'use client';

import { useQueryClient } from '@tanstack/react-query';
import { useState } from 'react';
import { CheckoutModal } from '@/components/subscription/checkout-modal';
import { Badge } from '@/components/ui/badge';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
import { Link } from '@/i18n/navigation';
import { formatVND } from '@/lib/currency';
import { usePlans, useBillingHistory, useQuota, subscriptionKeys } from '@/lib/hooks/use-subscription';
import {
  subscriptionApi,
  type PlanDto,
  type QuotaCheckResult,
} from '@/lib/subscription-api';

const PLAN_TIER_ORDER = ['FREE', 'AGENT_PRO', 'INVESTOR', 'ENTERPRISE'];
const PLAN_TIER_LABELS: Record<string, string> = {
  FREE: 'Miễn phí',
  AGENT_PRO: 'Môi giới Pro',
  INVESTOR: 'Nhà đầu tư',
  ENTERPRISE: 'Doanh nghiệp',
};

const STATUS_MAP: Record<string, { label: string; variant: 'default' | 'secondary' | 'destructive' | 'outline' }> = {
  ACTIVE: { label: 'Đang hoạt động', variant: 'default' },
  PAST_DUE: { label: 'Quá hạn', variant: 'destructive' },
  CANCELLED: { label: 'Đã hủy', variant: 'outline' },
  EXPIRED: { label: 'Hết hạn', variant: 'secondary' },
};

const PAYMENT_STATUS_MAP: Record<string, { label: string; variant: 'default' | 'secondary' | 'destructive' | 'outline' }> = {
  COMPLETED: { label: 'Thành công', variant: 'default' },
  FAILED: { label: 'Thất bại', variant: 'destructive' },
  PENDING: { label: 'Chờ xử lý', variant: 'secondary' },
  CANCELLED: { label: 'Đã hủy', variant: 'outline' },
};

const PAYMENT_TYPE_LABELS: Record<string, string> = {
  SUBSCRIPTION: 'Đăng ký gói',
  LISTING_FEE: 'Phí đăng tin',
  DEPOSIT: 'Đặt cọc',
  FEATURED_LISTING: 'Tin nổi bật',
};

export default function SubscriptionPage() {
  const queryClient = useQueryClient();
  const { data: plansData, isLoading: plansLoading } = usePlans();
  const { data: billing, isLoading: billingLoading } = useBillingHistory();
  const { data: listingsQuota } = useQuota('listings');
  const { data: savedSearchesQuota } = useQuota('saved_searches');
  const [billingCycle, setBillingCycle] = useState<'monthly' | 'yearly'>('monthly');
  const [cancelProcessing, setCancelProcessing] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [activeTab, setActiveTab] = useState('plan');

  // Checkout modal state
  const [checkoutPlan, setCheckoutPlan] = useState<PlanDto | null>(null);
  const [checkoutOpen, setCheckoutOpen] = useState(false);

  const loading = plansLoading || billingLoading;
  const plans = (plansData ?? []).slice().sort(
    (a, b) => PLAN_TIER_ORDER.indexOf(a.tier) - PLAN_TIER_ORDER.indexOf(b.tier),
  );
  const quotas = [listingsQuota, savedSearchesQuota].filter(
    (q): q is QuotaCheckResult => q != null,
  );

  const currentTier = billing?.subscription?.planTier ?? 'FREE';
  const currentTierIndex = PLAN_TIER_ORDER.indexOf(currentTier);
  const subStatus = billing?.subscription?.status
    ? STATUS_MAP[billing.subscription.status] ?? { label: 'Đang hoạt động', variant: 'default' as const }
    : null;

  const handleUpgrade = (plan: PlanDto) => {
    setCheckoutPlan(plan);
    setCheckoutOpen(true);
  };

  const handleCancel = async () => {
    setCancelProcessing(true);
    setError(null);
    try {
      await subscriptionApi.cancelSubscription('Hủy từ trang quản lý');
      await queryClient.invalidateQueries({ queryKey: subscriptionKeys.billing() });
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Hủy gói thất bại');
    } finally {
      setCancelProcessing(false);
    }
  };

  return (
    <div className="space-y-6">
      <div>
        <h1 className="text-2xl font-bold sm:text-3xl">Gói dịch vụ</h1>
        <p className="mt-2 text-muted-foreground">
          Quản lý gói đăng ký và theo dõi hạn mức sử dụng
        </p>
      </div>

      {error && (
        <div className="rounded-lg border border-red-200 bg-red-50 p-4 text-sm text-red-700">
          {error}
          <button onClick={() => setError(null)} className="ml-2 font-medium underline">
            Đóng
          </button>
        </div>
      )}

      {loading ? (
        <div className="flex h-64 items-center justify-center text-muted-foreground">
          Đang tải...
        </div>
      ) : (
        <Tabs value={activeTab} onValueChange={setActiveTab}>
          <TabsList className="w-full justify-start overflow-x-auto">
            <TabsTrigger value="plan" className="min-w-fit">Gói hiện tại</TabsTrigger>
            <TabsTrigger value="plans" className="min-w-fit">So sánh gói</TabsTrigger>
            <TabsTrigger value="history" className="min-w-fit">Lịch sử thanh toán</TabsTrigger>
          </TabsList>

          {/* Current plan tab */}
          <TabsContent value="plan" className="space-y-6">
            <Card>
              <CardHeader>
                <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
                  <div>
                    <CardTitle className="text-lg">
                      Gói {PLAN_TIER_LABELS[currentTier] ?? currentTier}
                    </CardTitle>
                    <CardDescription>
                      {billing?.subscription
                        ? `Kỳ hiện tại: ${new Date(billing.subscription.currentPeriodStart).toLocaleDateString('vi-VN')} — ${new Date(billing.subscription.currentPeriodEnd).toLocaleDateString('vi-VN')}`
                        : 'Bạn đang sử dụng gói miễn phí'}
                    </CardDescription>
                  </div>
                  <div className="flex items-center gap-2">
                    {subStatus && <Badge variant={subStatus.variant}>{subStatus.label}</Badge>}
                  </div>
                </div>
              </CardHeader>
              <CardContent className="space-y-6">
                {/* Quota usage */}
                {quotas.length > 0 && (
                  <div className="space-y-4">
                    <h3 className="font-semibold">Hạn mức sử dụng</h3>
                    {quotas.map((q) => {
                      const pct = q.limit > 0 ? (q.used / q.limit) * 100 : 0;
                      return (
                        <div key={q.metric} className="space-y-1">
                          <div className="flex justify-between text-sm">
                            <span className="text-muted-foreground">
                              {q.metric === 'listings' ? 'Tin đăng' : q.metric === 'saved_searches' ? 'Tìm kiếm đã lưu' : q.metric}
                            </span>
                            <span>
                              {q.used}/{q.limit}
                            </span>
                          </div>
                          <div className="h-2 w-full rounded-full bg-muted">
                            <div
                              className={`h-2 rounded-full transition-all ${pct > 90 ? 'bg-red-500' : pct > 70 ? 'bg-yellow-500' : 'bg-primary'}`}
                              style={{ width: `${Math.min(pct, 100)}%` }}
                            />
                          </div>
                        </div>
                      );
                    })}
                  </div>
                )}

                {/* Quick actions */}
                <div className="flex flex-col gap-2 border-t pt-4 sm:flex-row">
                  {currentTier !== 'ENTERPRISE' && (
                    <Button onClick={() => setActiveTab('plans')}>
                      Nâng cấp gói
                    </Button>
                  )}
                  {billing?.subscription && billing.subscription.status === 'ACTIVE' && (
                    <Button
                      variant="outline"
                      onClick={handleCancel}
                      disabled={cancelProcessing}
                      className="text-red-600 hover:text-red-700"
                    >
                      {cancelProcessing ? 'Đang xử lý...' : 'Hủy gói'}
                    </Button>
                  )}
                  <Link href={'/pricing' as const}>
                    <Button variant="outline">Xem bảng giá</Button>
                  </Link>
                </div>
              </CardContent>
            </Card>
          </TabsContent>

          {/* Plan comparison tab */}
          <TabsContent value="plans" className="space-y-6">
            {/* Billing cycle toggle */}
            <div className="flex items-center justify-center gap-3">
              <Button
                variant={billingCycle === 'monthly' ? 'default' : 'outline'}
                size="sm"
                onClick={() => setBillingCycle('monthly')}
              >
                Theo tháng
              </Button>
              <Button
                variant={billingCycle === 'yearly' ? 'default' : 'outline'}
                size="sm"
                onClick={() => setBillingCycle('yearly')}
              >
                Theo năm
                <Badge variant="secondary" className="ml-2">
                  -17%
                </Badge>
              </Button>
            </div>

            <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-4">
              {plans.map((plan) => {
                const tierIndex = PLAN_TIER_ORDER.indexOf(plan.tier);
                const isCurrent = plan.tier === currentTier;
                const isUpgrade = tierIndex > currentTierIndex;
                const price = billingCycle === 'monthly' ? plan.priceMonthlyVND : plan.priceYearlyVND;

                return (
                  <Card
                    key={plan.id}
                    className={isCurrent ? 'border-green-500 ring-1 ring-green-500' : ''}
                  >
                    <CardHeader>
                      <div className="flex items-center justify-between">
                        <CardTitle className="text-lg">
                          {PLAN_TIER_LABELS[plan.tier] ?? plan.name}
                        </CardTitle>
                        {isCurrent && (
                          <Badge className="bg-green-600 text-white">Hiện tại</Badge>
                        )}
                      </div>
                      <CardDescription>
                        <span className="text-2xl font-bold text-foreground">
                          {formatVND(price)}
                        </span>
                        {Number(price) > 0 && (
                          <span className="text-sm">
                            /{billingCycle === 'monthly' ? 'tháng' : 'năm'}
                          </span>
                        )}
                      </CardDescription>
                    </CardHeader>
                    <CardContent className="space-y-3">
                      <div className="space-y-2 text-sm">
                        <div className="flex justify-between">
                          <span className="text-muted-foreground">Tin đăng</span>
                          <span className="font-medium">
                            {plan.maxListings === -1 ? 'Không giới hạn' : plan.maxListings}
                          </span>
                        </div>
                        <div className="flex justify-between">
                          <span className="text-muted-foreground">Tìm kiếm lưu</span>
                          <span className="font-medium">
                            {plan.maxSavedSearches === -1
                              ? 'Không giới hạn'
                              : plan.maxSavedSearches}
                          </span>
                        </div>
                      </div>

                      {isCurrent ? (
                        <Button variant="outline" className="w-full" disabled>
                          Gói hiện tại
                        </Button>
                      ) : isUpgrade ? (
                        plan.tier === 'ENTERPRISE' ? (
                          <Link href={'/pricing' as const} className="block w-full">
                            <Button variant="outline" className="w-full">
                              Liên hệ tư vấn
                            </Button>
                          </Link>
                        ) : (
                          <Button className="w-full" onClick={() => handleUpgrade(plan)}>
                            Nâng cấp
                          </Button>
                        )
                      ) : (
                        <Button variant="outline" className="w-full" disabled>
                          —
                        </Button>
                      )}
                    </CardContent>
                  </Card>
                );
              })}
            </div>
          </TabsContent>

          {/* Payment history tab */}
          <TabsContent value="history">
            <Card>
              <CardHeader>
                <CardTitle className="text-lg">Lịch sử thanh toán</CardTitle>
                <CardDescription>Các giao dịch liên quan đến gói dịch vụ</CardDescription>
              </CardHeader>
              <CardContent>
                {!billing || billing.payments.length === 0 ? (
                  <div className="flex h-32 items-center justify-center text-muted-foreground">
                    Chưa có giao dịch nào
                  </div>
                ) : (
                  <div className="space-y-3">
                    {billing.payments.map((p) => {
                      const pStatus = PAYMENT_STATUS_MAP[p.status] ?? { label: p.status, variant: 'secondary' as const };
                      return (
                        <div
                          key={p.id}
                          className="flex items-center justify-between rounded-lg border p-3"
                        >
                          <div>
                            <p className="text-sm font-medium">
                              {PAYMENT_TYPE_LABELS[p.type] ?? p.type}
                            </p>
                            <p className="text-xs text-muted-foreground">
                              {new Date(p.createdAt).toLocaleDateString('vi-VN')} — {p.provider}
                            </p>
                          </div>
                          <div className="text-right">
                            <p className="font-semibold">{formatVND(p.amountVND)}</p>
                            <Badge variant={pStatus.variant}>
                              {pStatus.label}
                            </Badge>
                          </div>
                        </div>
                      );
                    })}
                  </div>
                )}
              </CardContent>
            </Card>
          </TabsContent>
        </Tabs>
      )}

      {/* Checkout modal */}
      <CheckoutModal
        open={checkoutOpen}
        onOpenChange={setCheckoutOpen}
        plan={checkoutPlan}
        billingCycle={billingCycle}
        isUpgrade={currentTierIndex > 0}
        currentTier={currentTier}
      />
    </div>
  );
}