#!/usr/bin/php
<?php
// This script can be used to automatically glue all the .php files of Predis
// into a single monolithic script file that can be used without an autoloader,
// just like the other previous versions of the library.
//
// Much of its complexity is due to the fact that we cannot simply join PHP
// files, but namespaces and classes definitions must follow a precise order
// when dealing with subclassing and inheritance.
//
// The current implementation is pretty naïve, but it should do for now.
//
// TODO: add some kind of blacklisting mechanism to leave out certain classes
//       that may be considered useless for developers.
//

/* -------------------------------------------------------------------------- */

class PredisFile {
    const NS_ROOT = 'Predis';
    private $_namespaces;

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

    public static function from($libraryPath) {
        $nsroot = self::NS_ROOT;
        $predisFile = new PredisFile();
        $libIterator = new RecursiveDirectoryIterator("$libraryPath$nsroot");

        foreach (new RecursiveIteratorIterator($libIterator) as $classFile) {
            if (!$classFile->isFile()) {
                continue;
            }
            $namespace = strtr(str_replace($libraryPath, '', $classFile->getPath()), '/', '\\');
            $phpNamespace = $predisFile->getNamespace($namespace);
            if ($phpNamespace === false) {
                $phpNamespace = new PhpNamespace($namespace);
                $predisFile->addNamespace($phpNamespace);
            }
            $phpClass = new PhpClass($phpNamespace, $classFile);
        }
        return $predisFile;
    }

    public function addNamespace(PhpNamespace $namespace) {
        if (isset($this->_namespaces[(string)$namespace])) {
            throw new InvalidArgumentException("Duplicated namespace");
        }
        $this->_namespaces[(string)$namespace] = $namespace;
    }

    public function getNamespaces() {
        return $this->_namespaces;
    }

    public function getNamespace($namespace) {
        if (!isset($this->_namespaces[$namespace])) {
            return false;
        }
        return $this->_namespaces[$namespace];
    }

    public function getClassByFQN($classFqn) {
        if (($nsLastPos = strrpos($classFqn, '\\')) !== false) {
            $namespace = $this->getNamespace(substr($classFqn, 0, $nsLastPos));
            if ($namespace === false) {
                return null;
            }
            $className = substr($classFqn, $nsLastPos + 1);
            return $namespace->getClass($className);
        }
        return null;
    }

    private function calculateDependencyScores(&$classes, $fqn) {
        if (!isset($classes[$fqn])) {
            $classes[$fqn] = 0;
        }
        $classes[$fqn] += 1;
        $phpClass = $this->getClassByFQN($fqn);
        foreach ($phpClass->getDependencies() as $fqn) {
            $this->calculateDependencyScores($classes, $fqn);
        }
    }

    private function getDependencyScores() {
        $classes = array();
        foreach ($this->getNamespaces() as $phpNamespace) {
            foreach ($phpNamespace->getClasses() as $phpClass) {
                $this->calculateDependencyScores($classes, $phpClass->getFQN());
            }
        }
        return $classes;
    }

    private function getOrderedNamespaces($dependencyScores) {
        $namespaces = array_fill_keys(array_unique(
            array_map(
                function($fqn) { return PhpNamespace::extractName($fqn); },
                array_keys($dependencyScores)
            )
        ), 0);
        foreach ($dependencyScores as $classFqn => $score) {
            $namespaces[PhpNamespace::extractName($classFqn)] += $score;
        }
        arsort($namespaces);
        return array_keys($namespaces);
    }

    private function getOrderedClasses(PhpNamespace $phpNamespace, $classes) {
        $nsClassesFQNs = array_map(
            function($cl) { return $cl->getFQN(); },
            $phpNamespace->getClasses()
        );
        $nsOrderedClasses = array();
        foreach ($nsClassesFQNs as $nsClassFQN) {
            $nsOrderedClasses[$nsClassFQN] = $classes[$nsClassFQN];
        }
        arsort($nsOrderedClasses);
        return array_keys($nsOrderedClasses);
    }

    public function getPhpCode() {
        $buffer = array("<?php\n\n");
        $classes = $this->getDependencyScores();
        $namespaces = $this->getOrderedNamespaces($classes);

        foreach ($namespaces as $namespace) {
            $phpNamespace = $this->getNamespace($namespace);

            // generate namespace directive
            $buffer[] = $phpNamespace->getPhpCode();
            $buffer[] = "\n";

            // generate use directives
            $useDirectives = $phpNamespace->getUseDirectives();
            if (count($useDirectives) > 0) {
                $buffer[] = $useDirectives->getPhpCode();
                $buffer[] = "\n";
            }

            // generate classes bodies
            $nsClasses = $this->getOrderedClasses($phpNamespace, $classes);
            foreach ($nsClasses as $classFQN) {
                $buffer[] = $this->getClassByFQN($classFQN)->getPhpCode();
                $buffer[] = "\n\n";
            }

            $buffer[] = "/* " . str_repeat("-", 75) . " */";
            $buffer[] = "\n\n";
        }
        return implode($buffer);
    }

    public function saveTo($outputFile) {
        // TODO: add more sanity checks
        if ($outputFile === null || $outputFile === '') {
            throw new InvalidArgumentException('You must specify a valid output file');
        }
        file_put_contents($outputFile, $this->getPhpCode());
    }
}

class PhpNamespace implements IteratorAggregate {
    private $_namespace, $_classes;

    public function __construct($namespace) {
        $this->_namespace = $namespace;
        $this->_classes = array();
        $this->_useDirectives = new PhpUseDirectives($this);
    }

    public static function extractName($fqn) {
        $nsSepLast = strrpos($fqn, '\\');
        if ($nsSepLast === false) {
            return $fqn;
        }
        $ns = substr($fqn, 0, $nsSepLast);
        return $ns !== '' ? $ns : null;
    }

    public function addClass(PhpClass $class) {
        $this->_classes[$class->getName()] = $class;
    }

    public function getClass($className) {
        return $this->_classes[$className];
    }

    public function getClasses() {
        return array_values($this->_classes);
    }

    public function getIterator() {
        return new \ArrayIterator($this->getClasses());
    }

    public function getUseDirectives() {
        return $this->_useDirectives;
    }

    public function getPhpCode() {
        return "namespace $this->_namespace;\n";
    }

    public function __toString() {
        return $this->_namespace;
    }
}

class PhpUseDirectives implements Countable, IteratorAggregate {
    private $_use, $_aliases, $_namespace;

    public function __construct(PhpNamespace $namespace) {
        $this->_use = array();
        $this->_aliases = array();
        $this->_namespace = $namespace;
    }

    public function add($use, $as = null) {
        if (!in_array($use, $this->_use)) {
            $this->_use[] = $use;
            $this->_aliases[$as ?: PhpClass::extractName($use)] = $use;
        }
    }

    public function getList() {
        return $this->_use;
    }

    public function getIterator() {
        return new \ArrayIterator($this->getList());
    }

    public function getPhpCode() {
        $reducer = function($str, $use) { return $str .= "use $use;\n"; };
        return array_reduce($this->getList(), $reducer, '');
    }

    public function getNamespace() {
        return $this->_namespace;
    }

    public function getFQN($className) {
        if (($nsSepFirst = strpos($className, '\\')) === false) {
            if (isset($this->_aliases[$className])) {
                return $this->_aliases[$className];
            }
            return (string)$this->getNamespace() . "\\$className";
        }
        if ($nsSepFirst != 0) {
            throw new InvalidArgumentException("Partially qualified names are not supported");
        }
        return $className;
    }

    public function count() {
        return count($this->_use);
    }
}

class PhpClass {
    private $_namespace, $_file, $_body, $_implements, $_extends, $_name;

    public function __construct(PhpNamespace $namespace, SplFileInfo $classFile) {
        $this->_namespace = $namespace;
        $this->_file = $classFile;
        $this->_implements = array();
        $this->_extends = array();
        $this->extractData();
        $namespace->addClass($this);
    }

    public static function extractName($fqn) {
        $nsSepLast = strrpos($fqn, '\\');
        if ($nsSepLast === false) {
            return $fqn;
        }
        return substr($fqn, $nsSepLast + 1);
    }

    private function extractData() {
        $useDirectives = $this->getNamespace()->getUseDirectives();

        $useExtractor = function($m) use($useDirectives) {
            $useDirectives->add(($namespacedPath = $m[1]));
        };

        $classBuffer = stream_get_contents(fopen($this->getFile()->getPathname(), 'r'));

        $classBuffer = preg_replace('/<\?php\s?\\n\s?/', '', $classBuffer);
        $classBuffer = preg_replace('/\s?\?>\n?/ms', '', $classBuffer);
        $classBuffer = preg_replace('/namespace\s+[\w\d_\\\]+;\s?/', '', $classBuffer);
        $classBuffer = preg_replace_callback('/use\s+([\w\d_\\\]+)(\s+as\s+.*)?;\s?\n?/', $useExtractor, $classBuffer);

        $this->_body = trim($classBuffer);

        $this->extractHierarchy();
    }

    private function extractHierarchy() {
        $implements = array();
        $extends =  array();

        $extractor = function($iterator, $callback) {
            $className = '';
            $iterator->seek($iterator->key() + 1);
            while ($iterator->valid()) {
                $token = $iterator->current();
                if (is_string($token)) {
                    if (preg_match('/\s?,\s?/', $token)) {
                        $callback(trim($className));
                        $className = '';
                    }
                    else if ($token == '{') {
                        $callback(trim($className));
                        return;
                    }
                }
                switch ($token[0]) {
                    case T_NS_SEPARATOR:
                        $className .= '\\';
                        break;
                    case T_STRING:
                        $className .= $token[1];
                        break;
                    case T_IMPLEMENTS:
                    case T_EXTENDS:
                        $callback(trim($className));
                        $iterator->seek($iterator->key() - 1);
                        return;
                }
                $iterator->next();
            }
        };

        $tokens = token_get_all("<?php\n" . trim($this->getPhpCode()));

        $iterator = new ArrayIterator($tokens);
        while ($iterator->valid()) {
            $token = $iterator->current();
            if (is_string($token)) {
                $iterator->next();
                continue;
            }

            switch ($token[0]) {
                case T_CLASS:
                case T_INTERFACE:
                    $iterator->seek($iterator->key() + 2);
                    $tk = $iterator->current();
                    $this->_name = $tk[1];
                    break;
                case T_IMPLEMENTS:
                    $extractor($iterator, function($fqn) use (&$implements) {
                        $implements[] = $fqn;
                    });
                    break;
                case T_EXTENDS:
                    $extractor($iterator, function($fqn) use (&$extends) {
                        $extends[] = $fqn;
                    });
                    break;
            }
            $iterator->next();
        }

        $this->_implements = $this->guessFQN($implements);
        $this->_extends = $this->guessFQN($extends);
    }

    public function guessFQN($classes) {
        $useDirectives = $this->getNamespace()->getUseDirectives();
        return array_map(array($useDirectives, 'getFQN'), $classes);
    }

    public function getImplementedInterfaces($all = false) {
        if ($all) {
            return $this->_implements;
        }
        else {
            return array_filter(
                $this->_implements,
                function ($cn) { return strpos($cn, 'Predis\\') === 0; }
            );
        }
    }

    public function getExtendedClasses($all = false) {
        if ($all) {
            return $this->_extemds;
        }
        else {
            return array_filter(
                $this->_extends,
                function ($cn) { return strpos($cn, 'Predis\\') === 0; }
            );
        }
    }

    public function getDependencies($all = false) {
        return array_merge(
            $this->getImplementedInterfaces($all),
            $this->getExtendedClasses($all)
        );
    }

    public function getNamespace() {
        return $this->_namespace;
    }

    public function getFile() {
        return $this->_file;
    }

    public function getName() {
        return $this->_name;
    }

    public function getFQN() {
        return (string)$this->getNamespace() . '\\' . $this->_name;
    }

    public function getPhpCode() {
        return $this->_body;
    }

    public function __toString() {
        return "class " . $this->getName() . '{ ... }';
    }
}

/* -------------------------------------------------------------------------- */

$predisFile = PredisFile::from(__DIR__ . "/../lib/");
$predisFile->saveTo(isset($argv[1]) ? $argv[1] : PredisFile::NS_ROOT . ".php");