const API_BASE_URL = import.meta.env.VITE_API_BASE_URL || 'http://localhost:3000/api';

class ApiService {
  private baseURL: string;

  constructor(baseURL: string) {
    this.baseURL = baseURL;
  }

  private getToken(): string | null {
    return localStorage.getItem('token');
  }

  private async request<T>(endpoint: string, options: RequestInit = {}): Promise<T> {
    const token = this.getToken();
    const headers: HeadersInit = {
      'Content-Type': 'application/json',
      ...options.headers,
    };

    if (token) {
      headers['Authorization'] = `Bearer ${token}`;
    }

    const response = await fetch(`${this.baseURL}${endpoint}`, {
      ...options,
      headers,
    });

    if (response.status === 401) {
      localStorage.removeItem('token');
      localStorage.removeItem('user');
      window.location.href = '/';
      throw new Error('Unauthorized');
    }

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

    return response.json();
  }

  // Auth
  async login(username: string, password: string) {
    return this.request<{ token: string; user: any }>('/auth/login', {
      method: 'POST',
      body: JSON.stringify({ username, password }),
    });
  }

  async getMe() {
    return this.request<any>('/auth/me');
  }

  async changePassword(currentPassword: string, newPassword: string) {
    return this.request<{ message: string }>('/auth/change-password', {
      method: 'POST',
      body: JSON.stringify({ currentPassword, newPassword }),
    });
  }

  // Users
  async getUsers(params?: { role?: string; departmentId?: number }) {
    const query = new URLSearchParams(params as any).toString();
    return this.request<any[]>(`/users${query ? `?${query}` : ''}`);
  }

  async getUser(id: number) {
    return this.request<any>(`/users/${id}`);
  }

  async createUser(data: any) {
    return this.request<any>('/users', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async updateUser(id: number, data: any) {
    return this.request<any>(`/users/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data),
    });
  }

  async deleteUser(id: number) {
    return this.request<{ message: string }>(`/users/${id}`, {
      method: 'DELETE',
    });
  }

  // Departments
  async getDepartments() {
    return this.request<any[]>('/departments');
  }

  async getDepartment(id: number) {
    return this.request<any>(`/departments/${id}`);
  }

  async getSubDepartments(departmentId: number) {
    return this.request<any[]>(`/departments/${departmentId}/sub-departments`);
  }

  async createDepartment(name: string) {
    return this.request<any>('/departments', {
      method: 'POST',
      body: JSON.stringify({ name }),
    });
  }

  // Work Allocations
  async getWorkAllocations(params?: { employeeId?: number; status?: string; departmentId?: number }) {
    const query = new URLSearchParams(params as any).toString();
    return this.request<any[]>(`/work-allocations${query ? `?${query}` : ''}`);
  }

  async getWorkAllocation(id: number) {
    return this.request<any>(`/work-allocations/${id}`);
  }

  async createWorkAllocation(data: any) {
    return this.request<any>('/work-allocations', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async updateWorkAllocationStatus(id: number, status: string, completionDate?: string) {
    return this.request<any>(`/work-allocations/${id}/status`, {
      method: 'PUT',
      body: JSON.stringify({ status, completionDate }),
    });
  }

  async deleteWorkAllocation(id: number) {
    return this.request<{ message: string }>(`/work-allocations/${id}`, {
      method: 'DELETE',
    });
  }

  // Attendance
  async getAttendance(params?: { employeeId?: number; startDate?: string; endDate?: string; status?: string }) {
    const query = new URLSearchParams(params as any).toString();
    return this.request<any[]>(`/attendance${query ? `?${query}` : ''}`);
  }

  async checkIn(employeeId: number, workDate: string) {
    return this.request<any>('/attendance/check-in', {
      method: 'POST',
      body: JSON.stringify({ employeeId, workDate }),
    });
  }

  async checkOut(employeeId: number, workDate: string) {
    return this.request<any>('/attendance/check-out', {
      method: 'POST',
      body: JSON.stringify({ employeeId, workDate }),
    });
  }

  async getAttendanceSummary(params?: { startDate?: string; endDate?: string; departmentId?: number }) {
    const query = new URLSearchParams(params as any).toString();
    return this.request<any[]>(`/attendance/summary/stats${query ? `?${query}` : ''}`);
  }

  async updateAttendanceStatus(id: number, status: string, remark?: string) {
    return this.request<any>(`/attendance/${id}/status`, {
      method: 'PUT',
      body: JSON.stringify({ status, remark }),
    });
  }

  async markAbsent(employeeId: number, workDate: string, remark?: string) {
    return this.request<any>('/attendance/mark-absent', {
      method: 'POST',
      body: JSON.stringify({ employeeId, workDate, remark }),
    });
  }

  // Employee Swaps
  async getEmployeeSwaps(params?: { status?: string; employeeId?: number; startDate?: string; endDate?: string }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<any[]>(`/employee-swaps${query ? `?${query}` : ''}`);
  }

  async getEmployeeSwap(id: number) {
    return this.request<any>(`/employee-swaps/${id}`);
  }

  async createEmployeeSwap(data: {
    employeeId: number;
    targetDepartmentId: number;
    targetContractorId?: number;
    swapReason: string;
    reasonDetails?: string;
    workCompletionPercentage?: number;
    swapDate: string;
  }) {
    return this.request<any>('/employee-swaps', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async completeEmployeeSwap(id: number) {
    return this.request<any>(`/employee-swaps/${id}/complete`, {
      method: 'PUT',
    });
  }

  async cancelEmployeeSwap(id: number) {
    return this.request<any>(`/employee-swaps/${id}/cancel`, {
      method: 'PUT',
    });
  }

  // Contractor Rates
  async getContractorRates(params?: { contractorId?: number; subDepartmentId?: number }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<any[]>(`/contractor-rates${query ? `?${query}` : ''}`);
  }

  async getCurrentRate(contractorId: number, subDepartmentId?: number) {
    const query = subDepartmentId ? `?subDepartmentId=${subDepartmentId}` : '';
    return this.request<any>(`/contractor-rates/contractor/${contractorId}/current${query}`);
  }

  async setContractorRate(data: { 
    contractorId: number; 
    subDepartmentId?: number; 
    activity?: string; 
    rate: number; 
    effectiveDate: string 
  }) {
    return this.request<any>('/contractor-rates', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async updateContractorRate(id: number, data: { rate?: number; activity?: string; effectiveDate?: string }) {
    return this.request<any>(`/contractor-rates/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data),
    });
  }

  async deleteContractorRate(id: number) {
    return this.request<{ message: string }>(`/contractor-rates/${id}`, {
      method: 'DELETE',
    });
  }

  // Reports
  async getCompletedAllocationsReport(params?: { 
    startDate?: string; 
    endDate?: string; 
    departmentId?: number;
    contractorId?: number;
    employeeId?: number;
  }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<{ 
      allocations: any[]; 
      summary: { totalAllocations: number; totalAmount: string; totalUnits: string } 
    }>(`/reports/completed-allocations${query ? `?${query}` : ''}`);
  }

  async getReportSummary(params?: { startDate?: string; endDate?: string }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<{
      byContractor: any[];
      bySubDepartment: any[];
      byActivity: any[];
    }>(`/reports/summary${query ? `?${query}` : ''}`);
  }

  // Standard Rates
  async getStandardRates(params?: { departmentId?: number; subDepartmentId?: number; activity?: string }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<any[]>(`/standard-rates${query ? `?${query}` : ''}`);
  }

  async getAllRates(params?: { departmentId?: number; startDate?: string; endDate?: string }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<{
      allRates: any[];
      summary: { totalContractorRates: number; totalStandardRates: number; totalRates: number };
    }>(`/standard-rates/all-rates${query ? `?${query}` : ''}`);
  }

  async compareRates(params?: { contractorId?: number; subDepartmentId?: number }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<{
      standardRates: any[];
      contractorRates: any[];
      comparisons: any[];
    }>(`/standard-rates/compare${query ? `?${query}` : ''}`);
  }

  async createStandardRate(data: { 
    subDepartmentId?: number; 
    activity?: string; 
    rate: number; 
    effectiveDate: string 
  }) {
    return this.request<any>('/standard-rates', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async updateStandardRate(id: number, data: { rate?: number; activity?: string; effectiveDate?: string }) {
    return this.request<any>(`/standard-rates/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data),
    });
  }

  async deleteStandardRate(id: number) {
    return this.request<{ message: string }>(`/standard-rates/${id}`, {
      method: 'DELETE',
    });
  }

  // Activities
  async getActivities(params?: { departmentId?: number; subDepartmentId?: number }) {
    const query = params ? new URLSearchParams(params as any).toString() : '';
    return this.request<any[]>(`/activities${query ? `?${query}` : ''}`);
  }

  async getActivity(id: number) {
    return this.request<any>(`/activities/${id}`);
  }

  async createActivity(data: { sub_department_id: number; name: string; unit_of_measurement?: string }) {
    return this.request<any>('/activities', {
      method: 'POST',
      body: JSON.stringify(data),
    });
  }

  async updateActivity(id: number, data: { name?: string; unit_of_measurement?: string }) {
    return this.request<any>(`/activities/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data),
    });
  }

  async deleteActivity(id: number) {
    return this.request<{ message: string }>(`/activities/${id}`, {
      method: 'DELETE',
    });
  }
}

export const api = new ApiService(API_BASE_URL);