import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}

		builder.WriteByte('*')
	}
}

func (s Select) MergeClause(clause *Clause) {
	if s.Expression != nil {
		if s.Distinct {
			if expr, ok := s.Expression.(Expr); ok {
				expr.SQL = "DISTINCT " + expr.SQL
				clause.Expression = expr
				return
			}
		}

		clause.Expression = s.Expression
	} else {
		clause.Expression = s
	}
}

// CommaExpression represents a group of expressions separated by commas.

        boostExpression = expression;
    }

    /**
     * Gets the current match expression.
     *
     * @return the match expression string
     */
    public String getMatchExpression() {
        return matchExpression;
    }

    /**
     * Sets the match expression used to determine if documents should be boosted.
     *
     * @param expression the match expression string
     */

  private Preconditions() {}

  /**
   * Ensures the truth of an expression involving one or more parameters to the calling method.
   *
   * @param expression a boolean expression
   * @throws IllegalArgumentException if {@code expression} is false
   */
  public static void checkArgument(boolean expression) {
    if (!expression) {
      throw new IllegalArgumentException();
    }
  }

  /**

        List<Expression> expressions = documentation.getExpressions();

        Map<String, Expression> bySyntax = new HashMap<>();

        if (expressions != null && !expressions.isEmpty()) {
            for (Expression expression : expressions) {
                bySyntax.put(expression.getSyntax(), expression);
            }
        }

        return bySyntax;
    }

        this.expression = expression;
        this.originalMessage = message;
    }

    public ModelInterpolationException(String expression, String message) {
        super("The POM expression: " + expression + " could not be evaluated. Reason: " + message);

        this.expression = expression;
        this.originalMessage = message;
    }

type Join struct {
	Type       JoinType
	Table      Table
	ON         Where
	Using      []string
	Expression Expression
}

func JoinTable(names ...string) Table {
	return Table{
		Name: utils.JoinNestedRelationNames(names),
	}
}

func (join Join) Build(builder Builder) {
	if join.Expression != nil {
		join.Expression.Build(builder)
	} else {
		if join.Type != "" {
			builder.WriteString(string(join.Type))

			},
			sql: "INNER JOIN `user` USING (`id`)",
		},
		{
			name: "Expression",
			join: clause.Join{
				// Invalid
				Type:  clause.LeftJoin,
				Table: clause.Table{Name: "user"},
				ON: clause.Where{
					Exprs: []clause.Expression{clause.Eq{clause.Column{Table: "user_info", Name: "user_id"}, clause.PrimaryColumn}},
				},
				// Valid
				Expression: clause.Join{
					Type:  clause.InnerJoin,

type Clause struct {
	Name                string // WHERE
	BeforeExpression    Expression
	AfterNameExpression Expression
	AfterExpression     Expression
	Expression          Expression
	Builder             ClauseBuilder
}

// Build build clause
func (c Clause) Build(builder Builder) {
	if c.Builder != nil {
		c.Builder(c, builder)
	} else if c.Expression != nil {
		if c.BeforeExpression != nil {
			c.BeforeExpression.Build(builder)

				Exprs: []clause.Expression{clause.Or(clause.Neq{Column: "name", Value: "jinzhu"}), clause.Eq{Column: clause.PrimaryColumn, Value: "1"}, clause.Gt{Column: "age", Value: 18}},
			}},
			"SELECT * FROM `users` WHERE `users`.`id` = ? OR `name` <> ? AND `age` > ?",
			[]interface{}{"1", "jinzhu", 18},
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Where{