import { useEffect, useMemo, useState } from 'react'
import { GalleryHorizontalEnd, Layers } from 'lucide-react'

import { libraryAPI } from '../api/library'
import { MediaCard } from '../components/MediaCard'
import { groupSeries } from '../utils/groupSeries'
import type { Media } from '../types'

const POSTER_WALL_PAGE_SIZE = 2000

// PosterWallPage 把所有媒体的代表海报聚合到同一面墙，便于一目了然
// 浏览整个站点的内容。所有 episode 行会按剧集折叠，避免同一海报刷屏。
export function PosterWallPage() {
  const [items, setItems] = useState<Media[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')

  useEffect(() => {
    let cancelled = false
    async function loadPosterWall() {
      setLoading(true)
      setError('')
      try {
        const libraries = await libraryAPI.list()
        const all = (
          await Promise.all(
            libraries.map(async (library) => {
              const rows: Media[] = []
              let page = 1
              for (;;) {
                const data = await libraryAPI.listMedia(library.id, page, POSTER_WALL_PAGE_SIZE, { groupVersions: false })
                rows.push(...(data.items || []))
                if (rows.length >= data.total || data.items.length === 0) break
                page += 1
              }
              return rows
            }),
          )
        ).flat()
        if (!cancelled) setItems(all)
      } catch (err) {
        if (!cancelled) {
          setError((err as { response?: { data?: { error?: string } } })?.response?.data?.error ?? '海报墙加载失败')
        }
      } finally {
        if (!cancelled) setLoading(false)
      }
    }
    loadPosterWall()
    return () => {
      cancelled = true
    }
  }, [])

  const cards = useMemo(() => groupSeries(items).slice(0, 240), [items])

  return (
    <div className="space-y-6">
      <header className="flex items-center gap-3">
        <GalleryHorizontalEnd className="h-6 w-6 text-brand-500" />
        <div>
          <h1 className="font-display text-3xl font-bold text-ink-600">海报墙</h1>
          <p className="text-sm text-ink-50">
            按剧集聚合 · 共 {cards.length} 个条目
          </p>
        </div>
      </header>

      {loading && <p className="text-sand-500">加载中…</p>}
      {!loading && error && (
        <p className="rounded-2xl border border-red-200 bg-red-50 px-4 py-3 text-sm text-red-700">
          {error}
        </p>
      )}
      {!loading && !error && cards.length === 0 && (
        <p className="text-ink-50">暂无媒体。请先添加媒体库并扫描。</p>
      )}
      <div className="grid grid-cols-3 gap-3 sm:grid-cols-4 md:grid-cols-6 lg:grid-cols-8 xl:grid-cols-10">
        {cards.map((s) => (
          <div key={s.rep.id} className="relative">
            <MediaCard media={s.rep} />
            {s.count > 1 && (
              <span className="pointer-events-none absolute right-1.5 top-1.5 inline-flex items-center gap-0.5 rounded-xl bg-black/60 px-1.5 py-0.5 text-[10px] font-medium text-ink-600 backdrop-blur-sm">
                <Layers size={10} />
                {s.count}
              </span>
            )}
          </div>
        ))}
      </div>
    </div>
  )
}