<?php

/*
 * 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\Casing;

use PhpCsFixer\AbstractFixer;
use PhpCsFixer\FixerDefinition\CodeSample;
use PhpCsFixer\FixerDefinition\FixerDefinition;
use PhpCsFixer\FixerDefinition\VersionSpecification;
use PhpCsFixer\FixerDefinition\VersionSpecificCodeSample;
use PhpCsFixer\Tokenizer\Analyzer\Analysis\TypeAnalysis;
use PhpCsFixer\Tokenizer\Analyzer\FunctionsAnalyzer;
use PhpCsFixer\Tokenizer\Token;
use PhpCsFixer\Tokenizer\Tokens;

/**
 * @author SpacePossum
 */
final class NativeFunctionTypeDeclarationCasingFixer extends AbstractFixer
{
    /**
     * https://secure.php.net/manual/en/functions.arguments.php#functions.arguments.type-declaration.
     *
     * self     PHP 5.0.0
     * array    PHP 5.1.0
     * callable PHP 5.4.0
     * bool     PHP 7.0.0
     * float    PHP 7.0.0
     * int      PHP 7.0.0
     * string   PHP 7.0.0
     * iterable PHP 7.1.0
     * void     PHP 7.1.0
     * object   PHP 7.2.0
     *
     * @var array<string, true>
     */
    private $hints;

    /**
     * @var FunctionsAnalyzer
     */
    private $functionsAnalyzer;

    public function __construct()
    {
        parent::__construct();

        $this->hints = [
            'array' => true,
            'callable' => true,
            'self' => true,
        ];

        if (\PHP_VERSION_ID >= 70000) {
            $this->hints = array_merge(
                $this->hints,
                [
                    'bool' => true,
                    'float' => true,
                    'int' => true,
                    'string' => true,
                ]
            );
        }

        if (\PHP_VERSION_ID >= 70100) {
            $this->hints = array_merge(
                $this->hints,
                [
                    'iterable' => true,
                    'void' => true,
                ]
            );
        }

        if (\PHP_VERSION_ID >= 70200) {
            $this->hints = array_merge($this->hints, ['object' => true]);
        }

        $this->functionsAnalyzer = new FunctionsAnalyzer();
    }

    /**
     * {@inheritdoc}
     */
    public function getDefinition()
    {
        return new FixerDefinition(
            'Native type hints for functions should use the correct case.',
            [
                new CodeSample("<?php\nclass Bar {\n    public function Foo(CALLABLE \$bar)\n    {\n        return 1;\n    }\n}\n"),
                new VersionSpecificCodeSample(
                    "<?php\nfunction Foo(INT \$a): Bool\n{\n    return true;\n}\n",
                    new VersionSpecification(70000)
                ),
                new VersionSpecificCodeSample(
                    "<?php\nfunction Foo(Iterable \$a): VOID\n{\n    echo 'Hello world';\n}\n",
                    new VersionSpecification(70100)
                ),
                new VersionSpecificCodeSample(
                    "<?php\nfunction Foo(Object \$a)\n{\n    return 'hi!';\n}\n",
                    new VersionSpecification(70200)
                ),
            ]
        );
    }

    /**
     * {@inheritdoc}
     */
    public function isCandidate(Tokens $tokens)
    {
        return $tokens->isAllTokenKindsFound([T_FUNCTION, T_STRING]);
    }

    /**
     * {@inheritdoc}
     */
    protected function applyFix(\SplFileInfo $file, Tokens $tokens)
    {
        for ($index = $tokens->count() - 1; $index >= 0; --$index) {
            if ($tokens[$index]->isGivenKind(T_FUNCTION)) {
                if (\PHP_VERSION_ID >= 70000) {
                    $this->fixFunctionReturnType($tokens, $index);
                }

                $this->fixFunctionArgumentTypes($tokens, $index);
            }
        }
    }

    /**
     * @param int $index
     */
    private function fixFunctionArgumentTypes(Tokens $tokens, $index)
    {
        foreach ($this->functionsAnalyzer->getFunctionArguments($tokens, $index) as $argument) {
            $this->fixArgumentType($tokens, $argument->getTypeAnalysis());
        }
    }

    /**
     * @param int $index
     */
    private function fixFunctionReturnType(Tokens $tokens, $index)
    {
        $this->fixArgumentType($tokens, $this->functionsAnalyzer->getFunctionReturnType($tokens, $index));
    }

    private function fixArgumentType(Tokens $tokens, TypeAnalysis $type = null)
    {
        if (null === $type) {
            return;
        }

        $argumentIndex = $type->getStartIndex();
        if ($argumentIndex !== $type->getEndIndex()) {
            return; // the type to fix are always unqualified and so are always composed as one token
        }

        $lowerCasedName = strtolower($type->getName());
        if (!isset($this->hints[$lowerCasedName])) {
            return; // check of type is of interest based on name (slower check than previous index based)
        }

        $tokens[$argumentIndex] = new Token([$tokens[$argumentIndex]->getId(), $lowerCasedName]);
    }
}