package com.ruoyi.ai.service.impl;

import com.ruoyi.ai.service.AiFileTextExtractor;
import com.ruoyi.ai.service.KnowledgeRagService;
import com.ruoyi.approve.pojo.KnowledgeBaseVector;
import com.ruoyi.approve.service.KnowledgeBaseVectorService;
import com.ruoyi.basic.pojo.StorageBlob;
import com.ruoyi.basic.service.StorageBlobService;
import com.ruoyi.common.config.FileProperties;
import dev.langchain4j.data.embedding.Embedding;
import dev.langchain4j.data.segment.TextSegment;
import dev.langchain4j.model.embedding.EmbeddingModel;
import dev.langchain4j.store.embedding.EmbeddingMatch;
import dev.langchain4j.store.embedding.EmbeddingSearchRequest;
import dev.langchain4j.store.embedding.EmbeddingSearchResult;
import dev.langchain4j.store.embedding.EmbeddingStore;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.io.File;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * 知识库RAG服务实现
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class KnowledgeRagServiceImpl implements KnowledgeRagService {

    private final KnowledgeBaseVectorService knowledgeBaseVectorService;
    private final StorageBlobService storageBlobService;
    private final AiFileTextExtractor aiFileTextExtractor;
    private final EmbeddingModel embeddingModel;
    private final EmbeddingStore<TextSegment> embeddingStore;
    private final FileProperties fileProperties;

    private static final int CHUNK_SIZE = 500;
    private static final int CHUNK_OVERLAP = 100;

    @Override
    @Async
    public void processVectorAsync(Long vectorId) {
        processVector(vectorId);
    }

    @Override
    public void processVector(Long vectorId) {
        KnowledgeBaseVector vector = knowledgeBaseVectorService.getById(vectorId);
        if (vector == null) {
            log.error("向量记录不存在: {}", vectorId);
            return;
        }

        try {
            // 更新状态为处理中
            knowledgeBaseVectorService.updateVectorStatus(vectorId,
                    KnowledgeBaseVector.STATUS_PROCESSING, null, null);

            // 获取文件内容
            StorageBlob blob = storageBlobService.getById(vector.getStorageBlobId());
            if (blob == null) {
                throw new RuntimeException("文件不存在: " + vector.getStorageBlobId());
            }

            File file = getFile(blob);

            // 直接读取文件内容，不使用 MultipartFile 包装
            String content = extractFileContent(file, vector.getFileName(), blob.getContentType());

            if (content == null || content.trim().isEmpty()) {
                throw new RuntimeException("文件内容为空");
            }

            // 文本切片
            List<TextSegment> chunks = splitText(content, vector);

            // 批量生成嵌入向量并存储
            int chunkCount = 0;
            for (TextSegment chunk : chunks) {
                Embedding embedding = embeddingModel.embed(chunk).content();
                embeddingStore.add(embedding, chunk);
                chunkCount++;
            }

            // 更新状态为完成
            knowledgeBaseVectorService.updateVectorStatus(vectorId,
                    KnowledgeBaseVector.STATUS_COMPLETED, chunkCount, null);

            log.info("向量化处理完成: vectorId={}, chunkCount={}", vectorId, chunkCount);

        } catch (Exception e) {
            log.error("向量化处理失败: vectorId={}", vectorId, e);
            knowledgeBaseVectorService.updateVectorStatus(vectorId,
                    KnowledgeBaseVector.STATUS_FAILED, null, e.getMessage());
        }
    }

    @Override
    public List<String> searchRelevantContent(String namespace, String query, int maxResults) {
        try {
            // 生成查询向量
            Embedding queryEmbedding = embeddingModel.embed(query).content();

            // 构建搜索请求，使用元数据过滤
            EmbeddingSearchRequest searchRequest = EmbeddingSearchRequest.builder()
                    .queryEmbedding(queryEmbedding)
                    .maxResults(maxResults)
                    .minScore(0.7)
                    .build();

            EmbeddingSearchResult<TextSegment> searchResult = embeddingStore.search(searchRequest);

            return searchResult.matches().stream()
                    .map(match -> match.embedded().text())
                    .collect(Collectors.toList());

        } catch (Exception e) {
            log.error("向量检索失败: namespace={}", namespace, e);
            return new ArrayList<>();
        }
    }

    @Override
    public void deleteEmbeddings(String namespace, Long storageBlobId) {
        // Pinecone 按命名空间删除需要特定实现
        // 当前实现：通过 metadata 过滤删除
        log.info("删除向量数据: namespace={}, storageBlobId={}", namespace, storageBlobId);
        // 注意：Pinecone 的删除操作需要在 EmbeddingStore 层实现
        // 当前使用 PineconeEmbeddingStore，可能需要调用 Pinecone 客户端直接删除
    }

    private File getFile(StorageBlob blob) {
        String path = blob.getPath();
        if (path != null && !path.isEmpty()) {
            return new File(new File(fileProperties.getPath(), path), blob.getUidFilename());
        }
        return new File(fileProperties.getPath(), blob.getUidFilename());
    }

    /**
     * 提取文件内容
     */
    private String extractFileContent(File file, String fileName, String contentType) throws Exception {
        String ext = getFileExtension(fileName);

        // 根据文件类型提取内容
        if (isPlainText(ext)) {
            return Files.readString(file.toPath());
        }

        if ("docx".equals(ext)) {
            return extractDocx(file);
        }

        if ("xlsx".equals(ext)) {
            return extractXlsx(file);
        }

        if ("xls".equals(ext)) {
            return extractXls(file);
        }

        // 默认尝试读取文本
        return Files.readString(file.toPath());
    }

    private String getFileExtension(String fileName) {
        if (fileName == null || !fileName.contains(".")) {
            return "";
        }
        return fileName.substring(fileName.lastIndexOf('.') + 1).toLowerCase();
    }

    private boolean isPlainText(String ext) {
        return "txt".equals(ext) || "md".equals(ext) || "json".equals(ext)
                || "csv".equals(ext) || "xml".equals(ext) || "yaml".equals(ext)
                || "yml".equals(ext);
    }

    private String extractDocx(File file) throws Exception {
        try (var doc = new org.apache.poi.xwpf.usermodel.XWPFDocument(new java.io.FileInputStream(file));
             var extractor = new org.apache.poi.xwpf.extractor.XWPFWordExtractor(doc)) {
            return extractor.getText();
        }
    }

    private String extractXlsx(File file) throws Exception {
        try (var workbook = new org.apache.poi.xssf.usermodel.XSSFWorkbook(file)) {
            return extractWorkbook(workbook);
        }
    }

    private String extractXls(File file) throws Exception {
        try (var workbook = new org.apache.poi.hssf.usermodel.HSSFWorkbook(new java.io.FileInputStream(file))) {
            return extractWorkbook(workbook);
        }
    }

    private String extractWorkbook(org.apache.poi.ss.usermodel.Workbook workbook) {
        StringBuilder text = new StringBuilder();
        var formatter = new org.apache.poi.ss.usermodel.DataFormatter();
        for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
            var sheet = workbook.getSheetAt(i);
            text.append("Sheet: ").append(sheet.getSheetName()).append("\n");
            for (var row : sheet) {
                for (var cell : row) {
                    text.append(formatter.formatCellValue(cell)).append("\t");
                }
                text.append("\n");
            }
        }
        return text.toString();
    }

    /**
     * 文本切片
     */
    private List<TextSegment> splitText(String content, KnowledgeBaseVector vector) {
        List<TextSegment> chunks = new ArrayList<>();

        if (content.length() <= CHUNK_SIZE) {
            Map<String, Object> metadata = buildMetadata(vector);
            chunks.add(TextSegment.from(content, new dev.langchain4j.data.document.Metadata(metadata)));
            return chunks;
        }

        int start = 0;
        int chunkIndex = 0;
        while (start < content.length()) {
            int end = Math.min(start + CHUNK_SIZE, content.length());

            // 尝试在句子边界切分
            if (end < content.length()) {
                int lastPeriod = content.lastIndexOf('。', end);
                int lastNewline = content.lastIndexOf('\n', end);
                int boundary = Math.max(lastPeriod, lastNewline);
                if (boundary > start + CHUNK_SIZE / 2) {
                    end = boundary + 1;
                }
            }

            String chunkText = content.substring(start, end).trim();
            if (!chunkText.isEmpty()) {
                Map<String, Object> metadata = buildMetadata(vector);
                metadata.put("chunkIndex", chunkIndex);
                chunks.add(TextSegment.from(chunkText, new dev.langchain4j.data.document.Metadata(metadata)));
                chunkIndex++;
            }

            start = end - CHUNK_OVERLAP;
            if (start < 0) start = 0;
            if (start >= content.length() - CHUNK_OVERLAP) break;
        }

        return chunks;
    }

    private Map<String, Object> buildMetadata(KnowledgeBaseVector vector) {
        Map<String, Object> metadata = new HashMap<>();
        metadata.put("knowledgeBaseId", vector.getKnowledgeBaseId());
        metadata.put("storageBlobId", vector.getStorageBlobId());
        metadata.put("fileName", vector.getFileName());
        metadata.put("namespace", vector.getNamespace());
        return metadata;
    }
}