package com.jsql.util;
   
   import com.jsql.model.InjectionModel;
   import com.jsql.model.exception.JSqlException;
   import com.jsql.model.injection.method.AbstractMethodInjection;
   import org.apache.commons.lang3.StringUtils;
   import org.apache.logging.log4j.LogManager;
   import org.apache.logging.log4j.Logger;
   import org.json.JSONArray;
  import org.json.JSONException;
  import org.json.JSONObject;
  
  import java.util.AbstractMap.SimpleEntry;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.regex.Pattern;
  
  public class JsonUtil {
      
      /**
       * Log4j logger sent to view.
       */
      private static final Logger LOGGER = LogManager.getRootLogger();
  
      private final InjectionModel injectionModel;
      
      public JsonUtil(InjectionModel injectionModel) {
          this.injectionModel = injectionModel;
      }
  
      public static boolean isJson(String param) {
          
          var isJson = false;
          
          try {
              // Test for JSON Object
              new JSONObject(param);
              isJson = true;
              
          } catch (JSONException exceptionJSONObject) {
              try {
                  // Test for JSON Array
                  new JSONArray(param);
                  isJson = true;
                  
              } catch (JSONException exceptionJSONArray) {
                  // Not a JSON entity
              }
          }
          
          return isJson;
      }
  
      public static Object getJson(String param) {
  
          Object jsonEntity;  // Will test if current value is a JSON entity
          
          try {
              jsonEntity = new JSONObject(param);  // Test for JSON Object
          } catch (JSONException exceptionJSONObject) {
              try {
                  jsonEntity = new JSONArray(param);  // Test for JSON Array
              } catch (JSONException exceptionJSONArray) {
                  jsonEntity = new Object();  // Not a JSON entity
              }
          }
          
          return jsonEntity;
      }
  
      public static List<SimpleEntry<String, String>> createEntries(Object jsonEntity, String parentName, SimpleEntry<String, String> parentXPath) {
          
          List<SimpleEntry<String, String>> attributesXPath = new ArrayList<>();
          
          if (jsonEntity instanceof JSONObject) {
              JsonUtil.scanJsonObject(jsonEntity, parentName, parentXPath, attributesXPath);
          } else if (jsonEntity instanceof JSONArray) {
              JsonUtil.scanJsonArray(jsonEntity, parentName, parentXPath, attributesXPath);
          }
          
          return attributesXPath;
      }
  
      private static void scanJsonArray(Object jsonEntity, String parentName, SimpleEntry<String, String> parentXPath, List<SimpleEntry<String, String>> attributesXPath) {
          
          var jsonArrayEntity = (JSONArray) jsonEntity;
          
          for (var i = 0; i < jsonArrayEntity.length(); i++) {
              
              Object value = jsonArrayEntity.get(i);
              String xpath = parentName +"["+ i +"]";
              
              // Not possible to make generic with scanJsonObject() because of JSONArray.put(int) != JSONObject.put(String)
              if (value instanceof JSONArray || value instanceof JSONObject) {
                  attributesXPath.addAll(JsonUtil.createEntries(value, xpath, parentXPath));
              } else if (value instanceof String) {
                  
                  SimpleEntry<String, String> stringValue = new SimpleEntry<>(xpath, (String) value);
                 attributesXPath.add(stringValue);
                 
                 if (parentXPath == null) {
                     jsonArrayEntity.put(i, value.toString().replaceAll(Pattern.quote(InjectionModel.STAR) +"$", StringUtils.EMPTY));
                 } else if (stringValue.equals(parentXPath)) {
                     jsonArrayEntity.put(i, value + InjectionModel.STAR);
                 }
             }
         }
     }
 
     private static void scanJsonObject(Object jsonEntity, String parentName, SimpleEntry<String, String> parentXPath, List<SimpleEntry<String, String>> attributesXPath) {
         
         var jsonObjectEntity = (JSONObject) jsonEntity;
         
         Iterator<?> keys = jsonObjectEntity.keys();
         
         while (keys.hasNext()) {
             
             String key = (String) keys.next();
             var value = jsonObjectEntity.get(key);
             String xpath = parentName +"."+ key;
             
             // Not possible to make generic with scanJsonObject() because of JSONArray.put(int) != JSONObject.put(String)
             if (value instanceof JSONArray || value instanceof JSONObject) {
                 attributesXPath.addAll(JsonUtil.createEntries(value, xpath, parentXPath));
             } else if (value instanceof String) {
                 
                 SimpleEntry<String, String> stringValue = new SimpleEntry<>(xpath, (String) value);
                 attributesXPath.add(stringValue);
                 
                 if (parentXPath == null) {
                     jsonObjectEntity.put(key, value.toString().replaceAll(Pattern.quote(InjectionModel.STAR) +"$", StringUtils.EMPTY));
                 } else if (stringValue.equals(parentXPath)) {
                     jsonObjectEntity.put(key, value + InjectionModel.STAR);
                 }
             }
         }
     }
     
     public boolean testJsonParam(AbstractMethodInjection methodInjection, SimpleEntry<String, String> paramStar) {
         
         var hasFoundInjection = false;
         
         // Remove STAR at the end of parameter, STAR will be added inside json data instead
         paramStar.setValue(paramStar.getValue().replace(InjectionModel.STAR, StringUtils.EMPTY));
         
         // Will test if current value is a JSON entity
         Object jsonEntity = JsonUtil.getJson(paramStar.getValue());
         
         // Define a tree of JSON attributes with path as the key: root.a => value of a
         List<SimpleEntry<String, String>> attributesJson = JsonUtil.createEntries(jsonEntity, "root", null);
         
         // Loop through each JSON values
         for (SimpleEntry<String, String> parentXPath: attributesJson) {
             
             JsonUtil.createEntries(jsonEntity, "root", null);  // Erase previously defined *
             JsonUtil.createEntries(jsonEntity, "root", parentXPath);  // Add * to current parameter's value
 
             paramStar.setValue(jsonEntity.toString());  // Replace param value by marked one
             
             try {
                 LOGGER.log(
                     LogLevelUtil.CONSOLE_INFORM,
                     "Checking JSON {} parameter {}={}",
                     methodInjection::name,
                     parentXPath::getKey,
                     () -> parentXPath.getValue().replace(InjectionModel.STAR, StringUtils.EMPTY)
                 );
                 
                 // Test current JSON value marked with * for injection
                 // Keep original param
                 hasFoundInjection = this.injectionModel.getMediatorStrategy().testStrategies(paramStar);
                 
                 // Injection successful
                 break;
                 
             } catch (JSqlException e) {
                 
                 // Injection failure
                 LOGGER.log(
                     LogLevelUtil.CONSOLE_ERROR,
                     String.format(
                         "No injection found for JSON %s parameter %s=%s",
                         methodInjection.name(),
                         parentXPath.getKey(),
                         parentXPath.getValue().replace(InjectionModel.STAR, StringUtils.EMPTY)
                     )
                 );
             } finally {
                 
                 // Erase * at the end of each params
                 // TODO useless
                 methodInjection.getParams()
                     .forEach(e -> e.setValue(
                         e.getValue().replaceAll(Pattern.quote(InjectionModel.STAR) +"$", StringUtils.EMPTY)
                     ));
                 
                 // Erase * from JSON if failure
                 if (!hasFoundInjection) {
                     paramStar.setValue(
                         paramStar.getValue().replace(InjectionModel.STAR, StringUtils.EMPTY)
                     );
                 }
             }
         }
         
         return hasFoundInjection;
     }
 }