<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Flex;

use Composer\Factory;
use Composer\Package\Version\VersionParser;
use Composer\Repository\PlatformRepository;
use Composer\Semver\Constraint\MatchAllConstraint;

/**
 * @author Fabien Potencier <fabien@symfony.com>
 */
class PackageResolver
{
    private static $SYMFONY_VERSIONS = ['lts', 'previous', 'stable', 'next', 'dev'];
    private $downloader;

    public function __construct(Downloader $downloader)
    {
        $this->downloader = $downloader;
    }

    public function resolve(array $arguments = [], bool $isRequire = false): array
    {
        // first pass split on : and = to resolve package names
        $packages = [];
        foreach ($arguments as $i => $argument) {
            if ((false !== $pos = strpos($argument, ':')) || (false !== $pos = strpos($argument, '='))) {
                $package = $this->resolvePackageName(substr($argument, 0, $pos), $i, $isRequire);
                $version = substr($argument, $pos + 1);
                $packages[] = $package.':'.$version;
            } else {
                $packages[] = $this->resolvePackageName($argument, $i, $isRequire);
            }
        }

        // second pass to resolve versions
        $versionParser = new VersionParser();
        $requires = [];
        $toGuess = [];
        foreach ($versionParser->parseNameVersionPairs($packages) as $package) {
            $version = $this->parseVersion($package['name'], $package['version'] ?? '', $isRequire);
            if ('' !== $version) {
                unset($toGuess[$package['name']]);
            } elseif (!isset($requires[$package['name']])) {
                $toGuess[$package['name']] = new MatchAllConstraint();
            }
            $requires[$package['name']] = $package['name'].$version;
        }

        if ($toGuess && $isRequire) {
            foreach ($this->downloader->getSymfonyPacks($toGuess) as $package) {
                $requires[$package] .= ':*';
            }
        }

        return array_values($requires);
    }

    public function parseVersion(string $package, string $version, bool $isRequire): string
    {
        $guess = 'guess' === ($version ?: 'guess');

        if (0 !== strpos($package, 'symfony/')) {
            return $guess ? '' : ':'.$version;
        }

        $versions = $this->downloader->getVersions();

        if (!isset($versions['splits'][$package])) {
            return $guess ? '' : ':'.$version;
        }

        if ($guess || '*' === $version) {
            try {
                $config = @json_decode(file_get_contents(Factory::getComposerFile()), true);
            } finally {
                if (!$isRequire || !isset($config['extra']['symfony']['require'])) {
                    return '';
                }
            }
            $version = $config['extra']['symfony']['require'];
        } elseif ('dev' === $version) {
            $version = '^'.$versions['dev-name'].'@dev';
        } elseif ('next' === $version) {
            $version = '^'.$versions[$version].'@dev';
        } elseif (\in_array($version, self::$SYMFONY_VERSIONS, true)) {
            $version = '^'.$versions[$version];
        }

        return ':'.$version;
    }

    private function resolvePackageName(string $argument, int $position, bool $isRequire): string
    {
        $skippedPackages = ['mirrors', 'nothing', ''];

        if (!$isRequire) {
            $skippedPackages[] = 'lock';
        }

        if (false !== strpos($argument, '/') || preg_match(PlatformRepository::PLATFORM_PACKAGE_REGEX, $argument) || preg_match('{(?<=[a-z0-9_/-])\*|\*(?=[a-z0-9_/-])}i', $argument) || \in_array($argument, $skippedPackages)) {
            return $argument;
        }

        $aliases = $this->downloader->getAliases();

        if (isset($aliases[$argument])) {
            $argument = $aliases[$argument];
        } else {
            // is it a version or an alias that does not exist?
            try {
                $versionParser = new VersionParser();
                $versionParser->parseConstraints($argument);
            } catch (\UnexpectedValueException $e) {
                // is it a special Symfony version?
                if (!\in_array($argument, self::$SYMFONY_VERSIONS, true)) {
                    $this->throwAlternatives($argument, $position);
                }
            }
        }

        return $argument;
    }

    /**
     * @throws \UnexpectedValueException
     */
    private function throwAlternatives(string $argument, int $position)
    {
        $alternatives = [];
        foreach ($this->downloader->getAliases() as $alias => $package) {
            $lev = levenshtein($argument, $alias);
            if ($lev <= \strlen($argument) / 3 || ('' !== $argument && false !== strpos($alias, $argument))) {
                $alternatives[$package][] = $alias;
            }
        }

        // First position can only be a package name, not a version
        if ($alternatives || 0 === $position) {
            $message = \sprintf('"%s" is not a valid alias.', $argument);
            if ($alternatives) {
                if (1 === \count($alternatives)) {
                    $message .= " Did you mean this:\n";
                } else {
                    $message .= " Did you mean one of these:\n";
                }
                foreach ($alternatives as $package => $aliases) {
                    $message .= \sprintf("  \"%s\", supported aliases: \"%s\"\n", $package, implode('", "', $aliases));
                }
            }
        } else {
            $message = \sprintf('Could not parse version constraint "%s".', $argument);
        }

        throw new \UnexpectedValueException($message);
    }
}