package com.nanri.aiimage.config;

import org.junit.jupiter.api.Test;
import org.springframework.boot.env.YamlPropertySourceLoader;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.StandardEnvironment;
import org.springframework.core.io.ClassPathResource;

import java.io.IOException;
import java.util.Collections;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * application.yml 默认值与 env 覆盖测试（任务 53）。
 * 用 Spring 的 YamlPropertySourceLoader 真实解析 application.yml，
 * 再经 StandardEnvironment 验证 ${VAR:default} 占位符的默认值与 env 覆盖语义。
 */
class RequestTraceConfigTest {

    private static final String KEY = "aiimage.instance-routing.request-body-cache-limit-bytes";

    private static String rawYmlValue() throws IOException {
        YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
        List<PropertySource<?>> sources =
                loader.load("app.yml", new ClassPathResource("application.yml"));
        for (PropertySource<?> source : sources) {
            Object value = source.getProperty(KEY);
            if (value != null) {
                return String.valueOf(value);
            }
        }
        throw new AssertionError("application.yml 未包含 " + KEY);
    }

    private static String resolve(String raw, String envValue) {
        StandardEnvironment environment = new StandardEnvironment();
        environment.getPropertySources().addFirst(new MapPropertySource(
                "test-env", envValue == null
                        ? Collections.emptyMap()
                        : Collections.singletonMap("AIIMAGE_INSTANCE_ROUTE_REQUEST_BODY_CACHE_LIMIT_BYTES", envValue)));
        return environment.resolvePlaceholders(raw);
    }

    @Test
    void ymlDefaultIs1MiB() throws IOException {
        assertTrue(rawYmlValue().contains("1048576"), "yml 默认值 1048576（1MB）");
    }

    @Test
    void envOverrideTakesEffect() throws IOException {
        assertEquals("2097152", resolve(rawYmlValue(), "2097152"), "env 覆盖生效");
    }

    @Test
    void envOverrideLarge() throws IOException {
        assertEquals("104857600", resolve(rawYmlValue(), "104857600"), "大值覆盖生效");
    }

    @Test
    void envOverrideSmallIsKeptThenClampedByCode() throws IOException {
        // env 注入 1024（<1MB）：yml 层原样解析，钳制在代码层 Math.max(1024*1024, …)
        assertEquals("1024", resolve(rawYmlValue(), "1024"));
    }

    @Test
    void placeholderFormat() throws IOException {
        assertTrue(rawYmlValue().matches("\\$\\{AIIMAGE_INSTANCE_ROUTE_REQUEST_BODY_CACHE_LIMIT_BYTES:1048576}"),
                "占位符格式 ${VAR:default}");
    }

    @Test
    void defaultMatchesCodeConstant() throws IOException {
        assertEquals("1048576", resolve(rawYmlValue(), null), "未设 env 时解析为 1048576，与代码 @Value 默认一致");
    }

    @Test
    void envUnsetUsesDefault() throws IOException {
        assertFalse(resolve(rawYmlValue(), null).startsWith("${"), "未设 env 时占位符被解析为默认值而非保留原文");
        assertEquals("1048576", resolve(rawYmlValue(), null));
    }

    @Test
    void ymlLoadsUnderSpringEnv() throws IOException {
        YamlPropertySourceLoader loader = new YamlPropertySourceLoader();
        List<PropertySource<?>> sources =
                loader.load("app.yml", new ClassPathResource("application.yml"));
        assertFalse(sources.isEmpty(), "application.yml 能被 YamlPropertySourceLoader 加载");
        boolean found = false;
        for (PropertySource<?> source : sources) {
            if (source.containsProperty(KEY)) {
                found = true;
            }
        }
        assertTrue(found, "instance-routing.request-body-cache-limit-bytes 存在于 yml 配置源");
    }
}