#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>

#define MAX_BUFFER 1024
#define PORT 8888
#define SERVER_IP "8.137.76.175"
#define MAX_FRIENDS 50

// 好友结构体
typedef struct {
    char username[50];
    int index;
} Friend;

// 全局变量
int client_socket;
int current_user_index = -1;
char current_username[50];
pthread_t receive_thread;
Friend friends[MAX_FRIENDS];
int friend_count = 0;

// 函数声明
void connect_to_server();
void* receive_messages(void* arg);
void show_login_menu();
void show_main_menu();
void login();
void register_user();
void add_friend();
void remove_friend();
void chat_with_friend();
void logout();
void get_friends_list();
void display_friends_list();

int main() {
    connect_to_server();
    show_login_menu();
    return 0;
}

void connect_to_server() {
    struct sockaddr_in server_addr;

    // 创建socket
    client_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (client_socket < 0) {
        perror("创建Socket失败");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);

    // 连接服务器
    if (connect(client_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0) {
        perror("连接服务器失败");
        exit(EXIT_FAILURE);
    }

    printf("成功连接到服务器！\n");
    // 不要在这里启动接收线程
}

void* receive_messages(void* arg) {
    char buffer[MAX_BUFFER];
    while (1) {
        memset(buffer, 0, MAX_BUFFER);
        if (recv(client_socket, buffer, MAX_BUFFER, 0) <= 0) {
            printf("\n连接已断开\n");
            current_user_index = -1;  
            close(client_socket);  
            connect_to_server();  
            return NULL;
        }
        
        // 处理PING消息
        if (strcmp(buffer, "PING") == 0) {
            continue;
        }
        
        // 处理好友列表消息
        if (strncmp(buffer, "FRIENDLIST", 10) == 0) {
            friend_count = 0; // 重置好友计数
            char* token = strtok(buffer + 11, " ");
            while (token != NULL && friend_count < MAX_FRIENDS) {
                char* comma = strchr(token, ',');
                if (comma != NULL) {
                    *comma = '\0';
                    strncpy(friends[friend_count].username, token, sizeof(friends[friend_count].username)-1);
                    friends[friend_count].username[sizeof(friends[friend_count].username)-1] = '\0';
                    friends[friend_count].index = atoi(comma + 1);
                    friend_count++;
                }
                token = strtok(NULL, " ");
            }
            printf("\n好友列表已更新\n");
            continue;
        }
        
        // 处理好友操作响应
        if (strncmp(buffer, "FRIEND_ADD_SUCCESS", 17) == 0 || 
            strncmp(buffer, "FRIEND_REMOVE_SUCCESS", 20) == 0) {
            printf("\n%s\n", buffer);
            get_friends_list();
            continue;
        }
        
        // 处理聊天消息
        if (strncmp(buffer, "CHAT", 4) == 0) {
            printf("\n%s\n", buffer + 5);
        }
        // 处理系统消息
        else if (strncmp(buffer, "系统消息", 8) == 0 || 
                 strncmp(buffer, "FRIEND_", 7) == 0) {
            printf("\n%s\n", buffer);
        }
        // 处理其他消息
        else {
            printf("\n%s\n", buffer);
        }
        
        if (current_user_index != -1) {
            printf("> ");
            fflush(stdout);
        }
    }
    return NULL;
}

void show_login_menu() {
    int choice;
    while (1) {
        printf("\n=== 登录菜单 ===\n");
        printf("1. 登录\n");
        printf("2. 注册\n");
        printf("3. 退出\n");
        printf("请选择: ");
        scanf("%d", &choice);
        getchar(); // 清除输入缓冲

        switch (choice) {
            case 1:
                login();
                break;
            case 2:
                register_user();
                break;
            case 3:
                logout();  // 确保在退出前发送登出消息
                close(client_socket);
                exit(EXIT_SUCCESS);
            default:
                printf("无效选择\n");
        }
    }
}

void show_main_menu() {
    int choice;
    while (current_user_index != -1) {  // 只在用户已登录时显示菜单
        printf("\n=== 主菜单 ===\n");
        printf("1. 添加好友\n");
        printf("2. 删除好友\n");
        printf("3. 与好友聊天\n");
        printf("4. 查看好友列表\n");
        printf("5. 退出登录\n");
        printf("6. 退出程序\n");
        printf("请选择: ");
        
        if (scanf("%d", &choice) != 1) {
            // 清除输入缓冲
            int c;
            while ((c = getchar()) != '\n' && c != EOF);
            printf("无效输入，请重新选择\n");
            continue;
        }
        getchar(); // 清除输入缓冲

        switch (choice) {
            case 1:
                add_friend();
                break;
            case 2:
                remove_friend();
                break;
            case 3:
                chat_with_friend();
                break;
            case 4:
                get_friends_list();
                display_friends_list();
                break;
            case 5:
                logout();
                return;
            case 6:
                logout();
                close(client_socket);
                exit(EXIT_SUCCESS);
            default:
                printf("无效选择\n");
        }
    }
}

void login() {
    char username[50], password[50];
    char buffer[MAX_BUFFER];
    char response[MAX_BUFFER];

    printf("用户名: ");
    scanf("%s", username);
    printf("密码: ");
    scanf("%s", password);
    getchar(); // 清除输入缓冲

    snprintf(buffer, MAX_BUFFER, "LOGIN %s %s", username, password);
    send(client_socket, buffer, MAX_BUFFER, 0);

    // 等待服务器响应
    memset(response, 0, MAX_BUFFER);
    if (recv(client_socket, response, MAX_BUFFER, 0) <= 0) {
        printf("登录失败：连接已断开\n");
        return;
    }

    if (strncmp(response, "SUCCESS", 7) == 0) {
        sscanf(response, "SUCCESS %d", &current_user_index);
        strncpy(current_username, username, sizeof(current_username) - 1);
        current_username[sizeof(current_username) - 1] = '\0';
        printf("登录成功！\n");
        // 登录成功后再启动接收线程
        if (pthread_create(&receive_thread, NULL, receive_messages, NULL) != 0) {
            perror("创建线程失败");
            exit(EXIT_FAILURE);
        }
        get_friends_list();
        show_main_menu();
    } else {
        printf("登录失败: %s\n", response + 5);
    }
}

void register_user() {
    char username[50], password[50];
    char buffer[MAX_BUFFER];

    printf("用户名: ");
    scanf("%s", username);
    printf("密码: ");
    scanf("%s", password);

    snprintf(buffer, MAX_BUFFER, "REGISTER %s %s", username, password);
    send(client_socket, buffer, MAX_BUFFER, 0);

    // 等待服务器响应
    memset(buffer, 0, MAX_BUFFER);
    recv(client_socket, buffer, MAX_BUFFER, 0);

    if (strcmp(buffer, "SUCCESS") == 0) {
        printf("注册成功！\n");
    } else {
        printf("注册失败: %s\n", buffer + 5);
    }
}

void get_friends_list() {
    char buffer[MAX_BUFFER];
    snprintf(buffer, MAX_BUFFER, "GETFRIENDS %d", current_user_index);
    send(client_socket, buffer, MAX_BUFFER, 0);
    // 等待接收线程处理好友列表
    usleep(100000); // 等待100ms
}

void display_friends_list() {
    printf("\n=== 好友列表 ===\n");
    if (friend_count == 0) {
        printf("暂无好友\n");
    } else {
        for (int i = 0; i < friend_count; i++) {
            printf("%d. %s\n", i + 1, friends[i].username);
        }
    }
    printf("----------------\n");
}

void chat_with_friend() {
    char buffer[MAX_BUFFER];
    char message[MAX_BUFFER];
    int choice;

    get_friends_list();
    if (friend_count == 0) {
        printf("您还没有好友，请先添加好友！\n");
        return;
    }

    display_friends_list();
    printf("请选择要聊天的好友编号: ");
    scanf("%d", &choice);
    getchar(); // 清除输入缓冲

    if (choice < 1 || choice > friend_count) {
        printf("无效的选择！\n");
        return;
    }

    int friend_index = friends[choice - 1].index;
    printf("\n开始与 %s 聊天（输入'exit'退出）:\n", friends[choice - 1].username);
    printf("> ");
    fflush(stdout);
    
    while (1) {
        fgets(message, sizeof(message), stdin);
        message[strcspn(message, "\n")] = 0; // 移除换行符
        // 限制 message 长度
        message[sizeof(message)-1] = '\0';
        if (strcmp(message, "exit") == 0) {
            break;
        }
        int n = snprintf(buffer, MAX_BUFFER, "CHAT %d %d %s", current_user_index, friend_index, message);
        if (n < 0 || n >= MAX_BUFFER) {
            strcpy(&buffer[MAX_BUFFER-5], "...");
        }
        send(client_socket, buffer, MAX_BUFFER, 0);
        printf("> ");
        fflush(stdout);
    }
}

void add_friend() {
    char friend_name[50];
    char buffer[MAX_BUFFER];

    printf("请输入要添加的好友用户名: ");
    if (scanf("%49s", friend_name) != 1) {
        getchar();
        printf("输入无效\n");
        return;
    }
    getchar();

    snprintf(buffer, MAX_BUFFER, "ADDFRIEND %d %s", current_user_index, friend_name);
    
    // 设置发送超时
    struct timeval tv;
    tv.tv_sec = 5;
    tv.tv_usec = 0;
    setsockopt(client_socket, SOL_SOCKET, SO_SNDTIMEO, (const char*)&tv, sizeof tv);
    
    if (send(client_socket, buffer, MAX_BUFFER, 0) <= 0) {
        printf("发送请求失败\n");
        return;
    }
    
    printf("添加好友请求已发送，等待服务器响应...\n");
}

void remove_friend() {
    char buffer[MAX_BUFFER];
    
    get_friends_list();
    usleep(100000); // 等待好友列表更新
    
    if (friend_count == 0) {
        printf("您还没有好友！\n");
        return;
    }

    display_friends_list();
    printf("请输入要删除的好友编号: ");
    int choice;
    if (scanf("%d", &choice) != 1) {
        getchar();
        printf("输入无效！\n");
        return;
    }
    getchar();

    if (choice < 1 || choice > friend_count) {
        printf("无效的选择！\n");
        return;
    }

    // 设置发送超时
    struct timeval tv;
    tv.tv_sec = 5;
    tv.tv_usec = 0;
    setsockopt(client_socket, SOL_SOCKET, SO_SNDTIMEO, (const char*)&tv, sizeof tv);
    
    snprintf(buffer, MAX_BUFFER, "REMOVEFRIEND %d %s", 
             current_user_index, 
             friends[choice - 1].username);
             
    if (send(client_socket, buffer, MAX_BUFFER, 0) <= 0) {
        printf("发送请求失败\n");
        return;
    }
    
    printf("删除好友请求已发送，等待服务器响应...\n");
}

void logout() {
    if (current_user_index != -1) {
        char buffer[MAX_BUFFER];
        snprintf(buffer, MAX_BUFFER, "LOGOUT");
        send(client_socket, buffer, MAX_BUFFER, 0);
        current_user_index = -1;
        printf("已退出登录\n");
    }
}