import axios from 'axios';

// API base URL
const API_BASE_URL = 'http://localhost:8080/api/v1';

// Create axios instance with defaults
export const api = axios.create({
  baseURL: API_BASE_URL,
  headers: {
    'Content-Type': 'application/json',
  },
});

// Add auth interceptor
api.interceptors.request.use(
  (config) => {
    const token = localStorage.getItem('token');
    if (token) {
      config.headers.Authorization = `Bearer ${token}`;
    }
    return config;
  },
  (error) => Promise.reject(error)
);

// Handle auth errors
api.interceptors.response.use(
  (response) => response,
  (error) => {
    if (error.response && error.response.status === 401 && typeof window !== 'undefined') {
      localStorage.removeItem('token');
      window.location.href = '/login';
    }
    return Promise.reject(error);
  }
);

// Auth API
export const authApi = {
  login: async (email: string, password: string) => {
    const response = await api.post('/auth/login', { email, password });
    const { token } = response.data;
    localStorage.setItem('token', token);
    return response.data;
  },
  
  signup: async (name: string, email: string, password: string) => {
    const response = await api.post('/auth/signup', { name, email, password });
    return response.data;
  },
  
  logout: () => {
    localStorage.removeItem('token');
    window.location.href = '/login';
  }
};

// Account API
export interface Account {
  id: number;
  createdAt: string;
  updatedAt: string;
  deletedAt: string | null;
  userID: number;
  name: string;
  type: string;
  balance: number;
}

export interface AccountInput {
  name: string;
  type: string;
  balance: number;
}

export const accountApi = {
  getAccounts: () => api.get('/accounts').then(res => res.data),
  getAccount: (id: number) => api.get(`/accounts/${id}`).then(res => res.data),
  createAccount: (account: AccountInput) => api.post('/accounts', account).then(res => res.data),
  updateAccount: (id: number, account: Partial<AccountInput>) => api.put(`/accounts/${id}`, account).then(res => res.data),
  deleteAccount: (id: number) => api.delete(`/accounts/${id}`).then(res => res.data)
};

// Transaction API
export interface Transaction {
  id: number;
  createdAt: string;
  updatedAt: string;
  deletedAt: string | null;
  userID: number;
  accountID: number | null;
  description: string;
  amount: number;
  type: "Income" | "Expense";
  date: string;
  category: string;
}

export interface TransactionInput {
  description: string;
  amount: number;
  type: "Income" | "Expense";
  date: string; // YYYY-MM-DD format
  category: string;
  accountId?: number;
}

export interface TransactionFilters {
  type?: "Income" | "Expense";
  accountId?: number;
  category?: string;
  startDate?: string; // YYYY-MM-DD format
  endDate?: string; // YYYY-MM-DD format
  goalId?: number;
}

export const transactionApi = {
  getTransactions: (filters?: TransactionFilters) => {
    const params: Record<string, string | number | undefined> = {};
    if (filters) {
      if (filters.type) params.type = filters.type;
      if (filters.accountId) params.account_id = filters.accountId;
      if (filters.category) params.category = filters.category;
      if (filters.startDate) params.start_date = filters.startDate;
      if (filters.endDate) params.end_date = filters.endDate;
      if (filters.goalId) params.goal_id = filters.goalId;
    }
    return api.get('/transactions', { params }).then(res => res.data);
  },
  
  getTransaction: (id: number) => api.get(`/transactions/${id}`).then(res => res.data),
  
  createTransaction: (transaction: TransactionInput) => api.post('/transactions', transaction).then(res => res.data),
  
  updateTransaction: (id: number, transaction: Partial<TransactionInput>) => api.put(`/transactions/${id}`, transaction).then(res => res.data),
  
  deleteTransaction: (id: number) => api.delete(`/transactions/${id}`).then(res => res.data)
};

// Goal API
export interface Goal {
  id: number;
  createdAt: string;
  updatedAt: string;
  deletedAt: string | null;
  userID: number;
  name: string;
  targetAmount: number;
  currentAmount: number;
  targetDate: string | null;
  status: "Active" | "Paused" | "Achieved" | "Cancelled";
}

export interface GoalProgress {
  goal: Goal;
  percentComplete: number;
  amountRemaining: number;
  daysRemaining: number;
  requiredPerDay: number;
  requiredPerMonth: number;
  onTrack: boolean;
}

export interface GoalInput {
  name: string;
  targetAmount: number;
  currentAmount?: number;
  targetDate?: string; // YYYY-MM-DD format
  status?: "Active" | "Paused" | "Achieved" | "Cancelled";
}

export const goalApi = {
  getGoals: (status?: "Active" | "Paused" | "Achieved" | "Cancelled") => {
    const params = status ? { status } : {};
    return api.get('/goals', { params }).then(res => res.data);
  },
  
  getGoal: (id: number) => api.get(`/goals/${id}`).then(res => res.data),
  
  createGoal: (goal: GoalInput) => api.post('/goals', goal).then(res => res.data),
  
  updateGoal: (id: number, goal: Partial<GoalInput>) => api.put(`/goals/${id}`, goal).then(res => res.data),
  
  updateGoalProgress: (id: number, currentAmount: number) => 
    api.patch(`/goals/${id}/progress`, { currentAmount }).then(res => res.data),
  
  deleteGoal: (id: number) => api.delete(`/goals/${id}`).then(res => res.data),
  
  // New goal progress tracking endpoints
  getGoalProgress: (id: number) => api.get(`/goals/${id}/progress`).then(res => res.data),
  
  getAllGoalsProgress: (status?: string) => {
    const params = status ? { status } : {};
    return api.get('/goals/progress/all', { params }).then(res => res.data);
  },
  
  linkTransactionToGoal: (goalId: number, transactionId: number) => 
    api.post(`/goals/${goalId}/link-transaction`, { transactionId }).then(res => res.data),
  
  recalculateGoalProgress: (id: number) => api.post(`/goals/${id}/recalculate`).then(res => res.data)
};

// Loan API
export interface Loan {
  id: number;
  createdAt: string;
  updatedAt: string;
  deletedAt: string | null;
  userID: number;
  accountID: number | null;
  name: string;
  originalAmount: number;
  currentBalance: number;
  interestRate: number;
  startDate: string;
  endDate: string;
}

export interface LoanInput {
  name: string;
  originalAmount: number;
  currentBalance: number;
  interestRate: number;
  startDate: string;
  endDate: string;
  accountId?: number;
}

export const loanApi = {
  getLoans: () => api.get('/loans').then(res => res.data),
  getLoan: (id: number) => api.get(`/loans/${id}`).then(res => res.data),
  createLoan: (loan: LoanInput) => api.post('/loans', loan).then(res => res.data),
  updateLoan: (id: number, loan: Partial<LoanInput>) => api.put(`/loans/${id}`, loan).then(res => res.data),
  deleteLoan: (id: number) => api.delete(`/loans/${id}`).then(res => res.data)
};

// User API
export const userApi = {
  getProfile: () => api.get('/users/me').then(res => res.data)
};