import { NextResponse } from "next/server";
import { eq } from "drizzle-orm";
import { auth } from "@/app/(auth)/auth";
import { db } from "@/lib/db";
import { systemSettings } from "@/lib/db/schema";
import {
  checkUserImageQuota,
  getPointsSystemConfig,
  getUserById,
  getUserMonthlyImageCount,
} from "@/lib/db/queries";
import {
  defaultMembershipConfig,
  defaultMembershipUserOverrides,
  getMembershipPlanById,
  normalizeMembershipConfig,
  normalizeMembershipUserOverrides,
  resolveMembershipPlanIdForUser,
} from "@/lib/membership/config";

const MEMBERSHIP_CONFIG_KEY = "membership_config";
const MEMBERSHIP_USER_OVERRIDES_KEY = "membership_user_plan_overrides";

export async function GET() {
  try {
    const session = await auth();

    if (!session?.user?.id) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const [configSetting, overridesSetting, quota, totalImages, pointsConfig, dbUser] = await Promise.all([
      db
        .select()
        .from(systemSettings)
        .where(eq(systemSettings.key, MEMBERSHIP_CONFIG_KEY))
        .limit(1)
        .then((rows) => rows[0]),
      db
        .select()
        .from(systemSettings)
        .where(eq(systemSettings.key, MEMBERSHIP_USER_OVERRIDES_KEY))
        .limit(1)
        .then((rows) => rows[0]),
      checkUserImageQuota(session.user.id),
      getUserMonthlyImageCount(session.user.id),
      getPointsSystemConfig(),
      getUserById({ id: session.user.id }),
    ]);

    const config = configSetting?.value
      ? normalizeMembershipConfig(configSetting.value)
      : defaultMembershipConfig;
    const overrides = overridesSetting?.value
      ? normalizeMembershipUserOverrides(overridesSetting.value)
      : defaultMembershipUserOverrides;

    const currentPlanId = resolveMembershipPlanIdForUser(
      session.user.id,
      session.user.email,
      config,
      overrides
    );
    const currentPlan = getMembershipPlanById(config, currentPlanId);

    const currentCredits = pointsConfig.enabled
      ? Math.max(0, Number(dbUser?.pointsBalance || 0))
      : quota.remaining !== null
        ? Math.max(0, quota.remaining)
        : currentPlan.monthlyCredits;

    return NextResponse.json({
      config,
      pointsSystemConfig: pointsConfig,
      isHighVip: Boolean(dbUser?.isHighVip),
      currentPlanId,
      currentPlan,
      summary: {
        currentCredits,
        dailyFreeCredits: currentPlan.dailyFreeCredits,
        usedThisMonth: quota.used,
        monthlyLimit: quota.limit,
        remainingThisMonth: quota.remaining,
        totalImages,
      },
      updatedAt: new Date().toISOString(),
    });
  } catch (error) {
    console.error("[Membership Summary API] Error:", error);
    return NextResponse.json(
      { error: "Failed to fetch membership summary" },
      { status: 500 }
    );
  }
}