package com.music.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.resource.PathResourceResolver;

import java.io.IOException;

/**
 * 生产环境：前端 SPA 由 Spring Boot 托管时，未匹配到的路径回退到 index.html。
 */
@Configuration
public class SpaForwardConfig implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**")
                .addResourceLocations("classpath:/static/")
                .resourceChain(true)
                .addResolver(new PathResourceResolver() {
                    @Override
                    protected Resource getResource(String resourcePath, Resource location) throws IOException {
                        Resource resource = location.createRelative(resourcePath);
                        if (resource.exists() && resource.isReadable()) {
                            return resource;
                        }
                        // SPA 路由回退到 index.html
                        return location.createRelative("index.html");
                    }
                });
    }
}