import type { Metadata } from "next";
import Link from "next/link";
import { FileText, AudioLines, ImageIcon, Repeat, Infinity as InfinityIcon } from "lucide-react";
import { requireAuth } from "@/lib/auth/guards";
import { getEffectivePlan } from "@/lib/billing/subscription";
import { getUsageSummary } from "@/lib/usage/meter";
import { PageHeader } from "@/components/app/page-header";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Progress } from "@/components/ui/progress";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import { UNLIMITED, type UsageMetric } from "@/lib/billing/plans";

export const metadata: Metadata = { title: "Usage" };

const METRICS: { key: UsageMetric; label: string; icon: React.ComponentType<{ className?: string }> }[] = [
  { key: "script", label: "Scripts", icon: FileText },
  { key: "audio", label: "Audio generations", icon: AudioLines },
  { key: "art", label: "Cover art", icon: ImageIcon },
  { key: "repurpose", label: "Repurposed content", icon: Repeat },
];

function nextResetLabel(): string {
  const now = new Date();
  const next = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth() + 1, 1));
  return next.toLocaleDateString(undefined, { month: "long", day: "numeric" });
}

export default async function UsagePage() {
  const session = await requireAuth();
  const { plan, key, subjectId } = await getEffectivePlan(
    session.user.id,
    session.session.activeOrganizationId
  );
  const usage = await getUsageSummary(subjectId);

  return (
    <>
      <PageHeader
        title="Usage & limits"
        description={`Resets on ${nextResetLabel()}.`}
        action={
          key !== "agency" ? (
            <Button asChild>
              <Link href="/billing">Upgrade plan</Link>
            </Button>
          ) : undefined
        }
      />

      <div className="mb-6 flex items-center gap-2">
        <span className="text-sm text-muted-foreground">Current plan</span>
        <Badge className="capitalize">{plan.name}</Badge>
      </div>

      <div className="grid gap-4 sm:grid-cols-2">
        {METRICS.map((m) => {
          const used = usage[m.key];
          const limit = plan.limits[m.key];
          const unlimited = limit === UNLIMITED;
          const pct = unlimited ? 0 : Math.min(100, Math.round((used / Math.max(1, limit)) * 100));
          const atLimit = !unlimited && used >= limit;
          return (
            <Card key={m.key}>
              <CardHeader className="flex flex-row items-center justify-between pb-2">
                <CardTitle className="flex items-center gap-2 text-sm font-medium text-muted-foreground">
                  <m.icon className="h-4 w-4" /> {m.label}
                </CardTitle>
                {atLimit && <Badge variant="warning">Limit reached</Badge>}
              </CardHeader>
              <CardContent className="space-y-2">
                <div className="flex items-baseline justify-between">
                  <span className="font-display text-3xl font-extrabold tracking-tight">{used}</span>
                  <span className="flex items-center gap-1 text-sm text-muted-foreground">
                    {unlimited ? (
                      <>
                        <InfinityIcon className="h-4 w-4" /> Unlimited
                      </>
                    ) : (
                      <>of {limit}</>
                    )}
                  </span>
                </div>
                {!unlimited && (
                  <Progress
                    value={pct}
                    indicatorClassName={atLimit ? "bg-warning" : undefined}
                  />
                )}
              </CardContent>
            </Card>
          );
        })}
      </div>
    </>
  );
}