diff --git a/ChatGPT/src/Game.cpp b/ChatGPT/src/Game.cpp
index 8774b9f..f8e0bdb 100644
--- a/ChatGPT/src/Game.cpp
+++ b/ChatGPT/src/Game.cpp
@@ -1,14 +1,17 @@
 #include "../include/Game.h"
+#include "../include/Error.h"
 #include <vector>
 #include <fstream>
 #include <sstream>
 #include <string>
-#include <vector>
+#include <algorithm> // std::shuffle
+#include <random>    // std::default_random_engine
+#include <chrono>    // std::chrono::system_clock
 #include <tuple>
 #include <iostream>
 
-System::Game::Game() {
-    // get data from file
+
+System::Game::Game(){
     try {
         this->stories = readTextFile("ChatGPT/data/stories.txt");
     } catch (std::runtime_error& e) {
@@ -24,11 +27,25 @@ System::Story::~Story() {
     this->choices.clear();
 }
 
-std::vector< int > System::Game::getRandStoryIds(int num) {
-    std::vector< int > ids;
-    for (int i = 0; i < num; i++) {
-        ids.push_back(rand() % this->stories.size());
+std::vector<int> System::Game::getRandStoryIds(int num) {
+    std::vector<int> ids;
+
+    // 創建一個有所有可能索引的向量
+    for (int i = 0; i < this->stories.size(); ++i) {
+        ids.push_back(i);
+    }
+
+    // 使用當前時間作為隨機數生成器的種子
+    unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
+
+    // 打亂向量
+    std::shuffle(ids.begin(), ids.end(), std::default_random_engine(seed));
+
+    // 只保留所需數量的元素
+    if (num < ids.size()) {
+        ids.resize(num);
     }
+
     return ids;
 }
 
@@ -64,4 +81,52 @@ std::vector<System::Story> System::Game::readTextFile(const std::string& filenam
     }
 
     return data;
+}
+
+void System::Game::setOptions(int id, const std::vector< System::Option > &choices) {
+    System::Story* story_ptr = this->getStoryPtrById(id);
+    if (story_ptr == nullptr) {
+        std::cout<<"story_ptr is nullptr"<<std::endl;
+        return;
+    }
+    story_ptr->choices = choices;
+}
+
+void System::Game::printOptions(int id) {
+    System::Story* story_ptr = this->getStoryPtrById(id);
+    if (story_ptr == nullptr) {
+        return;
+    }
+    std::cout << "現在你在" << story_ptr->place << "，" << story_ptr->content << std::endl;
+    for (auto& choice : story_ptr->choices) {
+        std::cout << choice.id << ": " << choice.text << std::endl;
+    }
+}
+
+bool System::Game::setUserChoice(int story_id, const std::string &user_choice_id) {
+    System::Story* story_ptr = this->getStoryPtrById(story_id);
+    if (story_ptr == nullptr) {
+        return false;
+    }
+    for (auto& choice : story_ptr->choices) {
+        if (choice.id == user_choice_id) {
+            story_ptr->user_choice = choice.text;
+            story_ptr->is_answered = true;
+            return true;
+        }
+    }
+    return true;
+}
+
+OpenAI::Message System::Game::generateStoryPrompt(int story_index) {
+    std::string prompt = "";
+    // get previous story
+    if(this->current_count == 0){
+        prompt = "我在" + this->stories[story_index].place + "，我" + this->stories[story_index].content;
+    }else{
+        int previous_id = this->story_ids[story_index - 1];
+        prompt = "我在「" + this->stories[story_index].place + "，" + this->stories[story_index].content + "」";
+    }
+
+    return OpenAI::Message({"user", prompt});
 }
\ No newline at end of file