package com.gitee.gen.gen.mysql;

import com.gitee.gen.gen.ColumnDefinition;
import com.gitee.gen.gen.ColumnSelector;
import com.gitee.gen.gen.GeneratorConfig;
import com.gitee.gen.gen.TypeFormatter;
import com.gitee.gen.util.FieldUtil;
import org.apache.commons.lang.StringUtils;

import java.util.Map;
import java.util.Set;

/**
 * mysql表信息查询
 */
public class MySqlColumnSelector extends ColumnSelector {

    private static final TypeFormatter TYPE_FORMATTER = new MySqlTypeFormatter();

    private static final String SHOW_SQL = " SELECT " +
            " COLUMN_NAME AS 'Field', " +
            " COLUMN_DEFAULT AS 'Default', " +
            " IS_NULLABLE AS 'Null', " +
            " DATA_TYPE AS 'DataType', " +
            " CASE DATA_TYPE " +
            "     WHEN 'int' THEN NUMERIC_PRECISION " +
            "     WHEN 'varchar' THEN CHARACTER_MAXIMUM_LENGTH " +
            " END AS 'MaxLength', " +
            " IFNULL(NUMERIC_SCALE,0) AS 'Scale', " +
            " COLUMN_TYPE AS 'Type', " +
            " COLUMN_KEY 'KEY', " +
            " EXTRA AS 'Extra', " +
            " COLUMN_COMMENT AS 'Comment' " +
            " FROM information_schema.`COLUMNS` " +
            " WHERE 1=1 AND TABLE_SCHEMA = '%s' AND TABLE_NAME = '%s' " +
            " ORDER BY ORDINAL_POSITION ";

    public MySqlColumnSelector(GeneratorConfig generatorConfig) {
        super(generatorConfig);
    }

    /**
     * SHOW FULL COLUMNS FROM 表名
     */
    @Override
    protected String getColumnInfoSQL(String tableName) {
        return String.format(SHOW_SQL, getGeneratorConfig().getDbName(), tableName);
    }

    /*
     * {FIELD=username, EXTRA=, COMMENT=用户名, COLLATION=utf8_general_ci, PRIVILEGES=select,insert,update,references, KEY=PRI, NULL=NO, DEFAULT=null, TYPE=varchar(20)}
     */
    @Override
    protected ColumnDefinition buildColumnDefinition(Map<String, Object> rowMap) {
        Set<String> columnSet = rowMap.keySet();

        for (String columnInfo : columnSet) {
            rowMap.put(columnInfo.toUpperCase(), rowMap.get(columnInfo));
        }

        ColumnDefinition columnDefinition = new ColumnDefinition();

        columnDefinition.setColumnName(FieldUtil.convertString(rowMap.get("FIELD")));

        boolean isIdentity = "auto_increment".equalsIgnoreCase(FieldUtil.convertString(rowMap.get("EXTRA")));
        columnDefinition.setIsIdentity(isIdentity);

        boolean isPk = "PRI".equalsIgnoreCase(FieldUtil.convertString(rowMap.get("KEY")));
        columnDefinition.setIsPk(isPk);

        String type = FieldUtil.convertString(rowMap.get("TYPE"));
        columnDefinition.setType(TYPE_FORMATTER.format(type));

        columnDefinition.setComment(FieldUtil.convertString(rowMap.get("COMMENT")));

        String maxLength = FieldUtil.convertString(rowMap.get("MAXLENGTH"));
        columnDefinition.setMaxLength(new Integer(StringUtils.isEmpty(maxLength) ? "0" : maxLength));

        String scale = FieldUtil.convertString(rowMap.get("SCALE"));
        columnDefinition.setScale(new Integer(StringUtils.isEmpty(scale) ? "0" : scale));

        return columnDefinition;
    }

}