#!/usr/bin/env node
/* jshint esversion: 8,-W097, -W040, node: true, expr: true, undef: true */
const /* dependencies */
	[ fs, readline, https, { spawn } ]= [ "fs", "readline", "https", "child_process" ].map(p=> require(p));
const /* helper for coloring console | main program params */
	colors= { e: "\x1b[38;2;252;76;76m", s: "\x1b[38;2;76;252;125m", w: "\x1b[33m", R: "\x1b[0m", y: "\x1b[38;2;200;190;90m", g: "\x1b[38;2;150;150;150m" },
	info= {
		name: __filename.slice(__filename.lastIndexOf("/")+1, __filename.lastIndexOf(".")),
		version: "1.2.1",
		description: "Helper for working with “packages” stored in GitHub releases.",
		config: `${__filename.slice(0, __filename.lastIndexOf("."))}.json`,
		folder: __filename.slice(0, __filename.lastIndexOf("/")+1),
		commands: [
			{
				cmd: "help", args: [ "--help", "-h" ],
				desc: "Shows this text"
			},
			{
				cmd: "config", args: [ "--config" ],
				desc: "Opens config file in terminal editor (defaults to vim)"
			},
			{
				cmd: "check", args: [ "--check", "-c" ],
				desc: "Shows/checks updates for registered packages"
			},
			{
				cmd: "update", args: [ "--update", "-u" ], param: "group",
				desc: "Installs lates versions of registered packages"
			},
			{
				cmd: "uninstall", args: [ "--uninstall", "-u" ], param: "package",
				desc: "Deletes downloaded file and moves package to the 'skip' group"
			},
			{
				cmd: "register", args: [ "--register", "--change" ], param: "package",
				desc: "Add package infos to internal list to be able installing/updating"
			},
			{
				cmd: "remove", args: [ "--remove" ], param: "package",
				desc: ([
					"Uninstall package if needed (see `-u`)",
					"And remove it from internal list (see `--config`)"
				]).join(". ")
			}
		],
		params: {
			group: ([
				"You can label each package to update only choosen one",
				"There are sereved options:",
				"  - '' (empty): these packages are includes in all groups",
				"  - 'all': in case of `--update` process all packages (except skipped)",
				"  - 'skip': these packages are “uninstalled”",
				"			 No updates will be downloaded",
				"Group can be setted via '--register'"
			]).join(". "),
			package: ([
				"Represents package identificator, it is in fact GitHub repository path",
				"So, it schould be in the form `username/repository`"
			]).join(". ")
		}
	};
printMain();
const current= getCurrent(process.argv.slice(2));
(function main_(){
	const { cmd }= current.command;
	if(!cmd) return Promise.resolve("No arguments (use `--help` for showing all oprions).");
	switch(cmd){
		case "help":		return Promise.resolve(printHelp());
		case "config":		return vim_(info.config);
	}
	const config= getConfig();
	switch(cmd){
		case "register":	return register_(config);
	}
	if(!config.packages)	return Promise.resolve("No packages yet!");
	switch(cmd){
		case "check":		return check_(config);
		case "update":		return update_(config);
		case "uninstall":
		case "remove":
							return uninstall_(cmd, config);
	}
})()
.then(function(message){
	if(message)
		log(1, `Operation '${current.command.cmd}' successfull: @s_${message}`);
	process.exit();
})
.catch(error);

async function uninstall_(cmd, config){
	const progress= [
		[ "Deleting file", "not needed" ],
		[ "Check out from updates", "yes" ],
		[ "Remove from packages list", "no" ]
	];
	const pkg_name= current.param;
	const pkg_index= config.packages.findIndex(({ repository })=> repository===pkg_name);
	if(pkg_index===-1) return "nothing to do (maybe typo)";

	const pkg= config.packages[pkg_index];
	const { downloads }= pkg;
	if(downloads&&fs.existsSync(downloads)){
		try{ fs.unlinkSync(downloads); progress[0][1]= "done"; }
		catch (_){ progress[0][1]= colors.e+"error, try manually – "+downloads; }
	}
	Reflect.deleteProperty(pkg, "last_update");
	Reflect.set(pkg, "group", "skip");
	progress[1][1]= "done";
	if(cmd!=="remove") return gotoEnd();

	const y= await promt_(`Are you realy want to remove package ${pkg.repository} (yes/no)`, "no");
	if(y!=="yes") return gotoEnd();

	config.packages.splice(pkg_index, 1);
	progress[2][1]= "done";
	return gotoEnd();

	function gotoEnd(){
		const o= progress.reduce((o, [ k, v ])=> Reflect.set(o, k, v)&&o, {});
		logSection("  ", pkg_name, o);
		save(config);
	}
}
function vim_(file){ return new Promise(function(resolve, reject){
	const cmd= spawn((process.env.EDITOR||"vim")+(process.platform==="win32"?".bat":""), [ file ], { stdio: 'inherit' });
	cmd.on('exit', e=> e ? reject("Editor error, try manually: "+file) : resolve("OK"));
});}
async function update_(config){
	const filter= current.param;
	const is_all= filter==="all";
	let updates= [];
	log(1, "Collecting packages to download:");
	for(const [
		i, { repository, last_update, group, file_name, exec, downloaded, tag_name_regex }
	] of Object.entries(config.packages)){
		if(group==="skip") continue;
		if(!is_all&&group&&filter!==group) continue;

		const { tag_name, published_at, html_url, assets_url }= await githubRelease_(repository, tag_name_regex);
		const status= packageStatus(last_update, published_at);
		if(status!==3) continue;

		const assets= await downloadJSON_(repository, assets_url);
		if(!assets.length){
			console.log("  Nothing to download: Visit "+html_url);
			continue;
		}

		const options= assets.map(({ name, download_count, size })=>
			`${name} | size: ${Math.round(size/1048576)}MB | downloads: ${download_count}`);
		logSection("  ", " "+repository, {
			"Version": tag_name,
			"Url": html_url
		});
		logSection("   ", " Available assets:", options);
		const choose= await promt_("	  Choose (empty for skip)", "");
		if(choose==="") continue;

		const { browser_download_url: url, name: remote_name, size }= assets[choose];
		updates.push({
			index: i,
			file_name, exec, downloaded,
			repository, version: tag_name, last_update: published_at,
			url, remote_name, size
		});
	}
	if(!updates.length){
		log(2, "No packages in "+`group ${filter} needs updates.`);
		return Promise.resolve("nothing to update");
	}
	log(1, "Downloading:");
	return applySequentially_(updates, async function(todo){
		const to= todo.file_name ? info.folder+todo.file_name : (
				  todo.downloaded ? todo.downloaded : info.folder+todo.remote_name);
		const d= await downloadFile_(to, todo);
		return Object.assign(todo, d);
	})
	.then(function(dones){
		log(1, "Finalizing:");
		let e= 0;
		for(const nth of dones){
			if(!nth.success){
				e+= 1;
				log(2, `${nth.repository}: @e_${nth.message}`);
				continue;
			}
			Object.assign(config.packages[nth.index], registerDownloads(nth));
		}
		save(config);
		const { length }= dones;
		const msg= `updated ${length-e} of ${length} packages.`;
		return e ? Promise.reject(msg) : Promise.resolve(msg);
	});
}
function registerDownloads({ repository, last_update, message: downloads, exec, version }){
	let msg= colors.s+"OK";
	if(exec==="yes"){
		try{ fs.chmodSync(downloads, 0o755); }
		catch(e){ msg= colors.e+"try manual `chmod+x` for '"+downloads+"'"; }
	}
	log(2, `${repository}: ${msg}`);
	return { last_update, downloads, version };
}
async function check_({ packages }){
	let updates= 0, skipped= 0;
	for(const { repository, name, version, last_update, group, tag_name_regex } of packages){
		const { tag_name, published_at }= await githubRelease_(repository, tag_name_regex);
		const status= packageStatus(last_update, published_at);
		updates+= status===3;
		const skip= group==="skip";
		skipped+= skip;
		log(2, `@g_${repository} [${group}]: `+( !version ? "not installed" : packageStatusText(status, skip) ));
	}
	const u= updates-skipped;
	const s= skipped ? ` (inc. skipped: ${updates})` : "";
	return (!u ? "" : colors.w)+u+" update(s) available"+s;
}
async function register_(config){
	const { param: repository }= current;
	if(!Reflect.has(config, "packages")) Reflect.set(config, "packages", []);
	const packages= Reflect.get(config, "packages");
	let local_id= packages.findIndex(p=> p.repository===repository);
	if(local_id===-1)
		local_id= packages.push({ repository })-1;
	const local= config.packages[local_id];
	const remote= await githubRepo_(repository) || {};

	log(1, "Registering: "+repository);
	const spaces= "    ";
	local.name= await promt_(spaces+"Name", local.name || remote.name || "");
	if(!local.description) local.description= remote.description;
	logLines(2, [
		"@g_Group info:",
		"- you can update specific packages by using their group name",
		"- There some reserved options:",
		"  - '' (empty): will be included in all groups",
		"  - 'skip': will be always skipped"
	]);
	local.group= await promt_(spaces+"Group", local.group || "");
	local.file_name= await promt_(spaces+"File Name", local.file_name || local.name.toLowerCase().replace(/\s/g, "-") || "");
	local.exec= await promt_(spaces+"Make executable (yes/no)", local.exec || "no");
	save(config);
	return `${repository}: saved`;
}
function packageStatusText(status, skip){
	const s= skip ? colors.R+"skipped – "+colors.g : "";
	switch(status){
		case 0: return s+"nothing to compare";
		case 1: return s+"@s_up-to-date";
		case 2: return s+"newer";
		case 3: return s+"@e_outdated/not instaled";
	}
}
function packageStatus(local, remote){
	if(!remote) return 0;
	if(!local) return 3;
	if(remote===local) return 1;
	return 2+(local<remote);
}
function logSection(spaces, name, data){
	console.log(spaces+name);
	for(const [ key, value ] of Object.entries(data))
		console.log(spaces.repeat(2)+colors.g+key+": "+value.replace(/@(\w)_/g, (_, m)=> colors[m])+colors.R);
}
function githubRelease_(repository, tag_name_regex= ""){
	return downloadJSON_(repository, "https://api.github.com/repos/"+repository+"/releases")
	.then(data=> data.find(function find({ draft, published_at, tag_name }){
		if(draft||!published_at) return false;
		if(!tag_name_regex) return true;
		return (new RegExp(tag_name_regex, 'g')).test(tag_name);
	})||{});
}
function githubRepo_(repository){ return downloadJSON_(repository, "https://api.github.com/repos/"+repository); }
function promt_(q, def){
	const rl= readline.createInterface({ input: process.stdin, output: process.stdout });
	return new Promise(function(resolve){
		rl.question(q+": ", a=> { rl.close(); resolve(a); });
		rl.write(def);
	});
}
function getConfig(){
	let config;
	try{ config= JSON.parse(fs.readFileSync(info.config)); }
	catch(e){ config= {}; log(1, "@w_Missing or corrupted config file. Creates empty one."); }
	return config;
}
function save(config){
	return fs.writeFileSync(info.config, JSON.stringify(config, null, "    "));
}
function getCurrent(args){
	let command, command_arg, param;
	const hasArg= arg=> ({ args })=> args.includes(arg);
	for(let i=0, { length }= args, arg; i<length; i++){
		arg= args[i];
		if(!command){
			command= info.commands.find(hasArg(arg));
			command_arg= arg;
			continue;
		}
		if(!command.param||typeof param!=="undefined")
			break;
		param= arg;
	}
	if(!command)
		command= { cmd: "" };
	if(command.param&&typeof param==="undefined")
		return error(`Missign arguments for '${command_arg}'.`);
	return { command, param };
}
function downloadJSON_(repository, url){
	return downloadText_(url)
	.then(function(data){
		try{
			const response= JSON.parse(data);
			if(Reflect.has(response, "message")) throw new Error(response.message);
			return Promise.resolve(JSON.parse(data));
		} catch(e){
			log(1, "Received data: "+data);
			log(1, "@e_"+e);
			return Promise.reject(`JSON from '${repository}' failed.`);
		}
	});
}
function downloadText_(url){
	return get_(url)
	.then(function(response){ return new Promise(function(resolve){
		let data= "";
		response.on("data", chunk=> data+= chunk);
		response.on("end", ()=> resolve(data));
	}); });
}
function downloadFile_(to, { url, repository, size }){
	const file= fs.createWriteStream(to);
	return get_(url)
	.then(r=> get_(r.headers.location))
	.then(function(response){ return new Promise(function(resolve){
		let progress= 0, pc_prev= 0, avg= 0;
		const start= new Date();
		const i= setInterval(function(){
			readline.clearLine(process.stdout);
			const pc= (100*progress/size).toFixed(2);
			if(!pc_prev) pc_prev= pc;
			else {
				avg= ((100-pc)/(60*(pc-pc_prev))).toFixed(2);
				pc_prev= 0;
			}
			const running= ((new Date()-start)/60000).toFixed(2);
			log(2, repository+": "+pc+"%"+` (end in ~${avg} mins, running ${running} mins)`);
			readline.moveCursor(process.stdout, 0, -1);
		}, 500);
		response.on('data', function(chunk){
			file.write(chunk);
			progress+= chunk.length;
		});
		response.on('end', function(){
			clearInterval(i);
			readline.clearLine(process.stdout);
			log(2, repository+": @s_OK");
			file.close(()=> resolve({ success: 1, message: to })); /* close() is async, call cb after close completes. */
		});
	}); })
	.catch(({ message })=> {
		fs.unlink(to); // Delete the file async. (But we don't check the result)
		return { success: 0, message };
	});
}
function get_(url){ return new Promise(function(resolve, reject){
	https.get(
		url,
		{ headers: { 'Cache-Control': 'no-cache', 'User-Agent': 'node' } },
		resolve
	).on("error", reject);
});}
function applySequentially_(input, pF){
	const data= [];
	let p= pF(input[0]);
	const tie= nth=> result_mth=> ( data.push(result_mth), pF(input[nth]) );
	for(let i= 1, { length }= input; i<length; i++)
		p= p.then(tie(i));
	return p.then(o=> (data.push(o), data));
}
function error(message){
	const help_text= `@w_See help using '${info.commands[0].args[0]}'.`;
	log(1, `@e_Error: ${message} ${help_text}`);
	return process.exit(1);
}
function printMain(){
	const { name, version, description }= info;
	log(1, `@w_${name}@${version}`);
	log(1, description);
	const cmds= info.commands.map(({args})=> args[0].replace("--", "")).join(", ");
	log(1, `@w_Usage: ${name} --[cmd] [param]`);
	log(2, `…cmd: ${cmds}`);
	log(2, "…param: Based on cmd\n");
}
function printHelp(){
	log(1, "@s_Help:");
	log(2, "Commands:");
	info.commands.forEach(({ args, param, desc })=> {
		const args_text= args.join("|");
		param= param ? " "+param : "";
		log(3, `@g_${args_text}@R_${param}`);
		logLines(4, desc);
	});
	log(2, "Params:");
	for(const [ param, desc ] of Object.entries(info.params)){
		log(3, `@g_${param}`);
		logLines(4, desc);
	}
}
function log(tab, text){
	return console.log("  ".repeat(tab)+text.replace(/@(\w)_/g, (_, m)=> colors[m])+colors.R);
}
function logLines(tab, multiline_text){
	if(!Array.isArray(multiline_text)) multiline_text= multiline_text.split(/(?<=\.) /g);
	return log(tab, multiline_text.join("\n"+"	".repeat(tab)));
}