"use client";

import { useState, useEffect, useCallback } from "react";
import { useRouter } from "next/navigation";
import { ArrowLeft, Plus, Trash2, Eye, EyeOff, Edit, Wifi, WifiOff, Loader2, X } from "lucide-react";

interface Link {
  name: string;
  url: string;
  description?: string;
  image?: string;
  hidden?: boolean;
  rss?: string;
  addedAt?: string;
}

export default function LinksPage() {
  const router = useRouter();
  const [links, setLinks] = useState<Link[]>([]);
  const [loading, setLoading] = useState(true);
  const [showAll, setShowAll] = useState(false);
  const [message, setMessage] = useState<{ type: "success" | "error"; text: string } | null>(null);

  // Add form
  const [showAdd, setShowAdd] = useState(false);
  const [addForm, setAddForm] = useState({ name: "", url: "", description: "" });
  const [adding, setAdding] = useState(false);

  // Edit form
  const [editTarget, setEditTarget] = useState<string | null>(null);
  const [editForm, setEditForm] = useState({ name: "", url: "", description: "" });
  const [editing, setEditing] = useState(false);

  // Health
  const [health, setHealth] = useState<Map<string, { ok: boolean; status?: number; latency?: number }>>(new Map());
  const [checkingAll, setCheckingAll] = useState(false);
  const [checkingMap, setCheckingMap] = useState<Map<string, boolean>>(new Map());

  const fetchLinks = useCallback(async () => {
    setLoading(true);
    try {
      const res = await fetch(`/api/rss/links?all=1`); // always get all for admin
      const data = await res.json();
      const all = data.links || [];
      // Sort visible first, then hidden
      all.sort((a: Link, b: Link) => (a.hidden ? 1 : 0) - (b.hidden ? 1 : 0));
      setLinks(all);
    } catch { setMessage({ type: "error", text: "加载失败" }); }
    finally { setLoading(false); }
  }, []);

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

  const handleAdd = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!addForm.name || !addForm.url) return;
    setAdding(true);
    try {
      const res = await fetch("/api/rss/links", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(addForm),
      });
      if (!res.ok) throw new Error("添加失败");
      setShowAdd(false);
      setAddForm({ name: "", url: "", description: "" });
      fetchLinks();
    } catch (err: unknown) {
      setMessage({ type: "error", text: err instanceof Error ? err.message : "添加失败" });
    } finally { setAdding(false); }
  };

  const startEdit = (l: Link) => {
    setEditTarget(l.url);
    setEditForm({ name: l.name, url: l.url, description: l.description || "" });
  };

  const handleEdit = async () => {
    if (!editTarget) return;
    setEditing(true);
    try {
      const body = {
        oldUrl: editTarget,
        name: editForm.name,
        url: editForm.url,
        description: editForm.description,
      };
      const res = await fetch("/api/rss/links", {
        method: "PUT",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      if (!res.ok) throw new Error("保存失败");
      setEditTarget(null);
      fetchLinks();
    } catch (err: unknown) {
      setMessage({ type: "error", text: err instanceof Error ? err.message : "保存失败" });
    } finally { setEditing(false); }
  };

  const toggleHidden = async (l: Link) => {
    try {
      const res = await fetch("/api/rss/links", {
        method: "PUT",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          oldUrl: l.url,
          name: l.name,
          description: l.description || "",
          hidden: !l.hidden,
        }),
      });
      if (!res.ok) throw new Error("操作失败");
      setLinks((prev) => prev.map((x) => x.url === l.url ? { ...x, hidden: !x.hidden } : x));
    } catch (err: unknown) {
      setMessage({ type: "error", text: err instanceof Error ? err.message : "操作失败" });
    }
  };

  const handleDelete = async (url: string, name: string) => {
    if (!confirm(`确定删除「${name}」？`)) return;
    try {
      await fetch(`/api/rss/links?url=${encodeURIComponent(url)}`, { method: "DELETE" });
      setLinks((prev) => prev.filter((l) => l.url !== url));
    } catch { setMessage({ type: "error", text: "删除失败" }); }
  };

  const checkOne = async (url: string) => {
    setCheckingMap((prev) => new Map(prev).set(url, true));
    try {
      const res = await fetch(`/api/rss/links?health=${encodeURIComponent(url)}`);
      const data = await res.json();
      setHealth((prev) => new Map(prev).set(url, data));
    } catch {} finally {
      setCheckingMap((prev) => { const m = new Map(prev); m.delete(url); return m; });
    }
  };

  const checkAll = async () => {
    setCheckingAll(true);
    const visible = links.filter((l) => !l.hidden);
    for (let i = 0; i < visible.length; i += 3) {
      const batch = visible.slice(i, i + 3);
      await Promise.all(batch.map((l) => checkOne(l.url)));
    }
    setCheckingAll(false);
  };

  // Counts for display
  const visibleLinks = showAll ? links : links.filter((l) => !l.hidden);
  const hiddenCount = links.filter((l) => l.hidden).length;

  return (
    <div className="px-4 py-6 md:px-8 md:py-8">
      <div className="flex items-center justify-between mb-6 sm:mb-8 gap-3 flex-wrap">
        <div className="flex items-center gap-3">
          <button type="button" onClick={() => router.back()} className="p-1 -ml-1 rounded hover:bg-surface text-muted hover:text-text transition-colors">
            <ArrowLeft size={16} />
          </button>
          <h2 className="text-lg font-bold text-text">友链管理</h2>
          <span className="text-[13px] text-muted">{links.length} 个{hiddenCount > 0 && `（${hiddenCount} 隐藏）`}</span>
        </div>
        <div className="flex items-center gap-2">
          <button type="button" onClick={checkAll} disabled={checkingAll}
            className="flex items-center gap-1.5 px-3 py-1.5 text-[12px] rounded-md border border-line text-muted hover:text-accent transition-colors disabled:opacity-50">
            {checkingAll ? <Loader2 size={13} className="animate-spin" /> : <Wifi size={13} />}
            {checkingAll ? "检测中..." : "检测存活"}
          </button>
          <button type="button" onClick={() => setShowAll(!showAll)}
            className={`flex items-center gap-1.5 px-3 py-1.5 text-[12px] rounded-md border transition-colors ${
              showAll ? "bg-accent/5 border-accent/30 text-accent" : "border-line text-muted hover:text-accent"
            }`}>
            {showAll ? <Eye size={13} /> : <EyeOff size={13} />}
            {showAll ? "全部" : "可见"}
          </button>
          <button type="button" onClick={() => setShowAdd(true)}
            className="flex items-center gap-1.5 px-3 py-1.5 text-[12px] font-medium rounded-md bg-accent text-white hover:bg-accent-hover transition-colors">
            <Plus size={13} /> 添加
          </button>
        </div>
      </div>

      {message && (
        <div className={`mb-4 px-4 py-2.5 rounded-md text-[13px] flex items-center justify-between ${
          message.type === "success" ? "bg-[#d1fae5] text-[#065f46] border border-[#a7f3d0]" : "bg-[#fee2e2] text-[#991b1b] border border-[#fecaca]"
        }`}>
          {message.text}
          <button type="button" onClick={() => setMessage(null)} className="underline">关闭</button>
        </div>
      )}

      {/* Add form */}
      {showAdd && (
        <div className="mb-6 p-5 bg-card border border-line rounded-lg">
          <form onSubmit={handleAdd} className="flex flex-col sm:flex-row gap-3 sm:items-end">
            <div className="flex-1">
              <label className="block text-[12px] font-medium text-text/70 mb-1.5">网站名称</label>
              <input type="text" value={addForm.name} onChange={(e) => setAddForm({ ...addForm, name: e.target.value })}
                className="w-full bg-bg border border-line rounded-md px-3 py-2 text-[13px] focus:outline-none focus:border-accent/30" required />
            </div>
            <div className="flex-[2]">
              <label className="block text-[12px] font-medium text-text/70 mb-1.5">URL</label>
              <input type="text" value={addForm.url} onChange={(e) => setAddForm({ ...addForm, url: e.target.value })}
                className="w-full bg-bg border border-line rounded-md px-3 py-2 text-[13px] focus:outline-none focus:border-accent/30" required />
            </div>
            <div className="flex-1">
              <label className="block text-[12px] font-medium text-text/70 mb-1.5">描述</label>
              <input type="text" value={addForm.description} onChange={(e) => setAddForm({ ...addForm, description: e.target.value })}
                className="w-full bg-bg border border-line rounded-md px-3 py-2 text-[13px] focus:outline-none focus:border-accent/30" />
            </div>
            <button type="submit" disabled={adding} className="px-4 py-2 text-[13px] font-medium rounded-md bg-accent text-white hover:bg-accent-hover disabled:opacity-50 shrink-0" title="添加">
              {adding ? "..." : "添加"}
            </button>
            <button type="button" onClick={() => setShowAdd(false)} className="px-3 py-2 text-[13px] rounded-md border border-line text-muted hover:bg-surface shrink-0" title="取消">取消</button>
          </form>
        </div>
      )}

      {/* Loading */}
      {loading ? (
        <div className="text-center py-20 text-muted text-sm">加载中...</div>
      ) : visibleLinks.length === 0 ? (
        <div className="text-center py-20 text-muted text-sm">暂无友链</div>
      ) : (
        <div className="space-y-2">
          {visibleLinks.map((l) => {
            const h = health.get(l.url);
            const ck = checkingMap.get(l.url);
            return (
              <div key={l.url}
                className={`flex items-center gap-4 px-5 py-3.5 border rounded-md group transition-all ${
                  l.hidden ? "bg-surface/50 border-line/50 opacity-60" : "bg-card border-line"
                } ${editTarget === l.url ? "ring-2 ring-accent/20 border-accent" : ""}`}>

                {/* Health indicator */}
                {ck ? <Loader2 size={13} className="animate-spin text-muted shrink-0" />
                  : h ? (h.ok ? <span title={`${h.status} ${h.latency}ms`}><Wifi size={13} className="text-success shrink-0" /></span>
                    : <span title={h.status ? String(h.status) : "不可达"}><WifiOff size={13} className="text-danger shrink-0" /></span>)
                  : null}

                {/* Favicon */}
                {l.image && <img src={l.image} alt="" className="w-4 h-4 rounded shrink-0" onError={(e) => { (e.target as HTMLImageElement).style.display = "none"; }} />}

                {/* Info or Edit form */}
                {editTarget === l.url ? (
                  <div className="flex-1 flex flex-col sm:flex-row gap-2 sm:items-end">
                    <div className="flex-1">
                      <input type="text" value={editForm.name} onChange={(e) => setEditForm({ ...editForm, name: e.target.value })}
                        className="w-full bg-bg border border-line rounded-md px-2 py-1.5 text-[13px] focus:outline-none focus:border-accent/30" title="名称" placeholder="名称" />
                    </div>
                    <div className="flex-[2]">
                      <input type="text" value={editForm.url} onChange={(e) => setEditForm({ ...editForm, url: e.target.value })}
                        className="w-full bg-bg border border-line rounded-md px-2 py-1.5 text-[13px] focus:outline-none focus:border-accent/30" title="URL" placeholder="URL" />
                    </div>
                    <div className="flex-1">
                      <input type="text" value={editForm.description} onChange={(e) => setEditForm({ ...editForm, description: e.target.value })}
                        className="w-full bg-bg border border-line rounded-md px-2 py-1.5 text-[13px] focus:outline-none focus:border-accent/30" placeholder="描述" title="描述" />
                    </div>
                    <button type="button" onClick={handleEdit} disabled={editing}
                      className="px-3 py-1.5 text-[12px] font-medium rounded-md bg-accent text-white hover:bg-accent-hover shrink-0" title="保存">{editing ? "..." : "保存"}</button>
                    <button type="button" onClick={() => setEditTarget(null)}
                      className="p-1.5 rounded text-muted hover:text-text" title="取消"><X size={14} /></button>
                  </div>
                ) : (
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-2">
                      <span className="font-medium text-[14px] text-text">{l.name}</span>
                      {l.hidden && <span className="text-[10px] text-[#92400e] bg-[#fef3c7] px-1.5 py-px rounded font-medium">隐藏</span>}
                      {h && !h.ok && <span className="text-[10px] text-danger bg-danger/8 px-1.5 py-px rounded font-medium">失联</span>}
                    </div>
                    <div className="flex items-center gap-2 mt-0.5 text-[11px] text-muted">
                      <span className="truncate">{l.url}</span>
                      {l.description && <span className="text-line">·</span>}
                      {l.description && <span className="truncate">{l.description}</span>}
                    </div>
                  </div>
                )}

                {/* Actions */}
                <div className="flex items-center gap-0.5 shrink-0">
                  {editTarget !== l.url && (
                    <>
                      <button type="button" onClick={() => checkOne(l.url)} className="p-1.5 rounded hover:bg-surface text-muted hover:text-accent transition-colors"
                        title="检测">
                        {checkingMap.get(l.url) ? <Loader2 size={13} className="animate-spin" /> : <Wifi size={13} />}
                      </button>
                      <button type="button" onClick={() => startEdit(l)} className="p-1.5 rounded hover:bg-surface text-muted hover:text-text transition-colors"
                        title="编辑">
                        <Edit size={13} />
                      </button>
                      <button type="button" onClick={() => toggleHidden(l)} className="p-1.5 rounded hover:bg-surface text-muted hover:text-text transition-colors"
                        title={l.hidden ? "显示" : "隐藏"}>
                        {l.hidden ? <Eye size={13} /> : <EyeOff size={13} />}
                      </button>
                      <button type="button" onClick={() => handleDelete(l.url, l.name)} className="p-1.5 rounded hover:bg-danger/8 text-muted hover:text-danger transition-colors"
                        title="删除">
                        <Trash2 size={13} />
                      </button>
                    </>
                  )}
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}