import type { Metadata } from "next";
import Link from "next/link";
import { db } from "@epicure/db";
import { users, recipes, userUsage, recipePhotos, reports, cookingHistory, webhooks, apiKeys } from "@epicure/db";
import { count, eq, gte, sql } from "@epicure/db";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Users, BookOpen, Sparkles, Image, History, UserPlus, ChefHat, Flag, HardDrive, Webhook, KeyRound } from "lucide-react";
import { APP_VERSION, CHANGELOG } from "@/lib/changelog";

export const metadata: Metadata = {};

export default async function AdminPage() {
  const currentMonth = new Date().toISOString().slice(0, 7);
  const sevenDaysAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000);

  const [
    userCount,
    recipeCount,
    proUserCount,
    publicRecipeCount,
    aiUsage,
    imageCount,
    storageUsage,
    newUsers7d,
    newRecipes7d,
    cooked7d,
    pendingReports,
    webhookCount,
    apiKeyCount,
  ] = await Promise.all([
    db.select({ count: count() }).from(users).then((r) => r[0]),
    db.select({ count: count() }).from(recipes).then((r) => r[0]),
    db.select({ count: count() }).from(users).where(eq(users.tier, "pro")).then((r) => r[0]),
    db.select({ count: count() }).from(recipes).where(eq(recipes.visibility, "public")).then((r) => r[0]),
    db
      .select({ total: sql<string>`coalesce(sum(${userUsage.aiCallsUsed}), 0)` })
      .from(userUsage)
      .where(eq(userUsage.month, currentMonth))
      .then((r) => r[0]),
    db.select({ count: count() }).from(recipePhotos).then((r) => r[0]),
    db
      .select({ total: sql<string>`coalesce(sum(${userUsage.storageUsedMb}), 0)` })
      .from(userUsage)
      .where(eq(userUsage.month, currentMonth))
      .then((r) => r[0]),
    db.select({ count: count() }).from(users).where(gte(users.createdAt, sevenDaysAgo)).then((r) => r[0]),
    db.select({ count: count() }).from(recipes).where(gte(recipes.createdAt, sevenDaysAgo)).then((r) => r[0]),
    db.select({ count: count() }).from(cookingHistory).where(gte(cookingHistory.cookedAt, sevenDaysAgo)).then((r) => r[0]),
    db.select({ count: count() }).from(reports).where(eq(reports.status, "pending")).then((r) => r[0]),
    db.select({ count: count() }).from(webhooks).where(eq(webhooks.active, true)).then((r) => r[0]),
    db.select({ count: count() }).from(apiKeys).then((r) => r[0]),
  ]);

  const stats = [
    { label: "Total Users", value: userCount?.count ?? 0, sub: `${proUserCount?.count ?? 0} pro`, icon: Users },
    { label: "New Users (7d)", value: newUsers7d?.count ?? 0, icon: UserPlus },
    { label: "Total Recipes", value: recipeCount?.count ?? 0, sub: `${publicRecipeCount?.count ?? 0} public`, icon: BookOpen },
    { label: "New Recipes (7d)", value: newRecipes7d?.count ?? 0, icon: BookOpen },
    { label: "Cooked (7d)", value: cooked7d?.count ?? 0, icon: ChefHat },
    { label: "AI Calls This Month", value: Number(aiUsage?.total ?? 0), icon: Sparkles },
    { label: "Recipe Photos", value: imageCount?.count ?? 0, icon: Image },
    { label: "Storage This Month", value: Number(storageUsage?.total ?? 0), unit: "MB", icon: HardDrive },
    {
      label: "Pending Reports",
      value: pendingReports?.count ?? 0,
      icon: Flag,
      href: "/admin/reports",
      highlight: (pendingReports?.count ?? 0) > 0,
    },
    { label: "Active Webhooks", value: webhookCount?.count ?? 0, icon: Webhook },
    { label: "API Keys Issued", value: apiKeyCount?.count ?? 0, icon: KeyRound },
  ];

  return (
    <div className="space-y-6">
      <h1 className="text-2xl font-bold tracking-tight">Overview</h1>
      <div className="grid grid-cols-2 lg:grid-cols-4 gap-4">
        {stats.map(({ label, value, sub, unit, icon: Icon, href, highlight }) => {
          const card = (
            <Card className={highlight ? "border-destructive/50" : undefined}>
              <CardHeader className="flex flex-row items-center justify-between pb-2">
                <CardTitle className="text-sm font-medium text-muted-foreground">{label}</CardTitle>
                <Icon className={highlight ? "h-4 w-4 text-destructive" : "h-4 w-4 text-muted-foreground"} />
              </CardHeader>
              <CardContent>
                <div className={highlight ? "text-2xl font-bold text-destructive" : "text-2xl font-bold"}>
                  {value.toLocaleString()}{unit ? ` ${unit}` : ""}
                </div>
                {sub && <p className="text-xs text-muted-foreground mt-1">{sub}</p>}
              </CardContent>
            </Card>
          );
          return (
            <div key={label}>
              {href ? <Link href={href}>{card}</Link> : card}
            </div>
          );
        })}
      </div>

      <Card>
        <CardHeader className="flex flex-row items-center justify-between pb-2">
          <CardTitle className="text-sm font-medium text-muted-foreground">Version</CardTitle>
          <History className="h-4 w-4 text-muted-foreground" />
        </CardHeader>
        <CardContent>
          <div className="text-2xl font-bold">v{APP_VERSION}</div>
          <p className="text-xs text-muted-foreground mt-1">
            Released {CHANGELOG[0]?.date} ·{" "}
            <Link href="/admin/changelog" className="underline hover:text-foreground">
              View changelog
            </Link>
          </p>
        </CardContent>
      </Card>
    </div>
  );
}
