<?php

namespace kch42\ste;

/**
 * The default {@see StorageAccess} implementation for loading / saving templates into a directory structure.
 */
class FilesystemStorageAccess implements StorageAccess
{
    /** @var string */
    protected $sourcedir;

    /** @var string */
    protected $transcompileddir;

    /**
     * @param string $src - The directory with the sources (Writing permissions are not mandatory, because STE does not save template sources).
     * @param string $transc - The directory with the compiled templates (the PHP instance / the HTTP Server needs writing permissions to this directory).
     */
    public function __construct(string $src, string $transc)
    {
        $this->sourcedir        = $src;
        $this->transcompileddir = $transc;
    }

    public function load(string $tpl, string &$mode)
    {
        $src_fn    = $this->sourcedir        . "/" . $tpl;
        $transc_fn = $this->transcompileddir . "/" . $tpl . ".php";

        if ($mode == StorageAccess::MODE_SOURCE) {
            $content = @file_get_contents($src_fn);
            if ($content === false) {
                throw new CantLoadTemplate("Template not found.");
            }
            return $content;
        }

        $src_stat    = @stat($src_fn);
        $transc_stat = @stat($transc_fn);

        if ($src_stat === false && $transc_stat === false) {
            throw new CantLoadTemplate("Template not found.");
        } elseif ($transc_stat === false) {
            $mode = StorageAccess::MODE_SOURCE;
            return file_get_contents($src_fn);
        } elseif ($src_stat === false) {
            include($transc_fn);
            if (!isset($transcompile_fx)) {
                throw new CantLoadTemplate("Compiled template file $transc_fn does not set \$transcompile_fx");
            }
            return $transcompile_fx;
        } else {
            if ($src_stat["mtime"] > $transc_stat["mtime"]) {
                $mode = StorageAccess::MODE_SOURCE;
                return file_get_contents($src_fn);
            } else {
                include($transc_fn);
                if (!isset($transcompile_fx)) {
                    throw new CantLoadTemplate("Compiled template file $transc_fn does not set \$transcompile_fx");
                }
                return $transcompile_fx;
            }
        }
    }

    public function save(string $tpl, string $data, $mode): void
    {
        $fn = (($mode == StorageAccess::MODE_SOURCE) ? $this->sourcedir : $this->transcompileddir) . "/" . $tpl . (($mode == StorageAccess::MODE_TRANSCOMPILED) ? ".php" : "");
        @mkdir(dirname($fn), 0777, true);
        if (file_put_contents($fn, "<?php\n\$transcompile_fx = $data;") === false) {
            throw new CantSaveTemplate("Unable to save template.");
        }
    }
}