"use client";

import { useState, useEffect } from "react";
import Link from "next/link";
import { useSession, signIn } from "next-auth/react";
import {
  Search, Flame, Sparkles, TrendingUp, Loader2, Eye, MessageCircle, Filter,
} from "lucide-react";
import toast, { Toaster } from "react-hot-toast";

export default function ExplorePage() {
  const { data: session, status } = useSession();
  const [characters, setCharacters] = useState([]);
  const [loading, setLoading] = useState(true);
  const [search, setSearch] = useState("");

  useEffect(() => { fetchCharacters(); }, []);

  const fetchCharacters = async () => {
    setLoading(true);
    try {
      const res = await fetch("/api/characters");
      const data = await res.json();
      if (data.characters) {
        const publicCustom = data.characters.filter((c) => c.isPublic && c.isCustom);
        setCharacters(publicCustom);
      }
    } catch (err) {
      console.error("Failed to load characters", err);
      toast.error("Failed to load characters");
    } finally { setLoading(false); }
  };

  const filtered = characters.filter((c) => {
    const matchesSearch =
      !search ||
      c.name.toLowerCase().includes(search.toLowerCase()) ||
      c.description.toLowerCase().includes(search.toLowerCase()) ||
      c.personality.toLowerCase().includes(search.toLowerCase());
    return matchesSearch;
  });

  if (status === "loading") {
    return (
      <div className="min-h-dvh flex items-center justify-center bg-bg-page text-primary-text">
        <Loader2 className="w-8 h-8 animate-spin text-primary" />
      </div>
    );
  }

  return (
    <div className="min-h-dvh bg-bg-page text-primary-text pb-20">
      <Toaster position="top-right" />
      <div className="relative overflow-hidden border-b border-divider/50">
        <div className="absolute inset-0 bg-gradient-to-br from-yellow-500/5 via-transparent to-primary/5 pointer-events-none" />
        <div className="relative max-w-7xl mx-auto px-6 py-16">
          <div className="flex items-center gap-2 text-yellow-400 text-xs font-bold uppercase tracking-widest mb-3">
            <Sparkles className="w-3.5 h-3.5" />
            <span>HuggingFace Community Marketplace</span>
          </div>
          <h1 className="text-4xl md:text-5xl font-black tracking-tight mb-4">Explore Community Characters</h1>
          <p className="text-secondary-text text-sm max-w-2xl leading-relaxed">
            Discover personas crafted by other HuggingFace users. From historical figures to anime companions, find your next conversation partner — or publish your own creations to the community.
          </p>
          <div className="mt-8 flex flex-col sm:flex-row gap-3 max-w-2xl">
            <div className="relative flex-1">
              <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-secondary-text" />
              <input
                type="text" value={search} onChange={(e) => setSearch(e.target.value)}
                placeholder="Search characters, personalities, or topics..."
                className="w-full bg-bg-card border border-divider rounded-lg pl-10 pr-4 py-3 text-sm text-primary-text placeholder-secondary-text/50 focus:outline-none focus:border-primary/50"
              />
            </div>
            <Link href="/" className="bg-primary text-white px-6 py-3 rounded-lg text-sm font-bold flex items-center justify-center gap-2 hover:bg-primary/90 transition shadow-md">
              <Flame className="w-4 h-4" />
              Create Your Own
            </Link>
          </div>
        </div>
      </div>

      <div className="max-w-7xl mx-auto px-6 mt-10">
        <div className="flex items-center justify-between mb-6">
          <div className="flex items-center gap-2">
            <TrendingUp className="w-5 h-5 text-emerald-400" />
            <h2 className="text-lg font-black uppercase tracking-wider">
              {filtered.length} Public Character{filtered.length === 1 ? "" : "s"}
            </h2>
          </div>
          <span className="text-xs text-secondary-text">Sorted by most recent</span>
        </div>

        {loading ? (
          <div className="h-64 flex items-center justify-center">
            <Loader2 className="w-8 h-8 animate-spin text-primary" />
          </div>
        ) : filtered.length === 0 ? (
          <div className="h-64 border border-dashed border-divider/60 rounded-xl flex flex-col items-center justify-center text-center p-8">
            <span className="text-4xl mb-3">🎭</span>
            <h3 className="font-black text-lg mb-1">No characters found</h3>
            <p className="text-xs text-secondary-text max-w-sm">
              {search ? `No matches for "${search}". Try a different keyword.` : "Be the first to publish a public character to the marketplace!"}
            </p>
            <Link href="/" className="mt-4 bg-primary text-white px-5 py-2 rounded-full text-xs font-bold hover:bg-primary/90 transition">+ Create Character</Link>
          </div>
        ) : (
          <div className="grid grid-cols-2 sm:grid-cols-3 lg:grid-cols-4 xl:grid-cols-5 gap-4">
            {filtered.map((c) => <CharacterCard key={c.id} character={c} session={session} />)}
          </div>
        )}
      </div>
    </div>
  );
}

function CharacterCard({ character, session }) {
  const slug = character.name.toLowerCase().replace(/[^a-z0-9]+/g, "-");
  const [starting, setStarting] = useState(false);

  const handleStart = async (e) => {
    e.preventDefault();
    if (!session?.user) return;
    setStarting(true);
    try {
      const res = await fetch("/api/chats", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ character_id: character.id }),
      });
      if (res.ok) {
        const data = await res.json();
        if (data.chat) window.location.href = `/${slug}/${data.chat.id}`;
      }
    } catch (err) { console.error(err); }
    finally { setStarting(false); }
  };

  return (
    <div className="group relative bg-bg-card border border-divider/50 rounded-xl overflow-hidden hover:border-primary/40 transition-all duration-300 hover:shadow-lg hover:shadow-primary/5">
      <div className="aspect-square bg-bg-page/50 flex items-center justify-center overflow-hidden relative">
        {character.profileUrl || (character.avatar?.length > 2 && character.avatar?.startsWith("http")) ? (
          <img src={character.profileUrl || character.avatar} alt={character.name}
            className="w-full h-full object-cover group-hover:scale-105 transition-transform duration-500" />
        ) : (
          <span className="text-5xl">{character.avatar || "🤖"}</span>
        )}
        <div className="absolute top-2 right-2 bg-black/60 backdrop-blur-sm px-2 py-0.5 rounded text-[9px] font-bold uppercase tracking-wider text-emerald-400 border border-emerald-400/30">Public</div>
      </div>
      <div className="p-3 space-y-2">
        <div>
          <h3 className="font-black text-sm truncate">{character.name}</h3>
          <p className="text-[10px] text-secondary-text truncate">{character.description}</p>
        </div>
        <p className="text-[10px] text-zinc-500 line-clamp-2 leading-relaxed">{character.personality}</p>
        {session?.user ? (
          <button onClick={handleStart} disabled={starting}
            className="w-full mt-2 py-1.5 rounded-lg bg-primary/10 border border-primary/30 text-primary text-[10px] font-bold uppercase tracking-wider hover:bg-primary hover:text-white transition disabled:opacity-50 flex items-center justify-center gap-1.5">
            {starting ? <Loader2 className="w-3 h-3 animate-spin" /> : <MessageCircle className="w-3 h-3" />}
            <span>{starting ? "Starting..." : "Start Chat"}</span>
          </button>
        ) : (
          <Link href="/login" className="w-full mt-2 py-1.5 rounded-lg bg-bg-page border border-divider text-secondary-text text-[10px] font-bold uppercase tracking-wider hover:text-primary-text transition flex items-center justify-center gap-1.5">
            <Eye className="w-3 h-3" /> Sign in to chat
          </Link>
        )}
      </div>
    </div>
  );
}