package com.labelsys.backend.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
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.AnnotationTaskPageQuery;
import com.labelsys.backend.dto.request.CreateAnnotationTaskRequest;
import com.labelsys.backend.dto.request.UpdateAnnotationTaskRequest;
import com.labelsys.backend.dto.response.AnnotationTaskResponse;
import com.labelsys.backend.dto.response.TaskModelConfigResponse;
import com.labelsys.backend.dto.response.TaskPromptConfigResponse;
import com.labelsys.backend.entity.AnnotationTask;
import com.labelsys.backend.entity.AnnotationTaskResource;
import com.labelsys.backend.entity.SourceResource;
import com.labelsys.backend.enums.SourceStatus;
import com.labelsys.backend.enums.TaskStatus;
import com.labelsys.backend.mapper.AnnotationTaskMapper;
import com.labelsys.backend.mapper.AnnotationTaskResourceMapper;
import com.labelsys.backend.mapper.SourceResourceMapper;
import com.labelsys.backend.util.IdGenerator;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

@Slf4j
@Service
@RequiredArgsConstructor
public class AnnotationTaskService {

    private final AnnotationTaskMapper annotationTaskMapper;
    private final AnnotationTaskResourceMapper annotationTaskResourceMapper;
    private final SourceResourceMapper sourceResourceMapper;
    private final SysConfigService sysConfigService;
    private final DataPermissionService dataPermissionService;

    @Transactional
    public AnnotationTaskResponse createTask(LoginUser currentUser, CreateAnnotationTaskRequest request) {
        List<SourceResource> resources = loadAndValidateResources(currentUser, request.resourceIds());
        SysConfigService.ResolvedModelConfig extractModel = sysConfigService.resolveModelConfig(currentUser, request.extractModel());
        SysConfigService.ResolvedModelConfig verifyModel = sysConfigService.resolveModelConfig(currentUser, request.verifyModel());
        SysConfigService.ResolvedPromptConfig extractPrompt = sysConfigService.resolvePromptConfig(currentUser, request.extractPrompt());
        SysConfigService.ResolvedPromptConfig verifyPrompt = sysConfigService.resolvePromptConfig(currentUser, request.verifyPrompt());

        AnnotationTask task = AnnotationTask.builder()
            .id(IdGenerator.nextId())
            .companyId(currentUser.companyId())
            .creatorId(currentUser.userId())
            .creatorRole(currentUser.role())
            .taskName(request.taskName())
            .industryType(defaultIndustryType(request.industryType()))
            .taskType(defaultTaskType(request.taskType()))
            .extractModelConfigId(extractModel.configId())
            .extractModelName(extractModel.modelName())
            .extractModelUrl(extractModel.modelUrl())
            .extractModelApiKey(extractModel.apiKey())
            .verifyModelConfigId(verifyModel.configId())
            .verifyModelName(verifyModel.modelName())
            .verifyModelUrl(verifyModel.modelUrl())
            .verifyModelApiKey(verifyModel.apiKey())
            .extractPromptConfigId(extractPrompt.configId())
            .extractPrompt(extractPrompt.promptText())
            .verifyPromptConfigId(verifyPrompt.configId())
            .verifyPrompt(verifyPrompt.promptText())
            .taskStatus(TaskStatus.PENDING.name())
            .isDeleted(false)
            .build();
        annotationTaskMapper.insert(task);
        saveTaskBindings(task.getId(), currentUser.companyId(), resources);
        log.info("created annotation task, companyId={}, userId={}, taskId={}, resourceCount={}",
            currentUser.companyId(), currentUser.userId(), task.getId(), resources.size());
        return buildTaskResponse(task, resourceIds(resources), extractModel, verifyModel, extractPrompt, verifyPrompt);
    }

    @Transactional
    public AnnotationTaskResponse updateTask(LoginUser currentUser, Long taskId, UpdateAnnotationTaskRequest request) {
        AnnotationTask task = annotationTaskMapper.findByIdAndCompanyId(taskId, currentUser.companyId());
        if (task == null) {
            throw new BusinessException(ResultCode.NOT_FOUND, "任务不存在");
        }
        assertTaskPermission(currentUser, task);

        List<Long> currentResourceIds = normalizeIds(annotationTaskResourceMapper.listResourceIdsByTaskId(taskId));
        List<Long> targetResourceIds = normalizeIds(request.resourceIds());
        boolean resourcesChanged = !currentResourceIds.equals(targetResourceIds);
        if (TaskStatus.RUNNING.name().equals(task.getTaskStatus()) && resourcesChanged) {
            throw new BusinessException(ResultCode.CONFLICT, "运行中的任务不允许修改资源");
        }

        List<SourceResource> resources = loadAndValidateResources(currentUser, request.resourceIds());
        SysConfigService.ResolvedModelConfig extractModel = sysConfigService.resolveModelConfig(currentUser, request.extractModel());
        SysConfigService.ResolvedModelConfig verifyModel = sysConfigService.resolveModelConfig(currentUser, request.verifyModel());
        SysConfigService.ResolvedPromptConfig extractPrompt = sysConfigService.resolvePromptConfig(currentUser, request.extractPrompt());
        SysConfigService.ResolvedPromptConfig verifyPrompt = sysConfigService.resolvePromptConfig(currentUser, request.verifyPrompt());

        task.setIndustryType(defaultIndustryType(request.industryType()));
        task.setTaskType(defaultTaskType(request.taskType()));
        task.setExtractModelConfigId(extractModel.configId());
        task.setExtractModelName(extractModel.modelName());
        task.setExtractModelUrl(extractModel.modelUrl());
        task.setExtractModelApiKey(extractModel.apiKey());
        task.setVerifyModelConfigId(verifyModel.configId());
        task.setVerifyModelName(verifyModel.modelName());
        task.setVerifyModelUrl(verifyModel.modelUrl());
        task.setVerifyModelApiKey(verifyModel.apiKey());
        task.setExtractPromptConfigId(extractPrompt.configId());
        task.setExtractPrompt(extractPrompt.promptText());
        task.setVerifyPromptConfigId(verifyPrompt.configId());
        task.setVerifyPrompt(verifyPrompt.promptText());
        annotationTaskMapper.updateById(task);

        if (resourcesChanged) {
            annotationTaskResourceMapper.deleteByTaskId(taskId);
            saveTaskBindings(taskId, currentUser.companyId(), resources);
        }
        log.info("updated annotation task, companyId={}, userId={}, taskId={}, resourcesChanged={}",
            currentUser.companyId(), currentUser.userId(), taskId, resourcesChanged);
        return buildTaskResponse(task, resourceIds(resources), extractModel, verifyModel, extractPrompt, verifyPrompt);
    }

    public AnnotationTaskResponse getTask(LoginUser currentUser, Long taskId) {
        AnnotationTask task = annotationTaskMapper.findByIdAndCompanyId(taskId, currentUser.companyId());
        if (task == null) {
            throw new BusinessException(ResultCode.NOT_FOUND, "任务不存在");
        }
        assertTaskPermission(currentUser, task);
        return buildTaskResponse(task, normalizeIds(annotationTaskResourceMapper.listResourceIdsByTaskId(taskId)));
    }

    public PageResult<AnnotationTaskResponse> pageTasks(LoginUser currentUser, AnnotationTaskPageQuery query) {
        LambdaQueryWrapper<AnnotationTask> wrapper = new LambdaQueryWrapper<AnnotationTask>()
            .eq(AnnotationTask::getCompanyId, currentUser.companyId())
            .eq(StringUtils.hasText(query.taskType()), AnnotationTask::getTaskType, query.taskType())
            .eq(StringUtils.hasText(query.taskStatus()), AnnotationTask::getTaskStatus, query.taskStatus())
            .eq(query.isDeleted() != null, AnnotationTask::getIsDeleted, query.isDeleted())
            .like(StringUtils.hasText(query.keyword()), AnnotationTask::getTaskName, query.keyword())
            .orderByDesc(AnnotationTask::getCreatedAt);
        List<AnnotationTaskResponse> records = annotationTaskMapper.selectList(wrapper).stream()
            .filter(task -> dataPermissionService.canAccessCreator(currentUser, task.getCreatorId(), task.getCreatorRole()))
            .filter(task -> query.resourceId() == null || annotationTaskResourceMapper.listResourceIdsByTaskId(task.getId()).contains(query.resourceId()))
            .sorted(Comparator.comparing(AnnotationTask::getCreatedAt, Comparator.nullsLast(Comparator.naturalOrder())).reversed())
            .map(task -> buildTaskResponse(task, normalizeIds(annotationTaskResourceMapper.listResourceIdsByTaskId(task.getId()))))
            .toList();
        return paginate(records, query.pageNo(), query.pageSize());
    }

    @Transactional
    public void deleteTask(LoginUser currentUser, Long taskId) {
        AnnotationTask task = annotationTaskMapper.findByIdAndCompanyId(taskId, currentUser.companyId());
        if (task == null) {
            throw new BusinessException(ResultCode.NOT_FOUND, "任务不存在");
        }
        assertTaskPermission(currentUser, task);
        if (TaskStatus.RUNNING.name().equals(task.getTaskStatus())) {
            throw new BusinessException(ResultCode.CONFLICT, "运行中的任务不允许删除");
        }
        task.setIsDeleted(true);
        annotationTaskMapper.updateById(task);
        log.info("deleted annotation task logically, companyId={}, userId={}, taskId={}",
            currentUser.companyId(), currentUser.userId(), taskId);
    }

    private List<SourceResource> loadAndValidateResources(LoginUser currentUser, List<Long> resourceIds) {
        if (resourceIds == null || resourceIds.isEmpty()) {
            throw new BusinessException(ResultCode.BAD_REQUEST, "任务资源不能为空");
        }
        List<Long> normalizedIds = normalizeIds(resourceIds);
        List<SourceResource> resources = sourceResourceMapper.selectByCompanyIdAndIds(currentUser.companyId(), normalizedIds);
        if (resources.size() != normalizedIds.size()) {
            throw new BusinessException(ResultCode.BAD_REQUEST, "存在无效资源");
        }
        for (SourceResource resource : resources) {
            if (!dataPermissionService.canAccessCreator(currentUser, resource.getCreatorId(), resource.getCreatorRole())) {
                throw new BusinessException(ResultCode.FORBIDDEN, "无权访问资源");
            }
            if (!SourceStatus.READY.name().equals(resource.getSourceStatus())) {
                throw new BusinessException(ResultCode.BAD_REQUEST, "仅允许选择已就绪资源");
            }
        }
        resources.sort(Comparator.comparing(SourceResource::getId));
        return resources;
    }

    private void saveTaskBindings(Long taskId, Long companyId, List<SourceResource> resources) {
        for (SourceResource resource : resources) {
            annotationTaskResourceMapper.insert(AnnotationTaskResource.builder()
                .id(IdGenerator.nextId())
                .companyId(companyId)
                .taskId(taskId)
                .resourceId(resource.getId())
                .build());
        }
    }

    private AnnotationTaskResponse buildTaskResponse(AnnotationTask task,
                                                     List<Long> resourceIds,
                                                     SysConfigService.ResolvedModelConfig extractModel,
                                                     SysConfigService.ResolvedModelConfig verifyModel,
                                                     SysConfigService.ResolvedPromptConfig extractPrompt,
                                                     SysConfigService.ResolvedPromptConfig verifyPrompt) {
        return new AnnotationTaskResponse(
            task.getId(),
            task.getTaskName(),
            task.getIndustryType(),
            task.getTaskType(),
            task.getTaskStatus(),
            resourceIds,
            sysConfigService.toResponse(extractModel),
            sysConfigService.toResponse(verifyModel),
            sysConfigService.toResponse(extractPrompt),
            sysConfigService.toResponse(verifyPrompt),
            task.getCreatedAt(),
            task.getUpdatedAt());
    }

    private AnnotationTaskResponse buildTaskResponse(AnnotationTask task, List<Long> resourceIds) {
        return new AnnotationTaskResponse(
            task.getId(),
            task.getTaskName(),
            task.getIndustryType(),
            task.getTaskType(),
            task.getTaskStatus(),
            resourceIds,
            new TaskModelConfigResponse(task.getExtractModelConfigId(), null, task.getExtractModelName(),
                task.getExtractModelUrl(), maskSecret(task.getExtractModelApiKey())),
            new TaskModelConfigResponse(task.getVerifyModelConfigId(), null, task.getVerifyModelName(),
                task.getVerifyModelUrl(), maskSecret(task.getVerifyModelApiKey())),
            new TaskPromptConfigResponse(task.getExtractPromptConfigId(), null, task.getExtractPrompt()),
            new TaskPromptConfigResponse(task.getVerifyPromptConfigId(), null, task.getVerifyPrompt()),
            task.getCreatedAt(),
            task.getUpdatedAt());
    }

    private List<Long> resourceIds(List<SourceResource> resources) {
        return resources.stream().map(SourceResource::getId).sorted().toList();
    }

    private List<Long> normalizeIds(List<Long> resourceIds) {
        Set<Long> uniqueIds = new HashSet<>(resourceIds);
        List<Long> sortedIds = new ArrayList<>(uniqueIds);
        sortedIds.sort(Long::compareTo);
        return sortedIds;
    }

    private void assertTaskPermission(LoginUser currentUser, AnnotationTask task) {
        if (!dataPermissionService.canAccessCreator(currentUser, task.getCreatorId(), task.getCreatorRole())) {
            throw new BusinessException(ResultCode.FORBIDDEN, "无权操作任务");
        }
    }

    private String defaultIndustryType(String industryType) {
        return StringUtils.hasText(industryType) ? industryType : "transport";
    }

    private String defaultTaskType(String taskType) {
        return StringUtils.hasText(taskType) ? taskType : "EXTRACT_QA";
    }

    private String maskSecret(String secret) {
        if (!StringUtils.hasText(secret)) {
            return null;
        }
        if (secret.length() <= 4) {
            return "****";
        }
        return "****" + secret.substring(secret.length() - 4);
    }

    private <T> PageResult<T> paginate(List<T> records, Integer pageNo, Integer pageSize) {
        int actualPageNo = pageNo == null || pageNo < 1 ? 1 : pageNo;
        int actualPageSize = pageSize == null || pageSize < 1 ? 10 : pageSize;
        int fromIndex = Math.min((actualPageNo - 1) * actualPageSize, records.size());
        int toIndex = Math.min(fromIndex + actualPageSize, records.size());
        return new PageResult<>(records.subList(fromIndex, toIndex), (long) records.size(), actualPageNo, actualPageSize);
    }
}