<?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;

use PhpCsFixer\ConfigurationException\InvalidFixerConfigurationException;
use PhpCsFixer\Fixer\ConfigurableFixerInterface;
use PhpCsFixer\Fixer\FixerInterface;
use PhpCsFixer\Fixer\WhitespacesAwareFixerInterface;
use PhpCsFixer\RuleSet\RuleSetInterface;
use Symfony\Component\Finder\Finder as SymfonyFinder;
use Symfony\Component\Finder\SplFileInfo;

/**
 * Class provides a way to create a group of fixers.
 *
 * Fixers may be registered (made the factory aware of them) by
 * registering a custom fixer and default, built in fixers.
 * Then, one can attach Config instance to fixer instances.
 *
 * Finally factory creates a ready to use group of fixers.
 *
 * @author Dariusz Rumiński <dariusz.ruminski@gmail.com>
 *
 * @internal
 */
final class FixerFactory
{
    private FixerNameValidator $nameValidator;

    /**
     * @var list<FixerInterface>
     */
    private array $fixers = [];

    /**
     * @var array<string, FixerInterface>
     */
    private array $fixersByName = [];

    public function __construct()
    {
        $this->nameValidator = new FixerNameValidator();
    }

    public function setWhitespacesConfig(WhitespacesFixerConfig $config): self
    {
        foreach ($this->fixers as $fixer) {
            if ($fixer instanceof WhitespacesAwareFixerInterface) {
                $fixer->setWhitespacesConfig($config);
            }
        }

        return $this;
    }

    /**
     * @return list<FixerInterface>
     */
    public function getFixers(): array
    {
        $this->fixers = Utils::sortFixers($this->fixers);

        return $this->fixers;
    }

    /**
     * @return $this
     */
    public function registerBuiltInFixers(): self
    {
        static $builtInFixers = null;

        if (null === $builtInFixers) {
            /** @var list<class-string<FixerInterface>> */
            $builtInFixers = [];

            /** @var SplFileInfo $file */
            foreach (SymfonyFinder::create()->files()->in(__DIR__.'/Fixer')->name('*Fixer.php')->depth(1) as $file) {
                $relativeNamespace = $file->getRelativePath();
                $fixerClass = 'PhpCsFixer\\Fixer\\'.('' !== $relativeNamespace ? $relativeNamespace.'\\' : '').$file->getBasename('.php');
                $builtInFixers[] = $fixerClass;
            }
        }

        foreach ($builtInFixers as $class) {
            /** @var FixerInterface */
            $fixer = new $class();
            $this->registerFixer($fixer, false);
        }

        return $this;
    }

    /**
     * @param FixerInterface[] $fixers
     *
     * @return $this
     */
    public function registerCustomFixers(iterable $fixers): self
    {
        foreach ($fixers as $fixer) {
            $this->registerFixer($fixer, true);
        }

        return $this;
    }

    /**
     * @return $this
     */
    public function registerFixer(FixerInterface $fixer, bool $isCustom): self
    {
        $name = $fixer->getName();

        if (isset($this->fixersByName[$name])) {
            throw new \UnexpectedValueException(sprintf('Fixer named "%s" is already registered.', $name));
        }

        if (!$this->nameValidator->isValid($name, $isCustom)) {
            throw new \UnexpectedValueException(sprintf('Fixer named "%s" has invalid name.', $name));
        }

        $this->fixers[] = $fixer;
        $this->fixersByName[$name] = $fixer;

        return $this;
    }

    /**
     * Apply RuleSet on fixers to filter out all unwanted fixers.
     *
     * @return $this
     */
    public function useRuleSet(RuleSetInterface $ruleSet): self
    {
        $fixers = [];
        $fixersByName = [];
        $fixerConflicts = [];

        $fixerNames = array_keys($ruleSet->getRules());
        foreach ($fixerNames as $name) {
            if (!\array_key_exists($name, $this->fixersByName)) {
                throw new \UnexpectedValueException(sprintf('Rule "%s" does not exist.', $name));
            }

            $fixer = $this->fixersByName[$name];
            $config = $ruleSet->getRuleConfiguration($name);

            if (null !== $config) {
                if ($fixer instanceof ConfigurableFixerInterface) {
                    if (\count($config) < 1) {
                        throw new InvalidFixerConfigurationException($fixer->getName(), 'Configuration must be an array and may not be empty.');
                    }

                    $fixer->configure($config);
                } else {
                    throw new InvalidFixerConfigurationException($fixer->getName(), 'Is not configurable.');
                }
            }

            $fixers[] = $fixer;
            $fixersByName[$name] = $fixer;
            $conflicts = array_intersect($this->getFixersConflicts($fixer), $fixerNames);

            if (\count($conflicts) > 0) {
                $fixerConflicts[$name] = $conflicts;
            }
        }

        if (\count($fixerConflicts) > 0) {
            throw new \UnexpectedValueException($this->generateConflictMessage($fixerConflicts));
        }

        $this->fixers = $fixers;
        $this->fixersByName = $fixersByName;

        return $this;
    }

    /**
     * Check if fixer exists.
     */
    public function hasRule(string $name): bool
    {
        return isset($this->fixersByName[$name]);
    }

    /**
     * @return list<string>
     */
    private function getFixersConflicts(FixerInterface $fixer): array
    {
        static $conflictMap = [
            'blank_lines_before_namespace' => [
                'no_blank_lines_before_namespace',
                'single_blank_line_before_namespace',
            ],
            'no_blank_lines_before_namespace' => ['single_blank_line_before_namespace'],
            'single_import_per_statement' => ['group_import'],
        ];

        $fixerName = $fixer->getName();

        return \array_key_exists($fixerName, $conflictMap) ? $conflictMap[$fixerName] : [];
    }

    /**
     * @param array<string, string[]> $fixerConflicts
     */
    private function generateConflictMessage(array $fixerConflicts): string
    {
        $message = 'Rule contains conflicting fixers:';
        $report = [];

        foreach ($fixerConflicts as $fixer => $fixers) {
            // filter mutual conflicts
            $report[$fixer] = array_filter(
                $fixers,
                static fn (string $candidate): bool => !\array_key_exists($candidate, $report) || !\in_array($fixer, $report[$candidate], true)
            );

            if (\count($report[$fixer]) > 0) {
                $message .= sprintf("\n- \"%s\" with %s", $fixer, Utils::naturalLanguageJoin($report[$fixer]));
            }
        }

        return $message;
    }
}