package com.label.service;

import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.label.common.ai.AiServiceClient;
import com.label.common.exception.BusinessException;
import com.label.common.auth.TokenPrincipal;
import com.label.common.statemachine.StateValidator;
import com.label.common.statemachine.TaskStatus;
import com.label.entity.AnnotationResult;
import com.label.entity.TrainingDataset;
import com.label.event.ExtractionApprovedEvent;
import com.label.mapper.AnnotationResultMapper;
import com.label.mapper.TrainingDatasetMapper;
import com.label.entity.SourceData;
import com.label.mapper.SourceDataMapper;
import com.label.entity.AnnotationTask;
import com.label.mapper.AnnotationTaskMapper;
import com.label.service.TaskClaimService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.Collections;
import java.util.Map;

/**
 * 提取阶段标注服务：AI 预标注、更新结果、提交、审批、驳回。
 *
 * 关键设计：
 * - approve() 内禁止直接调用 AI，通过 ExtractionApprovedEvent 解耦（AFTER_COMMIT）
 * - 所有写操作包裹在 @Transactional 中，确保任务状态和历史的一致性
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class ExtractionService {

    private final AnnotationTaskMapper taskMapper;
    private final AnnotationResultMapper resultMapper;
    private final TrainingDatasetMapper datasetMapper;
    private final SourceDataMapper sourceDataMapper;
    private final TaskClaimService taskClaimService;
    private final AiServiceClient aiServiceClient;
    private final ApplicationEventPublisher eventPublisher;
    private final ObjectMapper objectMapper;

    @Value("${rustfs.bucket:label-source-data}")
    private String bucket;

    // ------------------------------------------------------------------ AI 预标注 --

    /**
     * AI 辅助预标注：调用 AI 服务，将结果写入 annotation_result。
     * 注：此方法在 @Transactional 外调用（AI 调用不应在事务内），由控制器直接调用。
     */
    public void aiPreAnnotate(Long taskId, TokenPrincipal principal) {
        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());

        SourceData source = sourceDataMapper.selectById(task.getSourceId());
        if (source == null) {
            throw new BusinessException("NOT_FOUND", "关联资料不存在", HttpStatus.NOT_FOUND);
        }

        // 调用 AI 服务（在事务外，避免长时间持有 DB 连接）
        AiServiceClient.ExtractionRequest req = AiServiceClient.ExtractionRequest.builder()
                .sourceId(source.getId())
                .filePath(source.getFilePath())
                .bucket(bucket)
                .build();

        AiServiceClient.ExtractionResponse aiResponse;
        try {
            if ("IMAGE".equals(source.getDataType())) {
                aiResponse = aiServiceClient.extractImage(req);
            } else {
                aiResponse = aiServiceClient.extractText(req);
            }
        } catch (Exception e) {
            log.warn("AI 预标注调用失败（任务 {}）：{}", taskId, e.getMessage());
            // AI 失败不阻塞流程，写入空结果
            aiResponse = new AiServiceClient.ExtractionResponse();
            aiResponse.setItems(Collections.emptyList());
        }

        // 将 AI 结果写入 annotation_result（UPSERT 语义）
        writeOrUpdateResult(taskId, principal.getCompanyId(), aiResponse.getItems());
    }

    // ------------------------------------------------------------------ 更新结果 --

    /**
     * 人工更新标注结果（整体覆盖，PUT 语义）。
     *
     * @param taskId     任务 ID
     * @param resultJson 新的标注结果 JSON 字符串
     * @param principal  当前用户
     */
    @Transactional
    public void updateResult(Long taskId, String resultJson, TokenPrincipal principal) {
        validateAndGetTask(taskId, principal.getCompanyId());

        // 校验 JSON 格式
        try {
            objectMapper.readTree(resultJson);
        } catch (Exception e) {
            throw new BusinessException("INVALID_JSON", "标注结果 JSON 格式不合法", HttpStatus.BAD_REQUEST);
        }

        int updated = resultMapper.updateResultJson(taskId, resultJson, principal.getCompanyId());
        if (updated == 0) {
            // 不存在则新建
            AnnotationResult result = new AnnotationResult();
            result.setTaskId(taskId);
            result.setCompanyId(principal.getCompanyId());
            result.setResultJson(resultJson);
            resultMapper.insert(result);
        }
    }

    // ------------------------------------------------------------------ 提交 --

    /**
     * 提交提取结果（IN_PROGRESS → SUBMITTED）。
     */
    @Transactional
    public void submit(Long taskId, TokenPrincipal principal) {
        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());

        StateValidator.assertTransition(TaskStatus.TRANSITIONS,
                TaskStatus.valueOf(task.getStatus()), TaskStatus.SUBMITTED);

        taskMapper.update(null, new LambdaUpdateWrapper<AnnotationTask>()
                .eq(AnnotationTask::getId, taskId)
                .set(AnnotationTask::getStatus, "SUBMITTED")
                .set(AnnotationTask::getSubmittedAt, LocalDateTime.now()));

        taskClaimService.insertHistory(taskId, principal.getCompanyId(),
                task.getStatus(), "SUBMITTED",
                principal.getUserId(), principal.getRole(), null);
    }

    // ------------------------------------------------------------------ 审批通过 --

    /**
     * 审批通过（SUBMITTED → APPROVED）。
     *
     * 两阶段：
     * 1. 同步事务：is_final=true，状态推进，写历史
     * 2. 事务提交后（AFTER_COMMIT）：AI 生成问答对 → training_dataset → QA 任务 → source_data 状态
     *
     * 注：AI 调用严禁在此事务内执行。
     */
    @Transactional
    public void approve(Long taskId, TokenPrincipal principal) {
        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());

        // 自审校验
        if (principal.getUserId().equals(task.getClaimedBy())) {
            throw new BusinessException("SELF_REVIEW_FORBIDDEN",
                    "不允许审批自己提交的任务", HttpStatus.FORBIDDEN);
        }

        StateValidator.assertTransition(TaskStatus.TRANSITIONS,
                TaskStatus.valueOf(task.getStatus()), TaskStatus.APPROVED);

        // 标记为最终结果
        taskMapper.update(null, new LambdaUpdateWrapper<AnnotationTask>()
                .eq(AnnotationTask::getId, taskId)
                .set(AnnotationTask::getStatus, "APPROVED")
                .set(AnnotationTask::getIsFinal, true)
                .set(AnnotationTask::getCompletedAt, LocalDateTime.now()));

        taskClaimService.insertHistory(taskId, principal.getCompanyId(),
                "SUBMITTED", "APPROVED",
                principal.getUserId(), principal.getRole(), null);

        // 获取资料信息，用于事件
        SourceData source = sourceDataMapper.selectById(task.getSourceId());
        String sourceType = source != null ? source.getDataType() : "TEXT";

        // 发布事件（@TransactionalEventListener(AFTER_COMMIT) 处理 AI 调用）
        eventPublisher.publishEvent(new ExtractionApprovedEvent(
                this, taskId, task.getSourceId(), sourceType,
                principal.getCompanyId(), principal.getUserId()));
    }

    // ------------------------------------------------------------------ 驳回 --

    /**
     * 驳回提取结果（SUBMITTED → REJECTED）。
     */
    @Transactional
    public void reject(Long taskId, String reason, TokenPrincipal principal) {
        if (reason == null || reason.isBlank()) {
            throw new BusinessException("REASON_REQUIRED", "驳回原因不能为空", HttpStatus.BAD_REQUEST);
        }

        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());

        // 自审校验
        if (principal.getUserId().equals(task.getClaimedBy())) {
            throw new BusinessException("SELF_REVIEW_FORBIDDEN",
                    "不允许驳回自己提交的任务", HttpStatus.FORBIDDEN);
        }

        StateValidator.assertTransition(TaskStatus.TRANSITIONS,
                TaskStatus.valueOf(task.getStatus()), TaskStatus.REJECTED);

        taskMapper.update(null, new LambdaUpdateWrapper<AnnotationTask>()
                .eq(AnnotationTask::getId, taskId)
                .set(AnnotationTask::getStatus, "REJECTED")
                .set(AnnotationTask::getRejectReason, reason));

        taskClaimService.insertHistory(taskId, principal.getCompanyId(),
                "SUBMITTED", "REJECTED",
                principal.getUserId(), principal.getRole(), reason);
    }

    // ------------------------------------------------------------------ 查询 --

    /**
     * 获取当前标注结果。
     */
    public Map<String, Object> getResult(Long taskId, TokenPrincipal principal) {
        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());
        AnnotationResult result = resultMapper.selectByTaskId(taskId);
        SourceData source = sourceDataMapper.selectById(task.getSourceId());

        return Map.of(
                "taskId", taskId,
                "sourceType", source != null ? source.getDataType() : "",
                "sourceFilePath", source != null && source.getFilePath() != null ? source.getFilePath() : "",
                "isFinal", task.getIsFinal() != null && task.getIsFinal(),
                "resultJson", result != null ? result.getResultJson() : "[]"
        );
    }

    // ------------------------------------------------------------------ 私有工具 --

    /**
     * 校验任务存在性（多租户自动过滤）。
     */
    private AnnotationTask validateAndGetTask(Long taskId, Long companyId) {
        AnnotationTask task = taskMapper.selectById(taskId);
        if (task == null || !companyId.equals(task.getCompanyId())) {
            throw new BusinessException("NOT_FOUND", "任务不存在: " + taskId, HttpStatus.NOT_FOUND);
        }
        return task;
    }

    private void writeOrUpdateResult(Long taskId, Long companyId, java.util.List<?> items) {
        try {
            String json = objectMapper.writeValueAsString(Map.of("items", items != null ? items : Collections.emptyList()));
            int updated = resultMapper.updateResultJson(taskId, json, companyId);
            if (updated == 0) {
                AnnotationResult result = new AnnotationResult();
                result.setTaskId(taskId);
                result.setCompanyId(companyId);
                result.setResultJson(json);
                resultMapper.insert(result);
            }
        } catch (Exception e) {
            log.error("写入 AI 预标注结果失败: taskId={}", taskId, e);
        }
    }
}