package com.zt.modules.oss.annotation;

import com.zt.common.annotation.OssField;
import com.zt.modules.oss.model.OssFieldDefine;
import io.swagger.annotations.ApiModel;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternUtils;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.stereotype.Component;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@Component("dataFieldParser")
public class DataFieldParser {

    @Autowired
    private ResourceLoader resourceLoader;

    private static final String VALUE = "value";

    /**
     * 获取指定包下所有添加了执行注解的方法信息
     *
     * @return
     * @throws Exception
     */
    public List<OssFieldDefine> getOssFields() throws Exception {
        List<OssFieldDefine> defines = new ArrayList<>();

        ResourcePatternResolver resolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
        MetadataReaderFactory metaReader = new CachingMetadataReaderFactory(resourceLoader);
        Resource[] resources = resolver.getResources("classpath*:com/zt/**/*.class");

        for (Resource r : resources) {
            MetadataReader reader = metaReader.getMetadataReader(r);
            defines.addAll(resolveClass(reader));
        }

        return defines;
    }

    private List<OssFieldDefine> resolveClass(MetadataReader reader) {
        List<OssFieldDefine> defines = new ArrayList<>();
        // 获取注解元数据
        AnnotationMetadata metadata = reader.getAnnotationMetadata();
        // 获取类中RequestMapping注解的value属性
        if (!metadata.hasAnnotation(ApiModel.class.getCanonicalName())) {
            return defines;
        }
        String apiName = getAttr(metadata.getAnnotationAttributes(ApiModel.class.getCanonicalName()), VALUE);
        try {
            Class clazz = Class.forName(metadata.getClassName());
            OssFieldDefine define = new OssFieldDefine(clazz.getSimpleName(), apiName);

            Field[] fields = clazz.getDeclaredFields();
            for (Field field : fields) {
                boolean isOssField = field.isAnnotationPresent(OssField.class);
                if (isOssField) {
                    OssField annotation = field.getAnnotation(OssField.class);
                    define.addField(field.getName(), annotation.value());
                }
            }
            if (define.getFields().size() > 0) {
                defines.add(define);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

        return defines;
    }

    /**
     * 获取注解的属性
     *
     * @param attributes
     * @param key
     * @return
     */
    private String getAttr(Map<String, Object> attributes, String key) {
        // 若类无注解
        if (attributes == null || attributes.get(key) == null) {
            return null;
        }
        // 获取注解的属性值
        Object value = attributes.get(key);
        if (value instanceof String) {
            return (String) value;
        } else if (value instanceof String[]) {
            String[] values = (String[]) attributes.get(key);
            if (0 == values.length) {
                return null;
            }
            return values[0];
        }
        return null;
    }
}