package cn.yinlihupo.service.ai.impl;

import cn.yinlihupo.domain.entity.AiDocument;
import cn.yinlihupo.domain.vo.KbDocumentVO;
import cn.yinlihupo.mapper.AiDocumentMapper;
import cn.yinlihupo.service.ai.AiKnowledgeBaseService;
import cn.yinlihupo.service.ai.rag.DocumentProcessor;
import cn.yinlihupo.service.oss.MinioService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.time.LocalDateTime;
import java.util.List;
import java.util.UUID;

/**
 * AI知识库服务实现
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class AiKnowledgeBaseServiceImpl implements AiKnowledgeBaseService {

    private final AiDocumentMapper documentMapper;
    private final DocumentProcessor documentProcessor;
    private final MinioService minioService;

    // 支持的文件类型
    private static final List<String> SUPPORTED_TYPES = List.of(
            "pdf", "doc", "docx", "txt", "md", "json", "csv"
    );

    @Override
    public KbDocumentVO uploadFile(Long projectId, MultipartFile file, Long userId) {
        // 1. 验证文件
        validateFile(file);

        // 2. 生成文档UUID
        String docId = UUID.randomUUID().toString();

        // 3. 上传文件到MinIO
        String originalFilename = file.getOriginalFilename();
        String fileExtension = getFileExtension(originalFilename);
        String filePath = String.format("kb/%d/%s.%s", projectId, docId, fileExtension);

        try {
            minioService.uploadFile(filePath, file.getInputStream(), file.getContentType());
        } catch (Exception e) {
            log.error("上传文件到MinIO失败: {}", e.getMessage(), e);
            throw new RuntimeException("文件上传失败: " + e.getMessage());
        }

        // 4. 保存文档元数据
        AiDocument doc = new AiDocument();
        doc.setDocId(docId);
        doc.setProjectId(projectId);
        doc.setSourceType("upload");
        doc.setTitle(originalFilename);
        doc.setDocType(detectDocType(fileExtension));
        doc.setFileType(fileExtension);
        doc.setFileSize(file.getSize());
        doc.setFilePath(filePath);
        doc.setContent("");
        doc.setStatus("pending"); // 待处理状态
        doc.setChunkTotal(0);
        doc.setCreateBy(userId);
        doc.setCreateTime(LocalDateTime.now());
        doc.setDeleted(0);

        documentMapper.insert(doc);

        // 5. 异步处理文档（解析、切片、向量化）
        documentProcessor.processDocumentAsync(doc.getId());

        log.info("文件上传成功: {}, docId: {}", originalFilename, docId);

        // 6. 返回VO
        return convertToVO(doc);
    }

    @Override
    public List<KbDocumentVO> getProjectDocuments(Long projectId) {
        return documentMapper.selectProjectDocuments(projectId);
    }

    @Override
    public void deleteDocument(String docId, Long userId) {
        // 1. 查询文档
        AiDocument doc = documentMapper.selectByDocId(docId);
        if (doc == null) {
            throw new RuntimeException("文档不存在");
        }

        // 2. 删除MinIO中的文件
        try {
            minioService.deleteFile(doc.getFilePath());
        } catch (Exception e) {
            log.error("删除MinIO文件失败: {}, 错误: {}", doc.getFilePath(), e.getMessage());
            // 继续删除数据库记录
        }

        // 3. 删除向量库中的向量（简化处理，实际可能需要更复杂的逻辑）
        documentProcessor.deleteDocumentVectors(docId);

        // 4. 删除数据库记录
        documentMapper.deleteByDocId(docId);

        log.info("文档删除成功: {}, userId: {}", docId, userId);
    }

    @Override
    public void reindexDocument(String docId, Long userId) {
        // 1. 查询文档
        AiDocument doc = documentMapper.selectByDocId(docId);
        if (doc == null) {
            throw new RuntimeException("文档不存在");
        }

        // 2. 更新状态为处理中
        doc.setStatus("processing");
        documentMapper.updateById(doc);

        // 3. 删除旧的向量
        documentProcessor.deleteDocumentVectors(docId);

        // 4. 重新处理
        documentProcessor.processDocumentAsync(doc.getId());

        log.info("文档重新索引: {}, userId: {}", docId, userId);
    }

    @Override
    public void processDocument(Long docId) {
        documentProcessor.processDocument(docId);
    }

    @Override
    @Async
    public void processDocumentAsync(Long docId) {
        documentProcessor.processDocument(docId);
    }

    /**
     * 验证文件
     */
    private void validateFile(MultipartFile file) {
        if (file == null || file.isEmpty()) {
            throw new RuntimeException("文件不能为空");
        }

        String filename = file.getOriginalFilename();
        if (filename == null || filename.isEmpty()) {
            throw new RuntimeException("文件名不能为空");
        }

        String extension = getFileExtension(filename);
        if (!SUPPORTED_TYPES.contains(extension.toLowerCase())) {
            throw new RuntimeException("不支持的文件类型: " + extension);
        }

        // 文件大小限制（50MB）
        long maxSize = 50 * 1024 * 1024;
        if (file.getSize() > maxSize) {
            throw new RuntimeException("文件大小超过限制（最大50MB）");
        }
    }

    /**
     * 获取文件扩展名
     */
    private String getFileExtension(String filename) {
        if (filename == null || filename.lastIndexOf('.') == -1) {
            return "";
        }
        return filename.substring(filename.lastIndexOf('.') + 1).toLowerCase();
    }

    /**
     * 检测文档类型
     */
    private String detectDocType(String extension) {
        return switch (extension.toLowerCase()) {
            case "pdf" -> "report";
            case "doc", "docx" -> "document";
            case "txt", "md" -> "text";
            case "json", "csv" -> "data";
            default -> "other";
        };
    }

    /**
     * 转换为VO
     */
    private KbDocumentVO convertToVO(AiDocument doc) {
        KbDocumentVO vo = new KbDocumentVO();
        vo.setId(doc.getId());
        vo.setDocId(doc.getDocId());
        vo.setTitle(doc.getTitle());
        vo.setDocType(doc.getDocType());
        vo.setFileType(doc.getFileType());
        vo.setFileSize(doc.getFileSize());
        vo.setFilePath(doc.getFilePath());
        vo.setSourceType(doc.getSourceType());
        vo.setChunkCount(doc.getChunkTotal());
        vo.setStatus(doc.getStatus());
        vo.setCreateTime(doc.getCreateTime());
        return vo;
    }
}