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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2013-2014 sagyf Yang. The Four Group.
 */

package goja.mvc.render.ftl.kit;

import goja.mvc.render.ftl.layout.BlockDirective;
import goja.mvc.render.ftl.layout.ExtendsDirective;
import goja.mvc.render.ftl.layout.OverrideDirective;
import goja.mvc.render.ftl.layout.SuperDirective;

import freemarker.core.Environment;
import freemarker.template.Configuration;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModelException;

import org.apache.commons.lang3.StringUtils;

import java.util.Map;

/**
 *  Freemarker 的工具类. 
 *
 * @author poplar.yfyang
 * @version 1.0 2012-04-20 上午7:30
 * @since JDK 1.5
 */
public class DirectiveKit {

    /**
     * override的标记
     */
    public static final String BLOCK                 = "__ftl_override__";
    public static final String OVERRIDE_CURRENT_NODE = "__ftl_override_current_node";

    /**
     * 返回override的标记与对应的名称信息
     *
     * @param name 名称
     * @return 标记名称信息
     */
    public static String getOverrideVariableName(String name) {
        return BLOCK + name;
    }

    public static void exposeIflytekMacros(Configuration conf) {
        conf.setSharedVariable(BlockDirective.DIRECTIVE_NAME, new BlockDirective());
        conf.setSharedVariable(ExtendsDirective.DIRECTIVE_NAME, new ExtendsDirective());
        conf.setSharedVariable(OverrideDirective.DIRECTIVE_NAME, new OverrideDirective());
        conf.setSharedVariable(SuperDirective.DIRECTIVE_NAME, new SuperDirective());
    }

    /**
     * 取得参数params中必须存在的指定Key的值，如果不存在，抛出异常
     *
     * @param params 参数Map
     * @param key    必须存在的Key
     * @return 对应key的值
     * @throws freemarker.template.TemplateException 异常，如果key不存在params中则会出现异常
     */
    @SuppressWarnings("rawtypes")
    public static String getRequiredParam(Map params, String key) throws TemplateException {
        Object value = params.get(key);
        if (value == null || StringUtils.isEmpty(value.toString())) {
            throw new TemplateModelException("not found required parameter:" + key + " for directive");
        }
        return value.toString();
    }

    /**
     * 取得params中指定Key的值，如果不存在返回默认信息
     *
     * @param params       参数Map
     * @param key          key信息
     * @param defaultValue 默认值
     * @return 对应Key的值，不存在返回默认
     */
    @SuppressWarnings("rawtypes")
    public static String getParam(Map params, String key, String defaultValue) {
        Object value = params.get(key);
        return value == null ? defaultValue : value.toString();
    }

    /**
     * 从Freemarker的运行环境中，取得指定名称的覆盖内容渲染器
     *
     * @param env  运行环境
     * @param name 指定名称
     * @return 覆盖内容渲染器
     * @throws freemarker.template.TemplateModelException 模板模型异常
     */
    public static TemplateDirectiveBodyOverrideWraper getOverrideBody(Environment env, String name)
            throws TemplateModelException {
        return (TemplateDirectiveBodyOverrideWraper)
                env.getVariable(DirectiveKit.getOverrideVariableName(name));
    }

    /**
     * 对指定的Body的渲染器，指定其父亲的内容区域
     *
     * @param topBody      内容渲染器
     * @param overrideBody 需要覆盖的内容渲染器
     */
    public static void setTopBodyForParentBody(TemplateDirectiveBodyOverrideWraper topBody,
                                               TemplateDirectiveBodyOverrideWraper overrideBody) {
        TemplateDirectiveBodyOverrideWraper parent = overrideBody;
        while (parent.parentBody != null) {
            parent = parent.parentBody;
        }
        parent.parentBody = topBody;
    }
}