"use client";

// ============================================================================
// Purchase Plans Overview Page
// ============================================================================

import { useEffect, useState } from "react";
import { useParams, useRouter } from "next/navigation";
import Link from "next/link";
import {
  Loader2,
  ClipboardList,
  ChevronRight,
  Tv,
  Calendar,
  DollarSign,
  CheckCircle,
  Clock,
  XCircle,
} from "lucide-react";
import { DashboardHeader } from "@/components/layout/dashboard-header";
import { useWorkspace } from "@/components/providers/workspace-provider";
import { demoAwarePurchasePlanApi } from "@/lib/demo";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card";
import type { Project, PurchasePlanChannel } from "@/lib/types/api";

// ============================================================================
// Helpers
// ============================================================================

const formatCurrency = (value: number | null) => {
  if (value === null) return "—";
  return new Intl.NumberFormat("ru-RU", {
    style: "currency",
    currency: "RUB",
    minimumFractionDigits: 0,
    maximumFractionDigits: 0,
  }).format(value);
};

interface ProjectPlanStats {
  totalChannels: number;
  plannedChannels: number;
  completedChannels: number;
  cancelledChannels: number;
  totalPlannedCost: number;
}

// ============================================================================
// Component
// ============================================================================

export default function PurchasePlansPage() {
  const params = useParams();
  const router = useRouter();
  const workspaceId = params?.workspaceId as string;
  const { projects, isLoadingProjects } = useWorkspace();

  const [projectStats, setProjectStats] = useState<Record<string, ProjectPlanStats>>({});
  const [loadingStats, setLoadingStats] = useState(true);

  useEffect(() => {
    if (projects.length > 0) {
      loadAllStats();
    } else {
      setLoadingStats(false);
    }
  }, [projects, workspaceId]);

  const loadAllStats = async () => {
    setLoadingStats(true);
    const stats: Record<string, ProjectPlanStats> = {};

    for (const project of projects) {
      try {
        const response = await demoAwarePurchasePlanApi.list(workspaceId, project.id, { size: 100 });
        const channels = response.items;

        stats[project.id] = {
          totalChannels: channels.length,
          plannedChannels: channels.filter((c) => c.status === "planned").length,
          completedChannels: channels.filter((c) => c.status === "completed").length,
          cancelledChannels: channels.filter((c) => c.status === "cancelled").length,
          totalPlannedCost: channels
            .filter((c) => c.status === "planned")
            .reduce((sum, c) => sum + (c.planned_cost || 0), 0),
        };
      } catch (err) {
        console.error(`Failed to load plan for project ${project.id}:`, err);
        stats[project.id] = {
          totalChannels: 0,
          plannedChannels: 0,
          completedChannels: 0,
          cancelledChannels: 0,
          totalPlannedCost: 0,
        };
      }
    }

    setProjectStats(stats);
    setLoadingStats(false);
  };

  const isLoading = isLoadingProjects || loadingStats;

  return (
    <>
      <DashboardHeader
        breadcrumbs={[
          { label: "Главная", href: `/dashboard/${workspaceId}` },
          { label: "Планы закупок" },
        ]}
        showProjectSelector={false}
      />

      <div className="flex flex-1 flex-col gap-4 p-4 pt-0 mt-4">
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-2xl font-bold tracking-tight">Планы закупок</h1>
            <p className="text-muted-foreground">
              Управление планами закупок по проектам
            </p>
          </div>
        </div>

        {isLoading ? (
          <div className="flex items-center justify-center py-12">
            <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
          </div>
        ) : projects.length === 0 ? (
          <Card>
            <CardContent className="flex flex-col items-center justify-center py-12">
              <ClipboardList className="h-12 w-12 text-muted-foreground mb-4" />
              <h3 className="text-lg font-semibold mb-2">Нет проектов</h3>
              <p className="text-muted-foreground text-center mb-4">
                Добавьте проект через Telegram бота для создания плана закупок
              </p>
              <Button asChild>
                <Link href={`/dashboard/${workspaceId}/projects`}>
                  Перейти к проектам
                </Link>
              </Button>
            </CardContent>
          </Card>
        ) : (
          <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
            {projects.map((project) => {
              const stats = projectStats[project.id];

              return (
                <Card
                  key={project.id}
                  className="cursor-pointer hover:bg-muted/50 transition-colors"
                  onClick={() =>
                    router.push(`/dashboard/${workspaceId}/purchase-plans/${project.id}`)
                  }
                >
                  <CardHeader className="pb-3">
                    <div className="flex items-start justify-between">
                      <div className="flex items-center gap-3">
                        <div className="flex h-10 w-10 items-center justify-center rounded-lg bg-primary/10">
                          <Tv className="h-5 w-5 text-primary" />
                        </div>
                        <div>
                          <CardTitle className="text-lg">{project.title}</CardTitle>
                          {project.username && (
                            <CardDescription>@{project.username}</CardDescription>
                          )}
                        </div>
                      </div>
                      <ChevronRight className="h-5 w-5 text-muted-foreground" />
                    </div>
                  </CardHeader>
                  <CardContent>
                    {stats ? (
                      <div className="space-y-3">
                        <div className="flex items-center justify-between text-sm">
                          <span className="text-muted-foreground">Всего каналов:</span>
                          <span className="font-medium">{stats.totalChannels}</span>
                        </div>

                        <div className="flex gap-2 flex-wrap">
                          {stats.plannedChannels > 0 && (
                            <Badge variant="outline" className="gap-1">
                              <Clock className="h-3 w-3" />
                              {stats.plannedChannels} план.
                            </Badge>
                          )}
                          {stats.completedChannels > 0 && (
                            <Badge variant="default" className="gap-1">
                              <CheckCircle className="h-3 w-3" />
                              {stats.completedChannels} заверш.
                            </Badge>
                          )}
                          {stats.cancelledChannels > 0 && (
                            <Badge variant="secondary" className="gap-1">
                              <XCircle className="h-3 w-3" />
                              {stats.cancelledChannels} отмен.
                            </Badge>
                          )}
                        </div>

                        {stats.totalPlannedCost > 0 && (
                          <div className="flex items-center gap-2 text-sm pt-2 border-t">
                            <DollarSign className="h-4 w-4 text-muted-foreground" />
                            <span className="text-muted-foreground">План. бюджет:</span>
                            <span className="font-medium ml-auto">
                              {formatCurrency(stats.totalPlannedCost)}
                            </span>
                          </div>
                        )}
                      </div>
                    ) : (
                      <div className="text-sm text-muted-foreground">Загрузка...</div>
                    )}
                  </CardContent>
                </Card>
              );
            })}
          </div>
        )}
      </div>
    </>
  );
}