/*
 * Copyright (c) 2017.
 *
 * 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 com.itfsw.mybatis.generator.plugins.tools;

import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
import org.apache.ibatis.reflection.factory.ObjectFactory;
import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;
import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeHandlerRegistry;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * ---------------------------------------------------------------------------
 * From http://git.oschina.net/free/Mybatis_Utils/blob/master/SqlHelper/SqlHelper.java
 * ---------------------------------------------------------------------------
 * @author: hewei
 * @time:2017/6/26 15:42
 * ---------------------------------------------------------------------------
 */
public class SqlHelper {
    private static final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory();
    private static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();

    /**
     * 通过Mapper接口和方法名(过滤掉回车多余空格信息,便于比对)
     * @param mapper
     * @param methodName
     * @param args
     * @return
     */
    public static String getFormatMapperSql(Object mapper, String methodName, Object... args) {
        String sql = getMapperSql(mapper, methodName, args);
        return sql == null ? null : sql.replaceAll("\n", " ").replaceAll("\\s+", " ");
    }

    /**
     * 通过接口获取sql
     * @param mapper
     * @param methodName
     * @param args
     * @return
     */
    public static String getMapperSql(Object mapper, String methodName, Object... args) {
        MetaObject metaObject = SystemMetaObject.forObject(mapper);
        SqlSession session = (SqlSession) metaObject.getValue("h.sqlSession");
        Class mapperInterface = (Class) metaObject.getValue("h.mapperInterface");
        String fullMethodName = mapperInterface.getCanonicalName() + "." + methodName;
        if (args == null || args.length == 0) {
            return getNamespaceSql(session, fullMethodName, null);
        } else {
            return getMapperSql(session, mapperInterface, methodName, args);
        }
    }

    /**
     * 通过Mapper方法名获取sql
     * @param session
     * @param fullMapperMethodName
     * @param args
     * @return
     */
    public static String getMapperSql(SqlSession session, String fullMapperMethodName, Object... args) {
        if (args == null || args.length == 0) {
            return getNamespaceSql(session, fullMapperMethodName, null);
        }
        String methodName = fullMapperMethodName.substring(fullMapperMethodName.lastIndexOf('.') + 1);
        Class mapperInterface = null;
        try {
            mapperInterface = Class.forName(fullMapperMethodName.substring(0, fullMapperMethodName.lastIndexOf('.')));
            return getMapperSql(session, mapperInterface, methodName, args);
        } catch (ClassNotFoundException e) {
            throw new IllegalArgumentException("参数" + fullMapperMethodName + "无效!");
        }
    }

    /**
     * 通过Mapper接口和方法名
     * @param session
     * @param mapperInterface
     * @param methodName
     * @param args
     * @return
     */
    public static String getMapperSql(SqlSession session, Class mapperInterface, String methodName, Object... args) {
        String fullMapperMethodName = mapperInterface.getCanonicalName() + "." + methodName;
        if (args == null || args.length == 0) {
            return getNamespaceSql(session, fullMapperMethodName, null);
        }
        Method method = getDeclaredMethods(mapperInterface, methodName);
        Map params = new HashMap();
        final Class<?>[] argTypes = method.getParameterTypes();
        for (int i = 0; i < argTypes.length; i++) {
            if (!RowBounds.class.isAssignableFrom(argTypes[i]) && !ResultHandler.class.isAssignableFrom(argTypes[i])) {
                String paramName = "param" + String.valueOf(params.size() + 1);
                paramName = getParamNameFromAnnotation(method, i, paramName);
                params.put(paramName, i >= args.length ? null : args[i]);
            }
        }
        if (useParameter(method, args)) {
            return getNamespaceSql(session, fullMapperMethodName, args[0]);
        }
        return getNamespaceSql(session, fullMapperMethodName, params);
    }


    /**
     * 通过命名空间方式获取sql
     * @param session
     * @param namespace
     * @return
     */
    public static String getNamespaceSql(SqlSession session, String namespace) {
        return getNamespaceSql(session, namespace, null);
    }

    /**
     * 通过命名空间方式获取sql
     * @param session
     * @param namespace
     * @param params
     * @return
     */
    public static String getNamespaceSql(SqlSession session, String namespace, Object params) {
        Configuration configuration = session.getConfiguration();
        MappedStatement mappedStatement = configuration.getMappedStatement(namespace);
        TypeHandlerRegistry typeHandlerRegistry = mappedStatement.getConfiguration().getTypeHandlerRegistry();
        BoundSql boundSql = mappedStatement.getBoundSql(params);
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        String sql = boundSql.getSql();
        if (parameterMappings != null) {
            for (int i = 0; i < parameterMappings.size(); i++) {
                ParameterMapping parameterMapping = parameterMappings.get(i);
                if (parameterMapping.getMode() != ParameterMode.OUT) {
                    Object value;
                    String propertyName = parameterMapping.getProperty();
                    if (boundSql.hasAdditionalParameter(propertyName)) {
                        value = boundSql.getAdditionalParameter(propertyName);
                    } else if (params == null) {
                        value = null;
                    } else if (typeHandlerRegistry.hasTypeHandler(params.getClass())) {
                        value = params;
                    } else {
                        MetaObject metaObject = configuration.newMetaObject(params);
                        value = metaObject.getValue(propertyName);
                    }
                    JdbcType jdbcType = parameterMapping.getJdbcType();
                    if (value == null && jdbcType == null) jdbcType = configuration.getJdbcTypeForNull();
                    sql = replaceParameter(sql, value, jdbcType, parameterMapping.getJavaType());
                }
            }
        }
        return sql;
    }

    /**
     * 根据类型替换参数
     *
     * 仅作为数字和字符串两种类型进行处理,需要特殊处理的可以继续完善这里
     * @param sql
     * @param value
     * @param jdbcType
     * @param javaType
     * @return
     */
    private static String replaceParameter(String sql, Object value, JdbcType jdbcType, Class javaType) {
        String strValue = String.valueOf(value);
        if (jdbcType != null) {
            switch (jdbcType) {
                //数字

                case BIT:
                case TINYINT:
                case SMALLINT:
                case INTEGER:
                case BIGINT:
                case FLOAT:
                case REAL:
                case DOUBLE:
                case NUMERIC:
                case DECIMAL:
                    break;
                //日期

                case DATE:
                case TIME:
                case TIMESTAMP:
                    //其他,包含字符串和其他特殊类型

                default:
                    strValue = "'" + strValue + "'";


            }
        } else if (Number.class.isAssignableFrom(javaType)) {
            //不加单引号

        } else {
            strValue = "'" + strValue + "'";
        }
        return sql.replaceFirst("\\?", strValue);
    }

    /**
     * 获取指定的方法
     * @param clazz
     * @param methodName
     * @return
     */
    private static Method getDeclaredMethods(Class clazz, String methodName) {
        Method[] methods = clazz.getDeclaredMethods();
        for (Method method : methods) {
            if (method.getName().equals(methodName)) {
                return method;
            }
        }
        throw new IllegalArgumentException("方法" + methodName + "不存在!");
    }

    /**
     * 获取参数注解名
     * @param method
     * @param i
     * @param paramName
     * @return
     */
    private static String getParamNameFromAnnotation(Method method, int i, String paramName) {
        final Object[] paramAnnos = method.getParameterAnnotations()[i];
        for (Object paramAnno : paramAnnos) {
            if (paramAnno instanceof Param) {
                paramName = ((Param) paramAnno).value();
            }
        }
        return paramName;
    }

    /**
     * 只有一个参数且没有使用注解
     * @param method
     * @param args
     * @return
     */
    private static boolean useParameter(Method method, Object... args){
        if (args != null && args.length == 1){
            final Object[] paramAnnos = method.getParameterAnnotations()[0];
            for (Object paramAnno : paramAnnos) {
                if (paramAnno instanceof Param) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }
}