package kr.re.etri.autoflow.service;

import io.minio.GetObjectArgs;
import io.minio.MinioClient;
import io.minio.PutObjectArgs;
import io.minio.StatObjectArgs;
import io.minio.RemoveObjectArgs;
import jakarta.transaction.Transactional;
import kr.re.etri.autoflow.entity.MinioAttachmentEntity;
import kr.re.etri.autoflow.payload.request.BaseSearchRequest;
import kr.re.etri.autoflow.payload.request.ProjectBaseSearchRequest;
import kr.re.etri.autoflow.payload.request.ScriptMergeRequest;
import kr.re.etri.autoflow.repository.MinioAttachmentRepository;
import kr.re.etri.autoflow.specification.MinioAttachmentSpecification;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.domain.*;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.UUID;
import java.io.ByteArrayOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

@Slf4j
@Service
@RequiredArgsConstructor
@Transactional
public class MinioAttachmentService {

    private final MinioClient minioClient;
    private final MinioAttachmentRepository minioAttachmentRepository;
    private final MinioAttachmentSpecification minioAttachmentSpecification;

    @Value("${minio.bucket}")
    private String bucketName;

    @Value("${minio.endpoint}")
    private String minioEndpoint;

    @Value("${minio.access-key:}")
    private String minioAccessKey;

    @Value("${minio.secret-key:}")
    private String minioSecretKey;

    /** Pod에서 접근할 MinIO 주소 (비어 있으면 클라이언트에서 직접 입력) */
    @Value("${minio.endpoint.pod:}")
    private String minioEndpointPod;

    /** KFP py→YAML 컴파일 시 사용할 Python 실행 파일 (Windows는 python, Linux는 python3 권장) */
    @Value("${kfp.compile.python-command:python3}")
    private String pythonCommand;

    private final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");

    /**
     * 파일 업로드 & DB 저장
     */
    public MinioAttachmentEntity uploadFile(MultipartFile file,
                                            String path,
                                            Long refId,
                                            String refType,
                                            String title,
                                            String description,
                                            Integer version,
                                            String regUserId,
                                            Long projectId
    ) throws Exception {

        try (InputStream is = file.getInputStream()) {
            String storedName = UUID.randomUUID() + "-" + file.getOriginalFilename();
            String objectName = (path == null || path.isEmpty())
                    ? storedName
                    : path + "/" + storedName;

            // MinIO 업로드
            minioClient.putObject(
                    PutObjectArgs.builder()
                            .bucket(bucketName)
                            .object(objectName)
                            .stream(is, is.available(), -1)
                            .contentType(file.getContentType())
                            .build()
            );

            // DB 저장
            MinioAttachmentEntity attachment = MinioAttachmentEntity.builder()
                    .refId(refId)
                    .refType(refType)
                    .originalName(file.getOriginalFilename())
                    .storedName(storedName)
                    .contentType(file.getContentType())
                    .size(file.getSize())
                    .storagePath(objectName)
                    .title(title != null ? title : file.getOriginalFilename())
                    .version(version)
                    .description(description)
                    .regUserId(regUserId)
                    .projectId(projectId)
                    .build();

            return minioAttachmentRepository.save(attachment);
        }
    }

    /**
     * 전체 조회
     */
    public List<MinioAttachmentEntity> findAll() {
        return minioAttachmentRepository.findAll();
    }

    /**
     * ID 조회
     */
    public Optional<MinioAttachmentEntity> findById(Long id) {
        return minioAttachmentRepository.findById(id);
    }

    /**
     * 검색 + 페이지네이션
     */
    public Page<MinioAttachmentEntity> search(ProjectBaseSearchRequest request, String refType, Integer refId) {
        int pageIndex = request.getPage() > 0 ? request.getPage() - 1 : 0;

        Pageable pageable = PageRequest.of(
                pageIndex,
                request.getSize(),
                Sort.by(Sort.Direction.fromString(request.getSortDirection()), request.getSortField())
        );

        LocalDate startDate = parseDate(request.getStartDate());
        LocalDate endDate = parseDate(request.getEndDate());

        Specification<MinioAttachmentEntity> spec =
                minioAttachmentSpecification.searchByConditions(
                        refType,
                        refId,
                        request.getSearchType(),
                        request.getKeyword(),
                        startDate,
                        endDate
                );

        if (request.getProjectId() != null) {
            spec = spec.and((root, query, cb) ->
                    cb.equal(root.get("projectId"), request.getProjectId())
            );
        }

        return minioAttachmentRepository.findAll(spec, pageable);
    }

    public List<MinioAttachmentEntity> findAllByIds(List<Long> ids) {
        return minioAttachmentRepository.findAllById(ids);
    }

    private LocalDate parseDate(String dateStr) {
        if (dateStr == null || dateStr.isBlank()) return null;
        try {
            return LocalDate.parse(dateStr, formatter);
        } catch (DateTimeParseException e) {
            throw new IllegalArgumentException("날짜 형식이 잘못되었습니다. yyyy-MM-dd 형식이어야 합니다: " + dateStr);
        }
    }

    public byte[] downloadFile(String bucketName, String objectName) {
        try (InputStream is = minioClient.getObject(
                GetObjectArgs.builder().bucket(bucketName).object(objectName).build()
        )) {
            return is.readAllBytes();
        } catch (Exception e) {
            throw new RuntimeException("MinIO 파일 다운로드 실패: " + objectName, e);
        }
    }


    // YAML 텍스트 읽기
    public String readYamlText(String bucketName, String objectName) {
        try (InputStream is = minioClient.getObject(
                GetObjectArgs.builder().bucket(bucketName).object(objectName).build()
        )) {
            return new String(is.readAllBytes(), StandardCharsets.UTF_8);
        } catch (Exception e) {
            throw new RuntimeException("MinIO YAML 읽기 실패: " + objectName, e);
        }
    }

    public MinioAttachmentEntity updateFile(
            Long id,
            Long projectId, // 추가
            MultipartFile file,
            String path,
            String title,
            String description,
            String regUserId
    ) throws Exception {
        // 기존 엔티티 조회
        MinioAttachmentEntity existing = minioAttachmentRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("첨부파일을 찾을 수 없습니다. ID=" + id));

        // 최신 버전 조회
        Integer latestVersion = minioAttachmentRepository
                .findTopByRefIdAndRefTypeOrderByVersionDesc(existing.getRefId(), existing.getRefType())
                .map(MinioAttachmentEntity::getVersion)
                .orElse(0);

        int newVersion = latestVersion + 1;

        // 새 파일 업로드
        String storedName = UUID.randomUUID() + "-" + file.getOriginalFilename();
        String objectName = (path == null || path.isEmpty())
                ? storedName
                : path + "/" + storedName;

        try (InputStream is = file.getInputStream()) {
            minioClient.putObject(
                    PutObjectArgs.builder()
                            .bucket(bucketName)
                            .object(objectName)
                            .stream(is, is.available(), -1)
                            .contentType(file.getContentType())
                            .build()
            );
        }

        // 새로운 엔티티 생성 (이전 데이터는 그대로 두고, 새로운 버전 생성)
        MinioAttachmentEntity newAttachment = MinioAttachmentEntity.builder()
                .projectId(projectId) // 추가
                .refId(existing.getRefId())
                .refType(existing.getRefType())
                .originalName(file.getOriginalFilename())
                .storedName(storedName)
                .contentType(file.getContentType())
                .size(file.getSize())
                .storagePath(objectName)
                .title(title != null ? title : existing.getTitle())
                .description(description != null ? description : existing.getDescription())
                .version(newVersion)
                .regUserId(regUserId)
                .build();

        return minioAttachmentRepository.save(newAttachment);
    }

    /**
     * 생성 (DB만 저장, 파일은 따로 업로드된 경우)
     */
    public MinioAttachmentEntity create(MinioAttachmentEntity entity) {
        return minioAttachmentRepository.save(entity);
    }

    /**
     * 업데이트
     */
    public Optional<MinioAttachmentEntity> update(Long id, MinioAttachmentEntity dto) {
        return minioAttachmentRepository.findById(id)
                .map(entity -> {
                    BeanUtils.copyProperties(dto, entity, "id", "regDt"); // ID, 등록일 제외
                    return minioAttachmentRepository.save(entity);
                });
    }

    /**
     * 삭제
     */
    @Transactional
    public boolean delete(Long id) {
        Optional<MinioAttachmentEntity> attachmentOpt = minioAttachmentRepository.findById(id);
        if (attachmentOpt.isEmpty()) {
            return false;
        }

        MinioAttachmentEntity attachment = attachmentOpt.get();
        try {
            // MinIO 파일 삭제
            minioClient.removeObject(
                    RemoveObjectArgs.builder()
                            .bucket(bucketName)
                            .object(attachment.getStoragePath())
                            .build()
            );

            // DB에서 삭제
            minioAttachmentRepository.deleteById(id);
            return true;

        } catch (Exception e) {
            log.error("MinIO 파일 삭제 실패: " + attachment.getStoragePath(), e);
            return false;
        }
    }

    /**
     * MinIO URL 반환
     */
    public String getFileUrl(String objectName) {
        return String.format("%s/%s/%s", minioEndpoint, bucketName, objectName);
    }

    /** 파이프라인 Pod에서 MinIO 직접 접근 시 사용 (endpoint) */
    public String getMinioEndpoint() {
        return minioEndpoint;
    }

    /** 파이프라인 Pod에서 MinIO 직접 접근 시 사용 (bucket) */
    public String getMinioBucket() {
        return bucketName;
    }

    public String getMinioAccessKey() {
        return minioAccessKey;
    }

    public String getMinioSecretKey() {
        return minioSecretKey;
    }

    /** Pod에서 접근할 MinIO endpoint (설정 시 YAML에 반영) */
    public String getMinioEndpointPod() {
        return minioEndpointPod != null ? minioEndpointPod : "";
    }

    private String buildMasterScript(List<MinioAttachmentEntity> scripts, String pipelineName) {
        // 파이프라인 본문(각 스텝)을 생성
        StringBuilder body = new StringBuilder();
        String prevOutput = "\"\""; // 첫 스텝은 input_dir = ""

        for (int i = 0; i < scripts.size(); i++) {
            MinioAttachmentEntity att = scripts.get(i);
            String safeTitle = att.getTitle() != null ? att.getTitle() : att.getOriginalName();
            safeTitle = safeTitle.replace("\"", "\\\""); // 파이썬 문자열용 이스케이프

            int stepIndex = i + 1;
            String stepVar = "step" + stepIndex;
            String outputDir = "/workspace/outputs/step_" + stepIndex;

            body.append("    ").append(stepVar).append(" = run_script_component(\n");
            body.append("        minio_endpoint_pod=minio_endpoint_pod,\n");
            body.append("        minio_bucket=minio_bucket,\n");
            body.append("        minio_access_key=minio_access_key,\n");
            body.append("        minio_secret_key=minio_secret_key,\n");
            body.append("        object_name=\"").append(att.getStoragePath().replace("\"", "\\\"")).append("\",\n");
            body.append("        step_name=\"step-").append(stepIndex).append("-").append(safeTitle).append("\",\n");
            body.append("        input_dir=").append(prevOutput).append(",\n");
            body.append("        output_dir=\"").append(outputDir).append("\",\n");
            body.append("    )\n\n");

            prevOutput = stepVar + ".output";
        }

        String endpointPod = getMinioEndpointPod();
        String bucket = getMinioBucket();
        String accessKey = getMinioAccessKey();
        String secretKey = getMinioSecretKey();
        if (endpointPod == null) {
            endpointPod = "";
        }
        if (bucket == null) {
            bucket = "mlpipeline";
        }
        if (accessKey == null) {
            accessKey = "";
        }
        if (secretKey == null) {
            secretKey = "";
        }
        // 공백/개행 제거 및 끝 슬래시 제거
        endpointPod = endpointPod.trim()
                .replaceFirst("^https?://", "")
                .replaceAll("/+$", "");

        String template = """
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from kfp import dsl


@dsl.component(base_image="python:3.10")
def run_script_component(
    minio_endpoint_pod: str,
    minio_bucket: str,
    minio_access_key: str,
    minio_secret_key: str,
    object_name: str,
    step_name: str,
    input_dir: str = "",
    output_dir: str = "/workspace/outputs",
) -> str:
    import os
    import subprocess
    import sys

    # 파라미터 정규화
    minio_endpoint_pod = (minio_endpoint_pod or "").strip().rstrip("/")
    minio_bucket = (minio_bucket or "").strip().strip("/")

    os.makedirs(output_dir, exist_ok=True)

    # MinIO Python SDK 설치
    print("[MASTER] installing minio client...")
    subprocess.run([sys.executable, "-m", "pip", "install", "minio"], check=True)

    from minio import Minio

    # 스크립트 파일을 MinIO에서 로컬로 다운로드
    client = Minio(
        minio_endpoint_pod,
        access_key=minio_access_key,
        secret_key=minio_secret_key,
        secure=False,
    )
    client.fget_object(minio_bucket, object_name, "script.py")

    # 사용자 스크립트 실행
    cmd_parts = []
    if input_dir:
        cmd_parts.append(f"export INPUT_DIR={input_dir}")
    cmd_parts.append(f"python script.py --input_dir \\"$INPUT_DIR\\" --output_dir \\"{output_dir}\\"")
    cmd = " && ".join(cmd_parts)

    print(f"[MASTER] STEP {step_name} 실행: {cmd}")
    result = subprocess.run(cmd, shell=True)
    if result.returncode != 0:
        raise RuntimeError(f"STEP {step_name} 실패 (exit={result.returncode})")

    print(f"[MASTER] STEP {step_name} 완료, output_dir={output_dir}")
    return output_dir


@dsl.pipeline(name="%s")
def pipeline(
    mlflow_experiment_name: str = "",
    minio_endpoint_pod: str = "%s",
    minio_bucket: str = "%s",
    minio_access_key: str = "%s",
    minio_secret_key: str = "%s",
):
%s
""";

        return String.format(
                template,
                pipelineName.replace("\"", "\\\""),
                endpointPod.replace("\\", "\\\\").replace("\"", "\\\""),
                bucket.replace("\\", "\\\\").replace("\"", "\\\""),
                accessKey.replace("\\", "\\\\").replace("\"", "\\\""),
                secretKey.replace("\\", "\\\\").replace("\"", "\\\""),
                body.toString()
        );
    }

    public MinioAttachmentEntity createMergedMaster(ScriptMergeRequest req, List<MinioAttachmentEntity> scripts) throws Exception {
        if (scripts == null || scripts.isEmpty()) {
            throw new IllegalArgumentException("머지할 스크립트가 없습니다.");
        }

        String pipelineName = (req.getTitle() != null && !req.getTitle().isBlank())
                ? req.getTitle()
                : "merged-training-script";

        String masterPy = buildMasterScript(scripts, pipelineName);
        byte[] bytes = masterPy.getBytes(StandardCharsets.UTF_8);

        String originalName = (req.getTitle() != null && !req.getTitle().isBlank())
                ? req.getTitle() + ".py"
                : "merged_pipeline.py";

        String path = "scripts/merged";
        Long refId = req.getRefId() != null ? req.getRefId() : 0L;
        String refType = (req.getRefType() != null && !req.getRefType().isBlank())
                ? req.getRefType()
                : "TRAINING_SCRIPT";
        String title = req.getTitle() != null ? req.getTitle() : "Merged Script";
        String description = req.getDescription();
        Integer version = 1;
        String regUserId = req.getRegUserId();
        Long projectId = req.getProjectId();

        // uploadFile 과 동일한 로직을 bytes 기반으로 수행
        String storedName = UUID.randomUUID() + "-" + originalName;
        String objectName = (path == null || path.isEmpty())
                ? storedName
                : path + "/" + storedName;

        try (InputStream is = new ByteArrayInputStream(bytes)) {
            minioClient.putObject(
                    PutObjectArgs.builder()
                            .bucket(bucketName)
                            .object(objectName)
                            .stream(is, bytes.length, -1)
                            .contentType("text/x-python")
                            .build()
            );
        }

        MinioAttachmentEntity attachment = MinioAttachmentEntity.builder()
                .refId(refId)
                .refType(refType)
                .originalName(originalName)
                .storedName(storedName)
                .contentType("text/x-python")
                .size((long) bytes.length)
                .storagePath(objectName)
                .title(title)
                .version(version)
                .description(description)
                .regUserId(regUserId)
                .projectId(projectId)
                .build();

        return minioAttachmentRepository.save(attachment);
    }

    /**
     * 업로드된 .py 파일을 KFP에서 학습 실행용 파이프라인 YAML로 컴파일합니다.
     * 서버에 Python 3 및 kfp 패키지(pip install kfp)가 설치되어 있어야 합니다.
     * 스크립트에는 @dsl.pipeline 데코레이터가 붙은 함수가 필요하며, 함수 이름은 'pipeline' 또는 'my_pipeline'을 권장합니다.
     *
     * @return yamlStoragePath(MinIO 객체 경로), yamlContent(생성된 YAML 본문)
     */
    public Map<String, String> compilePyToKfpYaml(Long id) throws Exception {
        MinioAttachmentEntity attachment = minioAttachmentRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("첨부파일을 찾을 수 없습니다. ID=" + id));

        String originalName = attachment.getOriginalName();
        if (originalName == null || !originalName.toLowerCase().endsWith(".py")) {
            throw new IllegalArgumentException("Python(.py) 파일만 컴파일할 수 있습니다. 파일: " + originalName);
        }

        String pyContent = readYamlText(bucketName, attachment.getStoragePath());
        Path tempDir = Files.createTempDirectory("kfp_compile_");
        try {
            Path pyPath = tempDir.resolve("pipeline.py");
            Files.writeString(pyPath, pyContent, StandardCharsets.UTF_8);
            Path yamlPath = tempDir.resolve("output.yaml");

            Path helperPath = tempDir.resolve("compile_kfp_pipeline.py");
            try (InputStream is = getClass().getResourceAsStream("/scripts/compile_kfp_pipeline.py")) {
                if (is == null) {
                    throw new IllegalStateException("컴파일 헬퍼 스크립트를 찾을 수 없습니다. (scripts/compile_kfp_pipeline.py)");
                }
                Files.copy(is, helperPath);
            }

            ProcessBuilder pb = new ProcessBuilder(
                    pythonCommand != null && !pythonCommand.isBlank() ? pythonCommand : "python3",
                    helperPath.toAbsolutePath().toString(),
                    pyPath.toAbsolutePath().toString(),
                    yamlPath.toAbsolutePath().toString()
            );
            pb.redirectErrorStream(true);
            Process p = pb.start();
            StringBuilder out = new StringBuilder();
            try (BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream(), StandardCharsets.UTF_8))) {
                String line;
                while ((line = r.readLine()) != null) {
                    out.append(line).append("\n");
                }
            }
            int exit = p.waitFor();
            if (exit != 0) {
                log.warn("KFP 컴파일 stderr/stdout: {}", out);
                throw new RuntimeException("스크립트 컴파일 실패: " + (out.length() > 0 ? out.toString().trim() : "exit " + exit));
            }

            if (!Files.exists(yamlPath)) {
                throw new RuntimeException("컴파일 결과 YAML 파일이 생성되지 않았습니다.");
            }
            String yamlContent = Files.readString(yamlPath, StandardCharsets.UTF_8);

            String baseName = originalName.replaceAll("\\.py$", "");
            String yamlObjectName = "compiled/" + id + "_" + baseName + ".yaml";
            byte[] yamlBytes = yamlContent.getBytes(StandardCharsets.UTF_8);
            minioClient.putObject(
                    PutObjectArgs.builder()
                            .bucket(bucketName)
                            .object(yamlObjectName)
                            .stream(new ByteArrayInputStream(yamlBytes), yamlBytes.length, -1)
                            .contentType("application/x-yaml")
                            .build()
            );

            Map<String, String> result = new HashMap<>();
            result.put("yamlStoragePath", yamlObjectName);
            result.put("yamlContent", yamlContent);
            return result;
        } finally {
            try {
                if (tempDir != null && Files.exists(tempDir)) {
                    Files.walk(tempDir).sorted((a, b) -> -a.compareTo(b)).forEach(path -> {
                        try {
                            Files.deleteIfExists(path);
                        } catch (Exception e) {
                            log.debug("temp 삭제 무시: {}", path, e);
                        }
                    });
                }
            } catch (Exception e) {
                log.debug("temp 정리 중 오류 무시", e);
            }
        }
    }

    /**
     * 해당 첨부파일 ID 기준으로 이미 컴파일된 YAML이 있는지 확인하고,
     * 존재하면 MinIO 객체 경로를 Optional로 반환합니다.
     */
    public Optional<String> findCompiledYamlPath(Long id) {
        MinioAttachmentEntity attachment = minioAttachmentRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("첨부파일을 찾을 수 없습니다. ID=" + id));

        String originalName = attachment.getOriginalName();
        if (originalName == null || !originalName.toLowerCase().endsWith(".py")) {
            throw new IllegalArgumentException("Python(.py) 파일만 컴파일 대상입니다. 파일: " + originalName);
        }

        String baseName = originalName.replaceAll("\\.py$", "");
        String yamlObjectName = "compiled/" + id + "_" + baseName + ".yaml";
        try {
            minioClient.statObject(
                    StatObjectArgs.builder()
                            .bucket(bucketName)
                            .object(yamlObjectName)
                            .build()
            );
            return Optional.of(yamlObjectName);
        } catch (Exception e) {
            log.debug("컴파일된 YAML이 존재하지 않음: id={}, objectName={}", id, yamlObjectName);
            return Optional.empty();
        }
    }

    /**
     * 컴파일된 YAML과 원본 .py 스크립트를 하나의 ZIP으로 묶어 반환합니다.
     * @param attachmentId 첨부파일 ID (원본 .py)
     * @param yamlObjectName MinIO에 저장된 YAML 객체 경로 (예: compiled/5_xxx.yaml)
     * @return ZIP 파일 byte[]
     */
    public byte[] downloadCompiledBundle(Long attachmentId, String yamlObjectName) throws Exception {
        MinioAttachmentEntity attachment = minioAttachmentRepository.findById(attachmentId)
                .orElseThrow(() -> new IllegalArgumentException("첨부파일을 찾을 수 없습니다. ID=" + attachmentId));
        if (yamlObjectName == null || yamlObjectName.isBlank()) {
            throw new IllegalArgumentException("yamlObjectName이 없습니다.");
        }

        byte[] pyBytes = downloadFile(bucketName, attachment.getStoragePath());
        byte[] yamlBytes = downloadFile(bucketName, yamlObjectName);

        String pyFileName = attachment.getOriginalName() != null ? attachment.getOriginalName() : "script.py";
        String yamlFileName = yamlObjectName.contains("/") ? yamlObjectName.substring(yamlObjectName.lastIndexOf('/') + 1) : yamlObjectName;

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try (ZipOutputStream zos = new ZipOutputStream(baos)) {
            zos.putNextEntry(new ZipEntry(pyFileName));
            zos.write(pyBytes);
            zos.closeEntry();
            zos.putNextEntry(new ZipEntry(yamlFileName));
            zos.write(yamlBytes);
            zos.closeEntry();
        }
        return baos.toByteArray();
    }
}