"use client";

// ============================================================================
// Analytics Overview Page
// ============================================================================

import React, { useEffect, useState } from "react";
import { DashboardHeader } from "@/components/layout/dashboard-header";
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { Alert, AlertDescription } from "@/components/ui/alert";
import { analyticsApi } from "@/lib/api";
import {
  formatNumber,
  formatMetric,
  formatCurrency,
  formatPercent,
} from "@/lib/utils/format";
import {
  BarChart3,
  Loader2,
  AlertCircle,
  TrendingUp,
  TrendingDown,
  Users,
  ShoppingCart,
  DollarSign,
} from "lucide-react";
import type { SpendingAnalytics } from "@/lib/types/api";
import { useTargetChannel } from "@/components/providers/target-channel-provider";
import {
  LineChart,
  Line,
  BarChart,
  Bar,
  XAxis,
  YAxis,
  CartesianGrid,
  Tooltip,
  Legend,
  ResponsiveContainer,
} from "recharts";

export default function AnalyticsPage() {
  const { selectedChannel } = useTargetChannel();
  const [spending, setSpending] = useState<SpendingAnalytics | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    if (selectedChannel) {
      loadData();
    } else {
      setLoading(false);
    }
  }, [selectedChannel]);

  const loadData = async () => {
    if (!selectedChannel) return;

    try {
      setLoading(true);
      const data = await analyticsApi.spending({
        grouping: "week",
        target_channel_id: selectedChannel.id,
      });
      setSpending(data);
    } catch (err: any) {
      setError(err?.error?.message || "Ошибка загрузки аналитики");
    } finally {
      setLoading(false);
    }
  };

  if (loading) {
    return (
      <>
        <DashboardHeader
          breadcrumbs={[
            { label: "Главная", href: "/" },
            { label: "Аналитика" },
          ]}
        />
        <div className="flex flex-1 items-center justify-center">
          <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
        </div>
      </>
    );
  }

  if (error || !spending) {
    return (
      <>
        <DashboardHeader
          breadcrumbs={[
            { label: "Главная", href: "/" },
            { label: "Аналитика" },
          ]}
        />
        <div className="flex flex-1 flex-col gap-4 p-4 pt-0 mt-4">
          <Alert variant="destructive">
            <AlertCircle className="h-4 w-4" />
            <AlertDescription>
              {error || "Не удалось загрузить аналитику"}
            </AlertDescription>
          </Alert>
        </div>
      </>
    );
  }

  return (
    <>
      <DashboardHeader
        breadcrumbs={[
          { label: "Главная", href: "/" },
          { label: "Аналитика" },
          { label: "Обзор" },
        ]}
      />
      <div className="flex flex-1 flex-col gap-4 p-4 pt-0 mt-4">
        <div>
          <h1 className="text-3xl font-bold tracking-tight">Аналитика</h1>
          <p className="text-muted-foreground mt-1">
            Сводная статистика за последний месяц
          </p>
        </div>

        <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
          <Card>
            <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
              <CardTitle className="text-sm font-medium">
                Всего затрат
              </CardTitle>
              <DollarSign className="h-4 w-4 text-muted-foreground" />
            </CardHeader>
            <CardContent>
              <div className="text-2xl font-bold">
                {formatCurrency(spending.total_cost)}
              </div>
              <p className="text-xs text-muted-foreground mt-1">
                За выбранный период
              </p>
            </CardContent>
          </Card>

          <Card>
            <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
              <CardTitle className="text-sm font-medium">
                Всего подписчиков
              </CardTitle>
              <Users className="h-4 w-4 text-muted-foreground" />
            </CardHeader>
            <CardContent>
              <div className="text-2xl font-bold">
                {formatNumber(spending.total_subscriptions)}
              </div>
              <p className="text-xs text-muted-foreground mt-1">
                Всего привлечено
              </p>
            </CardContent>
          </Card>

          <Card>
            <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
              <CardTitle className="text-sm font-medium">Средний CPF</CardTitle>
              <BarChart3 className="h-4 w-4 text-muted-foreground" />
            </CardHeader>
            <CardContent>
              <div className="text-2xl font-bold">
                {spending.avg_cpf ? `₽${formatMetric(spending.avg_cpf)}` : "—"}
              </div>
              <p className="text-xs text-muted-foreground mt-1">
                Стоимость подписки
              </p>
            </CardContent>
          </Card>

          <Card>
            <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
              <CardTitle className="text-sm font-medium">Средний CPM</CardTitle>
              <BarChart3 className="h-4 w-4 text-muted-foreground" />
            </CardHeader>
            <CardContent>
              <div className="text-2xl font-bold">
                {spending.avg_cpm ? `₽${formatMetric(spending.avg_cpm)}` : "—"}
              </div>
              <p className="text-xs text-muted-foreground mt-1">
                За 1000 просмотров
              </p>
            </CardContent>
          </Card>
        </div>

        <Card>
          <CardHeader>
            <CardTitle>Динамика затрат</CardTitle>
            <CardDescription>Расходы по периодам</CardDescription>
          </CardHeader>
          <CardContent>
            <ResponsiveContainer width="100%" height={300}>
              <LineChart data={spending.chart_data}>
                <CartesianGrid strokeDasharray="3 3" className="stroke-muted" />
                <XAxis
                  dataKey="period"
                  className="text-xs"
                  tick={{ fill: "hsl(var(--muted-foreground))" }}
                />
                <YAxis
                  className="text-xs"
                  tick={{ fill: "hsl(var(--muted-foreground))" }}
                  tickFormatter={(value) => `₽${formatNumber(value)}`}
                />
                <Tooltip
                  contentStyle={{
                    backgroundColor: "hsl(var(--background))",
                    border: "1px solid hsl(var(--border))",
                    borderRadius: "8px",
                  }}
                />
                <Line
                  type="monotone"
                  dataKey="cost"
                  stroke="hsl(var(--primary))"
                  strokeWidth={2}
                  name="Затраты"
                />
              </LineChart>
            </ResponsiveContainer>
          </CardContent>
        </Card>

      </div>
    </>
  );
}