class Path

final class Path {
    
    /**
     * The number of buffer entries that triggers a cleanup operation.
     */
    private const CLEANUP_THRESHOLD = 1250;
    
    /**
     * The buffer size after the cleanup operation.
     */
    private const CLEANUP_SIZE = 1000;
    
    /**
     * Buffers input/output of {@link canonicalize()}.
     *
     * @var array<string, string>
     */
    private static array $buffer = [];
    private static int $bufferSize = 0;
    
    /**
     * Canonicalizes the given path.
     *
     * During normalization, all slashes are replaced by forward slashes ("/").
     * Furthermore, all "." and ".." segments are removed as far as possible.
     * ".." segments at the beginning of relative paths are not removed.
     *
     * ```php
     * echo Path::canonicalize("\symfony\puli\..\css\style.css");
     * // => /symfony/css/style.css
     *
     * echo Path::canonicalize("../css/./style.css");
     * // => ../css/style.css
     * ```
     *
     * This method is able to deal with both UNIX and Windows paths.
     */
    public static function canonicalize(string $path) : string {
        if ('' === $path) {
            return '';
        }
        // This method is called by many other methods in this class. Buffer
        // the canonicalized paths to make up for the severe performance
        // decrease.
        if (isset(self::$buffer[$path])) {
            return self::$buffer[$path];
        }
        // Replace "~" with user's home directory.
        if ('~' === $path[0]) {
            $path = self::getHomeDirectory() . substr($path, 1);
        }
        $path = self::normalize($path);
        [
            $root,
            $pathWithoutRoot,
        ] = self::split($path);
        $canonicalParts = self::findCanonicalParts($root, $pathWithoutRoot);
        // Add the root directory again
        self::$buffer[$path] = $canonicalPath = $root . implode('/', $canonicalParts);
        ++self::$bufferSize;
        // Clean up regularly to prevent memory leaks
        if (self::$bufferSize > self::CLEANUP_THRESHOLD) {
            self::$buffer = \array_slice(self::$buffer, -self::CLEANUP_SIZE, null, true);
            self::$bufferSize = self::CLEANUP_SIZE;
        }
        return $canonicalPath;
    }
    
    /**
     * Normalizes the given path.
     *
     * During normalization, all slashes are replaced by forward slashes ("/").
     * Contrary to {@link canonicalize()}, this method does not remove invalid
     * or dot path segments. Consequently, it is much more efficient and should
     * be used whenever the given path is known to be a valid, absolute system
     * path.
     *
     * This method is able to deal with both UNIX and Windows paths.
     */
    public static function normalize(string $path) : string {
        return str_replace('\\', '/', $path);
    }
    
    /**
     * Returns the directory part of the path.
     *
     * This method is similar to PHP's dirname(), but handles various cases
     * where dirname() returns a weird result:
     *
     *  - dirname() does not accept backslashes on UNIX
     *  - dirname("C:/symfony") returns "C:", not "C:/"
     *  - dirname("C:/") returns ".", not "C:/"
     *  - dirname("C:") returns ".", not "C:/"
     *  - dirname("symfony") returns ".", not ""
     *  - dirname() does not canonicalize the result
     *
     * This method fixes these shortcomings and behaves like dirname()
     * otherwise.
     *
     * The result is a canonical path.
     *
     * @return string The canonical directory part. Returns the root directory
     *                if the root directory is passed. Returns an empty string
     *                if a relative path is passed that contains no slashes.
     *                Returns an empty string if an empty string is passed.
     */
    public static function getDirectory(string $path) : string {
        if ('' === $path) {
            return '';
        }
        $path = self::canonicalize($path);
        // Maintain scheme
        if (false !== ($schemeSeparatorPosition = strpos($path, '://'))) {
            $scheme = substr($path, 0, $schemeSeparatorPosition + 3);
            $path = substr($path, $schemeSeparatorPosition + 3);
        }
        else {
            $scheme = '';
        }
        if (false === ($dirSeparatorPosition = strrpos($path, '/'))) {
            return '';
        }
        // Directory equals root directory "/"
        if (0 === $dirSeparatorPosition) {
            return $scheme . '/';
        }
        // Directory equals Windows root "C:/"
        if (2 === $dirSeparatorPosition && ctype_alpha($path[0]) && ':' === $path[1]) {
            return $scheme . substr($path, 0, 3);
        }
        return $scheme . substr($path, 0, $dirSeparatorPosition);
    }
    
    /**
     * Returns canonical path of the user's home directory.
     *
     * Supported operating systems:
     *
     *  - UNIX
     *  - Windows8 and upper
     *
     * If your operating system or environment isn't supported, an exception is thrown.
     *
     * The result is a canonical path.
     *
     * @throws RuntimeException If your operating system or environment isn't supported
     */
    public static function getHomeDirectory() : string {
        // For UNIX support
        if (getenv('HOME')) {
            return self::canonicalize(getenv('HOME'));
        }
        // For >= Windows8 support
        if (getenv('HOMEDRIVE') && getenv('HOMEPATH')) {
            return self::canonicalize(getenv('HOMEDRIVE') . getenv('HOMEPATH'));
        }
        throw new RuntimeException("Cannot find the home directory path: Your environment or operating system isn't supported.");
    }
    
    /**
     * Returns the root directory of a path.
     *
     * The result is a canonical path.
     *
     * @return string The canonical root directory. Returns an empty string if
     *                the given path is relative or empty.
     */
    public static function getRoot(string $path) : string {
        if ('' === $path) {
            return '';
        }
        // Maintain scheme
        if (false !== ($schemeSeparatorPosition = strpos($path, '://'))) {
            $scheme = substr($path, 0, $schemeSeparatorPosition + 3);
            $path = substr($path, $schemeSeparatorPosition + 3);
        }
        else {
            $scheme = '';
        }
        $firstCharacter = $path[0];
        // UNIX root "/" or "\" (Windows style)
        if ('/' === $firstCharacter || '\\' === $firstCharacter) {
            return $scheme . '/';
        }
        $length = \strlen($path);
        // Windows root
        if ($length > 1 && ':' === $path[1] && ctype_alpha($firstCharacter)) {
            // Special case: "C:"
            if (2 === $length) {
                return $scheme . $path . '/';
            }
            // Normal case: "C:/ or "C:\"
            if ('/' === $path[2] || '\\' === $path[2]) {
                return $scheme . $firstCharacter . $path[1] . '/';
            }
        }
        return '';
    }
    
    /**
     * Returns the file name without the extension from a file path.
     *
     * @param string|null $extension if specified, only that extension is cut
     *                               off (may contain leading dot)
     */
    public static function getFilenameWithoutExtension(string $path, ?string $extension = null) : string {
        if ('' === $path) {
            return '';
        }
        if (null !== $extension) {
            // remove extension and trailing dot
            return rtrim(basename($path, $extension), '.');
        }
        return pathinfo($path, \PATHINFO_FILENAME);
    }
    
    /**
     * Returns the extension from a file path (without leading dot).
     *
     * @param bool $forceLowerCase forces the extension to be lower-case
     */
    public static function getExtension(string $path, bool $forceLowerCase = false) : string {
        if ('' === $path) {
            return '';
        }
        $extension = pathinfo($path, \PATHINFO_EXTENSION);
        if ($forceLowerCase) {
            $extension = self::toLower($extension);
        }
        return $extension;
    }
    
    /**
     * Returns whether the path has an (or the specified) extension.
     *
     * @param string               $path       the path string
     * @param string|string[]|null $extensions if null or not provided, checks if
     *                                         an extension exists, otherwise
     *                                         checks for the specified extension
     *                                         or array of extensions (with or
     *                                         without leading dot)
     * @param bool                 $ignoreCase whether to ignore case-sensitivity
     */
    public static function hasExtension(string $path, $extensions = null, bool $ignoreCase = false) : bool {
        if ('' === $path) {
            return false;
        }
        $actualExtension = self::getExtension($path, $ignoreCase);
        // Only check if path has any extension
        if ([] === $extensions || null === $extensions) {
            return '' !== $actualExtension;
        }
        if (\is_string($extensions)) {
            $extensions = [
                $extensions,
            ];
        }
        foreach ($extensions as $key => $extension) {
            if ($ignoreCase) {
                $extension = self::toLower($extension);
            }
            // remove leading '.' in extensions array
            $extensions[$key] = ltrim($extension, '.');
        }
        return \in_array($actualExtension, $extensions, true);
    }
    
    /**
     * Changes the extension of a path string.
     *
     * @param string $path      The path string with filename.ext to change.
     * @param string $extension new extension (with or without leading dot)
     *
     * @return string the path string with new file extension
     */
    public static function changeExtension(string $path, string $extension) : string {
        if ('' === $path) {
            return '';
        }
        $actualExtension = self::getExtension($path);
        $extension = ltrim($extension, '.');
        // No extension for paths
        if (str_ends_with($path, '/')) {
            return $path;
        }
        // No actual extension in path
        if (!$actualExtension) {
            return $path . (str_ends_with($path, '.') ? '' : '.') . $extension;
        }
        return substr($path, 0, -\strlen($actualExtension)) . $extension;
    }
    public static function isAbsolute(string $path) : bool {
        if ('' === $path) {
            return false;
        }
        // Strip scheme
        if (false !== ($schemeSeparatorPosition = strpos($path, '://')) && 1 !== $schemeSeparatorPosition) {
            $path = substr($path, $schemeSeparatorPosition + 3);
        }
        $firstCharacter = $path[0];
        // UNIX root "/" or "\" (Windows style)
        if ('/' === $firstCharacter || '\\' === $firstCharacter) {
            return true;
        }
        // Windows root
        if (\strlen($path) > 1 && ctype_alpha($firstCharacter) && ':' === $path[1]) {
            // Special case: "C:"
            if (2 === \strlen($path)) {
                return true;
            }
            // Normal case: "C:/ or "C:\"
            if ('/' === $path[2] || '\\' === $path[2]) {
                return true;
            }
        }
        return false;
    }
    public static function isRelative(string $path) : bool {
        return !self::isAbsolute($path);
    }
    
    /**
     * Turns a relative path into an absolute path in canonical form.
     *
     * Usually, the relative path is appended to the given base path. Dot
     * segments ("." and "..") are removed/collapsed and all slashes turned
     * into forward slashes.
     *
     * ```php
     * echo Path::makeAbsolute("../style.css", "/symfony/puli/css");
     * // => /symfony/puli/style.css
     * ```
     *
     * If an absolute path is passed, that path is returned unless its root
     * directory is different than the one of the base path. In that case, an
     * exception is thrown.
     *
     * ```php
     * Path::makeAbsolute("/style.css", "/symfony/puli/css");
     * // => /style.css
     *
     * Path::makeAbsolute("C:/style.css", "C:/symfony/puli/css");
     * // => C:/style.css
     *
     * Path::makeAbsolute("C:/style.css", "/symfony/puli/css");
     * // InvalidArgumentException
     * ```
     *
     * If the base path is not an absolute path, an exception is thrown.
     *
     * The result is a canonical path.
     *
     * @param string $basePath an absolute base path
     *
     * @throws InvalidArgumentException if the base path is not absolute or if
     *                                  the given path is an absolute path with
     *                                  a different root than the base path
     */
    public static function makeAbsolute(string $path, string $basePath) : string {
        if ('' === $basePath) {
            throw new InvalidArgumentException(\sprintf('The base path must be a non-empty string. Got: "%s".', $basePath));
        }
        if (!self::isAbsolute($basePath)) {
            throw new InvalidArgumentException(\sprintf('The base path "%s" is not an absolute path.', $basePath));
        }
        if (self::isAbsolute($path)) {
            return self::canonicalize($path);
        }
        if (false !== ($schemeSeparatorPosition = strpos($basePath, '://'))) {
            $scheme = substr($basePath, 0, $schemeSeparatorPosition + 3);
            $basePath = substr($basePath, $schemeSeparatorPosition + 3);
        }
        else {
            $scheme = '';
        }
        return $scheme . self::canonicalize(rtrim($basePath, '/\\') . '/' . $path);
    }
    
    /**
     * Turns a path into a relative path.
     *
     * The relative path is created relative to the given base path:
     *
     * ```php
     * echo Path::makeRelative("/symfony/style.css", "/symfony/puli");
     * // => ../style.css
     * ```
     *
     * If a relative path is passed and the base path is absolute, the relative
     * path is returned unchanged:
     *
     * ```php
     * Path::makeRelative("style.css", "/symfony/puli/css");
     * // => style.css
     * ```
     *
     * If both paths are relative, the relative path is created with the
     * assumption that both paths are relative to the same directory:
     *
     * ```php
     * Path::makeRelative("style.css", "symfony/puli/css");
     * // => ../../../style.css
     * ```
     *
     * If both paths are absolute, their root directory must be the same,
     * otherwise an exception is thrown:
     *
     * ```php
     * Path::makeRelative("C:/symfony/style.css", "/symfony/puli");
     * // InvalidArgumentException
     * ```
     *
     * If the passed path is absolute, but the base path is not, an exception
     * is thrown as well:
     *
     * ```php
     * Path::makeRelative("/symfony/style.css", "symfony/puli");
     * // InvalidArgumentException
     * ```
     *
     * If the base path is not an absolute path, an exception is thrown.
     *
     * The result is a canonical path.
     *
     * @throws InvalidArgumentException if the base path is not absolute or if
     *                                  the given path has a different root
     *                                  than the base path
     */
    public static function makeRelative(string $path, string $basePath) : string {
        $path = self::canonicalize($path);
        $basePath = self::canonicalize($basePath);
        [
            $root,
            $relativePath,
        ] = self::split($path);
        [
            $baseRoot,
            $relativeBasePath,
        ] = self::split($basePath);
        // If the base path is given as absolute path and the path is already
        // relative, consider it to be relative to the given absolute path
        // already
        if ('' === $root && '' !== $baseRoot) {
            // If base path is already in its root
            if ('' === $relativeBasePath) {
                $relativePath = ltrim($relativePath, './\\');
            }
            return $relativePath;
        }
        // If the passed path is absolute, but the base path is not, we
        // cannot generate a relative path
        if ('' !== $root && '' === $baseRoot) {
            throw new InvalidArgumentException(\sprintf('The absolute path "%s" cannot be made relative to the relative path "%s". You should provide an absolute base path instead.', $path, $basePath));
        }
        // Fail if the roots of the two paths are different
        if ($baseRoot && $root !== $baseRoot) {
            throw new InvalidArgumentException(\sprintf('The path "%s" cannot be made relative to "%s", because they have different roots ("%s" and "%s").', $path, $basePath, $root, $baseRoot));
        }
        if ('' === $relativeBasePath) {
            return $relativePath;
        }
        // Build a "../../" prefix with as many "../" parts as necessary
        $parts = explode('/', $relativePath);
        $baseParts = explode('/', $relativeBasePath);
        $dotDotPrefix = '';
        // Once we found a non-matching part in the prefix, we need to add
        // "../" parts for all remaining parts
        $match = true;
        foreach ($baseParts as $index => $basePart) {
            if ($match && isset($parts[$index]) && $basePart === $parts[$index]) {
                unset($parts[$index]);
                continue;
            }
            $match = false;
            $dotDotPrefix .= '../';
        }
        return rtrim($dotDotPrefix . implode('/', $parts), '/');
    }
    
    /**
     * Returns whether the given path is on the local filesystem.
     */
    public static function isLocal(string $path) : bool {
        return '' !== $path && !str_contains($path, '://');
    }
    
    /**
     * Returns the longest common base path in canonical form of a set of paths or
     * `null` if the paths are on different Windows partitions.
     *
     * Dot segments ("." and "..") are removed/collapsed and all slashes turned
     * into forward slashes.
     *
     * ```php
     * $basePath = Path::getLongestCommonBasePath(
     *     '/symfony/css/style.css',
     *     '/symfony/css/..'
     * );
     * // => /symfony
     * ```
     *
     * The root is returned if no common base path can be found:
     *
     * ```php
     * $basePath = Path::getLongestCommonBasePath(
     *     '/symfony/css/style.css',
     *     '/puli/css/..'
     * );
     * // => /
     * ```
     *
     * If the paths are located on different Windows partitions, `null` is
     * returned.
     *
     * ```php
     * $basePath = Path::getLongestCommonBasePath(
     *     'C:/symfony/css/style.css',
     *     'D:/symfony/css/..'
     * );
     * // => null
     * ```
     */
    public static function getLongestCommonBasePath(string ...$paths) : ?string {
        [
            $bpRoot,
            $basePath,
        ] = self::split(self::canonicalize(reset($paths)));
        for (next($paths); null !== key($paths) && '' !== $basePath; next($paths)) {
            [
                $root,
                $path,
            ] = self::split(self::canonicalize(current($paths)));
            // If we deal with different roots (e.g. C:/ vs. D:/), it's time
            // to quit
            if ($root !== $bpRoot) {
                return null;
            }
            // Make the base path shorter until it fits into path
            while (true) {
                if ('.' === $basePath) {
                    // No more base paths
                    $basePath = '';
                    // next path
                    continue 2;
                }
                // Prevent false positives for common prefixes
                // see isBasePath()
                if (str_starts_with($path . '/', $basePath . '/')) {
                    // next path
                    continue 2;
                }
                $basePath = \dirname($basePath);
            }
        }
        return $bpRoot . $basePath;
    }
    
    /**
     * Joins two or more path strings into a canonical path.
     */
    public static function join(string ...$paths) : string {
        $finalPath = null;
        $wasScheme = false;
        foreach ($paths as $path) {
            if ('' === $path) {
                continue;
            }
            if (null === $finalPath) {
                // For first part we keep slashes, like '/top', 'C:\' or 'phar://'
                $finalPath = $path;
                $wasScheme = str_contains($path, '://');
                continue;
            }
            // Only add slash if previous part didn't end with '/' or '\'
            if (!\in_array(substr($finalPath, -1), [
                '/',
                '\\',
            ], true)) {
                $finalPath .= '/';
            }
            // If first part included a scheme like 'phar://' we allow \current part to start with '/', otherwise trim
            $finalPath .= $wasScheme ? $path : ltrim($path, '/');
            $wasScheme = false;
        }
        if (null === $finalPath) {
            return '';
        }
        return self::canonicalize($finalPath);
    }
    
    /**
     * Returns whether a path is a base path of another path.
     *
     * Dot segments ("." and "..") are removed/collapsed and all slashes turned
     * into forward slashes.
     *
     * ```php
     * Path::isBasePath('/symfony', '/symfony/css');
     * // => true
     *
     * Path::isBasePath('/symfony', '/symfony');
     * // => true
     *
     * Path::isBasePath('/symfony', '/symfony/..');
     * // => false
     *
     * Path::isBasePath('/symfony', '/puli');
     * // => false
     * ```
     */
    public static function isBasePath(string $basePath, string $ofPath) : bool {
        $basePath = self::canonicalize($basePath);
        $ofPath = self::canonicalize($ofPath);
        // Append slashes to prevent false positives when two paths have
        // a common prefix, for example /base/foo and /base/foobar.
        // Don't append a slash for the root "/", because then that root
        // won't be discovered as common prefix ("//" is not a prefix of
        // "/foobar/").
        return str_starts_with($ofPath . '/', rtrim($basePath, '/') . '/');
    }
    
    /**
     * @return string[]
     */
    private static function findCanonicalParts(string $root, string $pathWithoutRoot) : array {
        $parts = explode('/', $pathWithoutRoot);
        $canonicalParts = [];
        // Collapse "." and "..", if possible
        foreach ($parts as $part) {
            if ('.' === $part || '' === $part) {
                continue;
            }
            // Collapse ".." with the previous part, if one exists
            // Don't collapse ".." if the previous part is also ".."
            if ('..' === $part && \count($canonicalParts) > 0 && '..' !== $canonicalParts[\count($canonicalParts) - 1]) {
                array_pop($canonicalParts);
                continue;
            }
            // Only add ".." prefixes for relative paths
            if ('..' !== $part || '' === $root) {
                $canonicalParts[] = $part;
            }
        }
        return $canonicalParts;
    }
    
    /**
     * Splits a canonical path into its root directory and the remainder.
     *
     * If the path has no root directory, an empty root directory will be
     * returned.
     *
     * If the root directory is a Windows style partition, the resulting root
     * will always contain a trailing slash.
     *
     * list ($root, $path) = Path::split("C:/symfony")
     * // => ["C:/", "symfony"]
     *
     * list ($root, $path) = Path::split("C:")
     * // => ["C:/", ""]
     *
     * @return array{string, string} an array with the root directory and the remaining relative path
     */
    private static function split(string $path) : array {
        if ('' === $path) {
            return [
                '',
                '',
            ];
        }
        // Remember scheme as part of the root, if any
        if (false !== ($schemeSeparatorPosition = strpos($path, '://'))) {
            $root = substr($path, 0, $schemeSeparatorPosition + 3);
            $path = substr($path, $schemeSeparatorPosition + 3);
        }
        else {
            $root = '';
        }
        $length = \strlen($path);
        // Remove and remember root directory
        if (str_starts_with($path, '/')) {
            $root .= '/';
            $path = $length > 1 ? substr($path, 1) : '';
        }
        elseif ($length > 1 && ctype_alpha($path[0]) && ':' === $path[1]) {
            if (2 === $length) {
                // Windows special case: "C:"
                $root .= $path . '/';
                $path = '';
            }
            elseif ('/' === $path[2]) {
                // Windows normal case: "C:/"..
                $root .= substr($path, 0, 3);
                $path = $length > 3 ? substr($path, 3) : '';
            }
        }
        return [
            $root,
            $path,
        ];
    }
    private static function toLower(string $string) : string {
        if (false !== ($encoding = mb_detect_encoding($string, null, true))) {
            return mb_strtolower($string, $encoding);
        }
        return strtolower($string);
    }
    private function __construct() {
    }

}