MySqlExpressionVisitor.php

<?php
/**
 * @author Roman Gemini <roman_gemini@ukr.net>
 * @date 25.03.2016
 * @time 15:56
 */

namespace Slang\Database\Fluorite\Concrete;


use Slang\Database\Fluorite\Expressions\Column;
use Slang\Database\Fluorite\Expressions\Comparison;
use Slang\Database\Fluorite\Expressions\CompositeExpression;
use Slang\Database\Fluorite\Expressions\Criteria;
use Slang\Database\Fluorite\Expressions\ExpressionVisitor;
use Slang\Database\Fluorite\Expressions\Table;
use Slang\Database\Fluorite\Expressions\Value;

class MySqlExpressionVisitor extends ExpressionVisitor
{
    /**
     * @param Column $column
     * @return string
     */
    public function visitColumn(Column $column)
    {
        $sql = "";

        if ($column->getDatabase()) {
            $sql .= "`{$column->getDatabase()}`.";
        }
        if ($column->getTable()) {
            $sql .= "`{$column->getTable()}`";
        }
        $sql .= "`{$column->getColumn()}`";

        if ($column->getAlias()) {
            $sql .= " AS `{$column->getAlias()}`";
        }

        return $sql;
    }

    /**
     * @param Comparison $comparison
     * @return string
     */
    public function visitComparison(Comparison $comparison)
    {
        $visitedLeft = $this->visit($comparison->getLeft());
        $visitedRight = $this->visit($comparison->getRight());

        $type = $comparison->getOperator();

        return $visitedLeft . $type . $visitedRight;
    }

    /**
     * @param CompositeExpression $compositeExpression
     * @return mixed
     */
    public function visitCompositeExpression(CompositeExpression $compositeExpression)
    {
        $visitedExpressions = [];

        foreach ($compositeExpression->getExpressionList() as $expression) {
            $visitedExpressions[] = $this->visit($expression);
        }

        return '(' . implode(
            str_pad($compositeExpression->getConjunctionType(), 1, ' ', STR_PAD_BOTH),
            $visitedExpressions
        ) . ')';
    }

    /**
     * @param Table $table
     * @return string
     */
    public function visitTable(Table $table)
    {
        $sql = "";

        if ($table->getDatabase()) {
            $sql .= "`{$table->getDatabase()}`.";
        }
        if ($table->getTable()) {
            $sql .= "`{$table->getTable()}`";
        }

        if ($table->getAlias()) {
            $sql .= " `{$table->getAlias()}`";
        }

        return $sql;
    }

    /**
     * @param Value $value
     * @return mixed
     */
    public function visitValue(Value $value)
    {
        return $value->getValue();
    }

    /**
     * @param Criteria $criteria
     * @return mixed
     */
    public function visitCriteria(Criteria $criteria)
    {
        return $this->visit($criteria->getExpression());
    }
}