#!/usr/bin/env php
<?php

set_error_handler(
    static function ($errno, $errstr, $errfile, $errline) {
        $msg = "Error {$errno}: {$errstr}\n";
        if ($errfile) {
            $msg .= "File: {$errfile}\n";
            if ($errline) {
                $msg .= "Line: {$errline}\n";
            }
        }

        throw new RuntimeException($msg);
    },
    -1
);

try {
    if (!isset($argv[1]) || isset($argv[2]) || !preg_match('/^\w+$/', $argv[1]) || in_array('-h', $argv, true) || in_array('--help', $argv, true)) {
        echo "Syntax: {$argv[0]} <extension>\n";
        exit(in_array('-h', $argv, true) || in_array('--help', $argv, true) ? 0 : 1);
    }
    define('TMP_DIR', __DIR__ . '/tmp');
    if (!is_dir(TMP_DIR)) {
        mkdir(TMP_DIR);
    }

    echo "# FETCHING DATA\n";
    echo 'Retrieving package versions... ';
    $versions = listPackageVersions($argv[1]);
    $numVersions = count($versions);
    echo "done.\n";
    $versionInfos = [];
    $versionCount = 0;
    foreach ($versions as $version) {
        $versionCount++;
        echo "Inspecting version {$version} [{$versionCount}/{$numVersions}]... ";
        $versionInfos[] = inspectPackageVersion($argv[1], $version);
        echo "done.\n";
    }
    echo "# PHP VERSION COMPATIBILITY LIST\n";
    $instance = null;
    foreach ($versionInfos as $versionInfo) {
        if ($instance === null || !$instance->isCompatibleWith($versionInfo)) {
            if ($instance !== null) {
                echo $instance, "\n";
            }
            $instance = new CompatiblePHPVersions($versionInfo->getMinPHPVersion(), $versionInfo->getMaxPHPVersion());
        }
        $instance->addVersion($versionInfo->getVersion());
    }
    if ($instance !== null) {
        echo $instance, "\n";
    }
    echo "# CONFIGURATION OPTIONS\n";
    $instance = null;
    foreach ($versionInfos as $versionInfo) {
        if ($instance === null || !$instance->isCompatibleWith($versionInfo)) {
            if ($instance !== null) {
                echo $instance, "\n";
            }
            $instance = new CompatibleConfigurationOptions($versionInfo->getConfigureOptions());
        }
        $instance->addVersion($versionInfo->getVersion());
    }
    if ($instance !== null) {
        echo $instance, "\n";
    }
} catch (RuntimeException $x) {
    echo $x->getMessage(), "\n";
    exit(1);
}

/**
 * @return string[]
 */
function listPackageVersions(string $package): array
{
    $cachedDir = TMP_DIR;
    $cachedFile = "{$cachedDir}/{$package}.xml";
    if (is_file($cachedFile) && filemtime($cachedFile) > (time() - 1800)) {
        return listPackageVersionsXml($package, file_get_contents($cachedFile));
    }

    try {
        $xml = file_get_contents("https://pecl.php.net/rest/r/{$package}/allreleases.xml");
    } catch (RuntimeException $x) {
        if (strpos($x->getMessage(), '404 Not Found') !== false) {
            throw new RuntimeException("Invalid PECL package name or no versions available for {$package}");
        }

        throw $x;
    }
    $versions = listPackageVersionsXml($package, $xml);
    if (!is_dir($cachedDir)) {
        mkdir($cachedDir, 0777, true);
    }
    file_put_contents($cachedFile, $xml);

    return $versions;
}

function listPackageVersionsXml(string $package, string $xml): array
{
    $dom = new DOMDocument();
    if (!$dom->loadXML($xml)) {
        throw new RuntimeException('Failed to parse the downloaded XML data.');
    }
    $xpath = new DOMXPath($dom);
    $xpath->registerNamespace('v', 'http://pear.php.net/dtd/rest.allreleases');
    $versionNodes = $xpath->query('/v:a/v:r/v:v');
    if ($versionNodes->count() === 0) {
        throw new RuntimeException("No versions available for {$package}");
    }
    $versions = [];
    foreach ($versionNodes as $versionNode) {
        $versions[] = $versionNode->nodeValue;
    }
    usort($versions, 'version_compare');

    return $versions;
}

function inspectPackageVersion(string $package, string $version): PackageVersionInfo
{
    $cachedDir = TMP_DIR . "/{$package}";
    $cachedFile = "{$cachedDir}/{$version}.xml";
    if (is_file($cachedFile)) {
        return inspectPackageVersionXml($package, $version, $cachedFile);
    }
    $tgzFile = tempnam(sys_get_temp_dir(), 'dpx');

    try {
        file_put_contents($tgzFile, file_get_contents("https://pecl.php.net/get/{$package}-{$version}.tgz"));
        $archive = new PharData($tgzFile);
        $archive->decompress('tar');
        $tarFile = preg_replace('/\.\w+$/', '.tar', $tgzFile);

        try {
            $extractedDir = preg_replace('/\.tar$/', '.decompressed', $tarFile);
            mkdir($extractedDir);

            try {
                try {
                    $archive->extractTo($extractedDir, 'package2.xml');
                    rename("{$extractedDir}/package2.xml", "{$extractedDir}/package.xml");
                } catch (PharException $x) {
                    $archive->extractTo($extractedDir, 'package.xml');
                }

                try {
                    $info = inspectPackageVersionXml($package, $version, "{$extractedDir}/package.xml");
                    if (!is_dir($cachedDir)) {
                        mkdir($cachedDir, 0777, true);
                    }
                    copy("{$extractedDir}/package.xml", $cachedFile);
                } finally {
                    unlink("{$extractedDir}/package.xml");
                }
            } finally {
                rmdir($extractedDir);
            }
        } finally {
            unlink($tarFile);
        }
    } finally {
        unlink($tgzFile);
    }

    return $info;
}

function inspectPackageVersionXml(string $package, string $version, string $xmlFile): PackageVersionInfo
{
    $dom = new DOMDocument();
    if (!$dom->loadXML(file_get_contents($xmlFile))) {
        throw new RuntimeException("Failed to parse the downloaded package.xml file located at {$xmlFile}.");
    }
    $xpath = new DOMXPath($dom);
    $xpath->registerNamespace('v2', 'http://pear.php.net/dtd/package-2.0');
    if ($xpath->query('/v2:package/v2:dependencies')->count() === 1) {
        $ns = 'v2:';
    } elseif ($xpath->query('/package/release/version')->count() === 1) {
        $ns = '';
    } else {
        throw new RuntimeException('Unsupported namespace');
    }
    $minPHPVersionNodes = $xpath->query("/{$ns}package/{$ns}dependencies/{$ns}required/{$ns}php/{$ns}min");
    $maxPHPVersionNodes = $xpath->query("/{$ns}package/{$ns}dependencies/{$ns}required/{$ns}php/{$ns}max");
    $info = new PackageVersionInfo(
        $version,
        $minPHPVersionNodes->count() === 0 ? '' : $minPHPVersionNodes[0]->nodeValue,
        $maxPHPVersionNodes->count() === 0 ? '' : $maxPHPVersionNodes[0]->nodeValue
    );
    foreach ($xpath->query("/{$ns}package/{$ns}extsrcrelease/{$ns}configureoption") as $configureOptionNode) {
        $info->addConfigureOption(new PackageConfigureOption(
            $configureOptionNode->getAttribute('name'),
            $configureOptionNode->getAttribute('prompt'),
            $configureOptionNode->hasAttribute('default') ? $configureOptionNode->getAttribute('default') : null
        ));
    }

    return $info;
}

class PackageVersionInfo
{
    private string $version;
    private string $minPHPVersion;
    private string $maxPHPVersion;
    private array $configureOptions = [];

    public function __construct(string $version, string $minPHPVersion, string $maxPHPVersion = '')
    {
        $this->version = $version;
        $this->minPHPVersion = $minPHPVersion;
        $this->maxPHPVersion = $maxPHPVersion;
    }

    public function getVersion(): string
    {
        return $this->version;
    }

    public function getMinPHPVersion(): string
    {
        return $this->minPHPVersion;
    }

    public function getMaxPHPVersion(): string
    {
        return $this->maxPHPVersion;
    }

    /**
     * @return $this
     */
    public function addConfigureOption(PackageConfigureOption $value): self
    {
        $this->configureOptions[] = $value;

        return $this;
    }

    /**
     * @return PackageConfigureOption[]
     */
    public function getConfigureOptions(): array
    {
        return $this->configureOptions;
    }
}

class PackageConfigureOption
{
    private string $name;
    private string $prompt;
    private ?string $default;

    public function __construct(string $name, string $prompt, ?string $default = null)
    {
        $this->name = $name;
        $this->prompt = $prompt;
        $this->default = $default;
    }

    public function __toString(): string
    {
        $result = "{$this->getName()} \"{$this->getPrompt()}\"";
        if ($this->getDefault() !== null) {
            $result .= " [{$this->getDefault()}]";
        }

        return $result;
    }

    public function getName(): string
    {
        return $this->name;
    }

    public function getPrompt(): string
    {
        return $this->prompt;
    }

    public function getDefault(): ?string
    {
        return $this->default;
    }
}

class CompatiblePHPVersions
{
    private string $minPHPVersion;
    private string $maxPHPVersion;
    private array $versions = [];

    public function __construct(string $minPHPVersion, string $maxPHPVersion)
    {
        $this->minPHPVersion = $minPHPVersion;
        $this->maxPHPVersion = $maxPHPVersion;
    }

    public function __toString(): string
    {
        $versions = $this->getVersions();

        return implode("\n", [
            "- Package versions: {$versions[0]}" . (isset($versions[1]) ? ' -> ' . $versions[count($versions) - 1] : ''),
            "  - Min PHP version: {$this->getMinPHPVersion()}",
            "  - Max PHP version: {$this->getMaxPHPVersion()}",
        ]);
    }

    public function getMinPHPVersion(): string
    {
        return $this->minPHPVersion;
    }

    public function getMaxPHPVersion(): string
    {
        return $this->maxPHPVersion;
    }

    /**
     * @return $this
     */
    public function addVersion(string $value): self
    {
        $this->versions[] = $value;

        return $this;
    }

    /**
     * @return string[]
     */
    public function getVersions(): array
    {
        return $this->versions;
    }

    public function isCompatibleWith(PackageVersionInfo $info): bool
    {
        return $this->getMinPHPVersion() === $info->getMinPHPVersion() && $this->getMaxPHPVersion() === $info->getMaxPHPVersion();
    }
}

class CompatibleConfigurationOptions
{
    /**
     * @var PackageConfigureOption[]
     */
    private array $configureOptions = [];
    private array $versions = [];

    public function __construct(array $configureOptions)
    {
        $this->configureOptions = $configureOptions;
    }

    public function __toString(): string
    {
        $versions = $this->getVersions();
        $lines = [
            "- Package versions: {$versions[0]}" . (isset($versions[1]) ? ' -> ' . $versions[count($versions) - 1] : ''),
        ];
        $options = $this->getConfigureOptions();
        if ($options === []) {
            $lines[] = '  <no options>';
        } else {
            foreach ($options as $index => $option) {
                $lines[] = $index + 1 . ') ' . (string) $option;
            }
        }

        return implode("\n", $lines);
    }

    /**
     * @return PackageConfigureOption[]
     */
    public function getConfigureOptions(): array
    {
        return $this->configureOptions;
    }

    /**
     * @return $this
     */
    public function addVersion(string $value): self
    {
        $this->versions[] = $value;

        return $this;
    }

    /**
     * @return string[]
     */
    public function getVersions(): array
    {
        return $this->versions;
    }

    public function isCompatibleWith(PackageVersionInfo $info): bool
    {
        return $this->getConfigureOptions() == $info->getConfigureOptions();
    }
}