package com.example.livestreaming;

import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.text.TextUtils;
import android.view.KeyEvent;
import android.view.MenuItem;
import android.view.View;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.PopupMenu;
import androidx.recyclerview.widget.LinearLayoutManager;

import com.example.livestreaming.databinding.ActivityConversationBinding;
import com.google.android.material.snackbar.Snackbar;

import java.util.ArrayList;
import java.util.List;

public class ConversationActivity extends AppCompatActivity {

    private static final String EXTRA_CONVERSATION_ID = "extra_conversation_id";
    private static final String EXTRA_CONVERSATION_TITLE = "extra_conversation_title";

    private ActivityConversationBinding binding;

    private ConversationMessagesAdapter adapter;
    private final List<ChatMessage> messages = new ArrayList<>();
    private Handler handler;
    private Runnable statusUpdateRunnable;

    public static void start(Context context, String conversationId, String title) {
        Intent intent = new Intent(context, ConversationActivity.class);
        intent.putExtra(EXTRA_CONVERSATION_ID, conversationId);
        intent.putExtra(EXTRA_CONVERSATION_TITLE, title);
        context.startActivity(intent);
    }

    private static final String EXTRA_UNREAD_COUNT = "extra_unread_count";
    
    private int initialUnreadCount = 0;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityConversationBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        handler = new Handler(Looper.getMainLooper());

        String title = getIntent() != null ? getIntent().getStringExtra(EXTRA_CONVERSATION_TITLE) : null;
        binding.titleText.setText(title != null ? title : "会话");
        
        // 获取该会话的初始未读数量
        initialUnreadCount = getIntent() != null ? getIntent().getIntExtra(EXTRA_UNREAD_COUNT, 0) : 0;

        binding.backButton.setOnClickListener(v -> finish());

        setupMessages();
        setupInput();
        
        // TODO: 接入后端接口 - 标记会话消息为已读
        // 接口路径: POST /api/conversations/{conversationId}/read
        // 请求参数:
        //   - conversationId: 会话ID（路径参数）
        //   - userId: 当前用户ID（从token中获取）
        // 返回数据格式: ApiResponse<{success: boolean}>
        // 用户进入会话时，标记该会话的所有消息为已读，减少未读数量
        if (initialUnreadCount > 0) {
            UnreadMessageManager.decrementUnreadCount(this, initialUnreadCount);
        }
    }
    
    @Override
    protected void onPause() {
        super.onPause();
        // 当用户离开会话时，更新总未读数量（如果会话未读数量已减少）
    }

    private void setupMessages() {
        adapter = new ConversationMessagesAdapter();
        
        // 设置长按监听
        adapter.setOnMessageLongClickListener((message, position, view) -> {
            showMessageMenu(message, position, view);
        });

        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setStackFromEnd(false);
        binding.messagesRecyclerView.setLayoutManager(layoutManager);
        binding.messagesRecyclerView.setAdapter(adapter);

        // TODO: 接入后端接口 - 获取会话消息列表
        // 接口路径: GET /api/conversations/{conversationId}/messages
        // 请求参数:
        //   - conversationId: 会话ID（路径参数）
        //   - page (可选): 页码，用于分页加载历史消息
        //   - pageSize (可选): 每页数量，默认20
        //   - beforeMessageId (可选): 获取指定消息ID之前的消息，用于上拉加载更多
        // 返回数据格式: ApiResponse<List<ChatMessage>>
        // ChatMessage对象应包含: messageId, userId, username, avatarUrl, message, timestamp, status等字段
        // 消息列表应按时间正序排列（最早的在前面）
        messages.clear();
        String title = binding.titleText.getText() != null ? binding.titleText.getText().toString() : "";
        ChatMessage incomingMsg = new ChatMessage(title, "你好～");
        incomingMsg.setStatus(ChatMessage.MessageStatus.SENT);
        messages.add(incomingMsg);
        
        ChatMessage outgoingMsg = new ChatMessage("我", "在的，有什么需要帮忙？");
        outgoingMsg.setStatus(ChatMessage.MessageStatus.READ);
        messages.add(outgoingMsg);
        
        adapter.submitList(new ArrayList<>(messages));
        scrollToBottom();
    }
    
    private void showMessageMenu(ChatMessage message, int position, View anchorView) {
        PopupMenu popupMenu = new PopupMenu(this, anchorView);
        popupMenu.getMenu().add(0, 0, 0, "复制");
        popupMenu.getMenu().add(0, 1, 0, "删除");
        
        popupMenu.setOnMenuItemClickListener(item -> {
            if (item.getItemId() == 0) {
                // 复制消息
                copyMessage(message);
                return true;
            } else if (item.getItemId() == 1) {
                // 删除消息
                deleteMessage(position);
                return true;
            }
            return false;
        });
        
        popupMenu.show();
    }
    
    private void copyMessage(ChatMessage message) {
        ClipboardManager clipboard = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
        ClipData clip = ClipData.newPlainText("消息", message.getMessage());
        clipboard.setPrimaryClip(clip);
        Snackbar.make(binding.getRoot(), "已复制到剪贴板", Snackbar.LENGTH_SHORT).show();
    }
    
    private void deleteMessage(int position) {
        // TODO: 接入后端接口 - 删除消息
        // 接口路径: DELETE /api/messages/{messageId}
        // 请求参数:
        //   - messageId: 消息ID（路径参数）
        //   - userId: 当前用户ID（从token中获取，验证是否为消息发送者）
        // 返回数据格式: ApiResponse<{success: boolean}>
        // 删除成功后，从本地消息列表移除
        if (position < 0 || position >= messages.size()) return;
        
        new AlertDialog.Builder(this)
                .setTitle("删除消息")
                .setMessage("确定要删除这条消息吗？")
                .setPositiveButton("删除", (dialog, which) -> {
                    messages.remove(position);
                    adapter.submitList(new ArrayList<>(messages));
                    Snackbar.make(binding.getRoot(), "消息已删除", Snackbar.LENGTH_SHORT).show();
                })
                .setNegativeButton("取消", null)
                .show();
    }

    private void setupInput() {
        binding.sendButton.setOnClickListener(v -> sendMessage());

        binding.messageInput.setOnEditorActionListener((v, actionId, event) -> {
            if (event != null && event.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
                sendMessage();
                return true;
            }
            return false;
        });

        binding.messageInput.setOnFocusChangeListener((v, hasFocus) -> {
            if (hasFocus) scrollToBottom();
        });
    }

    private void sendMessage() {
        // 检查登录状态，发送私信需要登录
        if (!AuthHelper.requireLoginWithToast(this, "发送私信需要登录")) {
            return;
        }
        
        // TODO: 接入后端接口 - 发送私信消息
        // 接口路径: POST /api/conversations/{conversationId}/messages
        // 请求参数:
        //   - conversationId: 会话ID（路径参数）
        //   - message: 消息内容
        //   - userId: 发送者用户ID（从token中获取）
        // 返回数据格式: ApiResponse<ChatMessage>
        // ChatMessage对象应包含: messageId, userId, username, avatarUrl, message, timestamp, status等字段
        // 发送成功后，更新消息状态为SENT，并添加到消息列表
        // TODO: 接入后端接口 - 接收对方已读状态（WebSocket或轮询）
        // 方案1: WebSocket实时推送
        //   - 连接: ws://api.example.com/conversations/{conversationId}
        //   - 接收消息格式: {type: "read", messageId: "xxx"} 或 {type: "new_message", data: ChatMessage}
        // 方案2: 轮询检查消息状态
        //   - 接口路径: GET /api/conversations/{conversationId}/messages/{messageId}/status
        //   - 返回数据格式: ApiResponse<{status: "sent"|"read"}>
        String text = binding.messageInput.getText() != null ? binding.messageInput.getText().toString().trim() : "";
        if (TextUtils.isEmpty(text)) return;

        ChatMessage newMessage = new ChatMessage("我", text);
        newMessage.setStatus(ChatMessage.MessageStatus.SENDING);
        messages.add(newMessage);
        adapter.submitList(new ArrayList<>(messages));
        binding.messageInput.setText("");
        scrollToBottom();
        
        // 模拟消息发送过程：发送中 -> 已发送 -> 已读
        if (statusUpdateRunnable != null) {
            handler.removeCallbacks(statusUpdateRunnable);
        }
        
        statusUpdateRunnable = () -> {
            // 1秒后更新为已发送
            newMessage.setStatus(ChatMessage.MessageStatus.SENT);
            adapter.notifyItemChanged(messages.size() - 1);
            
            // 再2秒后更新为已读
            handler.postDelayed(() -> {
                newMessage.setStatus(ChatMessage.MessageStatus.READ);
                adapter.notifyItemChanged(messages.size() - 1);
            }, 2000);
        };
        
        handler.postDelayed(statusUpdateRunnable, 1000);
    }

    private void scrollToBottom() {
        if (messages.isEmpty()) return;
        binding.messagesRecyclerView.post(() -> {
            int lastPosition = messages.size() - 1;
            if (lastPosition >= 0) {
                binding.messagesRecyclerView.smoothScrollToPosition(lastPosition);
            }
        });
    }
    
    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 清理Handler中的延迟任务，防止内存泄漏
        if (handler != null && statusUpdateRunnable != null) {
            handler.removeCallbacks(statusUpdateRunnable);
        }
        handler = null;
        statusUpdateRunnable = null;
    }
}