/*
    *    Copyright 2009-2021 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.annotation;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.util.Map;
  
  import org.apache.ibatis.annotations.Lang;
  import org.apache.ibatis.builder.BuilderException;
  import org.apache.ibatis.mapping.BoundSql;
  import org.apache.ibatis.mapping.SqlSource;
  import org.apache.ibatis.reflection.ParamNameResolver;
  import org.apache.ibatis.scripting.LanguageDriver;
  import org.apache.ibatis.session.Configuration;
  
  /**
   * @author Clinton Begin
   * @author Kazuki Shimizu
   */
  public class ProviderSqlSource implements SqlSource {
  
    private final Configuration configuration;
    private final Class<?> providerType;
    private final LanguageDriver languageDriver;
    private final Method mapperMethod;
    private final Method providerMethod;
    private final String[] providerMethodArgumentNames;
    private final Class<?>[] providerMethodParameterTypes;
    private final ProviderContext providerContext;
    private final Integer providerContextIndex;
  
    /**
     * This constructor will remove at a future version.
     *
     * @param configuration
     *          the configuration
     * @param provider
     *          the provider
     * @deprecated Since 3.5.3, Please use the {@link #ProviderSqlSource(Configuration, Annotation, Class, Method)}
     *             instead of this.
     */
    @Deprecated
    public ProviderSqlSource(Configuration configuration, Object provider) {
      this(configuration, provider, null, null);
    }
  
    /**
     * This constructor will remove at a future version.
     *
     * @param configuration
     *          the configuration
     * @param provider
     *          the provider
     * @param mapperType
     *          the mapper type
     * @param mapperMethod
     *          the mapper method
     * @since 3.4.5
     * @deprecated Since 3.5.3, Please use the {@link #ProviderSqlSource(Configuration, Annotation, Class, Method)} instead of this.
     */
    @Deprecated
    public ProviderSqlSource(Configuration configuration, Object provider, Class<?> mapperType, Method mapperMethod) {
      this(configuration, (Annotation) provider, mapperType, mapperMethod);
    }
  
    /**
     * Instantiates a new provider sql source.
     *
     * @param configuration
     *          the configuration
     * @param provider
     *          the provider
     * @param mapperType
     *          the mapper type
     * @param mapperMethod
     *          the mapper method
     * @since 3.5.3
     */
    public ProviderSqlSource(Configuration configuration, Annotation provider, Class<?> mapperType, Method mapperMethod) {
      String candidateProviderMethodName;
      Method candidateProviderMethod = null;
      try {
        this.configuration = configuration;
       this.mapperMethod = mapperMethod;
       Lang lang = mapperMethod == null ? null : mapperMethod.getAnnotation(Lang.class);
       this.languageDriver = configuration.getLanguageDriver(lang == null ? null : lang.value());
       this.providerType = getProviderType(configuration, provider, mapperMethod);
       candidateProviderMethodName = (String) provider.annotationType().getMethod("method").invoke(provider);
 
       if (candidateProviderMethodName.length() == 0 && ProviderMethodResolver.class.isAssignableFrom(this.providerType)) {
         candidateProviderMethod = ((ProviderMethodResolver) this.providerType.getDeclaredConstructor().newInstance())
             .resolveMethod(new ProviderContext(mapperType, mapperMethod, configuration.getDatabaseId()));
       }
       if (candidateProviderMethod == null) {
         candidateProviderMethodName = candidateProviderMethodName.length() == 0 ? "provideSql" : candidateProviderMethodName;
         for (Method m : this.providerType.getMethods()) {
           if (candidateProviderMethodName.equals(m.getName()) && CharSequence.class.isAssignableFrom(m.getReturnType())) {
             if (candidateProviderMethod != null) {
               throw new BuilderException("Error creating SqlSource for SqlProvider. Method '"
                   + candidateProviderMethodName + "' is found multiple in SqlProvider '" + this.providerType.getName()
                   + "'. Sql provider method can not overload.");
             }
             candidateProviderMethod = m;
           }
         }
       }
     } catch (BuilderException e) {
       throw e;
     } catch (Exception e) {
       throw new BuilderException("Error creating SqlSource for SqlProvider.  Cause: " + e, e);
     }
     if (candidateProviderMethod == null) {
       throw new BuilderException("Error creating SqlSource for SqlProvider. Method '"
           + candidateProviderMethodName + "' not found in SqlProvider '" + this.providerType.getName() + "'.");
     }
     this.providerMethod = candidateProviderMethod;
     this.providerMethodArgumentNames = new ParamNameResolver(configuration, this.providerMethod).getNames();
     this.providerMethodParameterTypes = this.providerMethod.getParameterTypes();
 
     ProviderContext candidateProviderContext = null;
     Integer candidateProviderContextIndex = null;
     for (int i = 0; i < this.providerMethodParameterTypes.length; i++) {
       Class<?> parameterType = this.providerMethodParameterTypes[i];
       if (parameterType == ProviderContext.class) {
         if (candidateProviderContext != null) {
           throw new BuilderException("Error creating SqlSource for SqlProvider. ProviderContext found multiple in SqlProvider method ("
               + this.providerType.getName() + "." + providerMethod.getName()
               + "). ProviderContext can not define multiple in SqlProvider method argument.");
         }
         candidateProviderContext = new ProviderContext(mapperType, mapperMethod, configuration.getDatabaseId());
         candidateProviderContextIndex = i;
       }
     }
     this.providerContext = candidateProviderContext;
     this.providerContextIndex = candidateProviderContextIndex;
   }
 
   @Override
   public BoundSql getBoundSql(Object parameterObject) {
     SqlSource sqlSource = createSqlSource(parameterObject);
     return sqlSource.getBoundSql(parameterObject);
   }
 
   private SqlSource createSqlSource(Object parameterObject) {
     try {
       String sql;
       if (parameterObject instanceof Map) {
         int bindParameterCount = providerMethodParameterTypes.length - (providerContext == null ? 0 : 1);
         if (bindParameterCount == 1
             && providerMethodParameterTypes[Integer.valueOf(0).equals(providerContextIndex) ? 1 : 0].isAssignableFrom(parameterObject.getClass())) {
           sql = invokeProviderMethod(extractProviderMethodArguments(parameterObject));
         } else {
           @SuppressWarnings("unchecked")
           Map<String, Object> params = (Map<String, Object>) parameterObject;
           sql = invokeProviderMethod(extractProviderMethodArguments(params, providerMethodArgumentNames));
         }
       } else if (providerMethodParameterTypes.length == 0) {
         sql = invokeProviderMethod();
       } else if (providerMethodParameterTypes.length == 1) {
         if (providerContext == null) {
           sql = invokeProviderMethod(parameterObject);
         } else {
           sql = invokeProviderMethod(providerContext);
         }
       } else if (providerMethodParameterTypes.length == 2) {
         sql = invokeProviderMethod(extractProviderMethodArguments(parameterObject));
       } else {
         throw new BuilderException("Cannot invoke SqlProvider method '" + providerMethod
           + "' with specify parameter '" + (parameterObject == null ? null : parameterObject.getClass())
           + "' because SqlProvider method arguments for '" + mapperMethod + "' is an invalid combination.");
       }
       Class<?> parameterType = parameterObject == null ? Object.class : parameterObject.getClass();
       return languageDriver.createSqlSource(configuration, sql, parameterType);
     } catch (BuilderException e) {
       throw e;
     } catch (Exception e) {
       throw new BuilderException("Error invoking SqlProvider method '" + providerMethod
           + "' with specify parameter '" + (parameterObject == null ? null : parameterObject.getClass()) + "'.  Cause: " + extractRootCause(e), e);
     }
   }
 
   private Throwable extractRootCause(Exception e) {
     Throwable cause = e;
     while (cause.getCause() != null) {
       cause = cause.getCause();
     }
     return cause;
   }
 
   private Object[] extractProviderMethodArguments(Object parameterObject) {
     if (providerContext != null) {
       Object[] args = new Object[2];
       args[providerContextIndex == 0 ? 1 : 0] = parameterObject;
       args[providerContextIndex] = providerContext;
       return args;
     } else {
       return new Object[] { parameterObject };
     }
   }
 
   private Object[] extractProviderMethodArguments(Map<String, Object> params, String[] argumentNames) {
     Object[] args = new Object[argumentNames.length];
     for (int i = 0; i < args.length; i++) {
       if (providerContextIndex != null && providerContextIndex == i) {
         args[i] = providerContext;
       } else {
         args[i] = params.get(argumentNames[i]);
       }
     }
     return args;
   }
 
   private String invokeProviderMethod(Object... args) throws Exception {
     Object targetObject = null;
     if (!Modifier.isStatic(providerMethod.getModifiers())) {
       targetObject = providerType.getDeclaredConstructor().newInstance();
     }
     CharSequence sql = (CharSequence) providerMethod.invoke(targetObject, args);
     return sql != null ? sql.toString() : null;
   }
 
   private Class<?> getProviderType(Configuration configuration, Annotation providerAnnotation, Method mapperMethod)
       throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
     Class<?> type = (Class<?>) providerAnnotation.annotationType().getMethod("type").invoke(providerAnnotation);
     Class<?> value = (Class<?>) providerAnnotation.annotationType().getMethod("value").invoke(providerAnnotation);
     if (value == void.class && type == void.class) {
       if (configuration.getDefaultSqlProviderType() != null) {
         return configuration.getDefaultSqlProviderType();
       }
       throw new BuilderException("Please specify either 'value' or 'type' attribute of @"
           + providerAnnotation.annotationType().getSimpleName()
           + " at the '" + mapperMethod.toString() + "'.");
     }
     if (value != void.class && type != void.class && value != type) {
       throw new BuilderException("Cannot specify different class on 'value' and 'type' attribute of @"
           + providerAnnotation.annotationType().getSimpleName()
           + " at the '" + mapperMethod.toString() + "'.");
     }
     return value == void.class ? type : value;
   }
 
 }