/**
 * Authentication Service Module
 * Handles login, logout, token management, and user session state
 */

(function (window) {
    'use strict';

    const AUTH_STORAGE_KEYS = {
        ACCESS_TOKEN: 'gb-access-token',
        REFRESH_TOKEN: 'gb-refresh-token',
        TOKEN_EXPIRES: 'gb-token-expires',
        USER_DATA: 'gb-user-data',
        REMEMBER_ME: 'gb-remember-me'
    };

    const AUTH_ENDPOINTS = {
        LOGIN: '/api/auth/login',
        LOGOUT: '/api/auth/logout',
        REFRESH: '/api/auth/refresh',
        CURRENT_USER: '/api/auth/me',
        VERIFY_2FA: '/api/auth/2fa/verify',
        RESEND_2FA: '/api/auth/2fa/resend'
    };

    const USER_ENDPOINTS = {
        LIST: '/api/directory/users/list',
        CREATE: '/api/directory/users/create',
        UPDATE: '/api/directory/users/:user_id/update',
        DELETE: '/api/directory/users/:user_id/delete',
        PROFILE: '/api/directory/users/:user_id/profile',
        ROLES: '/api/directory/users/:user_id/roles'
    };

    const GROUP_ENDPOINTS = {
        LIST: '/api/directory/groups/list',
        CREATE: '/api/directory/groups/create',
        UPDATE: '/api/directory/groups/:group_id/update',
        DELETE: '/api/directory/groups/:group_id/delete',
        MEMBERS: '/api/directory/groups/:group_id/members',
        ADD_MEMBER: '/api/directory/groups/:group_id/members/add',
        REMOVE_MEMBER: '/api/directory/groups/:group_id/members/remove'
    };

    class AuthService {
        constructor() {
            this.currentUser = null;
            this.tokenRefreshTimer = null;
            this.eventListeners = {};
            this.init();
        }

        init() {
            this.loadStoredUser();
            this.setupTokenRefresh();
            this.setupInterceptors();
        }

        loadStoredUser() {
            try {
                const userData = localStorage.getItem(AUTH_STORAGE_KEYS.USER_DATA);
                if (userData) {
                    this.currentUser = JSON.parse(userData);
                }
            } catch (e) {
                console.warn('Failed to load stored user data:', e);
                this.clearAuth();
            }
        }

        setupTokenRefresh() {
            const expiresAt = localStorage.getItem(AUTH_STORAGE_KEYS.TOKEN_EXPIRES);
            if (expiresAt) {
                const expiresMs = parseInt(expiresAt, 10) - Date.now();
                const refreshMs = expiresMs - (5 * 60 * 1000);

                if (refreshMs > 0) {
                    this.tokenRefreshTimer = setTimeout(() => {
                        this.refreshToken();
                    }, refreshMs);
                } else if (expiresMs > 0) {
                    this.refreshToken();
                } else {
                    this.handleTokenExpired();
                }
            }
        }

        setupInterceptors() {
            const originalFetch = window.fetch;
            const self = this;

            window.fetch = async function (url, options) {
                options = options || {};
                options.headers = options.headers || {};

                const token = self.getAccessToken();
                if (token && !options.headers['Authorization']) {
                    options.headers['Authorization'] = 'Bearer ' + token;
                }

                try {
                    const response = await originalFetch(url, options);

                    if (response.status === 401) {
                        const refreshed = await self.refreshToken();
                        if (refreshed) {
                            options.headers['Authorization'] = 'Bearer ' + self.getAccessToken();
                            return originalFetch(url, options);
                        } else {
                            self.handleTokenExpired();
                        }
                    }

                    return response;
                } catch (error) {
                    throw error;
                }
            };
        }

        async login(email, password, remember) {
            try {
                const response = await fetch(AUTH_ENDPOINTS.LOGIN, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    },
                    body: JSON.stringify({
                        email: email,
                        password: password,
                        remember: remember || false
                    })
                });

                const data = await response.json();

                if (!response.ok) {
                    throw new Error(data.error || 'Login failed');
                }

                if (data.requires_2fa) {
                    return {
                        success: false,
                        requires_2fa: true,
                        session_token: data.session_token
                    };
                }

                if (data.success && data.access_token) {
                    this.storeTokens(data, remember);
                    await this.fetchCurrentUser();
                    this.emit('login', this.currentUser);
                    return {
                        success: true,
                        redirect: data.redirect || '/'
                    };
                }

                throw new Error(data.message || 'Login failed');
            } catch (error) {
                console.error('Login error:', error);
                throw error;
            }
        }

        async verify2FA(sessionToken, code, trustDevice) {
            try {
                const response = await fetch(AUTH_ENDPOINTS.VERIFY_2FA, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    },
                    body: JSON.stringify({
                        session_token: sessionToken,
                        code: code,
                        trust_device: trustDevice || false
                    })
                });

                const data = await response.json();

                if (!response.ok) {
                    throw new Error(data.error || '2FA verification failed');
                }

                if (data.success && data.access_token) {
                    this.storeTokens(data, false);
                    await this.fetchCurrentUser();
                    this.emit('login', this.currentUser);
                    return {
                        success: true,
                        redirect: data.redirect || '/'
                    };
                }

                throw new Error(data.message || '2FA verification failed');
            } catch (error) {
                console.error('2FA verification error:', error);
                throw error;
            }
        }

        async resend2FA(sessionToken) {
            try {
                const response = await fetch(AUTH_ENDPOINTS.RESEND_2FA, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    },
                    body: JSON.stringify({
                        session_token: sessionToken
                    })
                });

                const data = await response.json();

                if (!response.ok) {
                    throw new Error(data.error || 'Failed to resend 2FA code');
                }

                return data;
            } catch (error) {
                console.error('Resend 2FA error:', error);
                throw error;
            }
        }

        async logout() {
            try {
                const token = this.getAccessToken();
                if (token) {
                    await fetch(AUTH_ENDPOINTS.LOGOUT, {
                        method: 'POST',
                        headers: {
                            'Authorization': 'Bearer ' + token,
                            'Content-Type': 'application/json'
                        }
                    });
                }
            } catch (error) {
                console.warn('Logout API call failed:', error);
            } finally {
                this.clearAuth();
                this.emit('logout');
                window.location.href = '/auth/login';
            }
        }

        async fetchCurrentUser() {
            try {
                const token = this.getAccessToken();
                if (!token) {
                    return null;
                }

                const response = await fetch(AUTH_ENDPOINTS.CURRENT_USER, {
                    headers: {
                        'Authorization': 'Bearer ' + token
                    }
                });

                if (!response.ok) {
                    if (response.status === 401) {
                        this.handleTokenExpired();
                    }
                    return null;
                }

                const userData = await response.json();
                this.currentUser = userData;
                localStorage.setItem(AUTH_STORAGE_KEYS.USER_DATA, JSON.stringify(userData));
                this.emit('userUpdated', userData);
                return userData;
            } catch (error) {
                console.error('Failed to fetch current user:', error);
                return null;
            }
        }

        async refreshToken() {
            const refreshToken = localStorage.getItem(AUTH_STORAGE_KEYS.REFRESH_TOKEN);
            if (!refreshToken) {
                return false;
            }

            try {
                const response = await fetch(AUTH_ENDPOINTS.REFRESH, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    },
                    body: JSON.stringify({
                        refresh_token: refreshToken
                    })
                });

                if (!response.ok) {
                    this.handleTokenExpired();
                    return false;
                }

                const data = await response.json();
                if (data.access_token) {
                    this.storeTokens(data, !!localStorage.getItem(AUTH_STORAGE_KEYS.REMEMBER_ME));
                    return true;
                }

                return false;
            } catch (error) {
                console.error('Token refresh failed:', error);
                this.handleTokenExpired();
                return false;
            }
        }

        storeTokens(data, remember) {
            const storage = remember ? localStorage : sessionStorage;

            if (data.access_token) {
                localStorage.setItem(AUTH_STORAGE_KEYS.ACCESS_TOKEN, data.access_token);
            }

            if (data.refresh_token) {
                localStorage.setItem(AUTH_STORAGE_KEYS.REFRESH_TOKEN, data.refresh_token);
            }

            if (data.expires_in) {
                const expiresAt = Date.now() + (data.expires_in * 1000);
                localStorage.setItem(AUTH_STORAGE_KEYS.TOKEN_EXPIRES, expiresAt.toString());
            }

            if (remember) {
                localStorage.setItem(AUTH_STORAGE_KEYS.REMEMBER_ME, 'true');
            }

            this.setupTokenRefresh();
        }

        clearAuth() {
            if (this.tokenRefreshTimer) {
                clearTimeout(this.tokenRefreshTimer);
                this.tokenRefreshTimer = null;
            }

            Object.values(AUTH_STORAGE_KEYS).forEach(key => {
                localStorage.removeItem(key);
                sessionStorage.removeItem(key);
            });

            this.currentUser = null;
        }

        handleTokenExpired() {
            this.clearAuth();
            this.emit('tokenExpired');

            const currentPath = window.location.pathname;
            if (!currentPath.startsWith('/auth/')) {
                window.location.href = '/auth/login?expired=1&redirect=' + encodeURIComponent(currentPath);
            }
        }

        getAccessToken() {
            return localStorage.getItem(AUTH_STORAGE_KEYS.ACCESS_TOKEN) ||
                sessionStorage.getItem(AUTH_STORAGE_KEYS.ACCESS_TOKEN);
        }

        isAuthenticated() {
            const token = this.getAccessToken();
            const expiresAt = localStorage.getItem(AUTH_STORAGE_KEYS.TOKEN_EXPIRES);

            if (!token) {
                return false;
            }

            if (expiresAt && Date.now() > parseInt(expiresAt, 10)) {
                return false;
            }

            return true;
        }

        getCurrentUser() {
            return this.currentUser;
        }

        hasRole(role) {
            if (!this.currentUser || !this.currentUser.roles) {
                return false;
            }
            return this.currentUser.roles.includes(role);
        }

        hasAnyRole(roles) {
            if (!this.currentUser || !this.currentUser.roles) {
                return false;
            }
            return roles.some(role => this.currentUser.roles.includes(role));
        }

        isAdmin() {
            return this.hasAnyRole(['admin', 'super_admin', 'superadmin']);
        }

        on(event, callback) {
            if (!this.eventListeners[event]) {
                this.eventListeners[event] = [];
            }
            this.eventListeners[event].push(callback);
        }

        off(event, callback) {
            if (!this.eventListeners[event]) {
                return;
            }
            this.eventListeners[event] = this.eventListeners[event].filter(cb => cb !== callback);
        }

        emit(event, data) {
            if (!this.eventListeners[event]) {
                return;
            }
            this.eventListeners[event].forEach(callback => {
                try {
                    callback(data);
                } catch (e) {
                    console.error('Event listener error:', e);
                }
            });
        }
    }

    class UserService {
        constructor(authService) {
            this.authService = authService;
        }

        async listUsers(page, perPage, search) {
            const params = new URLSearchParams();
            if (page) params.append('page', page);
            if (perPage) params.append('per_page', perPage);
            if (search) params.append('search', search);

            const url = USER_ENDPOINTS.LIST + (params.toString() ? '?' + params.toString() : '');

            const response = await fetch(url);
            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to list users');
            }
            return response.json();
        }

        async createUser(userData) {
            const response = await fetch(USER_ENDPOINTS.CREATE, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(userData)
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to create user');
            }
            return response.json();
        }

        async updateUser(userId, userData) {
            const url = USER_ENDPOINTS.UPDATE.replace(':user_id', userId);
            const response = await fetch(url, {
                method: 'PUT',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(userData)
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to update user');
            }
            return response.json();
        }

        async deleteUser(userId) {
            const url = USER_ENDPOINTS.DELETE.replace(':user_id', userId);
            const response = await fetch(url, {
                method: 'DELETE'
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to delete user');
            }
            return response.json();
        }

        async getUserProfile(userId) {
            const url = USER_ENDPOINTS.PROFILE.replace(':user_id', userId);
            const response = await fetch(url);

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to get user profile');
            }
            return response.json();
        }

        async getUserRoles(userId) {
            const url = USER_ENDPOINTS.ROLES.replace(':user_id', userId);
            const response = await fetch(url);

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to get user roles');
            }
            return response.json();
        }
    }

    class GroupService {
        constructor(authService) {
            this.authService = authService;
        }

        async listGroups(page, perPage, search) {
            const params = new URLSearchParams();
            if (page) params.append('page', page);
            if (perPage) params.append('per_page', perPage);
            if (search) params.append('search', search);

            const url = GROUP_ENDPOINTS.LIST + (params.toString() ? '?' + params.toString() : '');

            const response = await fetch(url);
            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to list groups');
            }
            return response.json();
        }

        async createGroup(groupData) {
            const response = await fetch(GROUP_ENDPOINTS.CREATE, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(groupData)
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to create group');
            }
            return response.json();
        }

        async updateGroup(groupId, groupData) {
            const url = GROUP_ENDPOINTS.UPDATE.replace(':group_id', groupId);
            const response = await fetch(url, {
                method: 'PUT',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(groupData)
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to update group');
            }
            return response.json();
        }

        async deleteGroup(groupId) {
            const url = GROUP_ENDPOINTS.DELETE.replace(':group_id', groupId);
            const response = await fetch(url, {
                method: 'DELETE'
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to delete group');
            }
            return response.json();
        }

        async getGroupMembers(groupId) {
            const url = GROUP_ENDPOINTS.MEMBERS.replace(':group_id', groupId);
            const response = await fetch(url);

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to get group members');
            }
            return response.json();
        }

        async addGroupMember(groupId, userId, roles) {
            const url = GROUP_ENDPOINTS.ADD_MEMBER.replace(':group_id', groupId);
            const response = await fetch(url, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    user_id: userId,
                    roles: roles || []
                })
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to add group member');
            }
            return response.json();
        }

        async removeGroupMember(groupId, userId) {
            const url = GROUP_ENDPOINTS.REMOVE_MEMBER.replace(':group_id', groupId);
            const response = await fetch(url, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    user_id: userId
                })
            });

            if (!response.ok) {
                const error = await response.json();
                throw new Error(error.error || 'Failed to remove group member');
            }
            return response.json();
        }
    }

    const authService = new AuthService();
    const userService = new UserService(authService);
    const groupService = new GroupService(authService);

    window.AuthService = authService;
    window.UserService = userService;
    window.GroupService = groupService;

    window.GBAuth = {
        service: authService,
        users: userService,
        groups: groupService,

        login: function (email, password, remember) {
            return authService.login(email, password, remember);
        },

        logout: function () {
            return authService.logout();
        },

        isAuthenticated: function () {
            return authService.isAuthenticated();
        },

        getCurrentUser: function () {
            return authService.getCurrentUser();
        },

        hasRole: function (role) {
            return authService.hasRole(role);
        },

        isAdmin: function () {
            return authService.isAdmin();
        },

        on: function (event, callback) {
            authService.on(event, callback);
        },

        off: function (event, callback) {
            authService.off(event, callback);
        }
    };

    document.addEventListener('DOMContentLoaded', function () {
        if (authService.isAuthenticated()) {
            authService.fetchCurrentUser().then(function (user) {
                if (user) {
                    document.body.classList.add('authenticated');
                    if (authService.isAdmin()) {
                        document.body.classList.add('is-admin');
                    }
                }
            });
        }
    });

})(window);