"use client";

import type { Metadata } from "next";
import { useState, useEffect } from "react";
import { useSession } from "next-auth/react";
import { useRouter } from "next/navigation";
import { Card, CardContent } from "@/components/ui/card";
import { FolderOpen, Plus, ChevronRight, Loader2, X } from "lucide-react";

interface Collection {
  id: number;
  name: string;
  description: string | null;
  createdAt: string;
  _count: { items: number };
}

export const metadata: Metadata = {
  title: "我的收藏夹 - 追光AI",
};

export default function CollectionsPage() {
  const { data: session, status } = useSession();
  const router = useRouter();
  const [collections, setCollections] = useState<Collection[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const [showCreate, setShowCreate] = useState(false);
  const [newName, setNewName] = useState("");
  const [newDesc, setNewDesc] = useState("");
  const [creating, setCreating] = useState(false);
  const [createError, setCreateError] = useState("");

  useEffect(() => {
    if (status === "loading") return;
    if (status === "unauthenticated") {
      setLoading(false);
      return;
    }
    fetchCollections();
  }, [status]);

  const fetchCollections = () => {
    setLoading(true);
    setError("");
    fetch("/api/user/collections")
      .then((r) => r.json())
      .then((data) => setCollections(data.collections || []))
      .catch(() => setError("加载收藏夹失败"))
      .finally(() => setLoading(false));
  };

  const handleCreate = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!newName.trim()) return;
    setCreating(true);
    setCreateError("");
    try {
      const res = await fetch("/api/user/collections", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ name: newName.trim(), description: newDesc.trim() || undefined }),
      });
      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.error || "创建失败");
      }
      setShowCreate(false);
      setNewName("");
      setNewDesc("");
      fetchCollections();
    } catch (err: any) {
      setCreateError(err.message);
    } finally {
      setCreating(false);
    }
  };

  if (status === "loading") {
    return (
      <div className="min-h-screen flex items-center justify-center">
        <div className="h-8 w-8 animate-spin rounded-full border-2 border-primary border-t-transparent" />
      </div>
    );
  }

  if (status === "unauthenticated") {
    return (
      <div className="min-h-screen flex items-center justify-center px-4">
        <Card className="w-full max-w-md p-8 text-center rounded-2xl border border-border/60 bg-white shadow-[0_4px_16px_rgba(0,0,0,0.06)]">
          <div className="mx-auto mb-4 flex h-16 w-16 items-center justify-center rounded-2xl bg-primary/10 border border-primary/20">
            <FolderOpen className="w-7 h-7 text-primary" />
          </div>
          <h2 className="text-xl font-bold">请先登录</h2>
          <p className="mt-2 text-sm text-muted-foreground">登录后即可管理收藏夹</p>
          <button onClick={() => router.push("/login")} className="mt-6 w-full py-2.5 bg-primary text-white rounded-lg hover:bg-primary/90 transition-colors">
            去登录
          </button>
        </Card>
      </div>
    );
  }

  return (
    <div className="relative">
      <div className="pointer-events-none absolute inset-0 overflow-hidden">
        <div className="absolute -top-32 left-1/4 h-[500px] w-[600px] rounded-full bg-primary/4 blur-[120px]" />
      </div>

      <div className="relative mx-auto max-w-4xl px-4 py-8 sm:px-6 lg:px-8">
        <div className="mb-8 animate-fade-in">
          <div className="flex items-center gap-2 text-sm text-muted-foreground">
            <button onClick={() => router.push("/")} className="transition-colors hover:text-foreground">首页</button>
            <svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path strokeLinecap="round" strokeLinejoin="round" d="M9 5l7 7-7 7" /></svg>
            <span className="text-foreground">我的收藏夹</span>
          </div>
          <div className="mt-3 flex items-center justify-between">
            <div className="flex items-center gap-3">
              <h1 className="text-3xl font-bold tracking-tight">
                我的<span className="gradient-text">收藏夹</span>
              </h1>
              <span className="rounded-full bg-primary/10 px-2.5 py-0.5 text-sm font-medium text-primary">
                {collections.length}
              </span>
            </div>
            <button
              onClick={() => { setShowCreate(true); setCreateError(""); }}
              className="flex items-center gap-1.5 rounded-lg bg-primary px-4 py-2 text-sm font-medium text-white hover:bg-primary/90 transition-colors shadow-sm shadow-primary/20"
            >
              <Plus className="w-4 h-4" />
              新建收藏夹
            </button>
          </div>
        </div>

        {showCreate && (
          <Card className="mb-6 border-border/60 bg-white shadow-[0_1px_3px_rgba(0,0,0,0.06)]">
            <CardContent className="p-5">
              <form onSubmit={handleCreate} className="space-y-4">
                <div className="flex items-center justify-between">
                  <h3 className="font-semibold text-sm">新建收藏夹</h3>
                  <button type="button" onClick={() => setShowCreate(false)} className="p-1 rounded-lg text-muted-foreground hover:bg-accent transition-colors">
                    <X className="w-4 h-4" />
                  </button>
                </div>
                <input
                  type="text"
                  placeholder="收藏夹名称"
                  value={newName}
                  onChange={(e) => setNewName(e.target.value)}
                  maxLength={50}
                  required
                  className="w-full px-3 py-2 bg-white rounded-lg border border-border/60 text-sm focus:outline-none focus:border-primary/50 focus:ring-2 focus:ring-primary/15 transition-colors"
                  autoFocus
                />
                <input
                  type="text"
                  placeholder="描述（选填）"
                  value={newDesc}
                  onChange={(e) => setNewDesc(e.target.value)}
                  className="w-full px-3 py-2 bg-white rounded-lg border border-border/60 text-sm focus:outline-none focus:border-primary/50 focus:ring-2 focus:ring-primary/15 transition-colors"
                />
                {createError && <p className="text-sm text-red-500">{createError}</p>}
                <button
                  type="submit"
                  disabled={creating || !newName.trim()}
                  className="w-full py-2 bg-primary text-white rounded-lg text-sm font-medium hover:bg-primary/90 transition-colors disabled:opacity-50"
                >
                  {creating ? <Loader2 className="w-4 h-4 animate-spin mx-auto" /> : "创建"}
                </button>
              </form>
            </CardContent>
          </Card>
        )}

        {error ? (
          <div className="flex flex-col items-center justify-center py-24">
            <div className="flex h-16 w-16 items-center justify-center rounded-2xl bg-red-50 border border-red-200/60">
              <svg className="w-7 h-7 text-red-500" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
                <path strokeLinecap="round" strokeLinejoin="round" d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126ZM12 15.75h.007v.008H12v-.008Z" />
              </svg>
            </div>
            <p className="mt-4 text-sm font-medium text-foreground">加载失败</p>
            <p className="mt-1 text-sm text-muted-foreground">{error}</p>
            <button onClick={fetchCollections} className="mt-4 rounded-lg bg-primary px-4 py-2 text-sm text-white hover:bg-primary/90 transition-colors">重新加载</button>
          </div>
        ) : loading ? (
          <div className="grid gap-3 sm:grid-cols-2">
            {Array.from({ length: 4 }).map((_, i) => (
              <Card key={i} className="border-border/50 bg-white">
                <CardContent className="p-5">
                  <div className="h-5 w-32 animate-pulse rounded bg-muted/40 mb-2" />
                  <div className="h-3 w-48 animate-pulse rounded bg-muted/30" />
                </CardContent>
              </Card>
            ))}
          </div>
        ) : collections.length === 0 ? (
          <div className="flex flex-col items-center justify-center py-24">
            <div className="flex h-20 w-20 items-center justify-center rounded-2xl bg-muted/30 border border-border/30">
              <FolderOpen className="w-8 h-8 text-muted-foreground/40" />
            </div>
            <p className="mt-5 text-base font-medium text-muted-foreground">暂无收藏夹</p>
            <p className="mt-1 text-sm text-muted-foreground/50">创建收藏夹来整理你的AI工具和技能</p>
            <button onClick={() => setShowCreate(true)} className="mt-4 flex items-center gap-1.5 rounded-lg border border-border/60 px-4 py-2 text-sm text-muted-foreground transition-colors hover:bg-muted/30 hover:text-foreground">
              <Plus className="w-4 h-4" />
              新建收藏夹
            </button>
          </div>
        ) : (
          <div className="grid gap-3 sm:grid-cols-2">
            {collections.map((c, i) => (
              <Card
                key={c.id}
                className="group cursor-pointer border-border/50 bg-white transition-all duration-300 hover:border-primary/30 hover:shadow-[0_4px_12px_rgba(0,0,0,0.06)] hover:-translate-y-0.5 shadow-[0_1px_2px_rgba(0,0,0,0.04)] animate-slide-up"
                style={{ animationDelay: `${i * 50}ms`, animationFillMode: "both" }}
                onClick={() => router.push(`/user/collections/${c.id}`)}
              >
                <CardContent className="p-5">
                  <div className="flex items-start justify-between">
                    <div className="min-w-0">
                      <h3 className="font-semibold text-foreground truncate group-hover:text-primary transition-colors">{c.name}</h3>
                      {c.description && (
                        <p className="mt-1 text-sm text-muted-foreground truncate">{c.description}</p>
                      )}
                      <div className="mt-2 flex items-center gap-3 text-xs text-muted-foreground/60">
                        <span>{c._count.items} 项</span>
                        <span>{new Date(c.createdAt).toLocaleDateString("zh-CN")} 创建</span>
                      </div>
                    </div>
                    <ChevronRight className="w-4 h-4 text-muted-foreground/0 group-hover:text-muted-foreground/50 transition-all mt-0.5" />
                  </div>
                </CardContent>
              </Card>
            ))}
          </div>
        )}
      </div>
    </div>
  );
}