<?php

declare(strict_types=1);

namespace Chill\MainBundle\Doctrine\DQL;

use Doctrine\ORM\Query\AST\Functions\FunctionNode;
use Doctrine\ORM\Query\AST\PathExpression;
use Doctrine\ORM\Query\Lexer;
use Doctrine\ORM\Query\Parser;

/**
 * DQL function for OVERLAPS function in postgresql
 *
 * If a value is null in period start, it will be replaced by -infinity.
 * If a value is null in period end, it will be replaced by infinity
 */
class OverlapsI extends FunctionNode
{
    private $firstPeriodStart;

    private $firstPeriodEnd;

    private $secondPeriodStart;

    private $secondPeriodEnd;

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        return sprintf(
            '(%s, %s) OVERLAPS (%s, %s)',
            $this->makeCase($sqlWalker, $this->firstPeriodStart, 'start'),
            $this->makeCase($sqlWalker, $this->firstPeriodEnd, 'end'),
            $this->makeCase($sqlWalker, $this->secondPeriodStart, 'start'),
            $this->makeCase($sqlWalker, $this->secondPeriodEnd, 'end')
        );
    }

    protected function makeCase($sqlWalker, $part, string $position): string
    {
        switch ($position) {
            case 'start' :
                $p = '-infinity';
                break;
            case 'end':
                $p = 'infinity';
                break;
            default:
                throw new \Exception('Unexpected position value.');
        }

        if ($part instanceof PathExpression) {
            return sprintf(
                "CASE WHEN %s IS NOT NULL THEN %s ELSE '%s'::date END",
                $part->dispatch($sqlWalker),
                $part->dispatch($sqlWalker),
                $p
            );
        }

        return sprintf(
            "CASE WHEN %s::date IS NOT NULL THEN %s::date ELSE '%s'::date END",
            $part->dispatch($sqlWalker),
            $part->dispatch($sqlWalker),
            $p
        );
    }

    public function parse(Parser $parser): void
    {
        $parser->match(Lexer::T_IDENTIFIER);

        $parser->match(Lexer::T_OPEN_PARENTHESIS);

        $this->firstPeriodStart = $parser->StringPrimary();

        $parser->match(Lexer::T_COMMA);

        $this->firstPeriodEnd = $parser->StringPrimary();

        $parser->match(Lexer::T_CLOSE_PARENTHESIS);

        $parser->match(Lexer::T_COMMA);

        $parser->match(Lexer::T_OPEN_PARENTHESIS);

        $this->secondPeriodStart = $parser->StringPrimary();

        $parser->match(Lexer::T_COMMA);

        $this->secondPeriodEnd = $parser->StringPrimary();

        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }
}