flatMap((item) => item.items)]
    return (
      <PosterGrid
        items={source.slice(0, sectionLimit(category.id, category.previewLimit ?? 6, sections))}
        onOpen={(itemId) => onOpenItem(category.id, itemId)}
      />
    )
  }

  const group = blockGroup(category)
  const source = group
    ? group.items
    : [...category.items, ...category.groups.flatMap((item) => item.items)]
  return (
    <ArticleGrid
      items={source.slice(0, sectionLimit(category.id, category.previewLimit ?? 4, sections))}
      onOpen={(itemId) => onOpenItem(category.id, itemId)}
    />
  )
}