<?php

namespace LimeSurvey\ExtensionInstaller;

use Exception;
use InvalidArgumentException;
use ExtensionConfig;

/**
 * Base class for different extension installers.
 *
 * All extension have this in common:
 * - Upload ZIP file or grab files from web (e.g. git repo)
 * - Read config.xml
 * - If config.xml is valid and the extension compatible with current version of LimeSurvey, then
 * -- Copy files to correct folder (depends on extension type)
 * -- Insert database row (depends on extension type)
 *
 * @since 2018-09-24
 * @author LimeSurvey GmbH
 */
abstract class ExtensionInstaller
{
    /**
     * Class responsible for fetching files from source.
     * @var FileFetcher
     */
    protected $fileFetcher;

    /**
     * @param FileFetcher $fileFetcher
     * @return void
     */
    public function setFileFetcher(FileFetcher $fileFetcher)
    {
        $this->fileFetcher = $fileFetcher;
    }

    /**
     * Order the file fetcher to fetch files.
     *
     * @return void
     * @throws Exception
     */
    public function fetchFiles()
    {
        if (empty($this->fileFetcher)) {
            throw new InvalidArgumentException('fileFetcher is not set');
        }

        $this->fileFetcher->fetch();
    }


    /**
     * Get the configuration from temp dir.
     * Before an extension is installed, we need to read the config
     * file. That's why the extension if fetched into a temp folder
     * first.
     *
     * @return ExtensionConfig|null
     */
    public function getConfig()
    {
        if ($this->fileFetcher) {
            return $this->fileFetcher->getConfig();
        } else {
            return null;
        }
    }

    /**
     * Install extension, which includes moving files
     * from temp dir to final dir, and creating the necessary
     * database changes.
     * @return void
     */
    abstract public function install();

    /**
     * Update extension.
     * @return void
     */
    abstract public function update();

    /**
     * Uninstall the extension.
     * @return void
     */
    abstract public function uninstall();

    /**
     * When installation procedure was not completed, abort changes.
     * @return void
     */
    public function abort()
    {
        if ($this->fileFetcher) {
            $this->fileFetcher->abort();
        }
    }
}