package com.label.service;

import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.label.common.exception.BusinessException;
import com.label.common.shiro.TokenPrincipal;
import com.label.common.statemachine.StateValidator;
import com.label.common.statemachine.TaskStatus;
import com.label.entity.TrainingDataset;
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.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

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

/**
 * 问答生成阶段标注服务：查询候选问答对、更新、提交、审批、驳回。
 *
 * 关键设计：
 * - QA 阶段无 AI 调用（候选问答对已由 ExtractionApprovedEventListener 生成）
 * - approve() 同一事务内完成：training_dataset → APPROVED、task → APPROVED、source_data → APPROVED
 * - reject() 清除候选问答对（deleteByTaskId），source_data 保持 QA_REVIEW 状态
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class QaService {

    private final AnnotationTaskMapper taskMapper;
    private final TrainingDatasetMapper datasetMapper;
    private final SourceDataMapper sourceDataMapper;
    private final TaskClaimService taskClaimService;
    private final ObjectMapper objectMapper;

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

    /**
     * 获取候选问答对（从 training_dataset.glm_format_json 解析）。
     */
    public Map<String, Object> getResult(Long taskId, TokenPrincipal principal) {
        AnnotationTask task = validateAndGetTask(taskId, principal.getCompanyId());
        TrainingDataset dataset = getDataset(taskId);

        SourceData source = sourceDataMapper.selectById(task.getSourceId());
        String sourceType = source != null ? source.getDataType() : "TEXT";

        List<?> items = Collections.emptyList();
        if (dataset != null && dataset.getGlmFormatJson() != null) {
            try {
                @SuppressWarnings("unchecked")
                Map<String, Object> parsed = objectMapper.readValue(dataset.getGlmFormatJson(), Map.class);
                Object conversations = parsed.get("conversations");
                if (conversations instanceof List) {
                    items = (List<?>) conversations;
                }
            } catch (Exception e) {
                log.warn("解析 QA JSON 失败（taskId={}）：{}", taskId, e.getMessage());
            }
        }

        return Map.of(
                "taskId", taskId,
                "sourceType", sourceType,
                "items", items
        );
    }

    // ------------------------------------------------------------------ 更新 --

    /**
     * 整体覆盖问答对（PUT 语义）。
     *
     * @param taskId    任务 ID
     * @param body      包含 items 数组的 JSON，格式：{"items": [...]}
     * @param principal 当前用户
     */
    @Transactional
    public void updateResult(Long taskId, String body, TokenPrincipal principal) {
        validateAndGetTask(taskId, principal.getCompanyId());

        // 校验 JSON 格式
        try {
            objectMapper.readTree(body);
        } catch (Exception e) {
            throw new BusinessException("INVALID_JSON", "请求体 JSON 格式不合法", HttpStatus.BAD_REQUEST);
        }

        // 将 items 格式包装为 GLM 格式：{"conversations": items}
        String glmJson;
        try {
            @SuppressWarnings("unchecked")
            Map<String, Object> parsed = objectMapper.readValue(body, Map.class);
            Object items = parsed.getOrDefault("items", Collections.emptyList());
            glmJson = objectMapper.writeValueAsString(Map.of("conversations", items));
        } catch (Exception e) {
            glmJson = "{\"conversations\":[]}";
        }

        TrainingDataset dataset = getDataset(taskId);
        if (dataset != null) {
            datasetMapper.update(null, new LambdaUpdateWrapper<TrainingDataset>()
                    .eq(TrainingDataset::getTaskId, taskId)
                    .set(TrainingDataset::getGlmFormatJson, glmJson)
                    .set(TrainingDataset::getUpdatedAt, LocalDateTime.now()));
        } else {
            // 若 training_dataset 不存在（异常情况），自动创建
            TrainingDataset newDataset = new TrainingDataset();
            newDataset.setCompanyId(principal.getCompanyId());
            newDataset.setTaskId(taskId);
            AnnotationTask task = taskMapper.selectById(taskId);
            newDataset.setSourceId(task.getSourceId());
            newDataset.setSampleType("TEXT");
            newDataset.setGlmFormatJson(glmJson);
            newDataset.setStatus("PENDING_REVIEW");
            datasetMapper.insert(newDataset);
        }
    }

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

    /**
     * 提交 QA 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）。
     *
     * 同一事务：
     * 1. 校验任务（先于一切 DB 写入）
     * 2. 自审校验
     * 3. StateValidator
     * 4. training_dataset → APPROVED
     * 5. annotation_task → APPROVED + is_final=true + completedAt
     * 6. source_data → APPROVED（整条流水线完成）
     * 7. 写任务历史
     */
    @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);

        // training_dataset → APPROVED
        datasetMapper.approveByTaskId(taskId, principal.getCompanyId());

        // annotation_task → APPROVED + is_final=true
        taskMapper.update(null, new LambdaUpdateWrapper<AnnotationTask>()
                .eq(AnnotationTask::getId, taskId)
                .set(AnnotationTask::getStatus, "APPROVED")
                .set(AnnotationTask::getIsFinal, true)
                .set(AnnotationTask::getCompletedAt, LocalDateTime.now()));

        // source_data → APPROVED（整条流水线终态）
        sourceDataMapper.updateStatus(task.getSourceId(), "APPROVED", principal.getCompanyId());

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

        log.info("QA 审批通过，整条流水线完成: taskId={}, sourceId={}", taskId, task.getSourceId());
    }

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

    /**
     * 驳回 QA 结果（SUBMITTED → REJECTED）。
     *
     * 清除候选问答对（deleteByTaskId），source_data 保持 QA_REVIEW 状态不变。
     */
    @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);

        // 清除候选问答对
        datasetMapper.deleteByTaskId(taskId, principal.getCompanyId());

        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);
    }

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

    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 TrainingDataset getDataset(Long taskId) {
        return datasetMapper.selectOne(
                new com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper<TrainingDataset>()
                        .eq(TrainingDataset::getTaskId, taskId)
                        .last("LIMIT 1"));
    }
}