<?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\PhpUnit;

use PhpCsFixer\DocBlock\DocBlock;
use PhpCsFixer\DocBlock\Line;
use PhpCsFixer\Fixer\AbstractPhpUnitFixer;
use PhpCsFixer\Fixer\ConfigurableFixerInterface;
use PhpCsFixer\Fixer\ConfigurableFixerTrait;
use PhpCsFixer\Fixer\WhitespacesAwareFixerInterface;
use PhpCsFixer\FixerConfiguration\FixerConfigurationResolver;
use PhpCsFixer\FixerConfiguration\FixerConfigurationResolverInterface;
use PhpCsFixer\FixerConfiguration\FixerOptionBuilder;
use PhpCsFixer\FixerDefinition\CodeSample;
use PhpCsFixer\FixerDefinition\FixerDefinition;
use PhpCsFixer\FixerDefinition\FixerDefinitionInterface;
use PhpCsFixer\Preg;
use PhpCsFixer\Tokenizer\Analyzer\WhitespacesAnalyzer;
use PhpCsFixer\Tokenizer\Token;
use PhpCsFixer\Tokenizer\Tokens;
use PhpCsFixer\Tokenizer\TokensAnalyzer;

/**
 * @author Gert de Pagter
 *
 * @implements ConfigurableFixerInterface<_AutogeneratedInputConfiguration, _AutogeneratedComputedConfiguration>
 *
 * @phpstan-type _AutogeneratedInputConfiguration array{
 *  style?: 'annotation'|'prefix',
 * }
 * @phpstan-type _AutogeneratedComputedConfiguration array{
 *  style: 'annotation'|'prefix',
 * }
 */
final class PhpUnitTestAnnotationFixer extends AbstractPhpUnitFixer implements ConfigurableFixerInterface, WhitespacesAwareFixerInterface
{
    /** @use ConfigurableFixerTrait<_AutogeneratedInputConfiguration, _AutogeneratedComputedConfiguration> */
    use ConfigurableFixerTrait;

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

    public function getDefinition(): FixerDefinitionInterface
    {
        return new FixerDefinition(
            'Adds or removes @test annotations from tests, following configuration.',
            [
                new CodeSample('<?php
class Test extends \PhpUnit\FrameWork\TestCase
{
    /**
     * @test
     */
    public function itDoesSomething() {} }'.$this->whitespacesConfig->getLineEnding()),
                new CodeSample('<?php
class Test extends \PhpUnit\FrameWork\TestCase
{
public function testItDoesSomething() {}}'.$this->whitespacesConfig->getLineEnding(), ['style' => 'annotation']),
            ],
            null,
            'This fixer may change the name of your tests, and could cause incompatibility with'
            .' abstract classes or interfaces.'
        );
    }

    /**
     * {@inheritdoc}
     *
     * Must run before NoEmptyPhpdocFixer, PhpUnitMethodCasingFixer, PhpdocTrimFixer.
     */
    public function getPriority(): int
    {
        return 10;
    }

    protected function applyPhpUnitClassFix(Tokens $tokens, int $startIndex, int $endIndex): void
    {
        if ('annotation' === $this->configuration['style']) {
            $this->applyTestAnnotation($tokens, $startIndex, $endIndex);
        } else {
            $this->applyTestPrefix($tokens, $startIndex, $endIndex);
        }
    }

    protected function createConfigurationDefinition(): FixerConfigurationResolverInterface
    {
        return new FixerConfigurationResolver([
            (new FixerOptionBuilder('style', 'Whether to use the @test annotation or not.'))
                ->setAllowedValues(['prefix', 'annotation'])
                ->setDefault('prefix')
                ->getOption(),
        ]);
    }

    private function applyTestAnnotation(Tokens $tokens, int $startIndex, int $endIndex): void
    {
        for ($i = $endIndex - 1; $i > $startIndex; --$i) {
            if (!$this->isTestMethod($tokens, $i)) {
                continue;
            }

            $functionNameIndex = $tokens->getNextMeaningfulToken($i);
            $functionName = $tokens[$functionNameIndex]->getContent();

            if ($this->hasTestPrefix($functionName) && !$this->hasProperTestAnnotation($tokens, $i)) {
                $newFunctionName = $this->removeTestPrefix($functionName);
                $tokens[$functionNameIndex] = new Token([T_STRING, $newFunctionName]);
            }

            $docBlockIndex = $this->getDocBlockIndex($tokens, $i);

            if ($this->isPHPDoc($tokens, $docBlockIndex)) {
                $lines = $this->updateDocBlock($tokens, $docBlockIndex);
                $lines = $this->addTestAnnotation($lines, $tokens, $docBlockIndex);
                $lines = implode('', $lines);

                $tokens[$docBlockIndex] = new Token([T_DOC_COMMENT, $lines]);
            } else {
                // Create a new docblock if it didn't have one before;
                $this->createDocBlock($tokens, $docBlockIndex);
            }
        }
    }

    private function applyTestPrefix(Tokens $tokens, int $startIndex, int $endIndex): void
    {
        for ($i = $endIndex - 1; $i > $startIndex; --$i) {
            // We explicitly check again if the function has a doc block to save some time.
            if (!$this->isTestMethod($tokens, $i)) {
                continue;
            }

            $docBlockIndex = $this->getDocBlockIndex($tokens, $i);

            if (!$this->isPHPDoc($tokens, $docBlockIndex)) {
                continue;
            }

            $lines = $this->updateDocBlock($tokens, $docBlockIndex);
            $lines = implode('', $lines);
            $tokens[$docBlockIndex] = new Token([T_DOC_COMMENT, $lines]);

            $functionNameIndex = $tokens->getNextMeaningfulToken($i);
            $functionName = $tokens[$functionNameIndex]->getContent();

            if ($this->hasTestPrefix($functionName)) {
                continue;
            }

            $newFunctionName = $this->addTestPrefix($functionName);
            $tokens[$functionNameIndex] = new Token([T_STRING, $newFunctionName]);
        }
    }

    private function isTestMethod(Tokens $tokens, int $index): bool
    {
        // Check if we are dealing with a (non-abstract, non-lambda) function
        if (!$this->isMethod($tokens, $index)) {
            return false;
        }

        // if the function name starts with test it is a test
        $functionNameIndex = $tokens->getNextMeaningfulToken($index);
        $functionName = $tokens[$functionNameIndex]->getContent();

        if ($this->hasTestPrefix($functionName)) {
            return true;
        }

        $docBlockIndex = $this->getDocBlockIndex($tokens, $index);

        // If the function doesn't have test in its name, and no doc block, it is not a test
        return
            $this->isPHPDoc($tokens, $docBlockIndex)
            && str_contains($tokens[$docBlockIndex]->getContent(), '@test');
    }

    private function isMethod(Tokens $tokens, int $index): bool
    {
        $tokensAnalyzer = new TokensAnalyzer($tokens);

        return $tokens[$index]->isGivenKind(T_FUNCTION) && !$tokensAnalyzer->isLambda($index);
    }

    private function hasTestPrefix(string $functionName): bool
    {
        return str_starts_with($functionName, 'test');
    }

    private function hasProperTestAnnotation(Tokens $tokens, int $index): bool
    {
        $docBlockIndex = $this->getDocBlockIndex($tokens, $index);
        $doc = $tokens[$docBlockIndex]->getContent();

        return Preg::match('/\*\s+@test\b/', $doc);
    }

    private function removeTestPrefix(string $functionName): string
    {
        $remainder = Preg::replace('/^test(?=[A-Z_])_?/', '', $functionName);

        if ('' === $remainder) {
            return $functionName;
        }

        return lcfirst($remainder);
    }

    private function addTestPrefix(string $functionName): string
    {
        return 'test'.ucfirst($functionName);
    }

    private function createDocBlock(Tokens $tokens, int $docBlockIndex): void
    {
        $lineEnd = $this->whitespacesConfig->getLineEnding();
        $originalIndent = WhitespacesAnalyzer::detectIndent($tokens, $tokens->getNextNonWhitespace($docBlockIndex));
        $toInsert = [
            new Token([T_DOC_COMMENT, '/**'.$lineEnd."{$originalIndent} * @test".$lineEnd."{$originalIndent} */"]),
            new Token([T_WHITESPACE, $lineEnd.$originalIndent]),
        ];
        $index = $tokens->getNextMeaningfulToken($docBlockIndex);
        $tokens->insertAt($index, $toInsert);
    }

    /**
     * @return list<Line>
     */
    private function updateDocBlock(Tokens $tokens, int $docBlockIndex): array
    {
        $doc = new DocBlock($tokens[$docBlockIndex]->getContent());
        $lines = $doc->getLines();

        return $this->updateLines($lines, $tokens, $docBlockIndex);
    }

    /**
     * @param list<Line> $lines
     *
     * @return list<Line>
     */
    private function updateLines(array $lines, Tokens $tokens, int $docBlockIndex): array
    {
        $needsAnnotation = 'annotation' === $this->configuration['style'];

        $doc = new DocBlock($tokens[$docBlockIndex]->getContent());
        for ($i = 0; $i < \count($lines); ++$i) {
            // If we need to add test annotation and it is a single line comment we need to deal with that separately
            if ($needsAnnotation && ($lines[$i]->isTheStart() && $lines[$i]->isTheEnd())) {
                if (!$this->doesDocBlockContainTest($doc)) {
                    $lines = $this->splitUpDocBlock($lines, $tokens, $docBlockIndex);

                    return $this->updateLines($lines, $tokens, $docBlockIndex);
                }
                // One we split it up, we run the function again, so we deal with other things in a proper way
            }

            if (!$needsAnnotation
                && str_contains($lines[$i]->getContent(), ' @test')
                && !str_contains($lines[$i]->getContent(), '@testWith')
                && !str_contains($lines[$i]->getContent(), '@testdox')
            ) {
                // We remove @test from the doc block
                $lines[$i] = new Line(str_replace(' @test', '', $lines[$i]->getContent()));
            }
            // ignore the line if it isn't @depends
            if (!str_contains($lines[$i]->getContent(), '@depends')) {
                continue;
            }

            $lines[$i] = $this->updateDependsAnnotation($lines[$i]);
        }

        return $lines;
    }

    /**
     * Take a one line doc block, and turn it into a multi line doc block.
     *
     * @param non-empty-list<Line> $lines
     *
     * @return list<Line>
     */
    private function splitUpDocBlock(array $lines, Tokens $tokens, int $docBlockIndex): array
    {
        $lineContent = $this->getSingleLineDocBlockEntry($lines);
        $lineEnd = $this->whitespacesConfig->getLineEnding();
        $originalIndent = WhitespacesAnalyzer::detectIndent($tokens, $tokens->getNextNonWhitespace($docBlockIndex));

        return [
            new Line('/**'.$lineEnd),
            new Line($originalIndent.' * '.$lineContent.$lineEnd),
            new Line($originalIndent.' */'),
        ];
    }

    /**
     * @todo check whether it's doable to use \PhpCsFixer\DocBlock\DocBlock::getSingleLineDocBlockEntry instead
     *
     * @param non-empty-list<Line> $lines
     */
    private function getSingleLineDocBlockEntry(array $lines): string
    {
        $line = $lines[0];
        $line = str_replace('*/', '', $line->getContent());
        $line = trim($line);
        $line = str_split($line);
        $i = \count($line);
        do {
            --$i;
        } while ('*' !== $line[$i] && '*' !== $line[$i - 1] && '/' !== $line[$i - 2]);
        if (' ' === $line[$i]) {
            ++$i;
        }
        $line = \array_slice($line, $i);

        return implode('', $line);
    }

    /**
     * Updates the depends tag on the current doc block.
     */
    private function updateDependsAnnotation(Line $line): Line
    {
        if ('annotation' === $this->configuration['style']) {
            return $this->removeTestPrefixFromDependsAnnotation($line);
        }

        return $this->addTestPrefixToDependsAnnotation($line);
    }

    private function removeTestPrefixFromDependsAnnotation(Line $line): Line
    {
        $line = str_split($line->getContent());

        $dependsIndex = $this->findWhereDependsFunctionNameStarts($line);
        $dependsFunctionName = implode('', \array_slice($line, $dependsIndex));

        if ($this->hasTestPrefix($dependsFunctionName)) {
            $dependsFunctionName = $this->removeTestPrefix($dependsFunctionName);
        }
        array_splice($line, $dependsIndex);

        return new Line(implode('', $line).$dependsFunctionName);
    }

    private function addTestPrefixToDependsAnnotation(Line $line): Line
    {
        $line = str_split($line->getContent());
        $dependsIndex = $this->findWhereDependsFunctionNameStarts($line);
        $dependsFunctionName = implode('', \array_slice($line, $dependsIndex));

        if (!$this->hasTestPrefix($dependsFunctionName)) {
            $dependsFunctionName = $this->addTestPrefix($dependsFunctionName);
        }

        array_splice($line, $dependsIndex);

        return new Line(implode('', $line).$dependsFunctionName);
    }

    /**
     * Helps to find where the function name in the doc block starts.
     *
     * @param list<string> $line
     */
    private function findWhereDependsFunctionNameStarts(array $line): int
    {
        $index = stripos(implode('', $line), '@depends') + 8;

        while (' ' === $line[$index]) {
            ++$index;
        }

        return $index;
    }

    /**
     * @param list<Line> $lines
     *
     * @return list<Line>
     */
    private function addTestAnnotation(array $lines, Tokens $tokens, int $docBlockIndex): array
    {
        $doc = new DocBlock($tokens[$docBlockIndex]->getContent());

        if (!$this->doesDocBlockContainTest($doc)) {
            $originalIndent = WhitespacesAnalyzer::detectIndent($tokens, $docBlockIndex);
            $lineEnd = $this->whitespacesConfig->getLineEnding();

            array_splice($lines, -1, 0, [new Line($originalIndent.' *'.$lineEnd.$originalIndent.' * @test'.$lineEnd)]);
            \assert(array_is_list($lines)); // we know it's list, but we need to tell PHPStan
        }

        return $lines;
    }

    private function doesDocBlockContainTest(DocBlock $doc): bool
    {
        return 0 !== \count($doc->getAnnotationsOfType('test'));
    }
}
