<?php

namespace SDK;

use SDK\Config;
use SDK\Cache;
use SDK\Exception;

class Cache
{
	protected $id;
	protected $hash;

	public function __construct(string $id)
	{/*{{{*/
		$this->id = $id;
		$this->hash = md5($id);
		/* XXX pass as arg, fine for now. */
	}/*}}}*/

	protected function getCacheablePath(string $path, bool $relative = false) : string
	{/*{{{*/
		if ($relative) {
			$dir = Config::getCacheDir();
			$name = $path;
		} else {
			$dir = dirname($path);
			$name = basename($path);
		}

		return $dir . DIRECTORY_SEPARATOR . $this->hash . "." . $name;
	}/*}}}*/

	public function fileIsCached(string $path, bool $relative = false) : bool
	{/*{{{*/
		return file_exists($this->getCacheablePath($path, $relative));
	}/*}}}*/

	/* TODO Sometimes a timestamp comparison might make sense. */
	public function cachedContentDiffers(string $path, string $content, bool $relative = false) : bool
	{/*{{{*/
		$p = $this->getCacheablePath($path, $relative);
		
		if (!file_exists($p)) {
			return true;
		}

		$old_sum = md5_file($p);
		$new_sum = md5($content);

		return $old_sum != $new_sum;
	}/*}}}*/

	public function cacheContent(string $path, string $content, bool $relative = false) : void
	{/*{{{*/
		$p = $this->getCacheablePath($path, $relative);

		if (strlen($content) !== file_put_contents($p, $content)) {
			throw new Exception("Couldn't cache '$p'");
		}
	}/*}}}*/

	public function getCachedContent(string $path, bool $relative = false) : ?string
	{/*{{{*/
		$p = $this->getCacheablePath($path, $relative);

		if ($this->isFileCached($p)) {
			return file_get_contents($p);
		}

		return NULL;
	}/*}}}*/
}

/*
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 * vim600: sw=4 ts=4 fdm=marker
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 */