/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.commons.jexl3;
  
  import org.apache.commons.jexl3.internal.Script;
  
  /**
   * Helper class to carry information such as a url/file name, line and column for
   * debugging information reporting.
   */
  public class JexlInfo {
  
      /**
       * Describes errors more precisely.
       */
      public interface Detail {
          /**
           * Gets the end column on the line that triggered the error
           * @return the end column on the line that triggered the error
           */
          int end();
  
          /**
           * Gets the start column on the line that triggered the error
           * @return the start column on the line that triggered the error
           */
          int start();
  
          /**
           * Gets the code that triggered the error
           * @return the actual part of code that triggered the error
           */
          @Override
          String toString();
      }
  
      /**
       * Gets the info from a script.
       * @param script the script
       * @return the info
       */
      public static JexlInfo from(final JexlScript script) {
          return script instanceof Script? ((Script) script).getInfo() :  null;
      }
  
      /** Line number. */
      private final int line;
  
      /** Column number. */
      private final int column;
  
      /** Name. */
      private final String name;
  
      /**
       * Create an information structure for dynamic set/get/invoke/new.
       * <p>This gathers the class, method and line number of the first calling method
       * outside of o.a.c.jexl3.</p>
       */
      public JexlInfo() {
          final StackTraceElement[] stack = new Throwable().getStackTrace();
          String cname = getClass().getName();
          final String pkgname = getClass().getPackage().getName();
          StackTraceElement se = null;
          for (int s = 1; s < stack.length; ++s) {
              se = stack[s];
              final String className = se.getClassName();
              if (!className.equals(cname)) {
                  // go deeper if called from jexl implementation classes
                  if (!className.startsWith(pkgname + ".internal.") && !className.startsWith(pkgname + ".Jexl")
                      && !className.startsWith(pkgname + ".parser")) {
                      break;
                  }
                  cname = className;
              }
          }
          this.name = se != null ? se.getClassName() + "." + se.getMethodName() + ":" + se.getLineNumber() : "?";
          this.line = 1;
          this.column = 1;
      }
  
      /**
       * The copy constructor.
       *
      * @param copy the instance to copy
      */
     protected JexlInfo(final JexlInfo copy) {
         this(copy.getName(), copy.getLine(), copy.getColumn());
     }
 
     /**
      * Create info.
      *
      * @param source source name
      * @param l line number
      * @param c column number
      */
     public JexlInfo(final String source, final int l, final int c) {
         name = source;
         line = l <= 0? 1: l;
         column = c <= 0? 1 : c;
     }
 
     /**
      * Creates info reusing the name.
      *
      * @param l the line
      * @param c the column
      * @return a new info instance
      */
     public JexlInfo at(final int l, final int c) {
         return new JexlInfo(name, l, c);
     }
 
     /**
      * Gets this instance or a copy without any decorations
      * @return this instance or a copy without any decorations
      */
     public JexlInfo detach() {
         return this;
     }
 
     /**
      * Gets the column number.
      *
      * @return the column.
      */
     public final int getColumn() {
         return column;
     }
 
     /**
      * Gets error detail
      * @return the detailed information in case of an error
      */
     public Detail getDetail() {
         return null;
     }
 
     /**
      * Gets the line number.
      *
      * @return line number.
      */
     public final int getLine() {
         return line;
     }
 
     /**
      * Gets the file/script/url name.
      *
      * @return template name
      */
     public final String getName() {
         return name;
     }
 
     /**
      * Formats this info in the form 'name&#064;line:column'.
      *
      * @return the formatted info
      */
     @Override
     public String toString() {
         final StringBuilder sb = new StringBuilder(name != null ? name : "");
         sb.append("@");
         sb.append(line);
         sb.append(":");
         sb.append(column);
         final JexlInfo.Detail dbg = getDetail();
         if (dbg!= null) {
             sb.append("![");
             sb.append(dbg.start());
             sb.append(",");
             sb.append(dbg.end());
             sb.append("]: '");
             sb.append(dbg.toString());
             sb.append("'");
         }
         return sb.toString();
     }
 }