import { MessageSquare, Shield, Terminal, Users } from "lucide-react";
import { redirect } from "next/navigation";
import { StatsCard } from "@/components/admin/stats-card";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
import { prisma } from "@/lib/prisma";

async function getActivityData() {
  const now = Math.floor(Date.now() / 1000);
  const todayStart = now - (now % 86400);
  const weekAgo = now - 7 * 86400;

  // Daily activity breakdown — 4 GROUP BY queries instead of 28 sequential queries
  const rangeStart = todayStart - 6 * 86400;
  const [chatRows, cmdRows, banRows, regRows] = await Promise.all([
    prisma.$queryRaw<{ day_bucket: bigint; count: bigint }[]>`
      SELECT FLOOR(timestamp / 86400) AS day_bucket, COUNT(*) AS count
      FROM chatlogs_room WHERE timestamp >= ${rangeStart} GROUP BY day_bucket`,
    prisma.$queryRaw<{ day_bucket: bigint; count: bigint }[]>`
      SELECT FLOOR(timestamp / 86400) AS day_bucket, COUNT(*) AS count
      FROM commandlogs WHERE timestamp >= ${rangeStart} GROUP BY day_bucket`,
    prisma.$queryRaw<{ day_bucket: bigint; count: bigint }[]>`
      SELECT FLOOR(timestamp / 86400) AS day_bucket, COUNT(*) AS count
      FROM bans WHERE timestamp >= ${rangeStart} GROUP BY day_bucket`,
    prisma.$queryRaw<{ day_bucket: bigint; count: bigint }[]>`
      SELECT FLOOR(account_created / 86400) AS day_bucket, COUNT(*) AS count
      FROM users WHERE account_created >= ${rangeStart} GROUP BY day_bucket`,
  ]);
  const toMap = (rows: { day_bucket: bigint; count: bigint }[]) =>
    new Map(rows.map((r) => [Number(r.day_bucket), Number(r.count)]));
  const chatMap = toMap(chatRows);
  const cmdMap = toMap(cmdRows);
  const banMap = toMap(banRows);
  const regMap = toMap(regRows);

  const dailyData = [];
  for (let i = 6; i >= 0; i--) {
    const dayStart = todayStart - i * 86400;
    const bucket = Math.floor(dayStart / 86400);
    const date = new Date(dayStart * 1000);
    dailyData.push({
      label: date.toLocaleDateString("en", { weekday: "short", month: "short", day: "numeric" }),
      chats: chatMap.get(bucket) ?? 0,
      commands: cmdMap.get(bucket) ?? 0,
      bans: banMap.get(bucket) ?? 0,
      registrations: regMap.get(bucket) ?? 0,
    });
  }

  // Totals
  const [weekChatRows, weekCommandRows, weekBans, weekRegistrations] = await Promise.all([
    prisma.$queryRaw<
      { count: bigint }[]
    >`SELECT COUNT(*) AS count FROM chatlogs_room WHERE timestamp >= ${weekAgo}`,
    prisma.$queryRaw<
      { count: bigint }[]
    >`SELECT COUNT(*) AS count FROM commandlogs WHERE timestamp >= ${weekAgo}`,
    prisma.ban.count({ where: { timestamp: { gte: weekAgo } } }),
    prisma.user.count({ where: { accountCreated: { gte: weekAgo } } }),
  ]);
  const weekChats = Number(weekChatRows[0]?.count ?? 0);
  const weekCommands = Number(weekCommandRows[0]?.count ?? 0);

  // Most active users (by chat messages)
  const topChatters = await prisma.$queryRaw<{ userId: number; messages: bigint }[]>`
    SELECT user_from_id AS userId, COUNT(*) AS messages
    FROM chatlogs_room WHERE timestamp >= ${weekAgo}
    GROUP BY user_from_id ORDER BY messages DESC LIMIT 10
  `;

  const userIds = topChatters.map((c) => c.userId);
  const users = await prisma.user.findMany({
    where: { id: { in: userIds } },
    select: { id: true, username: true },
  });
  const userMap = new Map(users.map((u) => [u.id, u.username]));

  const topChattersWithNames = topChatters.map((c) => ({
    userId: c.userId,
    username: userMap.get(c.userId) ?? `User #${c.userId}`,
    messages: Number(c.messages),
  }));

  return {
    dailyData,
    weekChats,
    weekCommands,
    weekBans,
    weekRegistrations,
    topChatters: topChattersWithNames,
  };
}

export default async function ActivityPage() {
  const { session, permissions } = await getAdminContext();
  if (!canAccess(permissions, PERMS.ANALYTICS_VIEW, session.user.rank)) {
    redirect("/admin");
  }

  const data = await getActivityData();

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-3xl font-bold tracking-tight">Activity</h1>
        <p className="text-muted-foreground">User activity breakdown and engagement metrics</p>
      </div>

      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
        <StatsCard
          title="Chat Messages"
          value={data.weekChats.toLocaleString()}
          description="Last 7 days"
          icon={<MessageSquare className="h-4 w-4" />}
        />
        <StatsCard
          title="Commands"
          value={data.weekCommands.toLocaleString()}
          description="Last 7 days"
          icon={<Terminal className="h-4 w-4" />}
        />
        <StatsCard
          title="Bans"
          value={data.weekBans.toLocaleString()}
          description="Last 7 days"
          icon={<Shield className="h-4 w-4" />}
        />
        <StatsCard
          title="Registrations"
          value={data.weekRegistrations.toLocaleString()}
          description="Last 7 days"
          icon={<Users className="h-4 w-4" />}
        />
      </div>

      <div className="grid gap-6 md:grid-cols-2">
        {/* Daily breakdown table */}
        <Card>
          <CardHeader>
            <CardTitle>Daily Breakdown (7 days)</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="overflow-x-auto">
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b text-muted-foreground">
                    <th className="text-left py-2 font-medium">Day</th>
                    <th className="text-right py-2 font-medium">Chats</th>
                    <th className="text-right py-2 font-medium">Cmds</th>
                    <th className="text-right py-2 font-medium">Bans</th>
                    <th className="text-right py-2 font-medium">Regs</th>
                  </tr>
                </thead>
                <tbody>
                  {data.dailyData.map((day) => (
                    <tr key={day.label} className="border-b last:border-0">
                      <td className="py-2">{day.label}</td>
                      <td className="text-right tabular-nums">{day.chats.toLocaleString()}</td>
                      <td className="text-right tabular-nums">{day.commands.toLocaleString()}</td>
                      <td className="text-right tabular-nums">{day.bans}</td>
                      <td className="text-right tabular-nums">{day.registrations}</td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          </CardContent>
        </Card>

        {/* Top chatters */}
        <Card>
          <CardHeader>
            <CardTitle>Most Active Users (7 days)</CardTitle>
          </CardHeader>
          <CardContent>
            {data.topChatters.length === 0 ? (
              <p className="text-sm text-muted-foreground">No chat activity</p>
            ) : (
              <div className="divide-y">
                {data.topChatters.map((user, i) => (
                  <div key={user.userId} className="flex items-center gap-3 py-2.5 first:pt-0 last:pb-0">
                    <span className="flex h-6 w-6 items-center justify-center rounded-full bg-accent text-xs font-bold">
                      {i + 1}
                    </span>
                    <span className="flex-1 text-sm font-medium">{user.username}</span>
                    <span className="text-sm tabular-nums text-muted-foreground">
                      {user.messages.toLocaleString()} msgs
                    </span>
                  </div>
                ))}
              </div>
            )}
          </CardContent>
        </Card>
      </div>
    </div>
  );
}