package com.tourguide.modules.review.service;

import com.tourguide.common.exception.BusinessException;
import com.tourguide.config.properties.StorageProperties;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

@Service
public class ReviewImageStorageService {
    private static final long MAX_FILE_SIZE = 5L * 1024 * 1024;
    private static final Map<String, String> CONTENT_TYPE_EXTENSIONS = createContentTypeExtensions();
    private final StorageProperties storageProperties;

    public ReviewImageStorageService(StorageProperties storageProperties) {
        this.storageProperties = storageProperties;
    }

    public String store(MultipartFile file) {
        if (file == null || file.isEmpty()) {
            throw new BusinessException(400, "请选择评价图片");
        }
        if (file.getSize() > MAX_FILE_SIZE) {
            throw new BusinessException(400, "评价图片不能超过5MB");
        }
        String extension = CONTENT_TYPE_EXTENSIONS.get(file.getContentType());
        if (extension == null) {
            throw new BusinessException(400, "评价图片仅支持 JPG、PNG 或 WebP 格式");
        }

        Path directory = Paths.get(storageProperties.getReviewImageDirectory()).toAbsolutePath().normalize();
        String filename = UUID.randomUUID().toString().replace("-", "") + extension;
        Path target = directory.resolve(filename).normalize();
        if (!target.startsWith(directory)) {
            throw new BusinessException(400, "评价图片文件路径不合法");
        }
        try {
            Files.createDirectories(directory);
            try (InputStream inputStream = file.getInputStream()) {
                Files.copy(inputStream, target, StandardCopyOption.REPLACE_EXISTING);
            }
        } catch (IOException exception) {
            throw new BusinessException(500, "评价图片保存失败，请稍后重试");
        }
        return normalizePublicPath(storageProperties.getReviewImagePublicPath()) + "/" + filename;
    }

    private String normalizePublicPath(String publicPath) {
        String normalized = publicPath == null ? "/uploads/review-images" : publicPath.trim();
        if (!normalized.startsWith("/")) normalized = "/" + normalized;
        while (normalized.endsWith("/")) normalized = normalized.substring(0, normalized.length() - 1);
        return normalized;
    }

    private static Map<String, String> createContentTypeExtensions() {
        Map<String, String> extensions = new HashMap<String, String>();
        extensions.put("image/jpeg", ".jpg");
        extensions.put("image/png", ".png");
        extensions.put("image/webp", ".webp");
        return extensions;
    }
}