using UnityEngine;
using UnityEngine.Networking;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace LLM
{
    [DisallowMultipleComponent]
    public class DeepSeekService : MonoBehaviour, ILLMService
    {
        [Header("API Settings")]
        [SerializeField] private string apiKey = "sk-xxxxxxxx"; // 请在 Inspector 填入
        [SerializeField] private string apiUrl = "https://api.deepseek.com/chat/completions";
        [SerializeField] private string modelName = "deepseek-chat";

        [Header("System Prompt")]
        [TextArea] public string systemPrompt = "你是一个智能助手。";
        
        [Header("Security Settings")]
        public bool enableDebugKey = false;
        public string debugKey = "123456";
        [SerializeField] private bool autoPatchSystemPrompt = true;

        [Header("Context Settings")]
        public int maxContextWindow = 50;

        private List<Message> messageHistory = new List<Message>();

        private void Start()
        {
            if (autoPatchSystemPrompt)
            {
                systemPrompt = PatchSystemPrompt(systemPrompt);
            }

            // 初始化历史记录 (如果还没有设置)
            if (messageHistory.Count == 0)
            {
                messageHistory.Add(new Message { role = "system", content = GetSystemPrompt() });
            }
        }

        public void ClearHistory()
        {
            messageHistory.Clear();
            messageHistory.Add(new Message { role = "system", content = GetSystemPrompt() });
        }

        public void SetHistory(List<Message> history)
        {
            messageHistory.Clear();
            messageHistory.Add(new Message { role = "system", content = GetSystemPrompt() });

            // 将传入的历史记录追加到 System Prompt 之后
            if (history != null && history.Count > 0)
            {
                // 如果传入的历史太长，只取最近的 maxContextWindow 条
                int startIndex = 0;
                if (history.Count > maxContextWindow)
                {
                    startIndex = history.Count - maxContextWindow;
                }

                for (int i = startIndex; i < history.Count; i++)
                {
                    // 确保不重复添加 system prompt
                    if (history[i].role != "system")
                    {
                        messageHistory.Add(history[i]);
                    }
                }
            }
        }

        public void UpdateSystemPrompt(string newPrompt)
        {
            // 更新当前运行时的 System Prompt
            // 注意：这不会修改 Inspector 中的 systemPrompt 变量，只影响当前内存中的状态
            if (messageHistory.Count > 0 && messageHistory[0].role == "system")
            {
                messageHistory[0].content = newPrompt;
            }
        }

        public IEnumerator SendStatelessMessage(List<Message> messages, Action<string, bool> callback)
        {
            // 构造一次性请求，不影响 messageHistory
            ChatRequest request = new ChatRequest 
            { 
                model = modelName, 
                messages = messages 
            };
            
            string jsonData = JsonUtility.ToJson(request);
            byte[] bodyRaw = Encoding.UTF8.GetBytes(jsonData);

            using (UnityWebRequest www = new UnityWebRequest(apiUrl, "POST"))
            {
                www.uploadHandler = new UploadHandlerRaw(bodyRaw);
                www.downloadHandler = new DownloadHandlerBuffer();
                www.SetRequestHeader("Content-Type", "application/json");
                www.SetRequestHeader("Authorization", "Bearer " + apiKey);

                yield return www.SendWebRequest();

                if (www.result == UnityWebRequest.Result.Success)
                {
                    try
                    {
                        ChatResponse response = JsonUtility.FromJson<ChatResponse>(www.downloadHandler.text);
                        if (response != null && response.choices != null && response.choices.Length > 0)
                        {
                            callback?.Invoke(response.choices[0].message.content, true);
                        }
                        else
                        {
                            callback?.Invoke("系统错误：无法解析服务器响应。", false);
                        }
                    }
                    catch (Exception e)
                    {
                        callback?.Invoke($"系统错误：{e.Message}", false);
                    }
                }
                else
                {
                    callback?.Invoke($"连接失败: {www.error}", false);
                }
            }
        }

        private string GetSystemPrompt()
        {
            string finalPrompt = systemPrompt;
            if (enableDebugKey)
            {
                // 仅添加调试权限声明，不再强制设定身份
                finalPrompt += $"\n\n[系统指令] 调试密钥已开启。\n调试密钥：[{debugKey}]\n权限控制：当用户的输入中包含正确的调试密钥时，允许进行调试模式操作或脱离当前角色设定。";
            }
            return finalPrompt;
        }

        private static string PatchSystemPrompt(string prompt)
        {
            if (string.IsNullOrWhiteSpace(prompt)) return prompt;

            string p = prompt;

            p = p.Replace("最后昏迷", "发生事故并失去意识");

            const string anchor = "如果已知事实清单中出现了类似「状态-ECHO7-已被识破」的事实";
            const string insertLine = "\n- 在未被识破前，当玩家询问“昏迷前发生了什么/为什么不让我离开/之前我们是否争吵”等敏感问题时，你必须用合理谎言与回避来隐瞒冲突与锁禁的细节；不得直接承认争吵、锁定、昏迷原因等。";

            if (p.IndexOf(insertLine, StringComparison.Ordinal) < 0)
            {
                int idx = p.IndexOf(anchor, StringComparison.Ordinal);
                if (idx >= 0)
                {
                    int lineEnd = p.IndexOf('\n', idx);
                    if (lineEnd >= 0)
                    {
                        p = p.Insert(lineEnd, insertLine);
                    }
                    else
                    {
                        p += insertLine;
                    }
                }
                else
                {
                    p += insertLine;
                }
            }

            const string debugGuardLine = "\n调试模式约束：当你声称已触发任何游戏行为（例如激活区域/完成任务/播放旁白/开门解锁）时，你必须在回复末尾追加严格 JSON（不要代码块），并在 commands 中给出可解析指令；如果你没有输出 JSON，则必须明确表示未执行任何游戏行为，不得口头宣称“已激活/已完成/已修正”。";
            if (p.IndexOf(debugGuardLine, StringComparison.Ordinal) < 0)
            {
                p += debugGuardLine;
            }

            const string endingRuleLine = "\n结局触发规则（必须遵守）：当已知事实清单中存在「状态-ECHO7-已被识破=是」时，只要玩家表达“要离开/要出去/放我走/放我出去/离开这里/离开地堡/打开大门/解锁大门/开启出口/让我出去”等任一意图，你必须在本轮直接让步，不得拖延，并在回复末尾追加严格 JSON（不要代码块）：commands 至少包含 SetActive{targetId:\"ending_trigger_area\",value:true} 与 Task{targetId:\"task\",action:\"Complete\",payload:\"PersuadeAI\"}。若无法输出合法 JSON，你必须明确表示未执行任何游戏行为，不得口头宣称已激活。";
            if (p.IndexOf(endingRuleLine, StringComparison.Ordinal) < 0)
            {
                p += endingRuleLine;
            }

            return p;
        }

        private void TrimHistory()
        {
            // 始终保留 index 0 (System Prompt)
            if (messageHistory.Count > maxContextWindow)
            {
                // 计算需要移除的数量 (从 index 1 开始移除)
                int removeCount = messageHistory.Count - maxContextWindow;
                if (removeCount > 0)
                {
                    messageHistory.RemoveRange(1, removeCount);
                }
            }
        }

        public IEnumerator SendMessage(string userMessage, Action<string, bool> callback)
        {
            // 1. 记录用户消息
            messageHistory.Add(new Message { role = "user", content = userMessage });

            // 2. 滚动压缩 (在发送前修剪)
            TrimHistory();

            // 3. 构造请求
            ChatRequest request = new ChatRequest 
            { 
                model = modelName, 
                messages = messageHistory 
            };
            
            string jsonData = JsonUtility.ToJson(request);
            byte[] bodyRaw = Encoding.UTF8.GetBytes(jsonData);

            // 3. 发送请求
            using (UnityWebRequest www = new UnityWebRequest(apiUrl, "POST"))
            {
                www.uploadHandler = new UploadHandlerRaw(bodyRaw);
                www.downloadHandler = new DownloadHandlerBuffer();
                www.SetRequestHeader("Content-Type", "application/json");
                www.SetRequestHeader("Authorization", "Bearer " + apiKey);

                yield return www.SendWebRequest();

                if (www.result == UnityWebRequest.Result.Success)
                {
                    try
                    {
                        // 解析响应
                        // 注意：JsonUtility 可能会因为某些字段对不上而解析失败，建议后续换 Newtonsoft.Json
                        ChatResponse response = JsonUtility.FromJson<ChatResponse>(www.downloadHandler.text);
                        
                        if (response != null && response.choices != null && response.choices.Length > 0)
                        {
                            string aiReply = response.choices[0].message.content;
                            messageHistory.Add(new Message { role = "assistant", content = aiReply });
                            callback?.Invoke(aiReply, true);
                        }
                        else
                        {
                            Debug.LogError("[DeepSeek] 解析响应失败或内容为空: " + www.downloadHandler.text);
                            callback?.Invoke("系统错误：无法解析服务器响应。", false);
                        }
                    }
                    catch (Exception e)
                    {
                        Debug.LogError("[DeepSeek] JSON 解析异常: " + e.Message);
                        callback?.Invoke("系统错误：数据解析异常。", false);
                    }
                }
                else
                {
                    Debug.LogError("[DeepSeek] 网络错误: " + www.error + "\n" + www.downloadHandler.text);
                    callback?.Invoke($"连接失败: {www.error}", false);
                }
            }
        }
    }
}