<?php

declare(strict_types=1);

/*
 * This file is part of PHP CS Fixer.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
 *
 * This source file is subject to the MIT license that is bundled
 * with this source code in the file LICENSE.
 */

namespace PhpCsFixer\Fixer\Alias;

use PhpCsFixer\AbstractFixer;
use PhpCsFixer\FixerDefinition\CodeSample;
use PhpCsFixer\FixerDefinition\FixerDefinition;
use PhpCsFixer\FixerDefinition\FixerDefinitionInterface;
use PhpCsFixer\Tokenizer\Analyzer\FunctionsAnalyzer;
use PhpCsFixer\Tokenizer\CT;
use PhpCsFixer\Tokenizer\Token;
use PhpCsFixer\Tokenizer\Tokens;

final class ArrayPushFixer extends AbstractFixer
{
    public function getDefinition(): FixerDefinitionInterface
    {
        return new FixerDefinition(
            'Converts simple usages of `array_push($x, $y);` to `$x[] = $y;`.',
            [new CodeSample("<?php\narray_push(\$x, \$y);\n")],
            null,
            'Risky when the function `array_push` is overridden.'
        );
    }

    public function isCandidate(Tokens $tokens): bool
    {
        return $tokens->isTokenKindFound(T_STRING) && $tokens->count() > 7;
    }

    public function isRisky(): bool
    {
        return true;
    }

    protected function applyFix(\SplFileInfo $file, Tokens $tokens): void
    {
        $functionsAnalyzer = new FunctionsAnalyzer();

        for ($index = $tokens->count() - 7; $index > 0; --$index) {
            if (!$tokens[$index]->equals([T_STRING, 'array_push'], false)) {
                continue;
            }

            if (!$functionsAnalyzer->isGlobalFunctionCall($tokens, $index)) {
                continue; // redeclare/override
            }

            // meaningful before must be `<?php`, `{`, `}` or `;`

            $callIndex = $index;
            $index = $tokens->getPrevMeaningfulToken($index);
            $namespaceSeparatorIndex = null;

            if ($tokens[$index]->isGivenKind(T_NS_SEPARATOR)) {
                $namespaceSeparatorIndex = $index;
                $index = $tokens->getPrevMeaningfulToken($index);
            }

            if (!$tokens[$index]->equalsAny([';', '{', '}', ')', [T_OPEN_TAG]])) {
                continue;
            }

            // figure out where the arguments list opens

            $openBraceIndex = $tokens->getNextMeaningfulToken($callIndex);
            $blockType = Tokens::detectBlockType($tokens[$openBraceIndex]);

            if (null === $blockType || Tokens::BLOCK_TYPE_PARENTHESIS_BRACE !== $blockType['type']) {
                continue;
            }

            // figure out where the arguments list closes

            $closeBraceIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $openBraceIndex);

            // meaningful after `)` must be `;`, `? >` or nothing

            $afterCloseBraceIndex = $tokens->getNextMeaningfulToken($closeBraceIndex);

            if (null !== $afterCloseBraceIndex && !$tokens[$afterCloseBraceIndex]->equalsAny([';', [T_CLOSE_TAG]])) {
                continue;
            }

            // must have 2 arguments

            // first argument must be a variable (with possibly array indexing etc.),
            // after that nothing meaningful should be there till the next `,` or `)`
            // if `)` than we cannot fix it (it is a single argument call)

            $firstArgumentStop = $this->getFirstArgumentEnd($tokens, $openBraceIndex);
            $firstArgumentStop = $tokens->getNextMeaningfulToken($firstArgumentStop);

            if (!$tokens[$firstArgumentStop]->equals(',')) {
                return;
            }

            // second argument can be about anything but ellipsis, we must make sure there is not
            // a third argument (or more) passed to `array_push`

            $secondArgumentStart = $tokens->getNextMeaningfulToken($firstArgumentStop);
            $secondArgumentStop = $this->getSecondArgumentEnd($tokens, $secondArgumentStart, $closeBraceIndex);

            if (null === $secondArgumentStop) {
                continue;
            }

            // candidate is valid, replace tokens

            $tokens->clearTokenAndMergeSurroundingWhitespace($closeBraceIndex);
            $tokens->clearTokenAndMergeSurroundingWhitespace($firstArgumentStop);
            $tokens->insertAt(
                $firstArgumentStop,
                [
                    new Token('['),
                    new Token(']'),
                    new Token([T_WHITESPACE, ' ']),
                    new Token('='),
                ]
            );
            $tokens->clearTokenAndMergeSurroundingWhitespace($openBraceIndex);
            $tokens->clearTokenAndMergeSurroundingWhitespace($callIndex);

            if (null !== $namespaceSeparatorIndex) {
                $tokens->clearTokenAndMergeSurroundingWhitespace($namespaceSeparatorIndex);
            }
        }
    }

    private function getFirstArgumentEnd(Tokens $tokens, int $index): int
    {
        $nextIndex = $tokens->getNextMeaningfulToken($index);
        $nextToken = $tokens[$nextIndex];

        while ($nextToken->equalsAny([
            '$',
            '[',
            '(',
            [CT::T_ARRAY_INDEX_CURLY_BRACE_OPEN],
            [CT::T_DYNAMIC_PROP_BRACE_OPEN],
            [CT::T_DYNAMIC_VAR_BRACE_OPEN],
            [CT::T_NAMESPACE_OPERATOR],
            [T_NS_SEPARATOR],
            [T_STATIC],
            [T_STRING],
            [T_VARIABLE],
        ])) {
            $blockType = Tokens::detectBlockType($nextToken);

            if (null !== $blockType) {
                $nextIndex = $tokens->findBlockEnd($blockType['type'], $nextIndex);
            }

            $index = $nextIndex;
            $nextIndex = $tokens->getNextMeaningfulToken($nextIndex);
            $nextToken = $tokens[$nextIndex];
        }

        if ($nextToken->isGivenKind(T_OBJECT_OPERATOR)) {
            return $this->getFirstArgumentEnd($tokens, $nextIndex);
        }

        if ($nextToken->isGivenKind(T_PAAMAYIM_NEKUDOTAYIM)) {
            return $this->getFirstArgumentEnd($tokens, $tokens->getNextMeaningfulToken($nextIndex));
        }

        return $index;
    }

    /**
     * @param int $endIndex boundary, i.e. tokens index of `)`
     */
    private function getSecondArgumentEnd(Tokens $tokens, int $index, int $endIndex): ?int
    {
        if ($tokens[$index]->isGivenKind(T_ELLIPSIS)) {
            return null;
        }

        for (; $index <= $endIndex; ++$index) {
            $blockType = Tokens::detectBlockType($tokens[$index]);

            while (null !== $blockType && $blockType['isStart']) {
                $index = $tokens->findBlockEnd($blockType['type'], $index);
                $index = $tokens->getNextMeaningfulToken($index);
                $blockType = Tokens::detectBlockType($tokens[$index]);
            }

            if ($tokens[$index]->equals(',') || $tokens[$index]->isGivenKind([T_YIELD, T_YIELD_FROM, T_LOGICAL_AND, T_LOGICAL_OR, T_LOGICAL_XOR])) {
                return null;
            }
        }

        return $endIndex;
    }
}