import {
  BadGatewayException,
  Injectable,
  Logger,
  UnauthorizedException,
} from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

export type MeshkeeBusinessUpdate = {
  name?: string;
  slug?: string;
  nameFa?: string;
  about?: string;
  categoryIds?: number[];
};

export type MeshkeeCreateBusinessInput = {
  name: string;
  nameFa: string;
  slug?: string;
  about?: string;
  categoryIds: number[];
  ownerFirstName: string;
  ownerLastName: string;
  ownerFirstNameEn: string;
  ownerLastNameEn: string;
  ownerCellNumber: string;
  ownerPassword: string;
};

export type MeshkeeAuthUser = {
  id: string;
  cellNumber: string;
  email: string | null;
  firstName: string | null;
  lastName: string | null;
  firstNameEn: string | null;
  lastNameEn: string | null;
  dashboard: string;
};

@Injectable()
export class MeshkeeClient {
  private readonly logger = new Logger(MeshkeeClient.name);

  constructor(private readonly config: ConfigService) {}

  private apiBase(): string {
    return (
      this.config.get<string>('MESHKEE_API_URL')?.replace(/\/$/, '') ||
      'http://localhost:3010/api/v1'
    );
  }

  private authHeader(authorization?: string): string | null {
    if (authorization?.trim()) return authorization.trim();
    const token = this.config.get<string>('MESHKEE_API_TOKEN')?.trim();
    return token ? `Bearer ${token}` : null;
  }

  private serviceAuth(): string {
    const auth = this.authHeader();
    if (!auth) {
      throw new UnauthorizedException(
        'MESHKEE_API_TOKEN is required for Meshkee admin operations',
      );
    }
    return auth;
  }

  private async parseError(response: Response, fallback: string) {
    const text = await response.text().catch(() => '');
    try {
      const json = JSON.parse(text) as { message?: string | string[] };
      if (Array.isArray(json.message)) return json.message.join(', ');
      if (typeof json.message === 'string') return json.message;
    } catch {
      /* ignore */
    }
    return text.slice(0, 300) || fallback;
  }

  async getMe(authorization: string): Promise<MeshkeeAuthUser> {
    const response = await fetch(`${this.apiBase()}/auth/me`, {
      headers: { Authorization: authorization },
    });
    if (!response.ok) {
      throw new UnauthorizedException('Invalid or expired Meshkee session');
    }
    const payload = (await response.json()) as { user: MeshkeeAuthUser };
    return payload.user;
  }

  async listBusinessCategories(authorization?: string) {
    const auth = this.authHeader(authorization) ?? this.serviceAuth();
    const response = await fetch(`${this.apiBase()}/business-categories`, {
      headers: { Authorization: auth },
    });
    if (!response.ok) {
      throw new BadGatewayException(
        await this.parseError(response, 'Failed to list Meshkee categories'),
      );
    }
    const payload = (await response.json()) as {
      items?: Array<{ id: string | number; slug?: string }>;
    };
    return payload.items ?? [];
  }

  async createBusiness(
    body: MeshkeeCreateBusinessInput,
    authorization?: string,
  ) {
    const auth = this.authHeader(authorization) ?? this.serviceAuth();
    const response = await fetch(`${this.apiBase()}/businesses`, {
      method: 'POST',
      headers: {
        Authorization: auth,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(body),
    });
    if (!response.ok) {
      throw new BadGatewayException(
        await this.parseError(response, 'Failed to create Meshkee business'),
      );
    }
    const data = (await response.json()) as {
      id: string | number;
      slug?: string;
      name?: string;
    };
    return { ...data, id: String(data.id) };
  }

  async addDomain(businessId: string, host: string, authorization?: string) {
    const auth = this.authHeader(authorization) ?? this.serviceAuth();
    const response = await fetch(
      `${this.apiBase()}/businesses/${businessId}/domains`,
      {
        method: 'POST',
        headers: {
          Authorization: auth,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          host,
          isPrimary: true,
          updateDns: false,
        }),
      },
    );
    if (!response.ok) {
      throw new BadGatewayException(
        await this.parseError(response, 'Failed to attach Meshkee domain'),
      );
    }
    return response.json();
  }

  /** Write profile / category fields to Meshkee (source of truth for content). */
  async updateBusiness(
    meshkeeBusinessId: string,
    body: MeshkeeBusinessUpdate,
    authorization?: string,
  ): Promise<void> {
    const auth = this.authHeader(authorization);
    if (!auth) {
      this.logger.warn(
        `Skipping Meshkee update for business ${meshkeeBusinessId}: no auth token`,
      );
      return;
    }

    const payload: Record<string, unknown> = {};
    if (body.name !== undefined) payload.name = body.name;
    if (body.slug !== undefined) payload.slug = body.slug;
    if (body.nameFa !== undefined) payload.nameFa = body.nameFa;
    if (body.about !== undefined) payload.about = body.about;
    if (body.categoryIds !== undefined) payload.categoryIds = body.categoryIds;

    if (Object.keys(payload).length === 0) return;

    const response = await fetch(
      `${this.apiBase()}/businesses/${meshkeeBusinessId}`,
      {
        method: 'PATCH',
        headers: {
          Authorization: auth,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(payload),
      },
    );

    if (!response.ok) {
      const text = await response.text().catch(() => '');
      this.logger.error(
        `Meshkee update failed (${response.status}): ${text.slice(0, 300)}`,
      );
      throw new BadGatewayException(
        `Failed to update Meshkee business (${response.status})`,
      );
    }
  }
}