import { writable } from 'svelte/store';
import type { Writable } from 'svelte/store';

// Types
export interface InternalUser {
  id: string;
  email: string;
  first_name: string;
  last_name: string;
  role: 'ADMIN' | 'SUPPORT_MANAGER' | 'AGENT' | 'AUDITOR';
  is_active: boolean;
  is_two_factor_enabled: boolean;
  created_at: string;
  tenant_id: string;
}

export interface AuthState {
  user: InternalUser | null;
  token: string | null;
  refreshToken: string | null;
  isAuthenticated: boolean;
  isLoading: boolean;
}

export interface LoginRequest {
  email: string;
  password: string;
  tenant_slug: string;
  totp_code?: string;
}

export interface LoginResponse {
  access_token: string;
  refresh_token: string;
  token_type: string;
  expires_in: number;
  user: InternalUser;
}

export interface RefreshTokenRequest {
  refresh_token: string;
}

export interface TokenResponse {
  access_token: string;
  token_type: string;
  expires_in: number;
}

// Initial state
const initialState: AuthState = {
  user: null,
  token: null,
  refreshToken: null,
  isAuthenticated: false,
  isLoading: false
};

// Create auth store
function createAuthStore() {
  const { subscribe, set, update } = writable<AuthState>(initialState);

  return {
    subscribe,
    
    // Initialize auth from localStorage
    init: () => {
      if (typeof window !== 'undefined') {
        const token = localStorage.getItem('internal_auth_token');
        const refreshToken = localStorage.getItem('internal_auth_refresh_token');
        const user = localStorage.getItem('internal_auth_user');
        
        if (token && user) {
          try {
            const parsedUser = JSON.parse(user);
            set({
              user: parsedUser,
              token,
              refreshToken: refreshToken || null,
              isAuthenticated: true,
              isLoading: false
            });
          } catch (error) {
            console.error('Error parsing stored auth data:', error);
            localStorage.removeItem('internal_auth_token');
            localStorage.removeItem('internal_auth_refresh_token');
            localStorage.removeItem('internal_auth_user');
          }
        }
      }
    },

    // Login
    login: async (credentials: LoginRequest): Promise<void> => {
      update(state => ({ ...state, isLoading: true }));
      
      try {
        const response = await fetch('/api/v1/auth/login', {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
          },
          body: JSON.stringify(credentials)
        });

        if (!response.ok) {
          const error = await response.json();
          throw new Error(error.detail || 'Login failed');
        }

        const data: LoginResponse = await response.json();
        
        // Store auth data
        if (typeof window !== 'undefined') {
          localStorage.setItem('internal_auth_token', data.access_token);
          if (data.refresh_token) {
              localStorage.setItem('internal_auth_refresh_token', data.refresh_token);
          }
          localStorage.setItem('internal_auth_user', JSON.stringify(data.user));
        }

        set({
          user: data.user,
          token: data.access_token,
          refreshToken: data.refresh_token,
          isAuthenticated: true,
          isLoading: false
        });
      } catch (error) {
        update(state => ({ ...state, isLoading: false }));
        throw error;
      }
    },

    // Refresh Session
    refreshSession: async (): Promise<void> => {
        // Need to get current state to access refresh token, logic simplified
        let currentRefreshToken: string | null = null;
        if (typeof window !== 'undefined') {
            currentRefreshToken = localStorage.getItem('internal_auth_refresh_token');
        }

        if (!currentRefreshToken) {
            throw new Error("No refresh token available");
        }

        update (state => ({ ...state, isLoading: true }));

        try {
            const response = await fetch('/api/v1/auth/refresh', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({ refresh_token: currentRefreshToken })
            });

            if (!response.ok) {
                 // If refresh fails, logout
                 if (response.status === 401 || response.status === 403) {
                     auth.logout();
                 }
                 const error = await response.json();
                 throw new Error(error.detail || 'Refresh failed');
            }

            const data: TokenResponse = await response.json();

            // Update token in storage and state
            if (typeof window !== 'undefined') {
                localStorage.setItem('internal_auth_token', data.access_token);
            }

            update(state => ({
                ...state,
                token: data.access_token,
                isLoading: false
            }));

        } catch (error) {
             update(state => ({ ...state, isLoading: false }));
             throw error;
        }
    },

    // Logout
    logout: () => {
      if (typeof window !== 'undefined') {
        localStorage.removeItem('internal_auth_token');
        localStorage.removeItem('internal_auth_refresh_token');
        localStorage.removeItem('internal_auth_user');
      }
      set(initialState);
      // Optional: Redirect to login
      if (typeof window !== 'undefined') {
          window.location.href = '/login';
      }
    },

    // Update user data
    updateUser: (user: InternalUser) => {
      update(state => ({ ...state, user }));
      if (typeof window !== 'undefined') {
        localStorage.setItem('internal_auth_user', JSON.stringify(user));
      }
    },

    // Set loading state
    setLoading: (isLoading: boolean) => {
      update(state => ({ ...state, isLoading }));
    }
  };
}

export const auth = createAuthStore();