import React, { useState } from 'react'
import PostActions   from './PostActions'
import PostComments  from './PostComments'
import ArtworkCard from '../artwork/ArtworkCard'
import VisibilityPill from './VisibilityPill'
import LinkPreviewCard from './LinkPreviewCard'

function formatRelative(isoString) {
  const diff = Date.now() - new Date(isoString).getTime()
  const s = Math.floor(diff / 1000)
  if (s < 60)  return 'just now'
  const m = Math.floor(s / 60)
  if (m < 60)  return `${m}m ago`
  const h = Math.floor(m / 60)
  if (h < 24)  return `${h}h ago`
  const d = Math.floor(h / 24)
  return `${d}d ago`
}

function formatScheduledDate(isoString) {
  const d = new Date(isoString)
  return d.toLocaleString(undefined, {
    month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit',
  })
}

/** Render plain text body with #hashtag links */
function BodyWithHashtags({ html }) {
  // The body may already be sanitised HTML from the server. We replace
  // #tag patterns in text nodes (not inside existing anchor elements) with
  // anchor links pointing to /tags/{tag}.
  const processed = html.replace(
    /(?<!["\w])#([A-Za-z][A-Za-z0-9_]{1,63})/g,
    (_, tag) => `<a href="/tags/${tag.toLowerCase()}" class="text-sky-400 hover:underline">#${tag}</a>`,
  )
  return (
    <div
      className="text-sm text-slate-300 leading-relaxed [&_a]:text-sky-400 [&_a]:hover:underline [&_strong]:text-white/90 [&_em]:text-slate-200"
      dangerouslySetInnerHTML={{ __html: processed }}
    />
  )
}

/**
 * PostCard
 * Renders a single post in the feed. Supports text + artwork_share types.
 *
 * Props:
 *   post             object   (formatted by PostFeedService::formatPost)
 *   isLoggedIn       boolean
 *   viewerUsername   string|null
 *   onDelete         function(postId)
 *   onUnsaved        function(postId)  — called when viewer unsaves this post
 */
export default function PostCard({ post, isLoggedIn = false, viewerUsername = null, onDelete, onUnsaved }) {
  const [showComments,   setShowComments]   = useState(false)
  const [postData,       setPostData]       = useState(post)
  const [editMode,       setEditMode]       = useState(false)
  const [editBody,       setEditBody]       = useState(post.body ?? '')
  const [saving,         setSaving]         = useState(false)
  const [menuOpen,       setMenuOpen]       = useState(false)
  const [saveLoading,    setSaveLoading]    = useState(false)
  const [analyticsOpen,  setAnalyticsOpen]  = useState(false)
  const [analytics,      setAnalytics]      = useState(null)

  const isOwn = viewerUsername && post.author.username === viewerUsername

  const handleSaveEdit = async () => {
    setSaving(true)
    try {
      const { default: axios } = await import('axios')
      const { data } = await axios.patch(`/api/posts/${post.id}`, { body: editBody })
      setPostData(data.post)
      setEditMode(false)
    } catch {
      //
    } finally {
      setSaving(false)
    }
  }

  const handleDelete = async () => {
    if (!window.confirm('Delete this post?')) return
    try {
      const { default: axios } = await import('axios')
      await axios.delete(`/api/posts/${post.id}`)
      onDelete?.(post.id)
    } catch {
      //
    }
  }

  const handlePin = async () => {
    const { default: axios } = await import('axios')
    try {
      if (postData.is_pinned) {
        await axios.delete(`/api/posts/${post.id}/pin`)
        setPostData((p) => ({ ...p, is_pinned: false, pinned_order: null }))
      } else {
        const { data } = await axios.post(`/api/posts/${post.id}/pin`)
        setPostData((p) => ({ ...p, is_pinned: true, pinned_order: data.pinned_order ?? 1 }))
      }
    } catch {
      //
    }
    setMenuOpen(false)
  }

  const handleSaveToggle = async () => {
    if (!isLoggedIn || saveLoading) return
    setSaveLoading(true)
    const { default: axios } = await import('axios')
    try {
      if (postData.viewer_saved) {
        await axios.delete(`/api/posts/${post.id}/save`)
        setPostData((p) => ({ ...p, viewer_saved: false, saves_count: Math.max(0, (p.saves_count ?? 1) - 1) }))
        onUnsaved?.(post.id)
      } else {
        await axios.post(`/api/posts/${post.id}/save`)
        setPostData((p) => ({ ...p, viewer_saved: true, saves_count: (p.saves_count ?? 0) + 1 }))
      }
    } catch {
      //
    } finally {
      setSaveLoading(false)
    }
  }

  const handleOpenAnalytics = async () => {
    if (!isOwn) return
    setAnalyticsOpen(true)
    if (!analytics) {
      const { default: axios } = await import('axios')
      try {
        const { data } = await axios.get(`/api/posts/${post.id}/analytics`)
        setAnalytics(data)
      } catch {
        setAnalytics(null)
      }
    }
  }

  return (
    <article className="rounded-2xl border border-white/[0.06] bg-white/[0.025] hover:border-white/10 transition-colors">
      {/* ── Pinned banner ──────────────────────────────────────────────── */}
      {postData.is_pinned && (
        <div className="flex items-center gap-1.5 px-5 pt-3 pb-0 text-[11px] text-slate-500">
          <i className="fa-solid fa-thumbtack fa-fw text-sky-500/60" />
          <span>Pinned post</span>
        </div>
      )}

      {/* ── Scheduled banner (owner only) ─────────────────────────────── */}
      {isOwn && postData.status === 'scheduled' && postData.publish_at && (
        <div className="flex items-center gap-1.5 px-5 pt-3 pb-0 text-[11px] text-amber-500/80">
          <i className="fa-regular fa-clock fa-fw" />
          <span>Scheduled for {formatScheduledDate(postData.publish_at)}</span>
        </div>
      )}

      {/* ── Achievement badge ──────────────────────────────────────────── */}
      {postData.type === 'achievement' && (
        <div className="flex items-center gap-1.5 px-5 pt-3 pb-0 text-[11px] text-amber-400/90">
          <i className="fa-solid fa-trophy fa-fw text-amber-400" />
          <span className="font-medium tracking-wide uppercase">Achievement unlocked</span>
        </div>
      )}

      {/* ── Header ─────────────────────────────────────────────────────── */}
      <div className="flex items-center gap-3 px-5 pt-4 pb-3">
        <a href={`/@${post.author.username}`} className="shrink-0">
          <img
            src={post.author.avatar ?? '/images/avatar_default.webp'}
            alt={post.author.name}
            className="w-9 h-9 rounded-full object-cover ring-1 ring-white/10 hover:ring-sky-500/40 transition-all"
            loading="lazy"
          />
        </a>

        <div className="flex-1 min-w-0">
          <div className="flex items-center gap-2 flex-wrap">
            <a
              href={`/@${post.author.username}`}
              className="text-sm font-semibold text-white/90 hover:text-sky-400 transition-colors"
            >
              {post.author.name || `@${post.author.username}`}
            </a>
            <span className="text-slate-600 text-xs">@{post.author.username}</span>
            {post.meta?.tagged_users?.length > 0 && (
              <span className="text-slate-600 text-xs flex items-center gap-1 flex-wrap">
                <span className="text-slate-700">with</span>
                {post.meta.tagged_users.map((u, i) => (
                  <React.Fragment key={u.id}>
                    {i > 0 && <span className="text-slate-700">,</span>}
                    <a href={`/@${u.username}`} className="text-sky-500/80 hover:text-sky-400 transition-colors">
                      @{u.username}
                    </a>
                  </React.Fragment>
                ))}
              </span>
            )}
          </div>
          <div className="flex items-center gap-1.5 text-[11px] text-slate-500 mt-0.5">
            <span>{formatRelative(post.created_at)}</span>
            <span aria-hidden>·</span>
            <VisibilityPill visibility={post.visibility} />
          </div>
        </div>

        {/* Right-side actions: save + owner menu */}
        <div className="flex items-center gap-1">
          {/* Save / bookmark button */}
          {isLoggedIn && !isOwn && (
            <button
              onClick={handleSaveToggle}
              disabled={saveLoading}
              title={postData.viewer_saved ? 'Remove bookmark' : 'Save post'}
              className={`flex items-center justify-center w-8 h-8 rounded-lg transition-colors ${
                postData.viewer_saved
                  ? 'text-amber-400 hover:bg-amber-500/10'
                  : 'text-slate-600 hover:text-slate-300 hover:bg-white/5'
              }`}
            >
              <i className={`${postData.viewer_saved ? 'fa-solid' : 'fa-regular'} fa-bookmark fa-fw text-sm`} />
            </button>
          )}

          {/* Analytics for owner */}
          {isOwn && (
            <button
              onClick={handleOpenAnalytics}
              title="Post analytics"
              className="flex items-center justify-center w-8 h-8 rounded-lg text-slate-600 hover:text-sky-400 hover:bg-sky-500/10 transition-colors"
            >
              <i className="fa-solid fa-chart-simple fa-fw text-sm" />
            </button>
          )}

          {/* Owner menu */}
          {isOwn && (
            <div className="relative">
              <button
                onClick={() => setMenuOpen((v) => !v)}
                className="text-slate-500 hover:text-slate-300 px-2 py-1 rounded-lg hover:bg-white/5 transition-colors"
                aria-label="Post options"
              >
                <i className="fa-solid fa-ellipsis-v fa-fw text-xs" />
              </button>
              {menuOpen && (
                <div className="absolute right-0 top-full mt-1 w-40 rounded-xl border border-white/10 bg-[#10192e] shadow-2xl z-50 overflow-hidden">
                  <button
                    onClick={() => { setEditMode(true); setMenuOpen(false) }}
                    className="w-full text-left px-4 py-2.5 text-sm text-slate-300 hover:bg-white/5 flex items-center gap-2"
                  >
                    <i className="fa-solid fa-pen fa-fw opacity-60" />
                    Edit
                  </button>
                  <button
                    onClick={handlePin}
                    className="w-full text-left px-4 py-2.5 text-sm text-slate-300 hover:bg-white/5 flex items-center gap-2"
                  >
                    <i className={`fa-solid fa-thumbtack fa-fw opacity-60 ${postData.is_pinned ? 'text-sky-400' : ''}`} />
                    {postData.is_pinned ? 'Unpin post' : 'Pin post'}
                  </button>
                  <button
                    onClick={() => { handleDelete(); setMenuOpen(false) }}
                    className="w-full text-left px-4 py-2.5 text-sm text-rose-400 hover:bg-white/5 flex items-center gap-2"
                  >
                    <i className="fa-solid fa-trash-can fa-fw opacity-60" />
                    Delete
                  </button>
                </div>
              )}
            </div>
          )}
        </div>
      </div>

      {/* ── Body ─────────────────────────────────────────────────────────── */}
      <div className="px-5 pb-3 space-y-3">
        {editMode ? (
          <div className="space-y-2">
            <textarea
              value={editBody}
              onChange={(e) => setEditBody(e.target.value)}
              maxLength={2000}
              rows={4}
              className="w-full bg-white/5 border border-white/10 rounded-xl px-3 py-2 text-sm text-white resize-none focus:outline-none focus:border-sky-500/50 transition-colors"
            />
            <div className="flex gap-2">
              <button
                onClick={handleSaveEdit}
                disabled={saving}
                className="px-4 py-1.5 rounded-lg bg-sky-600 hover:bg-sky-500 text-white text-xs transition-colors disabled:opacity-40"
              >
                {saving ? 'Saving…' : 'Save'}
              </button>
              <button
                onClick={() => setEditMode(false)}
                className="px-4 py-1.5 rounded-lg text-slate-400 hover:text-white hover:bg-white/5 text-xs transition-colors"
              >
                Cancel
              </button>
            </div>
          </div>
        ) : (
          postData.body && <BodyWithHashtags html={postData.body} />
        )}

        {/* Hashtag pills */}
        {!editMode && postData.hashtags && postData.hashtags.length > 0 && (
          <div className="flex flex-wrap gap-1.5 pt-0.5">
            {postData.hashtags.map((tag) => (
              <a
                key={tag}
                href={`/tags/${tag}`}
                className="text-[11px] text-sky-500/80 hover:text-sky-400 hover:bg-sky-500/10 px-2 py-0.5 rounded-full border border-sky-500/20 hover:border-sky-500/40 transition-all"
              >
                #{tag}
              </a>
            ))}
          </div>
        )}

        {/* Link preview (stored OG data) */}
        {!editMode && postData.meta?.link_preview?.url && (
          <LinkPreviewCard preview={postData.meta.link_preview} />
        )}

        {/* Artwork share embed */}
        {postData.type === 'artwork_share' && postData.artwork && (
          <ArtworkCard artwork={postData.artwork} variant="embed" showActions={false} showStats={false} />
        )}
      </div>

      {/* ── Actions ─────────────────────────────────────────────────────── */}
      <div className="border-t border-white/[0.04] px-5 py-2">
        <PostActions
          post={postData}
          isLoggedIn={isLoggedIn}
          onCommentToggle={() => setShowComments((v) => !v)}
          onReactionChange={({ liked, count }) =>
            setPostData((p) => ({ ...p, viewer_liked: liked, reactions_count: count }))
          }
        />
      </div>

      {/* ── Comments ────────────────────────────────────────────────────── */}
      {showComments && (
        <div className="border-t border-white/[0.04] px-5 py-4">
          <PostComments
            postId={post.id}
            isLoggedIn={isLoggedIn}
            isOwn={isOwn}
            initialCount={postData.comments_count}
          />
        </div>
      )}

      {/* ── Analytics modal ─────────────────────────────────────────────── */}
      {analyticsOpen && (
        <div
          className="fixed inset-0 z-50 flex items-center justify-center bg-black/70 px-4"
          onClick={(e) => { if (e.target === e.currentTarget) setAnalyticsOpen(false) }}
        >
          <div className="w-full max-w-sm rounded-2xl border border-white/10 bg-[#0d1628] p-6 shadow-2xl">
            <div className="flex items-center justify-between mb-4">
              <h3 className="font-semibold text-white">Post Analytics</h3>
              <button
                onClick={() => setAnalyticsOpen(false)}
                className="text-slate-500 hover:text-white w-7 h-7 flex items-center justify-center rounded-lg hover:bg-white/5 transition-colors"
              >
                <i className="fa-solid fa-xmark" />
              </button>
            </div>

            {!analytics ? (
              <div className="flex justify-center py-8">
                <i className="fa-solid fa-spinner fa-spin text-slate-500 text-xl" />
              </div>
            ) : (
              <div className="grid grid-cols-2 gap-3">
                {[
                  { label: 'Impressions', value: analytics.impressions?.toLocaleString() ?? '—', icon: 'fa-eye', color: 'text-sky-400' },
                  { label: 'Saves',       value: analytics.saves?.toLocaleString() ?? '—',       icon: 'fa-bookmark', color: 'text-amber-400' },
                  { label: 'Reactions',   value: analytics.reactions?.toLocaleString() ?? '—',   icon: 'fa-heart', color: 'text-rose-400' },
                  { label: 'Engagement',  value: analytics.engagement_rate ? `${analytics.engagement_rate}%` : '—', icon: 'fa-chart-simple', color: 'text-emerald-400' },
                ].map((item) => (
                  <div key={item.label} className="rounded-xl bg-white/[0.04] border border-white/[0.06] px-4 py-3">
                    <div className={`${item.color} text-sm mb-1`}>
                      <i className={`fa-solid ${item.icon} fa-fw`} />
                    </div>
                    <p className="text-xl font-bold text-white/90 tabular-nums leading-tight">{item.value}</p>
                    <p className="text-[11px] text-slate-500 mt-0.5">{item.label}</p>
                  </div>
                ))}
              </div>
            )}
          </div>
        </div>
      )}
    </article>
  )
}