'use strict'

import * as Logger from 'log4js';
import fetch = require('node-fetch');
import fs = require('fs');
import path = require('path')
import unzip = require('unzip')

Logger.configure({
    appenders: 
    {
    "plugin-manager": { type: 'stdout' },
    //app: { type: 'file', filename: 'application.log' }
    },
    categories: 
    {
    default: { appenders: [ 'plugin-manager' ], level: 'debug' }
    }
})
const logger = Logger.getLogger("plugin-manager") 


export class PluginManager{

    private installDir: string
    private cacheDir: string
    private loadedPlugins: string[]

    constructor(installDir: string = './plugins'){
        this.installDir = installDir
        this.cacheDir = path.join(installDir, '.cache')
        this.initialize()
    }

    private initialize() {
        logger.info('Initializing manager')

        try {
            fs.access(this.cacheDir, async err => {
                if (err && err.code === 'ENOENT') {
                    await fs.promises.mkdir(this.cacheDir, {recursive: true})
                    logger.info('Manager installed to ' + this.installDir)
                } else {
                    logger.info('Manager already installed at ' + this.installDir)
                }
            })
        } catch (error) {
            logger.error(error)
        }
    }

    public async getAvailablePlugins(): Promise<string[] | void> {
        return [
                'apiclient',
                'paymentmanager',
                'wallet',
                'htmlsupplier'
                ]
    }

    public async getInstalledPlugins(): Promise<string[] | void> {
        try {
            const installed = await fs.promises.readdir(this.installDir)
            return installed.filter( entry => entry[0] != '.')
        } catch (error) {
            logger.error(error)
            return
        }
    }

    public async getLoadedPlugins(): Promise<string[] | void> {
        return this.loadedPlugins
    }

    private async downloadFile(url: URL, dest: string) {
        try {
            fs.access(path.dirname(dest), err => {
                if (err && err.code === 'ENOENT') {
                    fs.mkdirSync(path.dirname(dest), {recursive: true})
                }
            })

            const file = fs.createWriteStream(dest)
            file.on('error', err => {throw new Error(err)})
            const response = await fetch(url)
            if (!response.ok) throw new Error(response.statusText)
            response.body.pipe(file)
        } catch (error) {
            logger.error(error)
            await fs.promises.unlink(dest)
        }
    }

    private async downloadPlugin(pluginName: string) {
        try {
            const response = await fetch('https://gitea.frontblock.me/api/v1/repos/fb-vendor/' + pluginName + '/releases')
            if (!response.ok) throw new Error(response.statusText)

            const releases = await response.json()
            if (!releases || !releases.length) throw new Error('Empty response')

            const latest = releases[0]
            const version = latest.tag_name
            const archiveURL = latest.assets.filter(asset => asset.name === pluginName + '.zip')[0].browser_download_url
            const checksumURL = latest.assets.filter(asset => asset.name === 'md5sum.txt')[0].browser_download_url
            if (!version || ! archiveURL || !checksumURL) throw new Error('Malformed response')

            await this.downloadFile(archiveURL, path.join(this.cacheDir, pluginName, version, 'plugin.zip'))
            await this.downloadFile(checksumURL, path.join(this.cacheDir, pluginName, version, 'md5sum.txt'))

        } catch (error) {
            logger.error(error)
        }
    }

    public async installPlugin(pluginName: string) {
        try {
            await this.downloadPlugin(pluginName)
        } catch (error) {
            logger.debug(error)
        }
    }

    public uninstallPlugin(pluginName: string) {
        
    }


    public async loadPlugin() {
        
    }

    public async unloadPlugin() {
        
    }
}