import {
  BadRequestException,
  Injectable,
  NotFoundException,
  UnauthorizedException,
} from '@nestjs/common';
import { Prisma } from '@prisma/client';
import { MeshkeeClient } from '../meshkee/meshkee.client';
import { PrismaService } from '../prisma/prisma.service';
import {
  CreateBusinessDto,
  ListBusinessesDto,
  RegisterShopDto,
  UpdateBusinessDto,
} from './dto/business.dto';

function slugify(value: string) {
  return value
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .slice(0, 80);
}

@Injectable()
export class BusinessesService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly meshkee: MeshkeeClient,
  ) {}

  async list(query: ListBusinessesDto) {
    const page = query.page ?? 1;
    const limit = Math.min(query.limit ?? 20, 100);
    const skip = (page - 1) * limit;

    const where: Prisma.BusinessWhereInput = {};

    if (query.status && query.status !== 'all') {
      where.status = query.status;
    } else if (!query.status) {
      where.status = 'published';
    }

    if (query.featured === true) {
      where.isFeatured = true;
    }

    if (query.q) {
      where.slug = { contains: query.q, mode: 'insensitive' };
    }

    const [items, total] = await Promise.all([
      this.prisma.business.findMany({
        where,
        orderBy: [
          { isFeatured: 'desc' },
          { sortWeight: 'desc' },
          { publishedAt: 'desc' },
          { id: 'desc' },
        ],
        skip,
        take: limit,
      }),
      this.prisma.business.count({ where }),
    ]);

    return { items, page, limit, total };
  }

  async getBySlug(slug: string) {
    const business = await this.prisma.business.findUnique({ where: { slug } });
    if (!business) {
      throw new NotFoundException(`Business "${slug}" not found`);
    }
    return business;
  }

  async getById(id: string) {
    const business = await this.prisma.business.findUnique({
      where: { id: BigInt(id) },
    });
    if (!business) {
      throw new NotFoundException(`Business ${id} not found`);
    }
    return business;
  }

  /**
   * Self-serve shop signup:
   * 1) Meshkee business owned by the logged-in IranBay user (NOT the iranbay.com tenant)
   * 2) IranBay marketplace listing (pending_review)
   */
  async registerShop(dto: RegisterShopDto, authorization?: string) {
    if (!authorization?.trim()) {
      throw new UnauthorizedException('Sign in required');
    }

    const user = await this.meshkee.getMe(authorization);
    const name = dto.name.trim();
    if (name.length < 2) {
      throw new BadRequestException('Business name is required');
    }

    const slug = (dto.slug?.trim() || slugify(name)).slice(0, 100);
    if (!slug) {
      throw new BadRequestException('Could not build a slug from the name');
    }

    let categoryIds = dto.meshkeeCategoryIds?.length
      ? this.parseMeshkeeCategoryIds(dto.meshkeeCategoryIds)
      : [];

    if (!categoryIds.length) {
      const categories = await this.meshkee.listBusinessCategories();
      const other =
        categories.find((item) => String(item.slug) === 'other') ??
        categories[0];
      if (!other) {
        throw new BadRequestException('No Meshkee categories available');
      }
      categoryIds = [Number(other.id)];
    }

    const firstName =
      user.firstNameEn?.trim() || user.firstName?.trim() || 'Owner';
    const lastName =
      user.lastNameEn?.trim() || user.lastName?.trim() || firstName;

    const created = await this.meshkee.createBusiness({
      name,
      nameFa: name,
      slug,
      about: dto.about?.trim() || undefined,
      categoryIds,
      ownerFirstName: firstName,
      ownerLastName: lastName.length >= 2 ? lastName : firstName,
      ownerFirstNameEn: firstName,
      ownerLastNameEn: lastName.length >= 2 ? lastName : firstName,
      ownerCellNumber: user.cellNumber,
      ownerPassword: dto.ownerPassword,
    });

    try {
      const listing = await this.prisma.business.create({
        data: {
          meshkeeBusinessId: BigInt(created.id),
          slug: created.slug || slug,
          status: 'pending_review',
          isFeatured: false,
          sortWeight: 0,
          publishedAt: null,
        },
      });
      return {
        listing,
        meshkeeBusinessId: created.id,
        message:
          'Shop created in Meshkee and submitted to IranBay for review.',
      };
    } catch (error) {
      this.rethrowUnique(error);
      throw error;
    }
  }

  async create(dto: CreateBusinessDto, authorization?: string) {
    const status = dto.status ?? 'draft';
    const now = new Date();

    const meshkeePatch: {
      name?: string;
      slug?: string;
      categoryIds?: number[];
    } = { slug: dto.slug };

    if (dto.name?.trim()) meshkeePatch.name = dto.name.trim();
    if (dto.meshkeeCategoryIds?.length) {
      meshkeePatch.categoryIds = this.parseMeshkeeCategoryIds(
        dto.meshkeeCategoryIds,
      );
    }

    await this.meshkee.updateBusiness(
      dto.meshkeeBusinessId,
      meshkeePatch,
      authorization,
    );

    try {
      return await this.prisma.business.create({
        data: {
          meshkeeBusinessId: BigInt(dto.meshkeeBusinessId),
          slug: dto.slug,
          status,
          isFeatured: dto.isFeatured ?? false,
          sortWeight: dto.sortWeight ?? 0,
          publishedAt: status === 'published' ? now : null,
        },
      });
    } catch (error) {
      this.rethrowUnique(error);
      throw error;
    }
  }

  async update(id: string, dto: UpdateBusinessDto, authorization?: string) {
    const existing = await this.getById(id);

    const data: Prisma.BusinessUpdateInput = {
      slug: dto.slug,
      status: dto.status,
      isFeatured: dto.isFeatured,
      sortWeight: dto.sortWeight,
    };

    if (dto.status === 'published' && existing.status !== 'published') {
      data.publishedAt = new Date();
    }

    const meshkeePatch: {
      name?: string;
      slug?: string;
      categoryIds?: number[];
    } = {};
    if (dto.name !== undefined) meshkeePatch.name = dto.name;
    if (dto.slug !== undefined) meshkeePatch.slug = dto.slug;
    if (dto.meshkeeCategoryIds !== undefined) {
      meshkeePatch.categoryIds = this.parseMeshkeeCategoryIds(
        dto.meshkeeCategoryIds,
      );
    }

    if (Object.keys(meshkeePatch).length) {
      await this.meshkee.updateBusiness(
        String(existing.meshkeeBusinessId),
        meshkeePatch,
        authorization,
      );
    }

    try {
      return await this.prisma.business.update({
        where: { id: BigInt(id) },
        data,
      });
    } catch (error) {
      this.rethrowUnique(error);
      throw error;
    }
  }

  async remove(id: string) {
    await this.getById(id);
    await this.prisma.business.delete({ where: { id: BigInt(id) } });
    return { ok: true };
  }

  private parseMeshkeeCategoryIds(ids: string[]): number[] {
    const parsed = [...new Set(ids)].map((id) => {
      const n = Number(id);
      if (!Number.isInteger(n) || n <= 0) {
        throw new BadRequestException(`Invalid Meshkee category id: ${id}`);
      }
      return n;
    });
    if (!parsed.length) {
      throw new BadRequestException('meshkeeCategoryIds cannot be empty');
    }
    return parsed;
  }

  private rethrowUnique(error: unknown): void {
    if (
      error instanceof Prisma.PrismaClientKnownRequestError &&
      error.code === 'P2002'
    ) {
      const target = Array.isArray(error.meta?.target)
        ? error.meta.target.join(', ')
        : 'field';
      throw new BadRequestException(`Business ${target} already exists`);
    }
  }
}