package xyz.wbsite.achat.chat;

import org.springframework.util.StringUtils;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

/**
 * 流式对话生成器
 *
 * @author wangbing
 * @version 0.0.1
 * @since 1.8
 */
public class StreamEmitter extends SseEmitter {

    /**
     * 流式输出默认超时时间
     */
    private static final Long DEFAULT_TIMEOUT = 5 * 60 * 1000L;

    /**
     * 对话请求
     */
    private ChatCompletionRequest request;

    /**
     * 当前对话状态
     */
    private Status status;

    /**
     * 当前对话ID
     */
    private String chatId;

    /**
     * 是否完成
     */
    private boolean complete;

    public StreamEmitter(ChatCompletionRequest request) {
        super(DEFAULT_TIMEOUT);
        this.request = request;
    }

//    /**
//     * 错误处理
//     */
//    private void onError(Throwable e) {
////        this.sendMessage(createPartialMessage("</think></think>" + e.getMessage()));
//        this.answer.append("</think></think>" + e.getMessage());
//        this.onCompleteResponse(null);
//    }
//
//    /**
//     * 部分响应处理
//     */
//    public void onPartialResponse(String msg) {
//        if (complete) {
//            return;
//        }
////        this.sendMessage(createPartialMessage(msg));
//        this.answer.append(msg);
//    }

    /**
     * 完成响应处理
     */
    public void onCompleteResponse(Object chatResponse) {
        if (this.complete) {
            return;
        }
        // 推送结束
//        this.sendMessage(createCompleteMessage());
        // 关闭链接
        this.complete();
    }

    /**
     * 重写send方法，处理异常
     */
    @Override
    public void send(SseEventBuilder builder) {
        try {
            super.send(builder);
        } catch (Exception e) {
            complete = true;
        }
    }

    /**
     * 发送片段
     */
    private void pushChunk(ChatCompletionChunk chunk) {
        try {
            this.send(chunk);
        } catch (Exception e) {
            complete = true;
        }
    }

    /**
     * 发送开始片段
     *
     * @param chatId 对话id
     */
    public void onStart(String chatId) {
        if (!StringUtils.hasText(chatId)) {
            throw new IllegalArgumentException("chatId is empty!");
        }
        if (this.status != null) {
            throw new IllegalArgumentException("chunk has been started!");
        }
        ChatCompletionChunk chunk = ChatCompletionChunk.builder()
                .id(chatId)
                .object("chat.completion.chunk")
                .created(System.currentTimeMillis() / 1000)
                .model(request.getModel())
                .withChoices(choices -> {
                    choices.add(ChatCompletionChunk.choiceBuilder().index(0)
                            .role(Role.ASSISTANT)
                            .build());
                })
                .build();
        this.pushChunk(chunk);
        this.status = Status.PENDING;
        this.chatId = chatId;
    }

    /**
     * 发送部分片段
     *
     * @param text 片段内容
     */
    public void onPartial(String text) {
        ChatCompletionChunk chunk = ChatCompletionChunk.builder()
                .id(chatId)
                .object("chat.completion.chunk")
                .created(System.currentTimeMillis() / 1000)
                .model(request.getModel())
                .withChoices(choices -> {
                    choices.add(ChatCompletionChunk.choiceBuilder().index(0)
                            .role(Role.ASSISTANT)
                            .content(text)
                            .build());
                })
                .build();
        this.pushChunk(chunk);
    }

    /**
     * 发送完成信号，根据OpenAI API规范，最后一个片段需要包含finish_reason字段
     */
    public void onComplete() {
        ChatCompletionChunk chunk = ChatCompletionChunk.builder()
                .id(chatId)
                .object("chat.completion.chunk")
                .created(System.currentTimeMillis() / 1000)
                .model(request.getModel())
                .withChoices(choices -> {
                    choices.add(ChatCompletionChunk.choiceBuilder().index(0)
                            .role(Role.ASSISTANT)
                            // 符合OpenAI规范，最后一个片段需要设置finish_reason
                            .finish_reason("stop")
                            .build());
                })
                .build();
        this.pushChunk(chunk);
        this.complete();
        this.status = Status.SUCCESS;
    }

    /**
     * 获取完成状态
     */
    public boolean isComplete() {
        return complete;
    }

    /**
     * 设置完成状态
     */
    public void setComplete(boolean complete) {
        this.complete = complete;
    }
}