"use client";

import { useState, useEffect, useCallback } from "react";
import { motion, AnimatePresence } from "framer-motion";
import {
  Shield, TrendingUp, AlertTriangle, Sparkles,
  DollarSign, X, CheckCheck, Bell, RefreshCw
} from "lucide-react";
import { notificationsApi, NotificationItem } from "@/lib/api";
import { useThemeStore } from "@/lib/stores/themeStore";

// ─── Type config ──────────────────────────────────────────────────────────────
const typeConfig: Record<string, {
  icon: React.ElementType;
  color: string;
  darkBg: string;
  lightBg: string;
}> = {
  alert:   { icon: Shield,        color: "text-red-500",     darkBg: "bg-red-500/10 border-red-500/20",        lightBg: "bg-red-50 border-red-200/70" },
  insight: { icon: Sparkles,      color: "text-blue-500",    darkBg: "bg-blue-500/10 border-blue-500/20",      lightBg: "bg-blue-50 border-blue-200/70" },
  warning: { icon: AlertTriangle, color: "text-amber-500",   darkBg: "bg-amber-500/10 border-amber-500/20",    lightBg: "bg-amber-50 border-amber-200/70" },
  success: { icon: TrendingUp,    color: "text-emerald-500", darkBg: "bg-emerald-500/10 border-emerald-500/20", lightBg: "bg-emerald-50 border-emerald-200/70" },
  default: { icon: DollarSign,    color: "text-slate-500",   darkBg: "bg-zinc-500/10 border-zinc-500/20",      lightBg: "bg-slate-50 border-slate-200/70" },
};

function getTypeConfig(type: string) {
  return typeConfig[type] || typeConfig.default;
}

function timeAgo(dateStr: string): string {
  const diff = Date.now() - new Date(dateStr).getTime();
  const mins = Math.floor(diff / 60000);
  if (mins < 1) return "Just now";
  if (mins < 60) return `${mins}m ago`;
  const hrs = Math.floor(mins / 60);
  if (hrs < 24) return `${hrs}h ago`;
  return `${Math.floor(hrs / 24)}d ago`;
}

// ─── Notification Item ────────────────────────────────────────────────────────
function NotifItem({
  notification,
  onDismiss,
  onRead,
  isLight,
}: {
  notification: NotificationItem;
  onDismiss: (id: string) => void;
  onRead: (id: string) => void;
  isLight: boolean;
}) {
  const config = getTypeConfig(notification.type);
  const Icon = config.icon;
  const bgClass = isLight ? config.lightBg : config.darkBg;

  return (
    <motion.div
      layout
      initial={{ opacity: 0, x: 20 }}
      animate={{ opacity: 1, x: 0 }}
      exit={{ opacity: 0, x: 20, height: 0, marginBottom: 0 }}
      transition={{ duration: 0.25 }}
      onClick={() => onRead(notification.id)}
      className={`relative flex gap-3 rounded-xl border p-3 cursor-pointer transition-all group ${bgClass} ${
        !notification.read ? "ring-1 ring-inset" : "opacity-60"
      }`}
    >
      {!notification.read && (
        <div className="absolute top-3 right-3 h-1.5 w-1.5 rounded-full bg-blue-500" />
      )}
      <div className={`flex h-8 w-8 flex-shrink-0 items-center justify-center rounded-lg border ${bgClass}`}>
        <Icon className={`h-4 w-4 ${config.color}`} />
      </div>
      <div className="flex-1 min-w-0 pr-4">
        <p className="text-xs font-semibold leading-tight" style={{ color: "var(--fg)" }}>
          {notification.title}
        </p>
        <p className="text-xs mt-0.5 leading-relaxed line-clamp-2" style={{ color: "var(--fg-muted)" }}>
          {notification.message}
        </p>
        <p className="text-xs mt-1" style={{ color: "var(--fg-subtle)" }}>
          {timeAgo(notification.created_at)}
        </p>
      </div>
      <button
        onClick={(e) => { e.stopPropagation(); onDismiss(notification.id); }}
        className={`absolute top-2 right-2 p-0.5 rounded transition-colors opacity-0 group-hover:opacity-100 ${
          isLight ? "text-slate-400 hover:text-slate-600" : "text-zinc-600 hover:text-zinc-400"
        }`}
      >
        <X className="h-3 w-3" />
      </button>
    </motion.div>
  );
}

// ─── Notification Panel ───────────────────────────────────────────────────────
export function NotificationPanel({
  isOpen,
  onClose,
}: {
  isOpen: boolean;
  onClose: () => void;
}) {
  const { theme } = useThemeStore();
  const isLight = theme === "light";

  const [notifications, setNotifications] = useState<NotificationItem[]>([]);
  const [unreadCount, setUnreadCount] = useState(0);
  const [filter, setFilter] = useState<"all" | "unread">("all");
  const [loading, setLoading] = useState(false);

  const loadNotifications = useCallback(async () => {
    setLoading(true);
    try {
      const res = await notificationsApi.list();
      setNotifications(res.notifications);
      setUnreadCount(res.unread_count);
    } catch {
      // backend offline — keep empty state
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    if (isOpen) loadNotifications();
  }, [isOpen, loadNotifications]);

  const dismiss = async (id: string) => {
    setNotifications((prev) => prev.filter((n) => n.id !== id));
    try { await notificationsApi.dismiss(id); } catch { /* ignore */ }
  };

  const markRead = async (id: string) => {
    setNotifications((prev) => prev.map((n) => n.id === id ? { ...n, read: true } : n));
    setUnreadCount((c) => Math.max(0, c - 1));
    try { await notificationsApi.markRead(id); } catch { /* ignore */ }
  };

  const markAllRead = async () => {
    setNotifications((prev) => prev.map((n) => ({ ...n, read: true })));
    setUnreadCount(0);
    try { await notificationsApi.markAllRead(); } catch { /* ignore */ }
  };

  const displayed = filter === "unread" ? notifications.filter((n) => !n.read) : notifications;

  return (
    <AnimatePresence>
      {isOpen && (
        <>
          <motion.div
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            onClick={onClose}
            className="fixed inset-0 z-40"
          />
          <motion.div
            initial={{ opacity: 0, y: -10, scale: 0.97 }}
            animate={{ opacity: 1, y: 0, scale: 1 }}
            exit={{ opacity: 0, y: -10, scale: 0.97 }}
            transition={{ duration: 0.2, ease: "easeOut" }}
            className="absolute right-0 top-full mt-2 z-50 w-80 rounded-2xl border backdrop-blur-2xl overflow-hidden"
            style={{
              background: isLight ? "rgba(255,255,255,0.97)" : "rgba(9,9,11,0.97)",
              borderColor: "var(--border-strong)",
              boxShadow: isLight
                ? "0 8px 40px rgba(15,23,42,0.14), 0 2px 8px rgba(15,23,42,0.08)"
                : "0 8px 40px rgba(0,0,0,0.6)",
            }}
          >
            {/* Header */}
            <div
              className="flex items-center justify-between border-b px-4 py-3"
              style={{ borderColor: "var(--border)" }}
            >
              <div className="flex items-center gap-2">
                <Bell className="h-4 w-4" style={{ color: "var(--fg-muted)" }} />
                <span className="text-sm font-semibold" style={{ color: "var(--fg)" }}>
                  Notifications
                </span>
                {unreadCount > 0 && (
                  <span className="flex h-4 w-4 items-center justify-center rounded-full bg-blue-500 text-[10px] font-bold text-white">
                    {unreadCount}
                  </span>
                )}
              </div>
              <div className="flex items-center gap-2">
                <button
                  onClick={loadNotifications}
                  className="transition-colors hover:text-emerald-500"
                  style={{ color: "var(--fg-subtle)" }}
                >
                  <RefreshCw className={`h-3.5 w-3.5 ${loading ? "animate-spin" : ""}`} />
                </button>
                {unreadCount > 0 && (
                  <button
                    onClick={markAllRead}
                    className="flex items-center gap-1 text-xs transition-colors hover:text-emerald-500"
                    style={{ color: "var(--fg-subtle)" }}
                  >
                    <CheckCheck className="h-3 w-3" />
                    All read
                  </button>
                )}
                <button
                  onClick={onClose}
                  className="transition-colors hover:text-red-500"
                  style={{ color: "var(--fg-subtle)" }}
                >
                  <X className="h-4 w-4" />
                </button>
              </div>
            </div>

            {/* Filter tabs */}
            <div
              className="flex gap-1 border-b px-4 py-2"
              style={{ borderColor: "var(--border)" }}
            >
              {(["all", "unread"] as const).map((f) => (
                <button
                  key={f}
                  onClick={() => setFilter(f)}
                  className={`rounded-lg px-3 py-1 text-xs font-medium capitalize transition-all ${
                    filter === f
                      ? isLight
                        ? "bg-slate-100 text-slate-800"
                        : "bg-white/10 text-white"
                      : ""
                  }`}
                  style={filter !== f ? { color: "var(--fg-subtle)" } : undefined}
                >
                  {f} {f === "unread" && unreadCount > 0 && `(${unreadCount})`}
                </button>
              ))}
            </div>

            {/* List */}
            <div className="max-h-96 overflow-y-auto p-3 space-y-2">
              <AnimatePresence mode="popLayout">
                {loading ? (
                  <div className="flex items-center justify-center py-8">
                    <RefreshCw className="h-5 w-5 animate-spin" style={{ color: "var(--fg-subtle)" }} />
                  </div>
                ) : displayed.length === 0 ? (
                  <motion.div
                    initial={{ opacity: 0 }}
                    animate={{ opacity: 1 }}
                    className="flex flex-col items-center gap-2 py-8 text-center"
                  >
                    <Bell className="h-8 w-8" style={{ color: "var(--fg-subtle)" }} />
                    <p className="text-sm" style={{ color: "var(--fg-muted)" }}>No notifications</p>
                  </motion.div>
                ) : (
                  displayed.map((n) => (
                    <NotifItem
                      key={n.id}
                      notification={n}
                      onDismiss={dismiss}
                      onRead={markRead}
                      isLight={isLight}
                    />
                  ))
                )}
              </AnimatePresence>
            </div>

            <div
              className="border-t px-4 py-2.5"
              style={{ borderColor: "var(--border)" }}
            >
              <p className="text-center text-xs" style={{ color: "var(--fg-subtle)" }}>
                Real-time · AI-powered · Encrypted
              </p>
            </div>
          </motion.div>
        </>
      )}
    </AnimatePresence>
  );
}

// ─── Notification Bell ────────────────────────────────────────────────────────
export function NotificationBell() {
  const { theme } = useThemeStore();
  const isLight = theme === "light";
  const [isOpen, setIsOpen] = useState(false);
  const [unreadCount, setUnreadCount] = useState(0);

  useEffect(() => {
    notificationsApi.list().then((res) => setUnreadCount(res.unread_count)).catch(() => {});
  }, []);

  return (
    <div className="relative">
      <motion.button
        whileHover={{ scale: 1.05 }}
        whileTap={{ scale: 0.95 }}
        onClick={() => setIsOpen((v) => !v)}
        className={`relative rounded-xl p-2.5 transition-all duration-200 focus:outline-none ${
          isLight
            ? "bg-slate-100 text-slate-500 hover:bg-slate-200 hover:text-slate-800"
            : "bg-white/5 text-zinc-400 hover:text-white hover:bg-white/10"
        }`}
      >
        <Bell className="h-5 w-5" aria-hidden="true" />
        {unreadCount > 0 && (
          <motion.span
            initial={{ scale: 0 }}
            animate={{ scale: 1 }}
            className="absolute -top-0.5 -right-0.5 flex h-4 w-4 items-center justify-center rounded-full bg-red-500 text-[9px] font-bold text-white"
          >
            {unreadCount > 9 ? "9+" : unreadCount}
          </motion.span>
        )}
      </motion.button>
      <NotificationPanel isOpen={isOpen} onClose={() => setIsOpen(false)} />
    </div>
  );
}