<?php
namespace Psalm\Tests;

use PhpParser;
use Psalm\Context;
use Psalm\Internal\Algebra\FormulaGenerator;
use Psalm\Internal\Analyzer\FileAnalyzer;
use Psalm\Internal\Analyzer\StatementsAnalyzer;
use Psalm\Internal\Algebra;
use Psalm\Internal\Clause;
use Psalm\Internal\Provider\StatementsProvider;

class AlgebraTest extends TestCase
{
    public function testNegateFormula(): void
    {
        $formula = [
            new Clause(['$a' => ['!falsy']], 1, 1),
        ];

        $negated_formula = Algebra::negateFormula($formula);

        $this->assertCount(1, $negated_formula);
        $this->assertSame(['$a' => ['falsy']], $negated_formula[0]->possibilities);

        $formula = [
            new Clause(['$a' => ['!falsy'], '$b' => ['!falsy']], 1, 1),
        ];

        $negated_formula = Algebra::negateFormula($formula);

        $this->assertCount(2, $negated_formula);
        $this->assertSame(['$a' => ['falsy']], $negated_formula[0]->possibilities);
        $this->assertSame(['$b' => ['falsy']], $negated_formula[1]->possibilities);

        $formula = [
            new Clause(['$a' => ['!falsy']], 1, 1),
            new Clause(['$b' => ['!falsy']], 1, 2),
        ];

        $negated_formula = Algebra::negateFormula($formula);

        $this->assertCount(1, $negated_formula);
        $this->assertSame(['$b' => ['falsy'], '$a' => ['falsy']], $negated_formula[0]->possibilities);

        $formula = [
            new Clause(['$a' => ['int', 'string'], '$b' => ['!falsy']], 1, 1),
        ];

        $negated_formula = Algebra::negateFormula($formula);

        $this->assertCount(3, $negated_formula);
        $this->assertSame(['$a' => ['!int']], $negated_formula[0]->possibilities);
        $this->assertSame(['$a' => ['!string']], $negated_formula[1]->possibilities);
        $this->assertSame(['$b' => ['falsy']], $negated_formula[2]->possibilities);
    }

    public function testNegateFormulaWithUnreconcilableTerm(): void
    {
        $formula = [
            new Clause(['$a' => ['int']], 1, 1),
            new Clause(['$b' => ['int']], 1, 2, false, false),
        ];

        $negated_formula = Algebra::negateFormula($formula);

        $this->assertCount(1, $negated_formula);
        $this->assertSame(['$a' => ['!int']], $negated_formula[0]->possibilities);
    }

    public function testCombinatorialExpansion(): void
    {
        $dnf = '<?php ($b0 === true && $b4 === true && $b8 === true)
                  || ($b0 === true && $b1 === true && $b2 === true)
                  || ($b0 === true && $b3 === true && $b6 === true)
                  || ($b1 === true && $b4 === true && $b7 === true)
                  || ($b2 === true && $b5 === true && $b8 === true)
                  || ($b2 === true && $b4 === true && $b6 === true)
                  || ($b3 === true && $b4 === true && $b5 === true)
                  || ($b6 === true && $b7 === true && $b8 === true);';

        $dnf_stmt = StatementsProvider::parseStatements($dnf, '7.4')[0];

        $this->assertInstanceOf(PhpParser\Node\Stmt\Expression::class, $dnf_stmt);

        $file_analyzer = new FileAnalyzer($this->project_analyzer, 'somefile.php', 'somefile.php');
        $file_analyzer->context = new Context();
        $statements_analyzer = new StatementsAnalyzer($file_analyzer, new \Psalm\Internal\Provider\NodeDataProvider());

        $dnf_clauses = FormulaGenerator::getFormula(
            \spl_object_id($dnf_stmt->expr),
            \spl_object_id($dnf_stmt->expr),
            $dnf_stmt->expr,
            null,
            $statements_analyzer
        );

        $this->assertCount(6561, $dnf_clauses);

        $simplified_dnf_clauses = Algebra::simplifyCNF($dnf_clauses);

        $this->assertCount(23, $simplified_dnf_clauses);
    }

    public function testContainsClause(): void
    {
        $this->assertTrue(
            (new Clause(
                [
                    '$a' => ['!falsy'],
                    '$b' => ['!falsy'],
                ],
                1,
                1
            ))->contains(
                new Clause(
                    [
                        '$a' => ['!falsy'],
                    ],
                    1,
                    1
                )
            )
        );

        $this->assertFalse(
            (new Clause(
                [
                    '$a' => ['!falsy'],
                ],
                1,
                1
            ))->contains(
                new Clause(
                    [
                        '$a' => ['!falsy'],
                        '$b' => ['!falsy'],
                    ],
                    1,
                    1
                )
            )
        );
    }

    public function testSimplifyCNF(): void
    {
        $formula = [
            new Clause(['$a' => ['!falsy']], 1, 1),
            new Clause(['$a' => ['falsy'], '$b' => ['falsy']], 1, 2),
        ];

        $simplified_formula = Algebra::simplifyCNF($formula);

        $this->assertCount(2, $simplified_formula);
        $this->assertSame(['$a' => ['!falsy']], $simplified_formula[0]->possibilities);
        $this->assertSame(['$b' => ['falsy']], $simplified_formula[1]->possibilities);
    }

    public function testSimplifyCNFWithUselessTerm(): void
    {
        $formula = [
            new Clause(['$a' => ['!falsy'], '$b' => ['!falsy']], 1, 1),
            new Clause(['$a' => ['falsy'], '$b' => ['!falsy']], 1, 2),
        ];

        $simplified_formula = Algebra::simplifyCNF($formula);

        $this->assertCount(1, $simplified_formula);
        $this->assertSame(['$b' => ['!falsy']], $simplified_formula[0]->possibilities);
    }

    public function testSimplifyCNFWithNonUselessTerm(): void
    {
        $formula = [
            new Clause(['$a' => ['!falsy'], '$b' => ['!falsy']], 1, 1),
            new Clause(['$a' => ['falsy'], '$b' => ['falsy']], 1, 2),
        ];

        $simplified_formula = Algebra::simplifyCNF($formula);

        $this->assertCount(2, $simplified_formula);
        $this->assertSame(['$a' => ['!falsy'], '$b' => ['!falsy']], $simplified_formula[0]->possibilities);
        $this->assertSame(['$a' => ['falsy'], '$b' => ['falsy']], $simplified_formula[1]->possibilities);
    }

    public function testSimplifyCNFWithUselessTermAndOneInMiddle(): void
    {
        $formula = [
            new Clause(['$a' => ['!falsy'], '$b' => ['!falsy']], 1, 1),
            new Clause(['$b' => ['!falsy']], 1, 2),
            new Clause(['$a' => ['falsy'], '$b' => ['!falsy']], 1, 3),
        ];

        $simplified_formula = Algebra::simplifyCNF($formula);

        $this->assertCount(1, $simplified_formula);
        $this->assertSame(['$b' => ['!falsy']], $simplified_formula[0]->possibilities);
    }

    public function testGroupImpossibilities() : void
    {
        $clause1 = (new \Psalm\Internal\Clause(
            [
                '$a' => ['=array']
            ],
            1,
            2,
            false,
            true,
            true,
            []
        ))->calculateNegation();

        $clause2 = (new \Psalm\Internal\Clause(
            [
                '$b' => ['isset']
            ],
            1,
            2,
            false,
            true,
            true,
            []
        ))->calculateNegation();

        $result_clauses = Algebra::groupImpossibilities([$clause1, $clause2]);

        $this->assertCount(0, $result_clauses);
    }
}
