const API_BASE = '/api/v1';

class APIClient {
  private async request<T>(
    endpoint: string,
    options: RequestInit = {}
  ): Promise<T> {
    const response = await fetch(`${API_BASE}${endpoint}`, {
      ...options,
      headers: {
        'Content-Type': 'application/json',
        ...options.headers,
      },
    });

    if (!response.ok) {
      const error = await response.json().catch(() => ({}));
      throw new APIError(response.status, error.error || 'Request failed');
    }

    return response.json();
  }

  private get<T>(endpoint: string, params?: Record<string, string>): Promise<T> {
    const url = params
      ? `${endpoint}?${new URLSearchParams(params)}`
      : endpoint;
    return this.request(url);
  }

  private post<T>(endpoint: string, body?: unknown): Promise<T> {
    return this.request(endpoint, {
      method: 'POST',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  private put<T>(endpoint: string, body?: unknown): Promise<T> {
    return this.request(endpoint, {
      method: 'PUT',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  private delete<T>(endpoint: string): Promise<T> {
    return this.request(endpoint, { method: 'DELETE' });
  }

  // Auth
  auth = {
    login: (email: string, password: string) =>
      this.post<{ user: any; token: string }>('/auth/login', { email, password }),
    signup: (data: { email: string; password: string; firstName: string; lastName: string }) =>
      this.post<{ user: any; token: string }>('/auth/signup', data),
    logout: () => this.post('/auth/logout'),
    me: () => this.get<{ user: any }>('/auth/me'),
    updateProfile: (data: { firstName?: string; lastName?: string; brokerage?: string }) =>
      this.put('/auth/me', data),
  };

  // Contacts
  contacts = {
    getAll: (params?: { limit?: number; offset?: number; query?: string }) =>
      this.get<{ data: any[]; meta: any }>('/contacts', params as any),
    getById: (id: string) => this.get<any>(`/contacts/${id}`),
    create: (data: any) => this.post<any>('/contacts', data),
    update: (id: string, data: any) => this.put<any>(`/contacts/${id}`, data),
    delete: (id: string) => this.delete(`/contacts/${id}`),
    addTags: (id: string, tags: string[]) => this.post(`/contacts/${id}/tags`, { tags }),
    removeTags: (id: string, tags: string[]) => this.delete(`/contacts/${id}/tags`),
    addToWorkflow: (contactId: string, workflowId: string) =>
      this.post(`/contacts/${contactId}/workflow/${workflowId}`),
  };

  // Conversations
  conversations = {
    getAll: (params?: { limit?: number; status?: string; contactId?: string }) =>
      this.get<{ data: any[] }>('/conversations', params as any),
    getById: (id: string) => this.get<any>(`/conversations/${id}`),
    getMessages: (id: string, limit = 50) =>
      this.get<{ data: any[] }>(`/conversations/${id}/messages`, { limit: String(limit) }),
    sendSMS: (contactId: string, message: string) =>
      this.post('/conversations/send', { type: 'SMS', contactId, message }),
    sendEmail: (contactId: string, subject: string, htmlBody: string) =>
      this.post('/conversations/send', { type: 'EMAIL', contactId, subject, htmlBody }),
    markAsRead: (id: string) => this.put(`/conversations/${id}/status`, { status: 'read' }),
    delete: (id: string) => this.delete(`/conversations/${id}`),
  };

  // Opportunities
  opportunities = {
    getAll: (params?: { pipelineId?: string; stageId?: string; status?: string }) =>
      this.get<{ data: any[] }>('/opportunities', params as any),
    getById: (id: string) => this.get<any>(`/opportunities/${id}`),
    create: (data: any) => this.post<any>('/opportunities', data),
    update: (id: string, data: any) => this.put<any>(`/opportunities/${id}`, data),
    delete: (id: string) => this.delete(`/opportunities/${id}`),
    moveToStage: (id: string, stageId: string) =>
      this.put(`/opportunities/${id}`, { pipelineStageId: stageId }),
  };

  // Pipelines
  pipelines = {
    getAll: () => this.get<{ pipelines: any[] }>('/opportunities/pipelines'),
    getById: (id: string) => this.get<any>(`/opportunities/pipelines/${id}`),
    create: (data: { name: string; stages: { name: string }[] }) =>
      this.post('/opportunities/pipelines', data),
    addStage: (pipelineId: string, name: string) =>
      this.post(`/opportunities/pipelines/${pipelineId}/stages`, { name }),
  };

  // Onboarding
  onboarding = {
    get: () => this.get<{ onboarding: any }>('/onboarding'),
    save: (data: any) => this.post('/onboarding', data),
    getStatus: () => this.get<{ status: any }>('/onboarding/status'),
    updateStatus: (data: any) => this.put('/onboarding/status', data),
  };

  // Admin
  admin = {
    getStats: () => this.get<{ stats: any }>('/admin/stats'),
    getUsers: (params?: { page?: number; limit?: number; search?: string; filter?: string }) =>
      this.get<{ users: any[]; pagination: any }>('/users', params as any),
    getSettings: () => this.get<{ settings: any }>('/admin/settings'),
    updateSettings: (data: any) => this.put('/admin/settings', data),
    testConnection: (service: 'ghl' | 'stripe') =>
      this.post<{ success: boolean; error?: string }>('/admin/settings/test', { service }),
  };
}

export class APIError extends Error {
  constructor(public status: number, message: string) {
    super(message);
    this.name = 'APIError';
  }
}

export const api = new APIClient();