package com.xxx.utils;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import java.util.List;

import java.util.Vector;

import org.apache.commons.lang3.reflect.FieldUtils;

public class ModelToSQL {

    private Object target;

    private String idName;

    private Object idValue;

    private SqlType currentType;

    public enum SqlType {

        INSERT, UPDATE, DELETE

    }

    public ModelToSQL(SqlType sqlType, Object target) {

        this.target = target;

        switch (sqlType) {

        case INSERT:

            currentType = SqlType.INSERT;

            createInsert();

            break;

        case UPDATE:

            currentType = SqlType.UPDATE;

            createUpdate();

            break;

        case DELETE:

            currentType = SqlType.DELETE;

            createDelete();

            break;

        }

    }

    public ModelToSQL(Class<?> target) {

        String tableName = getTableNameForClass(target);

        getFields(target);

        StringBuffer sqlBuffer = new StringBuffer();

        sqlBuffer.append("DELETE FROM ").append(tableName).append(" WHERE ");

        for (Field field : fields) {

            if (!Modifier.isStatic(field.getModifiers())) {

                ID id = field.getAnnotation(ID.class);

                if (null != id) {

                    sqlBuffer.append(field.getName()).append("=?");

                }

            }

        }

        this.sqlBuffer = sqlBuffer.toString();

    }

    /**

     * 创建跟删除

     */

    private void createDelete() {

        String tableName = getTableName();

        getFields(target.getClass());

        StringBuffer sqlBuffer = new StringBuffer();

        sqlBuffer.append("DELETE FROM ").append(tableName).append(" WHERE ");

        for (Field field : fields) {

            if (!Modifier.isStatic(field.getModifiers())) {

                ID id = field.getAnnotation(ID.class);

                if (null != id) {

                    sqlBuffer.append(field.getName()).append(" = ? ");

                    param.add(readField(field));

                }

            }

        }

        System.err.println("delete:\t"+sqlBuffer.toString());

        this.sqlBuffer = sqlBuffer.toString();

    }

    protected Object readField(Field field) {

        try {

            return FieldUtils.readField(field, target, true);

        } catch (Exception e) {

            throw new RuntimeException(currentType.name(), e);

        }

    }

    /**

     * 创建更新语句

     */

    private void createUpdate() {

        String tableName = getTableName();

        getFields(target.getClass());

        StringBuffer sqlBuffer = new StringBuffer();

        sqlBuffer.append("UPDATE ").append(tableName).append(" SET ");

        for (Field field : fields) {

            if (!Modifier.isStatic(field.getModifiers())) {

                ID id = field.getAnnotation(ID.class);

                if (id == null) {

                    sqlBuffer.append(field.getName()).append("=? , ");

                    param.add(readField(field));

                } else {

                    idName = field.getName();

                    idValue = readField(field);

                }

            }

        }

        sqlBuffer.replace(sqlBuffer.length()-2, sqlBuffer.length()-1, " ");

        if (idName == null) {

            throw new RuntimeException("not found of " + target.getClass() + "'s ID");

        }

        sqlBuffer.append(" WHERE ").append(idName).append("=?");

        param.add(idValue);

System.err.println("update:\t"+sqlBuffer.toString());

        this.sqlBuffer = sqlBuffer.toString();

    }

    /**

     * 根据注解获取表名

     */

    private String getTableName() {

        String tableName = null;

        Class<?> clazz = target.getClass();

        tableName = getTableNameForClass(clazz);

        return tableName;

    }

    private String getTableNameForClass(Class<?> clazz) {

        String tableName;

        Table table = clazz.getAnnotation(Table.class);

        if (null != table) {

            tableName = table.name();

            if ("".equalsIgnoreCase(tableName)) {

                tableName = clazz.getSimpleName();

            }

        } else {

            tableName = clazz.getSimpleName();

        }

        return tableName;

    }

    /**

     * 创建插入语句

     */

    private void createInsert() {

        String tableName = getTableName();

        getFields(target.getClass());

        StringBuffer sqlBuffer = new StringBuffer();

        sqlBuffer.append("INSERT INTO ").append(tableName).append("(");

        for (Field field : fields) {

            if (!Modifier.isStatic(field.getModifiers())) {

                ID id = field.getAnnotation(ID.class);

                if (id == null) {

                    sqlBuffer.append(field.getName()).append(",");

                    param.add(readField(field));

                }

            }

        }

        int length = sqlBuffer.length();

        sqlBuffer.delete(length - 1, length).append(")values(");

        int size = param.size();

        for (int x = 0; x < size; x++) {

            if (x != 0) {

                sqlBuffer.append(",");

            }

            sqlBuffer.append("?");

        }

        sqlBuffer.append(")");

System.err.println("insert:\t"+sqlBuffer.toString());

        this.sqlBuffer = sqlBuffer.toString();

    }

    private List<Object> param = new Vector<Object>();

    private String sqlBuffer;

    public List<Object> getParam() {

        return param;

    }

    public String getSqlBuffer() {

        return sqlBuffer;

    }

    public String getIdName() {

        return idName;

    }

    public Object getIdValue() {

        return idValue;

    }

    List<Field> fields = new Vector<Field>();

    protected void getFields(Class<?> clazz) {

        if (Object.class.equals(clazz)) {

            return;

        }

        Field[] fieldArray = clazz.getDeclaredFields();

        for (Field file : fieldArray) {

            fields.add(file);

        }

        getFields(clazz.getSuperclass());

    }

    //创建注解,标识该model的table名

    @java.lang.annotation.Target(value = { java.lang.annotation.ElementType.TYPE })

    @java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME)

    public @interface Table {

        String name() default "";

    }

    //创建注解,标识该model的id字段

    @java.lang.annotation.Target(value = { java.lang.annotation.ElementType.FIELD })

    @java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME)

    public @interface ID {

    }

}