/**
    *    Copyright 2009-2015 the original author or authors.
    *
    *    Licensed 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.ibatis.builder.xml;
  
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  
  import org.apache.ibatis.builder.BaseBuilder;
  import org.apache.ibatis.builder.BuilderException;
  import org.apache.ibatis.builder.CacheRefResolver;
  import org.apache.ibatis.builder.IncompleteElementException;
  import org.apache.ibatis.builder.MapperBuilderAssistant;
  import org.apache.ibatis.builder.ResultMapResolver;
  import org.apache.ibatis.cache.Cache;
  import org.apache.ibatis.executor.ErrorContext;
  import org.apache.ibatis.io.Resources;
  import org.apache.ibatis.mapping.Discriminator;
  import org.apache.ibatis.mapping.ParameterMapping;
  import org.apache.ibatis.mapping.ParameterMode;
  import org.apache.ibatis.mapping.ResultFlag;
  import org.apache.ibatis.mapping.ResultMap;
  import org.apache.ibatis.mapping.ResultMapping;
  import org.apache.ibatis.parsing.XNode;
  import org.apache.ibatis.parsing.XPathParser;
  import org.apache.ibatis.session.Configuration;
  import org.apache.ibatis.type.JdbcType;
  import org.apache.ibatis.type.TypeHandler;
  
  /**
   * @author Clinton Begin
   */
  public class XMLMapperBuilder extends BaseBuilder {
  
    private XPathParser parser;
    private MapperBuilderAssistant builderAssistant;
    private Map<String, XNode> sqlFragments;
    private String resource;
  
    @Deprecated
    public XMLMapperBuilder(Reader reader, Configuration configuration, String resource, Map<String, XNode> sqlFragments, String namespace) {
      this(reader, configuration, resource, sqlFragments);
      this.builderAssistant.setCurrentNamespace(namespace);
    }
  
    @Deprecated
    public XMLMapperBuilder(Reader reader, Configuration configuration, String resource, Map<String, XNode> sqlFragments) {
      this(new XPathParser(reader, true, configuration.getVariables(), new XMLMapperEntityResolver()),
          configuration, resource, sqlFragments);
    }
  
    public XMLMapperBuilder(InputStream inputStream, Configuration configuration, String resource, Map<String, XNode> sqlFragments, String namespace) {
      this(inputStream, configuration, resource, sqlFragments);
      this.builderAssistant.setCurrentNamespace(namespace);
    }
  
    public XMLMapperBuilder(InputStream inputStream, Configuration configuration, String resource, Map<String, XNode> sqlFragments) {
      this(new XPathParser(inputStream, true, configuration.getVariables(), new XMLMapperEntityResolver()),
          configuration, resource, sqlFragments);
    }
  
    private XMLMapperBuilder(XPathParser parser, Configuration configuration, String resource, Map<String, XNode> sqlFragments) {
      super(configuration);
      this.builderAssistant = new MapperBuilderAssistant(configuration, resource);
      this.parser = parser;
      this.sqlFragments = sqlFragments;
      this.resource = resource;
    }
  
    public void parse() {
      if (!configuration.isResourceLoaded(resource)) {
        configurationElement(parser.evalNode("/mapper"));
        configuration.addLoadedResource(resource);
        bindMapperForNamespace();
      }
  
      parsePendingResultMaps();
      parsePendingChacheRefs();
      parsePendingStatements();
   }
 
   public XNode getSqlFragment(String refid) {
     return sqlFragments.get(refid);
   }
 
   private void configurationElement(XNode context) {
     try {
       String namespace = context.getStringAttribute("namespace");
       if (namespace == null || namespace.equals("")) {
         throw new BuilderException("Mapper's namespace cannot be empty");
       }
       builderAssistant.setCurrentNamespace(namespace);
       cacheRefElement(context.evalNode("cache-ref"));
       cacheElement(context.evalNode("cache"));
       parameterMapElement(context.evalNodes("/mapper/parameterMap"));
       resultMapElements(context.evalNodes("/mapper/resultMap"));
       sqlElement(context.evalNodes("/mapper/sql"));
       buildStatementFromContext(context.evalNodes("select|insert|update|delete"));
     } catch (Exception e) {
       throw new BuilderException("Error parsing Mapper XML. Cause: " + e, e);
     }
   }
 
   private void buildStatementFromContext(List<XNode> list) {
     if (configuration.getDatabaseId() != null) {
       buildStatementFromContext(list, configuration.getDatabaseId());
     }
     buildStatementFromContext(list, null);
   }
 
   private void buildStatementFromContext(List<XNode> list, String requiredDatabaseId) {
     for (XNode context : list) {
       final XMLStatementBuilder statementParser = new XMLStatementBuilder(configuration, builderAssistant, context, requiredDatabaseId);
       try {
         statementParser.parseStatementNode();
       } catch (IncompleteElementException e) {
         configuration.addIncompleteStatement(statementParser);
       }
     }
   }
 
   private void parsePendingResultMaps() {
     Collection<ResultMapResolver> incompleteResultMaps = configuration.getIncompleteResultMaps();
     synchronized (incompleteResultMaps) {
       Iterator<ResultMapResolver> iter = incompleteResultMaps.iterator();
       while (iter.hasNext()) {
         try {
           iter.next().resolve();
           iter.remove();
         } catch (IncompleteElementException e) {
           // ResultMap is still missing a resource...
         }
       }
     }
   }
 
   private void parsePendingChacheRefs() {
     Collection<CacheRefResolver> incompleteCacheRefs = configuration.getIncompleteCacheRefs();
     synchronized (incompleteCacheRefs) {
       Iterator<CacheRefResolver> iter = incompleteCacheRefs.iterator();
       while (iter.hasNext()) {
         try {
           iter.next().resolveCacheRef();
           iter.remove();
         } catch (IncompleteElementException e) {
           // Cache ref is still missing a resource...
         }
       }
     }
   }
 
   private void parsePendingStatements() {
     Collection<XMLStatementBuilder> incompleteStatements = configuration.getIncompleteStatements();
     synchronized (incompleteStatements) {
       Iterator<XMLStatementBuilder> iter = incompleteStatements.iterator();
       while (iter.hasNext()) {
         try {
           iter.next().parseStatementNode();
           iter.remove();
         } catch (IncompleteElementException e) {
           // Statement is still missing a resource...
         }
       }
     }
   }
 
   private void cacheRefElement(XNode context) {
     if (context != null) {
       configuration.addCacheRef(builderAssistant.getCurrentNamespace(), context.getStringAttribute("namespace"));
       CacheRefResolver cacheRefResolver = new CacheRefResolver(builderAssistant, context.getStringAttribute("namespace"));
       try {
         cacheRefResolver.resolveCacheRef();
       } catch (IncompleteElementException e) {
         configuration.addIncompleteCacheRef(cacheRefResolver);
       }
     }
   }
 
   private void cacheElement(XNode context) throws Exception {
     if (context != null) {
       String type = context.getStringAttribute("type", "PERPETUAL");
       Class<? extends Cache> typeClass = typeAliasRegistry.resolveAlias(type);
       String eviction = context.getStringAttribute("eviction", "LRU");
       Class<? extends Cache> evictionClass = typeAliasRegistry.resolveAlias(eviction);
       Long flushInterval = context.getLongAttribute("flushInterval");
       Integer size = context.getIntAttribute("size");
       boolean readWrite = !context.getBooleanAttribute("readOnly", false);
       boolean blocking = context.getBooleanAttribute("blocking", false);
       Properties props = context.getChildrenAsProperties();
       builderAssistant.useNewCache(typeClass, evictionClass, flushInterval, size, readWrite, blocking, props);
     }
   }
 
   private void parameterMapElement(List<XNode> list) throws Exception {
     for (XNode parameterMapNode : list) {
       String id = parameterMapNode.getStringAttribute("id");
       String type = parameterMapNode.getStringAttribute("type");
       Class<?> parameterClass = resolveClass(type);
       List<XNode> parameterNodes = parameterMapNode.evalNodes("parameter");
       List<ParameterMapping> parameterMappings = new ArrayList<ParameterMapping>();
       for (XNode parameterNode : parameterNodes) {
         String property = parameterNode.getStringAttribute("property");
         String javaType = parameterNode.getStringAttribute("javaType");
         String jdbcType = parameterNode.getStringAttribute("jdbcType");
         String resultMap = parameterNode.getStringAttribute("resultMap");
         String mode = parameterNode.getStringAttribute("mode");
         String typeHandler = parameterNode.getStringAttribute("typeHandler");
         Integer numericScale = parameterNode.getIntAttribute("numericScale");
         ParameterMode modeEnum = resolveParameterMode(mode);
         Class<?> javaTypeClass = resolveClass(javaType);
         JdbcType jdbcTypeEnum = resolveJdbcType(jdbcType);
         @SuppressWarnings("unchecked")
         Class<? extends TypeHandler<?>> typeHandlerClass = (Class<? extends TypeHandler<?>>) resolveClass(typeHandler);
         ParameterMapping parameterMapping = builderAssistant.buildParameterMapping(parameterClass, property, javaTypeClass, jdbcTypeEnum, resultMap, modeEnum, typeHandlerClass, numericScale);
         parameterMappings.add(parameterMapping);
       }
       builderAssistant.addParameterMap(id, parameterClass, parameterMappings);
     }
   }
 
   private void resultMapElements(List<XNode> list) throws Exception {
     for (XNode resultMapNode : list) {
       try {
         resultMapElement(resultMapNode);
       } catch (IncompleteElementException e) {
         // ignore, it will be retried
       }
     }
   }
 
   private ResultMap resultMapElement(XNode resultMapNode) throws Exception {
     return resultMapElement(resultMapNode, Collections.<ResultMapping> emptyList());
   }
 
   private ResultMap resultMapElement(XNode resultMapNode, List<ResultMapping> additionalResultMappings) throws Exception {
     ErrorContext.instance().activity("processing " + resultMapNode.getValueBasedIdentifier());
     String id = resultMapNode.getStringAttribute("id",
         resultMapNode.getValueBasedIdentifier());
     String type = resultMapNode.getStringAttribute("type",
         resultMapNode.getStringAttribute("ofType",
             resultMapNode.getStringAttribute("resultType",
                 resultMapNode.getStringAttribute("javaType"))));
     String extend = resultMapNode.getStringAttribute("extends");
     Boolean autoMapping = resultMapNode.getBooleanAttribute("autoMapping");
     Class<?> typeClass = resolveClass(type);
     Discriminator discriminator = null;
     List<ResultMapping> resultMappings = new ArrayList<ResultMapping>();
     resultMappings.addAll(additionalResultMappings);
     List<XNode> resultChildren = resultMapNode.getChildren();
     for (XNode resultChild : resultChildren) {
       if ("constructor".equals(resultChild.getName())) {
         processConstructorElement(resultChild, typeClass, resultMappings);
       } else if ("discriminator".equals(resultChild.getName())) {
         discriminator = processDiscriminatorElement(resultChild, typeClass, resultMappings);
       } else {
         List<ResultFlag> flags = new ArrayList<ResultFlag>();
         if ("id".equals(resultChild.getName())) {
           flags.add(ResultFlag.ID);
         }
         resultMappings.add(buildResultMappingFromContext(resultChild, typeClass, flags));
       }
     }
     ResultMapResolver resultMapResolver = new ResultMapResolver(builderAssistant, id, typeClass, extend, discriminator, resultMappings, autoMapping);
     try {
       return resultMapResolver.resolve();
     } catch (IncompleteElementException  e) {
       configuration.addIncompleteResultMap(resultMapResolver);
       throw e;
     }
   }
 
   private void processConstructorElement(XNode resultChild, Class<?> resultType, List<ResultMapping> resultMappings) throws Exception {
     List<XNode> argChildren = resultChild.getChildren();
     for (XNode argChild : argChildren) {
       List<ResultFlag> flags = new ArrayList<ResultFlag>();
       flags.add(ResultFlag.CONSTRUCTOR);
       if ("idArg".equals(argChild.getName())) {
         flags.add(ResultFlag.ID);
       }
       resultMappings.add(buildResultMappingFromContext(argChild, resultType, flags));
     }
   }
 
   private Discriminator processDiscriminatorElement(XNode context, Class<?> resultType, List<ResultMapping> resultMappings) throws Exception {
     String column = context.getStringAttribute("column");
     String javaType = context.getStringAttribute("javaType");
     String jdbcType = context.getStringAttribute("jdbcType");
     String typeHandler = context.getStringAttribute("typeHandler");
     Class<?> javaTypeClass = resolveClass(javaType);
     @SuppressWarnings("unchecked")
     Class<? extends TypeHandler<?>> typeHandlerClass = (Class<? extends TypeHandler<?>>) resolveClass(typeHandler);
     JdbcType jdbcTypeEnum = resolveJdbcType(jdbcType);
     Map<String, String> discriminatorMap = new HashMap<String, String>();
     for (XNode caseChild : context.getChildren()) {
       String value = caseChild.getStringAttribute("value");
       String resultMap = caseChild.getStringAttribute("resultMap", processNestedResultMappings(caseChild, resultMappings));
       discriminatorMap.put(value, resultMap);
     }
     return builderAssistant.buildDiscriminator(resultType, column, javaTypeClass, jdbcTypeEnum, typeHandlerClass, discriminatorMap);
   }
 
   private void sqlElement(List<XNode> list) throws Exception {
     if (configuration.getDatabaseId() != null) {
       sqlElement(list, configuration.getDatabaseId());
     }
     sqlElement(list, null);
   }
 
   private void sqlElement(List<XNode> list, String requiredDatabaseId) throws Exception {
     for (XNode context : list) {
       String databaseId = context.getStringAttribute("databaseId");
       String id = context.getStringAttribute("id");
       id = builderAssistant.applyCurrentNamespace(id, false);
       if (databaseIdMatchesCurrent(id, databaseId, requiredDatabaseId)) {
         sqlFragments.put(id, context);
       }
     }
   }
   
   private boolean databaseIdMatchesCurrent(String id, String databaseId, String requiredDatabaseId) {
     if (requiredDatabaseId != null) {
       if (!requiredDatabaseId.equals(databaseId)) {
         return false;
       }
     } else {
       if (databaseId != null) {
         return false;
       }
       // skip this fragment if there is a previous one with a not null databaseId
       if (this.sqlFragments.containsKey(id)) {
         XNode context = this.sqlFragments.get(id);
         if (context.getStringAttribute("databaseId") != null) {
           return false;
         }
       }
     }
     return true;
   }
 
   private ResultMapping buildResultMappingFromContext(XNode context, Class<?> resultType, List<ResultFlag> flags) throws Exception {
     String property = context.getStringAttribute("property");
     String column = context.getStringAttribute("column");
     String javaType = context.getStringAttribute("javaType");
     String jdbcType = context.getStringAttribute("jdbcType");
     String nestedSelect = context.getStringAttribute("select");
     String nestedResultMap = context.getStringAttribute("resultMap",
         processNestedResultMappings(context, Collections.<ResultMapping> emptyList()));
     String notNullColumn = context.getStringAttribute("notNullColumn");
     String columnPrefix = context.getStringAttribute("columnPrefix");
     String typeHandler = context.getStringAttribute("typeHandler");
     String resulSet = context.getStringAttribute("resultSet");
     String foreignColumn = context.getStringAttribute("foreignColumn");
     boolean lazy = "lazy".equals(context.getStringAttribute("fetchType", configuration.isLazyLoadingEnabled() ? "lazy" : "eager"));
     Class<?> javaTypeClass = resolveClass(javaType);
     @SuppressWarnings("unchecked")
     Class<? extends TypeHandler<?>> typeHandlerClass = (Class<? extends TypeHandler<?>>) resolveClass(typeHandler);
     JdbcType jdbcTypeEnum = resolveJdbcType(jdbcType);
     return builderAssistant.buildResultMapping(resultType, property, column, javaTypeClass, jdbcTypeEnum, nestedSelect, nestedResultMap, notNullColumn, columnPrefix, typeHandlerClass, flags, resulSet, foreignColumn, lazy);
   }
   
   private String processNestedResultMappings(XNode context, List<ResultMapping> resultMappings) throws Exception {
     if ("association".equals(context.getName())
         || "collection".equals(context.getName())
         || "case".equals(context.getName())) {
       if (context.getStringAttribute("select") == null) {
         ResultMap resultMap = resultMapElement(context, resultMappings);
         return resultMap.getId();
       }
     }
     return null;
   }
 
   private void bindMapperForNamespace() {
     String namespace = builderAssistant.getCurrentNamespace();
     if (namespace != null) {
       Class<?> boundType = null;
       try {
         boundType = Resources.classForName(namespace);
       } catch (ClassNotFoundException e) {
         //ignore, bound type is not required
       }
       if (boundType != null) {
         if (!configuration.hasMapper(boundType)) {
           // Spring may not know the real resource name so we set a flag
           // to prevent loading again this resource from the mapper interface
           // look at MapperAnnotationBuilder#loadXmlResource
           configuration.addLoadedResource("namespace:" + namespace);
           configuration.addMapper(boundType);
         }
       }
     }
   }
 
 }