package com.labelsys.backend.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.labelsys.backend.common.ResultCode;
import com.labelsys.backend.common.exception.BusinessException;
import com.labelsys.backend.context.LoginUser;
import com.labelsys.backend.dto.common.PageResult;
import com.labelsys.backend.dto.request.AnnotationResultPageQuery;
import com.labelsys.backend.dto.request.MergeReviewResultRequest;
import com.labelsys.backend.dto.response.AnnotationResultCompareResponse;
import com.labelsys.backend.dto.response.AnnotationResultResponse;
import com.labelsys.backend.entity.AnnotationResult;
import com.labelsys.backend.entity.AnnotationResultHistory;
import com.labelsys.backend.entity.SourceResource;
import com.labelsys.backend.enums.AnnotationResultStatus;
import com.labelsys.backend.enums.UserRole;
import com.labelsys.backend.mapper.AnnotationResultHistoryMapper;
import com.labelsys.backend.mapper.AnnotationResultMapper;
import com.labelsys.backend.mapper.SourceResourceMapper;
import com.labelsys.backend.util.IdGenerator;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

import java.nio.charset.StandardCharsets;
import java.time.LocalDateTime;
import java.util.List;

@Slf4j
@Service
@RequiredArgsConstructor
public class AnnotationResultService {

    private final AnnotationResultMapper        annotationResultMapper;
    private final AnnotationResultHistoryMapper annotationResultHistoryMapper;
    private final SourceResourceMapper          sourceResourceMapper;
    private final DataPermissionService         dataPermissionService;
    private final ObjectStorageService          objectStorageService;
    private final ObjectMapper                  objectMapper;

    public PageResult<AnnotationResultResponse> pageResults(LoginUser currentUser, AnnotationResultPageQuery query) {
        List<String> allowedRoles = dataPermissionService.getAllowedRoles(currentUser);
        boolean shouldFilterByUserId = dataPermissionService.shouldFilterByUserId(currentUser);

        var wrapper = new LambdaQueryWrapper<AnnotationResult>()
                .eq(AnnotationResult::getCompanyId, currentUser.companyId())
                .eq(query.taskId() != null, AnnotationResult::getTaskId, query.taskId())
                .eq(query.resourceId() != null, AnnotationResult::getResourceId, query.resourceId())
                .eq(query.requiresManualReview() != null, AnnotationResult::getRequiresManualReview,
                        query.requiresManualReview())
                .orderByDesc(AnnotationResult::getCreatedAt);

        if (shouldFilterByUserId) {
            wrapper.eq(AnnotationResult::getCreatorId, currentUser.userId());
        } else if (!allowedRoles.isEmpty()) {
            wrapper.in(AnnotationResult::getCreatorRole, allowedRoles);
        }

        var page = new Page<AnnotationResult>(query.pageNo(), query.pageSize());
        var resultPage = annotationResultMapper.selectPage(page, wrapper);

        var records = resultPage.getRecords().stream()
                .map(this::toResponse)
                .filter(response -> query.runtimeStatus() == null
                        || query.runtimeStatus().equals(response.runtimeStatus()))
                .toList();

        return new PageResult<>(records, resultPage.getTotal(), (int) resultPage.getCurrent(),
                (int) resultPage.getSize());
    }

    public AnnotationResultResponse getResult(LoginUser currentUser, Long resultId) {
        AnnotationResult result = annotationResultMapper.findActiveByIdAndCompanyId(resultId, currentUser.companyId());
        if (result == null) {
            log.warn("Result not found or cross-tenant access attempt: resultId={}, companyId={}, userId={}", resultId,
                    currentUser.companyId(), currentUser.userId());
            throw new BusinessException(ResultCode.NOT_FOUND, "结果不存在");
        }
        //assertResultPermission(currentUser, result);
        return toResponse(result);
    }

    public AnnotationResultCompareResponse compareResult(LoginUser currentUser, Long resultId) {
        AnnotationResult result = annotationResultMapper.findActiveByIdAndCompanyId(resultId, currentUser.companyId());
        if (result == null) {
            log.warn("Result not found or cross-tenant access attempt: resultId={}, companyId={}, userId={}", resultId,
                    currentUser.companyId(), currentUser.userId());
            throw new BusinessException(ResultCode.NOT_FOUND, "结果不存在");
        }
        //assertResultPermission(currentUser, result);

        QaContent qaContent = loadQaContent(result);
        DiffContent diffContent = StringUtils.hasText(result.getDiffSummaryFilePath()) ?
                loadDiffSummary(result) : null;

        SourceResource resource = sourceResourceMapper.selectById(result.getResourceId());

        // 转换 QA 记录
        List<AnnotationResultCompareResponse.QaRecord> qaRecords = qaContent.records().stream()
                .map(qa -> new AnnotationResultCompareResponse.QaRecord(
                        qa.id(),
                        qa.question(),
                        qa.answer(),
                        qa.requiresReview()
                )).toList();

        // 转换差异记录
        List<AnnotationResultCompareResponse.DiffRecord> diffRecords = diffContent != null ?
                diffContent.records().stream()
                .map(diff -> new AnnotationResultCompareResponse.DiffRecord(
                        diff.qaId(),
                        diff.question(),
                        diff.extractAnswer(),
                        diff.verifyAnswer(),
                        diff.diffReason(),
                        diff.mergedAnswer()
                )).toList() : List.of();

        return new AnnotationResultCompareResponse(
                result.getId(),
                result.getTaskId(),
                result.getResourceId(),
                qaRecords,
                diffRecords,
                resource == null ? null : resource.getFilePath()
        );
    }

    @Transactional
    public void mergeReviewResult(LoginUser currentUser, Long resultId, MergeReviewResultRequest request) {
        AnnotationResult result = annotationResultMapper.findActiveByIdAndCompanyId(resultId, currentUser.companyId());
        if (result == null) {
            throw new BusinessException(ResultCode.NOT_FOUND, "结果不存在");
        }
        //assertResultPermission(currentUser, result);

        // 读取当前 qa.json
        QaContent qaContent = loadQaContent(result);

        // 更新 qa.json 的 answer 字段
        List<QaContent.QaRecord> updatedQaRecords = qaContent.records().stream()
                .map(record -> {
                    String mergedAnswer = request.mergedAnswers().get(record.id());
                    if (mergedAnswer != null) {
                        return new QaContent.QaRecord(
                                record.id(),
                                record.question(),
                                mergedAnswer,
                                false
                        );
                    }
                    return record;
                })
                .toList();

        QaContent updatedQaContent = new QaContent(
                qaContent.taskId(),
                qaContent.resourceId(),
                updatedQaRecords,
                new QaContent.Metadata(
                        qaContent.metadata().createdAt(),
                        LocalDateTime.now().toString()
                )
        );
        saveQaContent(result, updatedQaContent);

        // 更新数据库记录
        result.setReviewerId(currentUser.userId());
        result.setReviewComment(request.reviewComment());
        result.setReviewedAt(LocalDateTime.now());
        result.setRequiresManualReview(false);
        annotationResultMapper.updateById(result);

        // 归档到历史表
        archiveToHistory(result, currentUser, "审核通过后归档");

        log.info("merged review result, companyId={}, userId={}, resultId={}",
                currentUser.companyId(), currentUser.userId(), resultId);
    }

    private AnnotationResultResponse toResponse(AnnotationResult result) {
        return new AnnotationResultResponse(
                result.getId(),
                result.getTaskId(),
                result.getResourceId(),
                deriveStatus(result),
                result.getRequiresManualReview(),
                result.getIsDeleted(),
                result.getQaContentFilePath(),
                result.getDiffSummaryFilePath(),
                result.getReviewComment(),
                result.getReviewedAt(),
                result.getCreatedAt()
        );
    }

    private AnnotationResultStatus deriveStatus(AnnotationResult result) {
        if (Boolean.TRUE.equals(result.getIsDeleted())) {
            return AnnotationResultStatus.ARCHIVED;
        }
        if (Boolean.TRUE.equals(result.getRequiresManualReview())) {
            return AnnotationResultStatus.MANUAL_REVIEW_PENDING;
        }
        return AnnotationResultStatus.AUTO_ARCHIVE_PENDING;
    }

    private QaContent loadQaContent(AnnotationResult result) {
        try {
            String filePath = result.getQaContentFilePath();
            String bucketName = extractBucketName(filePath);
            String objectKey = extractObjectKey(filePath);
            byte[] content = objectStorageService.download(bucketName, objectKey);
            String jsonContent = new String(content, StandardCharsets.UTF_8);
            return objectMapper.readValue(jsonContent, new TypeReference<QaContent>() {
            });
        } catch (Exception e) {
            log.error("Failed to load qa content, resultId={}, filePath={}", result.getId(),
                    result.getQaContentFilePath(), e);
            throw new BusinessException(ResultCode.ERROR, "加载问答内容失败");
        }
    }

    private DiffContent loadDiffSummary(AnnotationResult result) {
        try {
            String filePath = result.getDiffSummaryFilePath();
            String bucketName = extractBucketName(filePath);
            String objectKey = extractObjectKey(filePath);
            byte[] content = objectStorageService.download(bucketName, objectKey);
            String jsonContent = new String(content, StandardCharsets.UTF_8);
            return objectMapper.readValue(jsonContent, new TypeReference<DiffContent>() {
            });
        } catch (Exception e) {
            log.error("Failed to load diff summary, resultId={}, filePath={}", result.getId(),
                    result.getDiffSummaryFilePath(), e);
            throw new BusinessException(ResultCode.ERROR, "加载差异摘要失败");
        }
    }

    private void saveQaContent(AnnotationResult result, QaContent qaContent) {
        try {
            String jsonContent = objectMapper.writeValueAsString(qaContent);
            String filePath = result.getQaContentFilePath();
            String bucketName = extractBucketName(filePath);
            String objectKey = extractObjectKey(filePath);
            objectStorageService.upload(bucketName, objectKey, jsonContent.getBytes(StandardCharsets.UTF_8),
                    "application/json");
        } catch (Exception e) {
            log.error("Failed to save qa content, resultId={}", result.getId(), e);
            throw new BusinessException(ResultCode.ERROR, "保存问答内容失败");
        }
    }

    private void assertResultPermission(LoginUser currentUser, AnnotationResult result) {
        if (!dataPermissionService.canAccessCreator(currentUser, result.getCreatorId(),
                UserRole.valueOf(result.getCreatorRole()))) {
            throw new BusinessException(ResultCode.FORBIDDEN, "无权访问该标注结果");
        }
    }

    private void archiveToHistory(AnnotationResult result, LoginUser currentUser, String archiveReason) {
        try {
            // 读取 qa.json 内容用于归档
            QaContent qaContent = loadQaContent(result);

            // 构建归档记录
            AnnotationResultHistory history = AnnotationResultHistory.builder()
                    .id(IdGenerator.nextId())
                    .companyId(result.getCompanyId())
                    .creatorId(currentUser.userId())
                    .creatorRole(currentUser.role().name())
                    .sourceResultId(result.getId())
                    .taskId(result.getTaskId())
                    .resourceId(result.getResourceId())
                    //.qaContentJson(objectMapper.writeValueAsString(qaContent))
                    .qaContentFilePath(result.getQaContentFilePath())
                    .archiveReason(archiveReason)
                    .archivedBy(currentUser.userId())
                    .archivedAt(LocalDateTime.now())
                    .createdAt(LocalDateTime.now())
                    .build();

            annotationResultHistoryMapper.insert(history);

            log.info("archived result to history, resultId={}, historyId={}", result.getId(), history.getId());
        } catch (Exception e) {
            log.error("Failed to archive result to history, resultId={}", result.getId(), e);
            throw new BusinessException(ResultCode.ERROR, "归档失败");
        }
    }

    private String extractBucketName(String filePath) {
        // 从文件路径中提取 bucket 名称
        // 例如：annotation-results/2/qa/801.json -> annotation-results
        int firstSlash = filePath.indexOf('/');
        return firstSlash > 0 ? filePath.substring(0, firstSlash) : filePath;
    }

    private String extractObjectKey(String filePath) {
        // 从文件路径中提取 object key
        // 例如：annotation-results/2/qa/801.json -> 2/qa/801.json
        int firstSlash = filePath.indexOf('/');
        return firstSlash > 0 ? filePath.substring(firstSlash + 1) : "";
    }

    // 内部类：qa.json 结构
    private record QaContent(
            Long taskId,
            Long resourceId,
            List<QaRecord> records,
            Metadata metadata
    ) {
        private record QaRecord(String id, String question, String answer, Boolean requiresReview) {
        }

        private record Metadata(String createdAt, String updatedAt) {
        }
    }

    // 内部类：diff.json 结构
    private record DiffContent(
            Long taskId,
            Long resourceId,
            List<DiffRecord> records,
            Metadata metadata
    ) {
        private record DiffRecord(String qaId, String question, String extractAnswer,
                                  String verifyAnswer, String diffReason, String mergedAnswer) {
        }

        private record Metadata(String createdAt) {
        }
    }
}