/**
    * Copyright By Grandsoft Company Limited.  
    * 2012-1-13 下午12:35:48
    */
   package gboat2.base.plugin.struts.convention;
   
   import gboat2.base.bridge.GboatAppConstants;
   import gboat2.base.bridge.debug.DefaultDebugHook;
   import gboat2.base.bridge.util.BundleUtil;
  
  import java.io.File;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.net.MalformedURLException;
  import java.util.Map;
  
  import javax.servlet.ServletContext;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.struts2.ServletActionContext;
  import org.apache.struts2.convention.ConventionUnknownHandler;
  import org.apache.struts2.osgi.DefaultBundleAccessor;
  import org.osgi.framework.Bundle;
  import org.springframework.util.ReflectionUtils;
  
  import com.opensymphony.xwork2.ActionContext;
  import com.opensymphony.xwork2.ActionInvocation;
  import com.opensymphony.xwork2.ObjectFactory;
  import com.opensymphony.xwork2.Result;
  import com.opensymphony.xwork2.config.Configuration;
  import com.opensymphony.xwork2.config.entities.ActionConfig;
  import com.opensymphony.xwork2.config.entities.ResultTypeConfig;
  import com.opensymphony.xwork2.inject.Container;
  import com.opensymphony.xwork2.inject.Inject;
  import com.opensymphony.xwork2.util.logging.Logger;
  import com.opensymphony.xwork2.util.logging.LoggerFactory;
  
  /**
   * 扩展 Struts2 内置的 {@link ConventionUnknownHandler}，使其支持 osgi 环境下 Action 类的加载
   * @date 2012-1-13
   * @author lysming
   * @since 1.0
   */
  public class GboatConventionUnknownHandler extends ConventionUnknownHandler {
  
      private static final Logger LOG = LoggerFactory.getLogger(GboatConventionUnknownHandler.class);
      private ActionContext actionContext;
      private String nameSeparator;
  
  	@Inject
  	public GboatConventionUnknownHandler(Configuration configuration, ObjectFactory objectFactory,
              ServletContext servletContext, Container container,
              @Inject("struts.convention.default.parent.package") String defaultParentPackageName,
              @Inject("struts.convention.redirect.to.slash") String redirectToSlash,
              @Inject("struts.convention.action.name.separator") String nameSeparator) {
  	    super(configuration, objectFactory, servletContext, container, defaultParentPackageName, redirectToSlash, nameSeparator);
  	    this.nameSeparator = nameSeparator;
      }
  	
  	@Override
  	public Result handleUnknownResult(ActionContext actionContext, String actionName, ActionConfig actionConfig, String resultCode)  {
          Result result = super.handleUnknownResult(actionContext, actionName, actionConfig, resultCode);
          if (result == null) {
              DefaultBundleAccessor.getInstance().loadResource(actionName);
          }
          this.actionContext = actionContext;
          return result;
      }
  
  	@Override
      protected Resource findResource(Map<String, ResultTypeConfig> resultsByExtension, String... parts) {
  	    String pathPrefix = string(parts); 
          DefaultDebugHook debugHook = DefaultDebugHook.getInstance();
          
          ActionInvocation invocation = actionContext.getActionInvocation();
  	    Bundle bundle = BundleUtil.getBundleForRequestJsp(pathPrefix, invocation, servletContext);
  	    
  	    String extendForView = getExtendForView(invocation);
  	    String[] canonicalPaths = null;
          boolean traceEnabled = LOG.isTraceEnabled();
          for (String ext : resultsByExtension.keySet()) {
              // 如果设置了 extendForView， 则先检查 xxx-extend.jsp 是否存在，不存在的时候再检查 xxx.jsp
              canonicalPaths = (StringUtils.isBlank(extendForView) ? new String[] { canonicalize(pathPrefix + "." + ext) }
                      : new String[] { canonicalize(pathPrefix + nameSeparator + extendForView + "." + ext),
                              canonicalize(pathPrefix + "." + ext) });
              for (String canonicalPath : canonicalPaths) {
                  if (bundle != null) {
                      // 是否为调试模式
                      boolean isDevMode = debugHook.isBundleDebugEnabled(bundle.getSymbolicName());
                      if (isDevMode) { // 调试模式下，检查是否存在源代码文件
                          File sourceFile = new File(debugHook.getSourceFilePath(bundle.getSymbolicName(), canonicalPath));
                          if (traceEnabled) {
                              LOG.trace("Checking for [#0]", sourceFile.getAbsolutePath());
                          }
                          if (sourceFile.isFile())
                              return new Resource(canonicalPath, ext);
                      }
  
                      if (traceEnabled) {
                         LOG.trace("Checking for [#0] from bundle [#1]", canonicalPath, bundle.getSymbolicName());
                     }
                     // 检查 Bundle jar 包中是否存在资源文件
                     if (bundle.getResource(canonicalPath) != null)
                         return new Resource(canonicalPath, ext);
                 }
 
                 if (traceEnabled) {
                     LOG.trace("Checking for [#0]", canonicalPath);
                 }
                 try {
                     // 检查 webapp 目录下是否存在资源文件
                     if (servletContext.getResource(canonicalPath) != null)
                         return new Resource(canonicalPath, ext);
                 } catch (MalformedURLException e) {
                     if (LOG.isErrorEnabled()) {
                         LOG.error("Unable to parse path to the web application resource [#0] skipping...", canonicalPath);
                     }
                 }
             }
         }
         return null;
     }
 
     @Override
     protected Result findResult(String path, String resultCode, String ext, ActionContext actionContext, Map<String, ResultTypeConfig> resultsByExtension) {
         DefaultDebugHook debugHook = DefaultDebugHook.getInstance();
         ActionInvocation invocation = actionContext.getActionInvocation();
         Bundle bundle = BundleUtil.getBundleForRequestJsp(path, invocation, servletContext);
         
         String extendForView = getExtendForView(invocation);
         String suffix = "." + ext;
         String[] paths = (StringUtils.isBlank(extendForView) ? new String[] { path } : new String[] {
                 (StringUtils.removeEnd(path, suffix) + nameSeparator + extendForView + suffix), path });
         for (String p : paths) {
             if(bundle != null) {
                 boolean traceEnabled = LOG.isTraceEnabled();
                 // 是否为调试模式
                 boolean isDevMode = debugHook.isBundleDebugEnabled(bundle.getSymbolicName());
                 if(isDevMode) { // 调试模式下，检查是否存在源代码文件
                     File sourceFile = new File(debugHook.getSourceFilePath(bundle.getSymbolicName(), p));
                     if (traceEnabled) {
                         LOG.trace("Checking for [#0]", sourceFile.getAbsolutePath());
                     }
                     if(sourceFile.isFile())
                         return buildResult(p, resultCode, resultsByExtension.get(ext), actionContext);
                 }
                 
                 if (traceEnabled)
                     LOG.trace("Checking bundle resource for [#0]", p);
                 // 检查 Bundle jar 包中是否有对应的资源文件
                 if (bundle.getEntry(p) != null) 
                     return buildResult(p, resultCode, resultsByExtension.get(ext), actionContext);
             }
             Result result = super.findResult(p, resultCode, ext, actionContext, resultsByExtension);
             if (result != null) {
                 return result;
             }
         }
         return null;
     }
 
     @Override
     protected Result buildResult(String path, String resultCode, ResultTypeConfig config, ActionContext invocationContext) {
         // 调用父类的方法创建 Result 实例
         Result result = super.buildResult(path, resultCode, config, invocationContext);
         /*
          * 往 request 中设置一个 key 为“javax.servlet.include.servlet_path”的 attribute，
          * 在调用 org.apache.struts2.components.Include.getContextRelativePath(request, relativePath) 方法的时候需要用到。
          * 注：使用 <s:include>、<g2:include> 和 <g2:page extend="..."> 标签时均会调用到 Include 类的 getContextRelativePath方法
          */
         ServletActionContext.getRequest().setAttribute(GboatAppConstants.INCLUDE_SERVLET_PATH_KEY, path);
         return result;
     }
     
     private String getExtendForView(ActionInvocation invocation) {
         Object action = invocation.getAction();
         Method method = ReflectionUtils.findMethod(action.getClass(), "getExtendForView");
         // 如果 getExtendForView 方法存在，且非私有， 则访问该方法
         if (method != null && !Modifier.isPrivate(method.getModifiers())) {
             if (!method.isAccessible()) {
                 method.setAccessible(true);
             }
             return (String) ReflectionUtils.invokeMethod(method, action);
         }
         return null;
     }
 }