import { useState } from 'react';
import { X, Minimize2, Trash2, Edit2, Check, Layers } from 'lucide-react';
import { useMeme, useDeleteMeme, useUpdateMeme } from '../hooks/useMemes';
import { useAuth } from '../hooks/useAuth';
import { SharePanel } from './SharePanel';
import { RescaleModal } from './RescaleModal';
import { api, type Meme } from '../api/client';

interface Props {
  memeId: string;
  onClose: () => void;
}

function formatBytes(bytes: number): string {
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${(bytes / 1024 / 1024).toFixed(1)} MB`;
}

function formatDate(iso: string): string {
  return new Date(iso).toLocaleDateString('en-US', {
    year: 'numeric', month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit',
  });
}

export function MemeDetail({ memeId, onClose }: Props) {
  const { data, isLoading, refetch } = useMeme(memeId);
  const deleteMeme = useDeleteMeme();
  const updateMeme = useUpdateMeme();
  const { data: auth } = useAuth();
  const isAdmin = auth?.authenticated === true;

  const [editing, setEditing] = useState(false);
  const [editTitle, setEditTitle] = useState('');
  const [editDesc, setEditDesc] = useState('');
  const [editTags, setEditTags] = useState('');
  const [showRescale, setShowRescale] = useState(false);
  const [activeChild, setActiveChild] = useState<Meme | null>(null);

  const meme = data;
  const displayMeme = activeChild ?? meme;

  function startEdit() {
    if (!meme) return;
    setEditTitle(meme.title);
    setEditDesc(meme.description ?? '');
    setEditTags(meme.tags.join(', '));
    setEditing(true);
  }

  async function saveEdit() {
    if (!meme) return;
    await updateMeme.mutateAsync({
      id: meme.id,
      title: editTitle,
      description: editDesc || undefined,
      tags: editTags.split(',').map((t) => t.trim()).filter(Boolean),
    });
    setEditing(false);
  }

  async function handleDelete() {
    if (!meme) return;
    if (!confirm(`Delete "${meme.title}"? This also removes all rescaled copies.`)) return;
    await deleteMeme.mutateAsync(meme.id);
    onClose();
  }

  if (isLoading) {
    return (
      <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/70">
        <div className="w-10 h-10 border-2 border-accent border-t-transparent rounded-full animate-spin" />
      </div>
    );
  }

  if (!meme) return null;

  return (
    <>
      <div
        className="fixed inset-0 z-40 bg-black/80 animate-fade-in"
        onClick={onClose}
      />

      <div className="fixed inset-4 md:inset-8 z-50 flex flex-col bg-zinc-900 rounded-2xl shadow-2xl border border-zinc-800 overflow-hidden animate-scale-in">
        {/* Header */}
        <div className="flex items-center justify-between px-5 py-4 border-b border-zinc-800 flex-shrink-0">
          {editing ? (
            <input
              autoFocus
              value={editTitle}
              onChange={(e) => setEditTitle(e.target.value)}
              className="flex-1 bg-zinc-800 border border-zinc-700 rounded-lg px-3 py-1.5 text-sm font-semibold focus:outline-none focus:border-accent mr-3"
            />
          ) : (
            <h2 className="text-lg font-semibold truncate flex-1 mr-3">{meme.title}</h2>
          )}
          <div className="flex items-center gap-2 flex-shrink-0">
            {isAdmin && (
              editing ? (
                <button
                  onClick={saveEdit}
                  disabled={updateMeme.isPending}
                  className="flex items-center gap-1 text-sm px-3 py-1.5 rounded-lg bg-accent hover:bg-accent-hover text-white transition-colors"
                >
                  <Check size={14} /> Save
                </button>
              ) : (
                <button
                  onClick={startEdit}
                  className="text-zinc-500 hover:text-zinc-300 transition-colors p-1"
                  title="Edit"
                >
                  <Edit2 size={16} />
                </button>
              )
            )}
            {isAdmin && !meme.parent_id && (
              <button
                onClick={() => setShowRescale(true)}
                className="flex items-center gap-1 text-sm px-3 py-1.5 rounded-lg bg-zinc-800 hover:bg-zinc-700 text-zinc-300 transition-colors"
                title="Create rescaled copy"
              >
                <Minimize2 size={14} />
                <span className="hidden sm:inline">Rescale</span>
              </button>
            )}
            {isAdmin && (
              <button
                onClick={handleDelete}
                disabled={deleteMeme.isPending}
                className="text-zinc-500 hover:text-red-400 transition-colors p-1"
                title="Delete"
              >
                <Trash2 size={16} />
              </button>
            )}
            <button onClick={onClose} className="text-zinc-500 hover:text-zinc-300 transition-colors p-1">
              <X size={20} />
            </button>
          </div>
        </div>

        {/* Body */}
        <div className="flex flex-col md:flex-row flex-1 overflow-hidden">
          {/* Image panel */}
          <div className="flex-1 flex items-center justify-center bg-zinc-950 p-4 overflow-hidden">
            {displayMeme && (
              <img
                key={displayMeme.id}
                src={api.imageUrl(displayMeme.file_path)}
                alt={displayMeme.title}
                className="max-w-full max-h-full object-contain rounded-lg animate-fade-in"
              />
            )}
          </div>

          {/* Sidebar */}
          <div className="md:w-80 border-t md:border-t-0 md:border-l border-zinc-800 flex flex-col overflow-y-auto">
            <div className="p-5 space-y-5 flex-1">

              {/* Share */}
              {displayMeme && (
                <section>
                  <h3 className="text-xs font-semibold text-zinc-500 uppercase tracking-wider mb-2">Share</h3>
                  <SharePanel meme={displayMeme} />
                </section>
              )}

              {/* Description */}
              <section>
                <h3 className="text-xs font-semibold text-zinc-500 uppercase tracking-wider mb-2">Description</h3>
                {isAdmin && editing ? (
                  <textarea
                    value={editDesc}
                    onChange={(e) => setEditDesc(e.target.value)}
                    rows={3}
                    placeholder="Add a description…"
                    className="w-full bg-zinc-800 border border-zinc-700 rounded-lg px-3 py-2 text-sm focus:outline-none focus:border-accent resize-none"
                  />
                ) : (
                  <p className="text-sm text-zinc-400">{meme.description ?? 'No description.'}</p>
                )}
              </section>

              {/* Tags */}
              <section>
                <h3 className="text-xs font-semibold text-zinc-500 uppercase tracking-wider mb-2">Tags</h3>
                {isAdmin && editing ? (
                  <input
                    type="text"
                    value={editTags}
                    onChange={(e) => setEditTags(e.target.value)}
                    placeholder="funny, reaction, wholesome"
                    className="w-full bg-zinc-800 border border-zinc-700 rounded-lg px-3 py-2 text-sm focus:outline-none focus:border-accent"
                  />
                ) : (
                  <div className="flex flex-wrap gap-1.5">
                    {meme.tags.length > 0
                      ? meme.tags.map((t) => (
                          <span key={t} className="text-xs px-2 py-0.5 rounded-full bg-accent/20 text-purple-300">
                            {t}
                          </span>
                        ))
                      : <span className="text-sm text-zinc-600">No tags</span>
                    }
                  </div>
                )}
              </section>

              {/* Metadata */}
              <section>
                <h3 className="text-xs font-semibold text-zinc-500 uppercase tracking-wider mb-2">Info</h3>
                <dl className="space-y-1.5 text-sm">
                  <div className="flex justify-between">
                    <dt className="text-zinc-500">Dimensions</dt>
                    <dd className="text-zinc-300">{meme.width} × {meme.height}</dd>
                  </div>
                  <div className="flex justify-between">
                    <dt className="text-zinc-500">Size</dt>
                    <dd className="text-zinc-300">{formatBytes(meme.file_size)}</dd>
                  </div>
                  <div className="flex justify-between">
                    <dt className="text-zinc-500">Type</dt>
                    <dd className="text-zinc-300">{meme.mime_type.replace('image/', '')}</dd>
                  </div>
                  <div className="flex justify-between">
                    <dt className="text-zinc-500">Uploaded</dt>
                    <dd className="text-zinc-300 text-right text-xs">{formatDate(meme.created_at)}</dd>
                  </div>
                </dl>
              </section>

              {/* Rescaled variants */}
              {meme.children && meme.children.length > 0 && (
                <section>
                  <h3 className="text-xs font-semibold text-zinc-500 uppercase tracking-wider mb-2 flex items-center gap-1">
                    <Layers size={12} /> Rescaled Copies ({meme.children.length})
                  </h3>
                  <div className="space-y-1.5">
                    <button
                      onClick={() => setActiveChild(null)}
                      className={`w-full text-left text-xs px-3 py-2 rounded-lg transition-colors ${
                        activeChild === null
                          ? 'bg-accent/20 text-purple-300'
                          : 'bg-zinc-800 text-zinc-400 hover:bg-zinc-700'
                      }`}
                    >
                      Original — {meme.width}×{meme.height} ({formatBytes(meme.file_size)})
                    </button>
                    {meme.children.map((child) => (
                      <button
                        key={child.id}
                        onClick={() => setActiveChild(activeChild?.id === child.id ? null : child)}
                        className={`w-full text-left text-xs px-3 py-2 rounded-lg transition-colors ${
                          activeChild?.id === child.id
                            ? 'bg-accent/20 text-purple-300'
                            : 'bg-zinc-800 text-zinc-400 hover:bg-zinc-700'
                        }`}
                      >
                        {child.title.replace(meme.title, '').trim() || child.title} — {child.width}×{child.height} ({formatBytes(child.file_size)})
                      </button>
                    ))}
                  </div>
                </section>
              )}
            </div>
          </div>
        </div>
      </div>

      {showRescale && (
        <RescaleModal
          meme={meme}
          onClose={() => setShowRescale(false)}
          onDone={() => {
            setShowRescale(false);
            refetch();
          }}
        />
      )}
    </>
  );
}