import { Empty, Layout, Notice } from '@stash/ui'
import { useEffect, useMemo, useRef, useState } from 'react'
import { BackToTop } from './components/common/BackToTop'
import { ArticleDetailView } from './components/content/ArticleDetailView'
import { DetailView } from './components/content/DetailView'
import { HomeView } from './components/content/HomeView'
import { ItemDetailView } from './components/content/ItemDetailView'
import { SiteHeader } from './components/header/SiteHeader'
import { SearchBar } from './components/search/SearchBar'
import { Sidebar } from './components/sidebar/Sidebar'
import { withLocalCategory } from './data/local'
import {
  appDetailModel,
  posterDetailModel,
  posterToRelatedItem,
  toRelatedItem,
} from './data/detail'
import { filterCategories } from './data/filter'
import type { NavTarget } from './data/nav'
import {
  type Category,
  findAppItem,
  findArticleItem,
  findPosterItem,
  relatedAppItems,
  relatedPosterItems,
} from './data/types'
import { useProjects } from './useProjects'
import { useCatalog } from './useCatalog'
import { useViewRoute } from './useViewRoute'
import type { ItemRoute, View } from './data/view'
import './App.css'

export default function App() {
  const { status, projects, error, live, refreshing, refresh } = useProjects()
  // 内容目录来自后端 SQLite 内容库；本地服务分类仍由托管项目动态生成
  const catalog = useCatalog()
  const [keyword, setKeyword] = useState('')
  // 当前视图由地址栏决定：刷新 / 收藏 / 前进后退都回到同一页（见 useViewRoute.ts）
  const { view, go, back } = useViewRoute()
  const [scrolled, setScrolled] = useState(false)
  const searchRef = useRef<HTMLInputElement>(null)

  const categories = useMemo(
    () => withLocalCategory(projects, catalog.categories),
    [projects, catalog.categories],
  )
  const visibleCategories = useMemo(
    () => filterCategories(categories, keyword),
    [categories, keyword],
  )

  // 侧栏不显示「本地服务」，也不显示被标记 show_in_sidebar = 0 的分区
  const sidebarCategories = useMemo(
    () =>
      categories.filter(
        (category) => category.id !== 'local' && category.showInSidebar !== false,
      ),
    [categories],
  )

  const detailView = view.type === 'detail' ? view : undefined
  const itemView = view.type === 'item' ? view : undefined

  const detailCategory =
    detailView !== undefined
      ? categories.find((category) => category.id === detailView.categoryId)
      : undefined

  const itemCategory =
    itemView !== undefined
      ? categories.find((category) => category.id === itemView.categoryId)
      : undefined

  // 应用与电影共用一个详情模型，这里按分类类型做映射
  const detailModel = useMemo(() => {
    if (itemView === undefined || itemCategory === undefined) return undefined

    if (itemCategory.kind === 'apps') {
      const item = findAppItem(itemCategory, itemView.itemId)
      return item !== undefined ? appDetailModel(item) : undefined
    }

    if (itemCategory.kind === 'posters') {
      const poster = findPosterItem(itemCategory, itemView.itemId)
      return poster !== undefined ? posterDetailModel(poster) : undefined
    }

    return undefined
  }, [itemView, itemCategory])

  const relatedItems = useMemo(() => {
    if (itemView === undefined || itemCategory === undefined) return []

    if (itemCategory.kind === 'apps') {
      return relatedAppItems(itemCategory, itemView.itemId, 4).map(toRelatedItem)
    }

    if (itemCategory.kind === 'posters') {
      return relatedPosterItems(itemCategory, itemView.itemId, 4).map(posterToRelatedItem)
    }

    return []
  }, [itemView, itemCategory])

  // 切换视图时把内容区（内部滚动）和窗口都回到顶部
  useEffect(() => {
    const scroller = document.getElementById('content-scroll')
    scroller?.scrollTo({ top: 0 })
    window.scrollTo({ top: 0 })
  }, [view])

  /**
   * 滚动状态同时驱动「顶部渐隐」和「回到顶部」。
   * 桌面端滚的是内容容器（scroll 事件不冒泡），所以用捕获阶段监听。
   */
  useEffect(() => {
    const sync = () => {
      const inner = document.getElementById('content-scroll')?.scrollTop ?? 0
      const next = Math.max(inner, window.scrollY) > 4
      setScrolled((current) => (current === next ? current : next))
    }

    sync()
    window.addEventListener('scroll', sync, { passive: true })
    document.addEventListener('scroll', sync, { passive: true, capture: true })

    return () => {
      window.removeEventListener('scroll', sync)
      document.removeEventListener('scroll', sync, { capture: true })
    }
  }, [])

  /**
   * 「打开这个分区」应该落到哪个视图。
   *
   * 应用类分区配了首页展示块时，直接落到那个分组；其余情况打开整个分区。
   */
  const detailViewFor = (categoryId: string): View => {
    const category = categories.find((item) => item.id === categoryId)

    if (category?.kind === 'apps' && category.block !== undefined) {
      const group = category.groups.find((item) => item.id === category.block?.nodeKey)
      if (group !== undefined) {
        return { type: 'detail', categoryId, groupId: group.id }
      }
    }

    return { type: 'detail', categoryId }
  }

  const openDetail = (categoryId: string) => go(detailViewFor(categoryId))

  /** 条目所在的分组：应用按组组织，海报 / 图文直接挂在分区下 */
  const groupOfItem = (category: Category, itemId: string): string | undefined => {
    if (category.kind !== 'apps') return undefined
    return category.groups.find((group) => group.items.some((item) => item.id === itemId))?.id
  }

  const openItem = (categoryId: string, itemId: string) => {
    const category = categories.find((item) => item.id === categoryId)

    go({
      type: 'item',
      categoryId,
      itemId,
      // 地址里带上条目自己的分组，刷新后「返回」才有确定的落点
      groupId: category === undefined ? undefined : groupOfItem(category, itemId),
    })
  }

  /**
   * 条目详情的「返回」目标：优先回到该条目所在的分组，
   * 没有分组（海报 / 图文）时回到分区，走和侧栏一样的展示块规则。
   */
  const detailTargetFor = (item: ItemRoute): View =>
    item.groupId === undefined
      ? detailViewFor(item.categoryId)
      : { type: 'detail', categoryId: item.categoryId, groupId: item.groupId }

  /**
   * 侧栏导航：带分组时直接打开那个分组；
   * 点分区本身时，交给 openDetail 按展示块落到对应节点。
   */
  const navigate = (target: NavTarget) => {
    if (target.groupId === undefined) {
      openDetail(target.categoryId)
      return
    }

    go({ type: 'detail', categoryId: target.categoryId, groupId: target.groupId })
  }

  const goHome = () => go({ type: 'home' })

  const searching = keyword.trim() !== ''

  const viewCategoryId = detailView?.categoryId ?? itemView?.categoryId

  /**
   * 首屏数据还没回来时，地址指向的分类 / 条目只是「暂时查不到」，
   * 不能直接报「不存在」——刷新详情页时最容易被这个误导。
   */
  const dataPending =
    viewCategoryId !== undefined &&
    (catalog.status === 'loading' || (viewCategoryId === 'local' && status === 'loading'))

  /**
   * 条目详情按分类类型分流：
   * 图文走长文版式，应用 / 电影走通用的条目版式。
   */
  function renderItemView() {
    if (itemView === undefined) return null
    if (itemCategory === undefined) {
      return <Empty text={dataPending ? '正在读取内容库…' : '分类不存在'} />
    }

    if (itemCategory.kind === 'articles') {
      const article = findArticleItem(itemCategory, itemView.itemId)
      if (article === undefined) {
        return <Empty text={dataPending ? '正在读取内容库…' : '条目不存在'} />
      }

      return (
        <ArticleDetailView
          article={article}
          categoryTitle={itemCategory.title}
          onBack={() => back(detailTargetFor(itemView))}
        />
      )
    }

    if (detailModel === undefined) {
      return <Empty text={dataPending ? '正在读取内容库…' : '条目不存在'} />
    }

    return (
      <ItemDetailView
        breadcrumb={`${itemCategory.title} / ${detailModel.title}`}
        model={detailModel}
        related={relatedItems}
        onBack={() => back(detailTargetFor(itemView))}
        onOpenItem={(itemId) => openItem(itemCategory.id, itemId)}
      />
    )
  }

  return (
    <>
      {/* 主题的顶部背景图：固定 65vh，底部渐隐到页面底色 */}
      <div className="site-background" aria-hidden="true" />

      <Layout
        contained
        maxWidth={1380}
        gutter={20}
        siderWidth={240}
        gap={20}
        headerHeight={60}
        headerVariant="solid"
        siderBordered={false}
        contentPadding="none"
        contentOffset={88}
        height="screen"
        scrollable
        contentId="content-scroll"
        className="app"
        header={
          <SiteHeader
            projectCount={projects.length}
            sampleProject={projects[0]?.name}
            live={live}
            onFocusSearch={() => searchRef.current?.focus()}
          />
        }
        sider={
          <Sidebar
            projects={projects}
            categories={sidebarCategories}
            live={live}
            refreshing={refreshing}
            onRefresh={refresh}
            activeCategoryId={viewCategoryId}
            activeGroupId={detailView?.groupId}
            onNavigate={navigate}
          />
        }
      >
        <div className="content">
          <SearchBar value={keyword} onChange={setKeyword} inputRef={searchRef} />

          <h1 className="sr-only">Stash 本地应用工作区</h1>

          {status === 'error' && (
            <Notice
              tone="error"
              title="连不上 Stash 服务"
              action={{ label: '重试', onClick: refresh }}
            >
              {error}
            </Notice>
          )}

          {/* 内容库读取失败通常是用户改坏了 data 列里的 JSON，错误信息会带条目 id */}
          {catalog.status === 'error' && (
            <Notice
              tone="error"
              title="内容库读取失败"
              action={{ label: '重试', onClick: catalog.reload }}
            >
              {catalog.error}
            </Notice>
          )}

          {detailView === undefined && itemView === undefined && (
            <>
              {catalog.status === 'loading' && <Empty text="正在读取内容库…" />}

              <HomeView
                categories={visibleCategories}
                onOpenDetail={openDetail}
                onOpenItem={openItem}
              />

              {searching && visibleCategories.length === 0 && (
                <Notice title={`没有匹配「${keyword.trim()}」的内容`}>
                  换个关键字试试，或清空搜索查看全部。
                </Notice>
              )}
            </>
          )}

          {detailView !== undefined && detailCategory !== undefined && (
            <DetailView
              category={detailCategory}
              groupId={detailView.groupId}
              onBack={goHome}
              onOpenItem={(itemId) => openItem(detailCategory.id, itemId)}
            />
          )}

          {detailView !== undefined && detailCategory === undefined && (
            <Empty text={dataPending ? '正在读取内容库…' : '分类不存在'} />
          )}

          {itemView !== undefined && renderItemView()}
        </div>
      </Layout>

      <BackToTop visible={scrolled} />
    </>
  )
}