import { NextRequest, NextResponse } from "next/server";
import { prisma } from "@/lib/prisma";
import { requireAuth } from "@/lib/auth";
import { getUserTier, HALAL_LIMITS } from "@/lib/tiers";

export async function GET(request: NextRequest) {
  try {
    const auth = await requireAuth(request);
    if (!auth) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const user = await prisma.user.findUnique({
      where: { id: auth.userId },
      include: { halalUsage: true },
    });
    if (!user) {
      return NextResponse.json({ error: "User not found" }, { status: 404 });
    }

    const tier = getUserTier(user.isPremium, user.isPro);
    const limits = HALAL_LIMITS[tier];

    // If no usage record exists yet, return defaults
    const usage = user.halalUsage;
    const queriesUsed = usage?.queriesUsed ?? 0;
    const queriesLimit = usage?.queriesLimit ?? limits.queriesPerDay;
    const periodEnd = usage?.periodEnd?.toISOString() ?? null;

    const remaining = Math.max(0, queriesLimit - queriesUsed);

    return NextResponse.json({
      queriesUsed,
      queriesLimit,
      remaining,
      periodEnd,
      tier,
      scope: limits.scope,
    });
  } catch (error) {
    console.error("GET /api/halal/usage error:", error);
    return NextResponse.json(
      { error: "Internal server error" },
      { status: 500 }
    );
  }
}

export async function POST(request: NextRequest) {
  try {
    const auth = await requireAuth(request);
    if (!auth) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const user = await prisma.user.findUnique({
      where: { id: auth.userId },
      include: { halalUsage: true },
    });
    if (!user) {
      return NextResponse.json({ error: "User not found" }, { status: 404 });
    }

    const tier = getUserTier(user.isPremium, user.isPro);
    const limits = HALAL_LIMITS[tier];

    // Get or create usage record
    let usage = user.halalUsage;

    // Check if period has expired — reset if so
    const now = new Date();
    if (usage && usage.periodEnd && new Date(usage.periodEnd) < now) {
      usage = await prisma.halalUsage.update({
        where: { userId: user.id },
        data: {
          queriesUsed: 0,
          queriesLimit: limits.queriesPerDay,
          periodEnd: new Date(now.getTime() + 24 * 60 * 60 * 1000),
        },
      });
    }

    if (!usage) {
      const queryLimit = limits.queriesPerDay === Infinity ? 999999 : limits.queriesPerDay;
      usage = await prisma.halalUsage.create({
        data: {
          userId: user.id,
          queriesUsed: 0,
          queriesLimit: queryLimit,
          periodEnd: new Date(now.getTime() + 24 * 60 * 60 * 1000),
        },
      });
    }

    // Check if allowed
    const effectiveLimit = limits.queriesPerDay === Infinity ? 999999 : usage.queriesLimit;
    if (usage.queriesUsed >= effectiveLimit && limits.queriesPerDay !== Infinity) {
      return NextResponse.json(
        {
          allowed: false,
          remaining: 0,
          queriesUsed: usage.queriesUsed,
          queriesLimit: usage.queriesLimit,
          error: "Daily query limit reached. Upgrade to Premium for unlimited queries.",
        },
        { status: 429 }
      );
    }

    // Increment usage
    const updated = await prisma.halalUsage.update({
      where: { userId: user.id },
      data: { queriesUsed: { increment: 1 } },
    });

    const remaining = Math.max(0, updated.queriesLimit - updated.queriesUsed);

    return NextResponse.json({
      allowed: true,
      remaining,
      queriesUsed: updated.queriesUsed,
      queriesLimit: updated.queriesLimit,
    });
  } catch (error) {
    console.error("POST /api/halal/usage error:", error);
    return NextResponse.json(
      { error: "Internal server error" },
      { status: 500 }
    );
  }
}