import type { Metadata } from "next";
import { headers } from "next/headers";
import { auth } from "@/lib/auth/server";
import { db, userAiKeys, userModelPrefs, users, tierDefinitions, userUsage, eq, and } from "@epicure/db";
import { UNLIMITED, getRecipeCount, getStorageUsedMb } from "@/lib/tiers";
import { ByokManager } from "@/components/settings/byok-manager";
import { ModelPrefsForm } from "@/components/settings/model-prefs-form";
import { UsageQuotaSection } from "@/components/settings/usage-quota-section";
import { getMessages, formatMessage } from "@/lib/i18n/server";

export const metadata: Metadata = {};

export default async function AiSettingsPage() {
  const session = await auth.api.getSession({ headers: await headers() });
  if (!session) return null;
  const m = getMessages((session.user as { locale?: string }).locale);

  const currentMonth = new Date().toISOString().slice(0, 7);

  const [aiKeys, modelPrefs, dbUser] = await Promise.all([
    db.query.userAiKeys.findMany({
      where: eq(userAiKeys.userId, session.user.id),
      columns: { provider: true },
    }),
    db.query.userModelPrefs.findFirst({
      where: eq(userModelPrefs.userId, session.user.id),
    }),
    // Tier comes from the DB, not the (up to 5-minute-stale) session cookie
    // cache, so a just-changed tier's limits show up immediately here.
    db.query.users.findFirst({ where: eq(users.id, session.user.id), columns: { tier: true, isByokEnabled: true } }),
  ]);

  const [tierDef, usage, recipeCount, storageUsedMb] = await Promise.all([
    db.query.tierDefinitions.findFirst({ where: eq(tierDefinitions.tier, dbUser?.tier ?? "free") }),
    db.query.userUsage.findFirst({ where: and(eq(userUsage.userId, session.user.id), eq(userUsage.month, currentMonth)) }),
    getRecipeCount(session.user.id),
    getStorageUsedMb(session.user.id),
  ]);

  const asLimit = (n: number | undefined) => (n === undefined || n === UNLIMITED ? null : n);

  const usageMetrics = [
    {
      label: m.settings.usage.aiCalls,
      used: usage?.aiCallsUsed ?? 0,
      limit: asLimit(tierDef?.aiCallsPerMonth),
      unlimitedLabel: m.settings.usage.unlimited,
    },
    {
      label: m.settings.usage.recipes,
      used: recipeCount,
      limit: asLimit(tierDef?.maxRecipes),
      unlimitedLabel: m.settings.usage.unlimited,
    },
    {
      label: m.settings.usage.storage,
      used: storageUsedMb,
      limit: asLimit(tierDef?.storageMb),
      unit: " MB",
      unlimitedLabel: m.settings.usage.unlimited,
    },
  ];

  return (
    <div className="space-y-8">
      <section className="rounded-xl border p-6 space-y-4">
        <div>
          <h2 className="font-semibold text-lg">{m.settings.usage.title}</h2>
          <p className="text-sm text-muted-foreground mt-1">
            {formatMessage(m.settings.usage.description, { month: currentMonth })}
          </p>
        </div>
        <UsageQuotaSection metrics={usageMetrics} />
      </section>

      {dbUser?.isByokEnabled && (
        <section className="rounded-xl border p-6 space-y-4">
          <div>
            <h2 className="font-semibold text-lg">{m.settings.byok.title}</h2>
            <p className="text-sm text-muted-foreground mt-1">
              {m.settings.byok.description}
            </p>
          </div>
          <ByokManager initialKeys={aiKeys.map((k) => k.provider)} />
        </section>
      )}

      {dbUser?.isByokEnabled && (
        <section className="rounded-xl border p-6 space-y-4">
          <div>
            <h2 className="font-semibold text-lg">{m.settings.modelPrefs.title}</h2>
            <p className="text-sm text-muted-foreground mt-1">
              {m.settings.modelPrefs.description}
            </p>
          </div>
          <ModelPrefsForm initialPrefs={modelPrefs ?? null} />
        </section>
      )}
    </div>
  );
}
