import {
  BadRequestException,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import type {
  CreateLoyaltyTierRequest,
  LoyaltyMemberDto,
  LoyaltyTierDto,
  UpdateLoyaltyTierRequest,
} from '@mento/shared';
import { PrismaService } from '../prisma/prisma.service';
import { type Actor, ownerWhere } from '../common/record-scope';

const DEFAULT_TIERS = [
  { name: 'برنزی', minPoints: 0, color: '#b87333' },
  { name: 'نقره‌ای', minPoints: 500, color: '#9aa0a6' },
  { name: 'طلایی', minPoints: 2000, color: '#d4af37' },
] as const;

@Injectable()
export class LoyaltyService {
  constructor(private readonly prisma: PrismaService) {}

  async ensureDefaultTiers(organizationId: string): Promise<void> {
    const count = await this.prisma.loyaltyTier.count({
      where: { organizationId },
    });
    if (count > 0) return;
    await this.prisma.loyaltyTier.createMany({
      data: DEFAULT_TIERS.map((t, position) => ({
        organizationId,
        name: t.name,
        minPoints: t.minPoints,
        color: t.color,
        position,
      })),
    });
  }

  async listTiers(organizationId: string): Promise<LoyaltyTierDto[]> {
    await this.ensureDefaultTiers(organizationId);
    const rows = await this.prisma.loyaltyTier.findMany({
      where: { organizationId },
      orderBy: [{ minPoints: 'asc' }, { position: 'asc' }],
      include: { _count: { select: { people: true } } },
    });
    return rows.map((r) => ({
      id: r.id,
      name: r.name,
      minPoints: r.minPoints,
      position: r.position,
      color: r.color,
      memberCount: r._count.people,
    }));
  }

  async createTier(
    organizationId: string,
    dto: CreateLoyaltyTierRequest,
  ): Promise<LoyaltyTierDto> {
    await this.ensureDefaultTiers(organizationId);
    const maxPos = await this.prisma.loyaltyTier.aggregate({
      where: { organizationId },
      _max: { position: true },
    });
    const row = await this.prisma.loyaltyTier.create({
      data: {
        organizationId,
        name: dto.name.trim(),
        minPoints: Math.max(0, Math.floor(dto.minPoints)),
        color: emptyToNull(dto.color),
        position: (maxPos._max.position ?? -1) + 1,
      },
    });
    await this.recomputeAllTiers(organizationId);
    return {
      id: row.id,
      name: row.name,
      minPoints: row.minPoints,
      position: row.position,
      color: row.color,
      memberCount: 0,
    };
  }

  async updateTier(
    organizationId: string,
    id: string,
    dto: UpdateLoyaltyTierRequest,
  ): Promise<LoyaltyTierDto> {
    const existing = await this.prisma.loyaltyTier.findFirst({
      where: { id, organizationId },
    });
    if (!existing) throw new NotFoundException('سطح پیدا نشد');

    const row = await this.prisma.loyaltyTier.update({
      where: { id },
      data: {
        ...(dto.name !== undefined ? { name: dto.name.trim() } : {}),
        ...(dto.minPoints !== undefined
          ? { minPoints: Math.max(0, Math.floor(dto.minPoints)) }
          : {}),
        ...('color' in dto ? { color: emptyToNull(dto.color ?? null) } : {}),
      },
      include: { _count: { select: { people: true } } },
    });
    await this.recomputeAllTiers(organizationId);
    return {
      id: row.id,
      name: row.name,
      minPoints: row.minPoints,
      position: row.position,
      color: row.color,
      memberCount: row._count.people,
    };
  }

  async deleteTier(organizationId: string, id: string): Promise<void> {
    const existing = await this.prisma.loyaltyTier.findFirst({
      where: { id, organizationId },
    });
    if (!existing) throw new NotFoundException('سطح پیدا نشد');
    await this.prisma.person.updateMany({
      where: { organizationId, loyaltyTierId: id },
      data: { loyaltyTierId: null },
    });
    await this.prisma.loyaltyTier.delete({ where: { id } });
    await this.recomputeAllTiers(organizationId);
  }

  async listMembers(
    actor: Actor,
    q?: string,
  ): Promise<LoyaltyMemberDto[]> {
    await this.ensureDefaultTiers(actor.organizationId);
    const rows = await this.prisma.person.findMany({
      where: {
        organizationId: actor.organizationId,
        ...ownerWhere(actor),
        ...(q?.trim()
          ? {
              OR: [
                { firstName: { contains: q.trim(), mode: 'insensitive' } },
                { lastName: { contains: q.trim(), mode: 'insensitive' } },
                { mobile: { contains: q.trim() } },
                { email: { contains: q.trim(), mode: 'insensitive' } },
              ],
            }
          : {}),
      },
      include: {
        company: { select: { id: true, name: true } },
        loyaltyTier: {
          select: { id: true, name: true, minPoints: true, color: true },
        },
      },
      orderBy: [{ loyaltyPoints: 'desc' }, { lastName: 'asc' }],
      take: 200,
    });
    return rows.map((r) => ({
      id: r.id,
      fullName: `${r.firstName} ${r.lastName}`.trim(),
      mobile: r.mobile,
      email: r.email,
      loyaltyPoints: r.loyaltyPoints,
      loyaltyTier: r.loyaltyTier,
      company: r.company,
    }));
  }

  async adjustPoints(
    actor: Actor,
    personId: string,
    delta: number,
  ): Promise<LoyaltyMemberDto> {
    if (!Number.isFinite(delta) || delta === 0) {
      throw new BadRequestException('مقدار امتیاز نامعتبر است');
    }
    const person = await this.prisma.person.findFirst({
      where: {
        id: personId,
        organizationId: actor.organizationId,
        ...ownerWhere(actor),
      },
    });
    if (!person) throw new NotFoundException('شخص پیدا نشد');

    const next = Math.max(0, person.loyaltyPoints + Math.trunc(delta));
    const tierId = await this.resolveTierId(actor.organizationId, next);
    const updated = await this.prisma.person.update({
      where: { id: personId },
      data: { loyaltyPoints: next, loyaltyTierId: tierId },
      include: {
        company: { select: { id: true, name: true } },
        loyaltyTier: {
          select: { id: true, name: true, minPoints: true, color: true },
        },
      },
    });
    return {
      id: updated.id,
      fullName: `${updated.firstName} ${updated.lastName}`.trim(),
      mobile: updated.mobile,
      email: updated.email,
      loyaltyPoints: updated.loyaltyPoints,
      loyaltyTier: updated.loyaltyTier,
      company: updated.company,
    };
  }

  /** برای اتوماسیون — بدون ACL مالکیت */
  async addPointsByOrg(
    organizationId: string,
    personId: string,
    points: number,
  ): Promise<void> {
    if (!personId || !points) return;
    const person = await this.prisma.person.findFirst({
      where: { id: personId, organizationId },
    });
    if (!person) return;
    const next = Math.max(0, person.loyaltyPoints + Math.trunc(points));
    const tierId = await this.resolveTierId(organizationId, next);
    await this.prisma.person.update({
      where: { id: personId },
      data: { loyaltyPoints: next, loyaltyTierId: tierId },
    });
  }

  async resolveTierId(
    organizationId: string,
    points: number,
  ): Promise<string | null> {
    await this.ensureDefaultTiers(organizationId);
    const tier = await this.prisma.loyaltyTier.findFirst({
      where: { organizationId, minPoints: { lte: points } },
      orderBy: { minPoints: 'desc' },
    });
    return tier?.id ?? null;
  }

  private async recomputeAllTiers(organizationId: string) {
    const people = await this.prisma.person.findMany({
      where: { organizationId },
      select: { id: true, loyaltyPoints: true },
    });
    const tiers = await this.prisma.loyaltyTier.findMany({
      where: { organizationId },
      orderBy: { minPoints: 'desc' },
    });
    for (const p of people) {
      const tier = tiers.find((t) => t.minPoints <= p.loyaltyPoints) ?? null;
      await this.prisma.person.update({
        where: { id: p.id },
        data: { loyaltyTierId: tier?.id ?? null },
      });
    }
  }
}

function emptyToNull(v?: string | null) {
  if (v == null) return null;
  const t = v.trim();
  return t ? t : null;
}