<?php

Prado::using('Application.layouts.Layout');

class ClientScriptManager extends TClientScriptManager {

    private $_page;
    public function __construct(TPage $page) {
        $this->_page = $page;
        parent::__construct($page);
    }

    // Base path of the entire application
    private function _getBasePath() {
        return Prado::getPathOfNamespace('Web');
    }

    // Translate URLs to filesystem paths, index return array by URLs
    private function _getBasePaths(array $urls) {
        $basePath = $this->_getBasePath();
        return array_combine(
            $urls,
            array_map(
                function(string $path) use($basePath) {
                    return $basePath . DIRECTORY_SEPARATOR . $path;
                },
                $urls
            )
        );
    }

    // Base cache path, suffixed with subdirectory, create on demand
    private function _getCachePath(string $subdir = 'assets') {
        $cachePath = $this->Application->RuntimePath
            . DIRECTORY_SEPARATOR
            . $subdir;
        if (!is_dir($cachePath)) {
            if (file_exists($cachePath)) {
                throw new TIOException(
                    sprintf(
                        'Client script manager cache path "%s" exists and is not a directory',
                        $cachePath
                    )
                );
            } else {
                mkdir($cachePath);
            }
        }
        return $cachePath;
    }

    // Cache path for a file of specified type
    private function _getCacheFilePath(string $path, string $type) {
        return $this->_getCachePath($type)
            . DIRECTORY_SEPARATOR
            . $path;
    }

    // Cache key for specific file set, including current theme
    private function _getFileCollectionCacheKey(array $files) {
        sort($files);
        if ($this->_page->Theme) {
            $files[] = $this->_page->Theme->Name;
        }
        return md5(implode(PHP_EOL, $files));
    }

    // Last modification time of a file set
    private function _getFileCollectionMTime(array $files) {
        return max(array_map('filemtime', $files));
    }

    // Storage (application cache) key for list of rendered assets of specified type
    // Rendered[ASSET_TYPE].[VIEW_ID] (VIEW_ID as rendered in Layout hidden field)
    private function _getRenderedAssetsStoreKey(string $type) {
        $template = $this->_page->Master;
        if (!$template instanceof Layout) {
            throw new TNotSupportedException(
                'Compiled assets may only be used within Layout master class controls'
            );
        }
        return sprintf('Rendered%s.%s', $type, $template->generateViewID());
    }

    // Shorthand for JS assets cache key
    private function _getRenderedScriptsStoreKey() {
        return $this->_getRenderedAssetsStoreKey('Scripts');
    }

    // Shorthand for CSS assets cache key
    private function _getRenderedSheetsStoreKey() {
        return $this->_getRenderedAssetsStoreKey('Sheets');
    }

    // Application (primary) cache module, required to keep track of assets rendered on current page
    private function _getCache() {
        $cache = $this->Application->Cache;
        if (!$cache) {
            throw new TNotSupportedException(
                'Compiled assets require cache to be configured'
            );
        }
        return $cache;
    }

    // Check cache file validity, comparing to source file set
    private function _isCacheValid(string $cacheFile, array $paths) {
        return file_exists($cacheFile)
            && (filemtime($cacheFile) >= $this->_getFileCollectionMTime($paths));
    }

    // Determine whether specific URL points to a local asset (i.e. existing on the filesystem)
    private function _isFileLocal(string $file) {
        $basePath = $this->_getBasePath();
        return file_exists($basePath . DIRECTORY_SEPARATOR . $file);
    }

    // Filter URL set to leave only local assets
    private function _determineLocalFiles(array $files) {
        return array_filter(
            $files, [$this, '_isFileLocal']
        );
    }

    // Scripts - internal methods

    private $_renderedScriptsInitialized = FALSE;

    // Retrieve scripts already rendered on current page from application cache,
    // maintaining the state over callbacks
    private function _getRenderedScripts() {
        $sessionKey = $this->_getRenderedScriptsStoreKey();
        if ($this->_page->IsCallBack || $this->_renderedScriptsInitialized) {
            return $this->_getCache()->get($sessionKey) ?: [];
        } else {
            $this->_getCache()->delete($sessionKey);
            $this->_renderedScriptsInitialized = TRUE;
            return [];
        }
    }

    // Store information on rendered scripts in application cache
    private function _appendRenderedScripts(array $newScripts, string $compiledFileKey) {
        $scripts = $this->_getRenderedScripts();
        if (!isset($scripts[$compiledFileKey])) {
            $scripts[$compiledFileKey] = [];
        }
        $scripts[$compiledFileKey] = array_unique(
            array_merge(
                $scripts[$compiledFileKey],
                $newScripts
            )
        );
        $this->_getCache()->set(
            $this->_getRenderedScriptsStoreKey(),
            $scripts
        );
    }

    // Compress JS file and return its content
    private function _getCompressedScript(string $path) {
        return trim(TJavaScript::JSMin(
            file_get_contents($path)
        ));
    }

    // Join multiple script files into single asset, mark all of them as rendered in parent
    private function _compileScriptFiles(array $files) {
        foreach ($files as $file) {
            $this->markScriptFileAsRendered($file);
        }
        $paths = $this->_getBasePaths($files);
        $cacheFile = $this->_getCacheFilePath(
            $this->_getFileCollectionCacheKey($paths) . '.js',
            'scripts'
        );
        $this->_appendRenderedScripts($files, $cacheFile);
        if (!$this->_isCacheValid($cacheFile, $paths)) {
            $scriptContent = implode(
                PHP_EOL,
                array_map(
                    [$this, '_getCompressedScript'],
                    $paths
                )
            );
            file_put_contents($cacheFile, $scriptContent);
        }
        return $this->Application->AssetManager->publishFilePath($cacheFile);
    }

    // Write output tag for a single, compiled JS asset, consisting of multiple local assets
    private function _renderLocalScriptFiles(THtmlWriter $writer, array $localFiles) {
        if ($localFiles) {
            $assetPath = $this->_compileScriptFiles($localFiles);
            $this->_setHTTP2PushHeader($assetPath);
            $writer->write(TJavascript::renderScriptFile($assetPath));
        }
    }

    // Keep track of external JS scripts rendered on the page
    private function _renderExternalScriptFiles(THtmlWriter $writer, array $externalFiles) {
        if ($externalFiles) {
            foreach ($externalFiles as $file) {
                $this->_setHTTP2PushHeader($file);
                $this->markScriptFileAsRendered($file);
                $this->_appendRenderedScripts([$file], $file);
            }
            parent::renderScriptFiles($writer, $externalFiles);
        }
    }

    // Determine actual asset URL that a source JS file was rendered as (after compilation/compression)
    // FALSE means script wasn't rendered at all (i.e. was just registered in current callback)
    private function _getRenderedScriptUrl(string $registeredScript) {
        $renderedScripts = $this->_getRenderedScripts();
        foreach ($renderedScripts as $compiledFile => $scripts) {
            if (in_array($registeredScript, $scripts)) {
                if (file_exists($compiledFile)) {
                    return $this->Application->AssetManager->getPublishedUrl(
                        $compiledFile
                    );
                } else {
                    return $registeredScript;
                }
            }
        }
        return FALSE;
    }

    // Scripts - public interface overrides

    // In application modes "higher" than Debug, compile JS assets to as few files as possible
    public function renderScriptFiles($writer, array $files) {
        if ($this->getApplication()->getMode() !== TApplicationMode::Debug) {
            if ($files) {
                $localFiles = $this->_determineLocalFiles($files);
                $this->_renderLocalScriptFiles($writer, $localFiles);
                $externalFiles = array_diff($files, $localFiles);
                $this->_renderExternalScriptFiles($writer, $externalFiles);
            }
        } else {
            foreach ($files as $file) {
                $this->_setHTTP2PushHeader($file);
            }
            parent::renderScriptFiles($writer, $files);
        }
    }

    // When above compilation occurs, list of JS URLs a callback requires
    // significantly deviates from parent implementation.
    // Also, new scripts that have been registered in current callback may need compiling, too.
    public function getScriptUrls() {
        if ($this->getApplication()->getMode() !== TApplicationMode::Debug) {
            $registeredScripts = array_unique(
                array_merge(
                    $this->_scripts, $this->_headScripts
                )
            );
            $scriptUrls = [];
            $newScripts = [];
            foreach ($registeredScripts as $registeredScript) {
                $renderedScriptUrl = $this->_getRenderedScriptUrl($registeredScript);
                if ($renderedScriptUrl) {
                    $scriptUrls[] = $renderedScriptUrl;
                } else {
                    $newScripts[] = $registeredScript;
                }
            }
            $newLocalScripts = $this->_determineLocalFiles($newScripts);
            $newRemoteScripts = array_diff($newScripts, $newLocalScripts);
            if ($newLocalScripts) {
                $scriptUrls[] = $this->_compileScriptFiles($newLocalScripts);
            }
            $scriptUrls = array_values(
                array_unique(array_merge($scriptUrls, $newRemoteScripts))
            );
            return $scriptUrls;
        }
        return parent::getScriptUrls();
    }

    private $_scripts = [];
    private $_headScripts = [];

    // Keep track of what we're registering
    public function registerScriptFile($key, $file) {
        $this->_scripts[$key] = $file;
        return parent::registerScriptFile($key, $file);
    }

    // Keep track of what we're registering
    public function registerHeadScriptFile($key, $file) {
        $this->_headScripts[$key] = $file;
        return parent::registerHeadScriptFile($key, $file);
    }

    // Stylesheets - internal methods

    private $_renderedSheetsInitialized = FALSE;

    // Retrieve stylesheets already rendered on current page from application cache,
    // maintaining the state over callbacks
    private function _getRenderedSheets() {
        $sessionKey = $this->_getRenderedSheetsStoreKey();
        if ($this->_page->IsCallBack || $this->_renderedSheetsInitialized) {
            return $this->_getCache()->get($sessionKey) ?: [];
        } else {
            $this->_getCache()->delete($sessionKey);
            $this->_renderedSheetsInitialized = TRUE;
            return [];
        }
    }

    // Store information on rendered stylesheets in application cache
    private function _appendRenderedSheets(array $newSheets, string $compiledFileKey) {
        $sheets = $this->_getRenderedSheets();
        if (!isset($sheets[$compiledFileKey])) {
            $sheets[$compiledFileKey] = [];
        }
        $sheets[$compiledFileKey] = array_merge(
            $sheets[$compiledFileKey],
            $newSheets
        );
        $this->_getCache()->set(
            $this->_getRenderedSheetsStoreKey(),
            $sheets
        );
    }

    // Resolve all "url(FILE)" CSS directives pointing
    // to relative resources to specified path
    private function _fixStyleSheetPaths(string $content, string $originalUrl) {
        $originalDir = dirname($originalUrl . '.');
        return preg_replace_callback(
            '/url\s*\([\'"]?(.*?)[\'"]?\)/',
            function($matches) use($originalDir) {
                $url = parse_url($matches[1]);
                // ignore absolute URLs and paths
                if (isset($url['scheme'])
                    || isset($url['host'])
                    || $url['path'][0] == '/') {
                    return $matches[0];
                }
                // resolve relative paths
                return str_replace(
                    $matches[1],
                    $originalDir . '/' . $matches[1],
                    $matches[0]
                );
            },
            $content
        );
    }

    // Compress CSS file and return its content
    private function _getCompressedSheet(string $origPath, string $path) {
        Prado::using('Lib.cssmin.CssMin');
        return trim(CssMin::minify(
            $this->_fixStyleSheetPaths(
                file_get_contents($path),
                $origPath
            )
        ));
    }

    // Join multiple stylesheet files into single asset
    private function _compileSheetFiles(array $files) {
        $paths = $this->_getBasePaths(
            array_map('reset', $files)
        );
        // determine if file was registered as a themed sheet
        $correctedPaths = [];
        foreach ($paths as $url => $path) {
            $correctedPaths[
                in_array($url, $this->_themeStyles) && $this->_page->Theme
                ? $this->_page->Theme->BaseUrl . DIRECTORY_SEPARATOR
                : $url
            ] = $path;
        }
        $cacheFile = $this->_getCacheFilePath(
            $this->_getFileCollectionCacheKey($paths) . '.css',
            'styles'
        );
        $this->_appendRenderedSheets($files, $cacheFile);
        if (!$this->_isCacheValid($cacheFile, $paths)) {
            $styleContent = implode(
                PHP_EOL,
                array_map(
                    [$this, '_getCompressedSheet'],
                    array_keys($correctedPaths),
                    $correctedPaths
                )
            );
            file_put_contents($cacheFile, $styleContent);
        }
        return $this->Application->AssetManager->publishFilePath($cacheFile);
    }

    // Filter only local stylesheet file entries
    private function _determineLocalSheetFiles(array $files) {
        $basePath = $this->_getBasePath();
        return array_filter(
            $files,
            function($file) use($basePath) {
                return file_exists($basePath . DIRECTORY_SEPARATOR . $file[0]);
            }
        );
    }

    // Write HTML markup for CSS stylesheet
    private function _renderSheetFileTag(THtmlWriter $writer, string $href, string $media) {
        $writer->addAttribute('rel', 'stylesheet');
        $writer->addAttribute('type', 'text/css');
        $writer->addAttribute('media', $media);
        $writer->addAttribute('href', $href);
        $writer->renderBeginTag('link');
        $writer->write(PHP_EOL);
    }

    // Group registered local CSS assets by media query string and render markup for compiled sheets
    private function _renderLocalSheetFiles(THtmlWriter $writer, array $localFiles) {
        if ($localFiles) {
            $fileTypes = [];
            foreach ($localFiles as $file) {
                $type = $file[1] ?: 'all';
                if (!isset($fileTypes[$type])) {
                    $fileTypes[$type] = [];
                }
                $fileTypes[$type][] = $file;
            }
            foreach ($fileTypes as $type => $files) {
                $assetPath = $this->_compileSheetFiles($files);
                $this->_setHTTP2PushHeader($assetPath);
                $this->_renderSheetFileTag($writer, $assetPath, $type);
            }
        }
    }

    // Render markup for external stylesheets
    private function _renderExternalSheetFiles(THtmlWriter $writer, array $externalFiles) {
        if ($externalFiles) {
            foreach ($externalFiles as $file) {
                $this->_appendRenderedSheets([$file], $file[0]);
                $this->_setHTTP2PushHeader($file[0]);
                $this->_renderSheetFileTag($writer, $file[0], $file[1] ?: 'all');
            }
        }
    }

    // Determine actual asset URL that a source CSS file was rendered as (after compilation/compression)
    // FALSE means sheet wasn't rendered at all (i.e. was just registered in current callback)
    // Media query types can easily be ignored in a callback request, only URLs matter
    private function _getRenderedSheetUrl(string $registeredSheet) {
        $renderedSheets = $this->_getRenderedSheets();
        foreach ($renderedSheets as $compiledFile => $sheets) {
            foreach ($sheets as $sheet) {
                if ($registeredSheet[0] == $sheet[0]) {
                    if (file_exists($compiledFile)) {
                        return $this->Application->AssetManager->getPublishedUrl(
                            $compiledFile
                        );
                    } else {
                        return $registeredSheet[0];
                    }
                }
            }
        }
        return FALSE;
    }

    // Stylesheets - public interface overrides

    // In application modes "higher" than Debug, compile CSS assets to as few files as possible
    public function renderStyleSheetFiles($writer) {
        if ($this->getApplication()->getMode() !== TApplicationMode::Debug) {
            $files = $this->_styles;
            if ($files) {
                $localFiles = $this->_determineLocalSheetFiles($files);
                $this->_renderLocalSheetFiles($writer, $localFiles);
                $externalFiles = array_diff_key($files, $localFiles);
                $this->_renderExternalSheetFiles($writer, $externalFiles);
            }
        } else {
            foreach ($this->getStyleSheetUrls() as $file) {
                $this->_setHTTP2PushHeader($file);
            }
            parent::renderStyleSheetFiles($writer);
        }
    }

    // When above compilation occurs, list of CSS URLs a callback requires
    // significantly deviates from parent implementation.
    // New stylesheets may need compiling, as well.
    public function getStyleSheetUrls() {
        if ($this->getApplication()->getMode() !== TApplicationMode::Debug) {
            $registeredSheets = $this->_styles;
            $sheetUrls = [];
            $newSheets = [];
            foreach ($registeredSheets as $registeredSheet) {
                $renderedSheetUrl = $this->_getRenderedSheetUrl(
                    $registeredSheet
                );
                if ($renderedSheetUrl) {
                    $sheetUrls[] = $renderedSheetUrl;
                } else {
                    $newSheets[] = $registeredSheet;
                }
            }
            $newLocalSheets = $this->_determineLocalSheetFiles($newSheets);
            $newLocalUrls = array_map('reset', $newLocalSheets);
            $newRemoteSheets = array_filter(
                $newSheets,
                function($sheet) use($newLocalUrls) {
                    return !in_array($sheet[0], $newLocalUrls);
                }
            );
            $newRemoteUrls = array_map('reset', $newRemoteSheets);
            if ($newLocalSheets) {
                $sheetUrls[] = $this->_compileSheetFiles($newLocalSheets);
            }
            $sheetUrls = array_values(
                array_unique(array_merge($sheetUrls, $newRemoteUrls))
            );
            return $sheetUrls;
        }
        // And even in Debug mode, theme sheets before fixing paths
        // might also have been published via assets manager,
        // so we have to discard these from parent list.
        return array_diff(
            parent::getStyleSheetUrls(),
            $this->_fixedStyleFiles
        );
    }

    private $_styles = [];

    // Keep track of what we're registering
    public function registerStyleSheetFile($key, $file, $media = '') {
        $this->_styles[$key] = [$file, $media];
        return parent::registerStyleSheetFile($key, $file, $media ?: 'all');
    }

    private $_themeStyles = [];
    private $_fixedStyleFiles = [];

    // New method, automatically corrects URLs within stylesheet to current page theme
    // when sheets are not compiled (when they are, it's done on compilation anyways).
    // Such files are rewritten (not in place, though) and registered so that they don't show up
    // within published assets returned from asset manager, as they don't end up in the markup.
    public function registerThemeStyleSheetFile(string $key, string $file, string $media = '') {
        if ($this->getApplication()->getMode() !== TApplicationMode::Debug) {
            $this->_themeStyles[$key] = $file;
        } else {
            if ($this->_isFileLocal($file) && $this->_page->Theme) {
                $tempFile = $this->_getCacheFilePath(
                    $this->_getFileCollectionCacheKey([
                        $this->_getBasePath()
                        . DIRECTORY_SEPARATOR
                        . $file
                    ])
                    . '.' . basename($file),
                    $this->_page->Theme->Name
                );
                file_put_contents(
                    $tempFile,
                    $this->_fixStyleSheetPaths(
                        file_get_contents(
                            $this->_getBasePath() . DIRECTORY_SEPARATOR . $file
                        ),
                        $this->_page->Theme->BaseUrl . DIRECTORY_SEPARATOR
                    )
                );
                $this->_fixedStyleFiles[] = $file;
                $file = $this->Application->AssetManager->publishFilePath($tempFile);
            }
        }
        return $this->registerStyleSheetFile($key, $file, $media ?: 'all');
    }

    private $_pushHeaders = [];

    // Set Link: header for HTTP2 Push
    private function _setHTTP2PushHeader($file) {
        if (!in_array($file, $this->_pushHeaders)) {
            $this->_pushHeaders[] = $file;
            $this->getResponse()->appendHeader('Link: "<' . $file . '>; rel=preload"', FALSE);
        }
    }

}

?>