import React, { useMemo, useState } from 'react'
import NovaConfirmDialog from '../ui/NovaConfirmDialog'

const AVATAR_FALLBACK = 'https://files.skinbase.org/default/missing_sq.webp'

function formatCount(value) {
  const n = Number(value || 0)
  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1).replace(/\.0$/, '')}M`
  if (n >= 1_000) return `${(n / 1_000).toFixed(1).replace(/\.0$/, '')}k`
  return `${n}`
}

function toCard(item) {
  return {
    id: item?.id || item?.slug || item?.url,
    title: item?.title,
    author: item?.author,
    url: item?.url,
    thumb: item?.thumb,
    thumbSrcSet: item?.thumb_srcset,
  }
}

export default function CreatorSpotlight({ artwork, presentSq, related = [] }) {
  const [following, setFollowing] = useState(Boolean(artwork?.viewer?.is_following_author))
  const [followersCount, setFollowersCount] = useState(Number(artwork?.user?.followers_count || 0))
  const [confirmOpen, setConfirmOpen] = useState(false)
  const [pendingFollowState, setPendingFollowState] = useState(null)

  const user = artwork?.user || {}
  const authorName = user.name || user.username || 'Artist'
  const profileUrl = user.profile_url || (user.username ? `/@${user.username}` : '#')
  const avatar = user.avatar_url || presentSq?.url || AVATAR_FALLBACK
  const csrfToken = typeof document !== 'undefined'
    ? document.querySelector('meta[name="csrf-token"]')?.getAttribute('content')
    : null

  const creatorItems = useMemo(() => {
    const filtered = (Array.isArray(related) ? related : []).filter((item) => {
      const sameAuthor = String(item?.author || '').trim().toLowerCase() === String(authorName || '').trim().toLowerCase()
      const notCurrent = item?.url && item.url !== artwork?.canonical_url
      return sameAuthor && notCurrent
    })

    const source = filtered.length > 0 ? filtered : (Array.isArray(related) ? related : [])
    return source.slice(0, 12).map(toCard)
  }, [related, authorName, artwork?.canonical_url])

  const persistFollowState = async (nextState) => {
    setFollowing(nextState)
    try {
      const response = await fetch(`/api/users/${user.id}/follow`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'X-CSRF-TOKEN': csrfToken || '',
        },
        credentials: 'same-origin',
        body: JSON.stringify({ state: nextState }),
      })

      if (!response.ok) throw new Error('Follow failed')
      const payload = await response.json()
      if (typeof payload?.followers_count === 'number') {
        setFollowersCount(payload.followers_count)
      }
      setFollowing(Boolean(payload?.is_following))
    } catch {
      setFollowing(!nextState)
    }
  }

  const onToggleFollow = async () => {
    const nextState = !following
    if (!nextState) {
      setPendingFollowState(nextState)
      setConfirmOpen(true)
      return
    }

    await persistFollowState(nextState)
  }

  const onConfirmUnfollow = async () => {
    if (pendingFollowState === null) return
    setConfirmOpen(false)
    await persistFollowState(pendingFollowState)
    setPendingFollowState(null)
  }

  const onCloseConfirm = () => {
    setConfirmOpen(false)
    setPendingFollowState(null)
  }

  return (
    <>
      <section className="rounded-2xl border border-white/[0.06] bg-white/[0.03] p-5">
        {/* Avatar + info — stacked for sidebar */}
        <div className="flex flex-col items-center text-center">
          <a href={profileUrl} className="group">
            <img
              src={avatar}
              alt={authorName}
              className="h-16 w-16 rounded-full border-2 border-white/10 object-cover shadow-lg shadow-black/40 transition-transform duration-200 group-hover:scale-105"
              loading="lazy"
              decoding="async"
              onError={(event) => {
                event.currentTarget.src = AVATAR_FALLBACK
              }}
            />
          </a>

          <a href={profileUrl} className="mt-3 block text-base font-bold text-white transition-colors hover:text-accent">
            {authorName}
          </a>
          {user.username && <p className="text-xs text-white/40">@{user.username}</p>}
          <p className="mt-1 text-xs font-medium text-white/30">
            {followersCount.toLocaleString()} Followers
          </p>

          {/* Profile + Follow buttons */}
          <div className="mt-4 flex w-full gap-2">
            <a
              href={profileUrl}
              title="View profile"
              className="flex flex-1 items-center justify-center gap-1.5 rounded-xl border border-white/[0.08] bg-white/[0.04] px-3 py-2.5 text-sm font-medium text-white/70 transition-all hover:border-white/[0.15] hover:bg-white/[0.07] hover:text-white"
            >
              <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="h-4 w-4">
                <path strokeLinecap="round" strokeLinejoin="round" d="M15.75 6a3.75 3.75 0 1 1-7.5 0 3.75 3.75 0 0 1 7.5 0ZM4.501 20.118a7.5 7.5 0 0 1 14.998 0A17.933 17.933 0 0 1 12 21.75c-2.676 0-5.216-.584-7.499-1.632Z" />
              </svg>
              Profile
            </a>
            <button
              type="button"
              aria-label={following ? 'Unfollow creator' : 'Follow creator'}
              onClick={onToggleFollow}
              className={[
                'flex flex-1 items-center justify-center gap-1.5 rounded-xl px-3 py-2.5 text-sm font-semibold transition-all duration-200',
                following
                  ? 'border border-white/[0.08] bg-white/[0.04] text-white/70 hover:bg-white/[0.07]'
                  : 'bg-accent text-deep shadow-lg shadow-accent/20 hover:brightness-110 hover:shadow-accent/30',
              ].join(' ')}
            >
              <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor" className="h-4 w-4">
                <path strokeLinecap="round" strokeLinejoin="round" d="M3 16.5v2.25A2.25 2.25 0 0 0 5.25 21h13.5A2.25 2.25 0 0 0 21 18.75V16.5M16.5 12 12 16.5m0 0L7.5 12m4.5 4.5V3" />
              </svg>
              {following ? 'Following' : 'Follow'}
            </button>
          </div>
        </div>

        {/* More from creator rail */}
        {creatorItems.length > 0 && (
          <div className="mt-5 border-t border-white/[0.06] pt-5">
            <div className="flex items-center justify-between">
              <h3 className="text-sm font-semibold text-white/80">More from {authorName}</h3>
              <a href={profileUrl} className="text-white/30 transition-colors hover:text-white/60">
                <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor" className="h-4 w-4">
                  <path strokeLinecap="round" strokeLinejoin="round" d="m8.25 4.5 7.5 7.5-7.5 7.5" />
                </svg>
              </a>
            </div>
            <div className="mt-3 grid grid-cols-3 gap-2">
              {creatorItems.slice(0, 3).map((item, idx) => (
                <a key={`${item.id || item.url}-${idx}`} href={item.url} className="group/mini relative overflow-hidden rounded-xl">
                  <div className="aspect-square overflow-hidden bg-deep">
                    <img
                      src={item.thumb || AVATAR_FALLBACK}
                      alt={item.title || 'Artwork'}
                      className="h-full w-full object-cover transition duration-300 group-hover/mini:scale-[1.06]"
                      loading="lazy"
                      decoding="async"
                    />
                  </div>
                  <div className="pointer-events-none absolute inset-0 bg-gradient-to-t from-black/50 via-transparent to-transparent" />
                  <div className="absolute bottom-1.5 left-1.5 right-1.5 flex items-center gap-1">
                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="currentColor" className="h-3 w-3 text-rose-400">
                      <path d="m9.653 16.915-.005-.003-.019-.01a20.759 20.759 0 0 1-1.162-.682 22.045 22.045 0 0 1-2.582-1.9C4.045 12.733 2 10.352 2 7.5a4.5 4.5 0 0 1 8-2.828A4.5 4.5 0 0 1 18 7.5c0 2.852-2.044 5.233-3.885 6.82a22.049 22.049 0 0 1-3.744 2.582l-.019.01-.005.003h-.002a.723.723 0 0 1-.69 0h-.002Z" />
                    </svg>
                    <span className="text-[10px] font-bold text-white drop-shadow">
                      {item.likes ? formatCount(item.likes) : ''}
                    </span>
                  </div>
                </a>
              ))}
            </div>
          </div>
        )}
      </section>

      <NovaConfirmDialog
        open={confirmOpen}
        title="Unfollow creator?"
        message={`You will stop seeing updates from @${user.username || authorName} in your following feed.`}
        confirmLabel="Unfollow"
        cancelLabel="Keep following"
        confirmTone="danger"
        onConfirm={onConfirmUnfollow}
        onClose={onCloseConfirm}
      />
    </>
  )
}