import { Injectable } from '@nestjs/common';
import { OrderStatus, Prisma } from '@prisma/client';
import { PrismaService } from '../../prisma/prisma.service';

/**
 * Dashboards — legacy views/DashboardECommerce.vue (`GET get-analytics`) and
 * views/DashboardAnalytics.vue (`GET get-analytics-tak`).
 *
 * Legacy's ECommerce page is a Vuexy template with most of its English demo
 * cards COMMENTED OUT (Congratulations, Support Tracker, Product Orders, Sales
 * Stats, Activity Timeline — verified line by line). What is actually live:
 *   - three 30-day stat cards: new customers, gold sold, order count
 *   - "عملکرد کارشناسان فروش": agents ranked by grams sold
 *   - "میزان فروش": sales volume
 *   - "سفارشات هفته جاری": this week's orders
 *
 * So this returns exactly those figures rather than the template's demo series.
 */
@Injectable()
export class AdminDashboardService {
  constructor(private readonly prisma: PrismaService) {}

  private daysAgo(n: number) {
    const d = new Date();
    d.setDate(d.getDate() - n);
    return d;
  }

  /** Orders that have reached the debt-recognition point count as "sold". */
  private static readonly SOLD: Prisma.OrderWhereInput = {
    status: { in: [OrderStatus.DELIVERED_TO_AGENT, OrderStatus.DELIVERED_TO_CUSTOMER] },
  };

  /** Legacy `GET get-analytics` — the wholesale dashboard. */
  async omdeAnalytics() {
    const since30 = this.daysAgo(30);
    const since7 = this.daysAgo(7);

    const [customerCount, gramsAgg, orderCount, lastOrderRows, agents, monthAgg] =
      await Promise.all([
        // تعداد مشتریان ثبت نامی در 30 روز گذشته
        this.prisma.customer.count({ where: { createdAt: { gte: since30 } } }),

        // طلای فروش رفته در 30 روز گذشته
        this.prisma.order.aggregate({
          where: { AND: [AdminDashboardService.SOLD, { createdAt: { gte: since30 } }] },
          _sum: { totalGoldWeightGrams: true },
        }),

        // تعداد سفارشات 30 روز گذشته
        this.prisma.order.count({ where: { createdAt: { gte: since30 } } }),

        // سفارشات هفته جاری
        this.prisma.order.findMany({
          where: { createdAt: { gte: since7 } },
          orderBy: { createdAt: 'desc' },
          take: 50,
          include: { customer: true, branch: true },
        }),

        // عملکرد کارشناسان فروش
        this.prisma.adminUser.findMany({
          where: { role: 'SALES_EXPERT', isActive: true },
          select: { id: true, fullName: true },
        }),

        // میزان فروش (same 30-day window, kept separate for clarity)
        this.prisma.order.aggregate({
          where: { AND: [AdminDashboardService.SOLD, { createdAt: { gte: since30 } }] },
          _sum: { totalGoldWeightGrams: true },
          _count: true,
        }),
      ]);

    // Grams sold per agent, through the customers they referred. The view sorts
    // this itself by grams_sell, so the shape matters more than the order.
    const reagent = await Promise.all(
      agents.map(async (a) => {
        const agg = await this.prisma.order.aggregate({
          where: {
            AND: [
              AdminDashboardService.SOLD,
              { customer: { referredByAgentId: a.id } },
              { createdAt: { gte: since30 } },
            ],
          },
          _sum: { totalGoldWeightGrams: true },
          _count: true,
        });
        return {
          id: a.id,
          name: a.fullName,
          grams_sell: agg._sum.totalGoldWeightGrams ?? new Prisma.Decimal(0),
          order_count: agg._count,
        };
      }),
    );

    return {
      customerCount,
      allgram: gramsAgg._sum.totalGoldWeightGrams ?? 0,
      ordercount: orderCount,
      reagent,
      lastOrder: lastOrderRows.map((o) => this.orderRow(o)),
      sumLastOrder: monthAgg._count,
      sumLastOrderMonth: monthAgg._sum.totalGoldWeightGrams ?? 0,
    };
  }

  /** Legacy `GET get-analytics-tak` — the retail dashboard. */
  async takAnalytics() {
    const since7 = this.daysAgo(7);

    const rows = await this.prisma.order.findMany({
      where: { createdAt: { gte: since7 } },
      orderBy: { createdAt: 'desc' },
      take: 50,
      include: { customer: true, branch: true },
    });

    // The retail view reads only `model.lastOrder`; the rest of its cards are
    // the Vuexy demo series and are not rendered from server data.
    return { lastOrder: rows.map((o) => this.orderRow(o)) };
  }

  /**
   * Legacy `report/order_item` — "گزارش تجمیعی سفارشات و اسناد مالی": order
   * lines aggregated over a date range.
   */
  async orderItemReport(from?: string, to?: string) {
    const where = this.dateWhere(from, to);

    const orders = await this.prisma.order.findMany({
      where,
      include: {
        customer: true,
        items: { include: { productVariant: { include: { product: true } } } },
      },
      orderBy: { createdAt: 'desc' },
    });

    const rows = orders.flatMap((o) =>
      o.items.map((it) => ({
        order_id: o.id,
        order_number: o.orderNumber,
        customer: o.customer.fullName,
        product: it.productVariant.product.title,
        variant: it.productVariant.title,
        qty: it.quantity,
        w: it.computedWeightGrams,
        total_w: it.computedWeightGrams.mul(it.quantity),
        caj: o.createdAt,
      })),
    );

    const totalWeight = rows.reduce(
      (s, r) => s.add(r.total_w),
      new Prisma.Decimal(0),
    );

    return {
      rows,
      summary: {
        order_count: orders.length,
        item_count: rows.length,
        total_weight: totalWeight,
      },
    };
  }

  /** Legacy `report/product` — per-product sales over a date range. */
  async productReport(from?: string, to?: string) {
    const where = this.dateWhere(from, to);

    const orders = await this.prisma.order.findMany({
      where,
      include: { items: { include: { productVariant: { include: { product: true } } } } },
    });

    const byProduct = new Map<
      string,
      { id: string; title: string; qty: number; weight: Prisma.Decimal; orders: Set<string> }
    >();

    for (const o of orders) {
      for (const it of o.items) {
        const p = it.productVariant.product;
        const row = byProduct.get(p.id) ?? {
          id: p.id,
          title: p.title,
          qty: 0,
          weight: new Prisma.Decimal(0),
          orders: new Set<string>(),
        };
        row.qty += it.quantity;
        row.weight = row.weight.add(it.computedWeightGrams.mul(it.quantity));
        row.orders.add(o.id);
        byProduct.set(p.id, row);
      }
    }

    const rows = [...byProduct.values()]
      .map((r) => ({
        id: r.id,
        title: r.title,
        total: r.qty,
        w: r.weight,
        order_count: r.orders.size,
      }))
      .sort((a, b) => Number(b.w) - Number(a.w));

    return { rows, summary: { product_count: rows.length } };
  }

  /** Shared date filter for both reports; an open end stays open. */
  private dateWhere(from?: string, to?: string): Prisma.OrderWhereInput {
    if (!from && !to) return {};
    const createdAt: Prisma.DateTimeFilter = {};
    if (from) createdAt.gte = new Date(from);
    if (to) {
      // Include the whole end day, not just its midnight.
      const end = new Date(to);
      end.setHours(23, 59, 59, 999);
      createdAt.lte = end;
    }
    return { createdAt };
  }

  /** The row shape both dashboards' tables read. */
  private orderRow(
    o: Prisma.OrderGetPayload<{ include: { customer: true; branch: true } }>,
  ) {
    const labels: Record<OrderStatus, string> = {
      SUSPENDED: 'معلق (سقف اعتبار)',
      PLACED: 'ثبت شده',
      ADMIN_APPROVED: 'تایید مدیر',
      SOURCING: 'در حال تامین',
      PREPARING: 'در حال آماده‌سازی',
      DELIVERED_TO_AGENT: 'تحویل به نماینده',
      DELIVERED_TO_CUSTOMER: 'تحویل به مشتری',
      CANCELLED: 'لغو شده',
    };
    // legacy reads `statusColor` straight off the row
    const colors: Record<OrderStatus, string> = {
      SUSPENDED: 'warning',
      PLACED: 'primary',
      ADMIN_APPROVED: 'primary',
      SOURCING: 'warning',
      PREPARING: 'warning',
      DELIVERED_TO_AGENT: 'success',
      DELIVERED_TO_CUSTOMER: 'success',
      CANCELLED: 'danger',
    };

    return {
      id: o.id,
      name: o.orderNumber,
      customer: o.customer.fullName,
      w: o.totalGoldWeightGrams,
      sts_str: labels[o.status],
      statusColor: colors[o.status],
      caj: o.createdAt,
      // legacy rendered a parent/children tree for split orders; the redesigned
      // schema has no such relation, so both are empty rather than faked.
      parent: null,
      children: [],
    };
  }
}