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package db.sql.api.impl.cmd.dbFun;

import db.sql.api.Cmd;
import db.sql.api.DbType;
import db.sql.api.SqlBuilderContext;
import db.sql.api.impl.tookit.Objects;
import db.sql.api.impl.tookit.SqlConst;

public class SubStr extends BasicFunction {

    private final int start;

    private final Integer length;

    public SubStr(Cmd key, int start) {
        this(key, start, null);
    }

    public SubStr(Cmd key, int start, Integer length) {
        super(null, key);
        this.start = start;
        this.length = length;
    }

    @Override
    public StringBuilder functionSql(Cmd module, Cmd parent, SqlBuilderContext context, StringBuilder sqlBuilder) {
        sqlBuilder.append(SqlConst.SUBSTR(context.getDbType())).append(SqlConst.BRACKET_LEFT);
        this.key.sql(module, this, context, sqlBuilder);
        sqlBuilder.append(SqlConst.DELIMITER).append(this.start);
        if (Objects.nonNull(length)) {
            sqlBuilder.append(SqlConst.DELIMITER).append(this.length);
        } else {
            if (context.getDbType() == DbType.SQL_SERVER) {
                sqlBuilder.append(SqlConst.DELIMITER).append("LEN(");
                this.key.sql(module, this, context, sqlBuilder);
                sqlBuilder.append(") - 1");
            }
        }
        sqlBuilder.append(SqlConst.BRACKET_RIGHT);
        return sqlBuilder;
    }

}