// ==UserScript==
// @name	Github Stats
// @namespace	stratehm.github
// @include	https://github.com/*/*
// @version	4
// @grant	GM_xmlhttpRequest
// @grant	GM_getValue
// @grant	GM_setValue
// @grant 	GM_deleteValue
// @require	http://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js
// @description Display download stats about the last release of Github projects.
// @downloadURL none
// ==/UserScript==

var lastReleaseItemList;

this.$ = this.jQuery = jQuery.noConflict(true);
$(document).ready(function() { 
	init();
});

function init() {
	lastReleaseItemList = $('<ul/>').attr({
		style: 'font-size: 11px; line-height: 10px; white-space: nowrap;'
	}).append('<b>Last release: </b>');
	$('div.repohead-details-container').find('h1').append(lastReleaseItemList);
	var userProject = getCurrentUserProjectUrlPart();
	if(userProject) {
		getDownloadCount(userProject);
	}
	if(window.location.pathname.indexOf("/settings/tokens") >= 0) {
		$('.column.three-fourths').append('<div class="boxed-group access-token-group" id="GM_Form"><h3>Set your Gihtub login credentials for the GreaseMonkey userscript</h3><div class="boxed-group-inner"><p>Your login credentials will be used by the userscript to show the number of downloads for repositories.</p><ul class="boxed-group-list"><li style="line-height:32px;"><p>Username: <input type="text" id="clientId" style="float:right;width:480px;" /></p><p style="line-height:32px;">Password: <input type="password" id="clientSecret" style="float:right;width:480px;"/></p></li><li><button id="GM_submit" type="submit" type="button" class="btn btn-primary">Save</button>&nbsp;&nbsp;<button id="GM_reset" type="submit" type="button" class="btn btn-danger">Clear</button></li></ul><p class="help"><i class="octicon octicon-question"></i>Without your login credentials, you are rate limited to <a href="https://developer.github.com/v3/#rate-limiting">60 api calls per hour</a>.</p></div></div>');
		$('#clientId').val(GM_getValue('clientId',''));
		$('#clientSecret').val(GM_getValue('clientSecret',''));
		$('#GM_submit').click(function() {
			GM_setValue("clientId",$('#clientId').val());
			GM_setValue("clientSecret",$('#clientSecret').val());
			console.log({clientId:GM_getValue("clientId"),clientSecret:GM_getValue("clientSecret")});
			$('#GM_submit').fadeTo(1000,0.01).fadeTo(1000,1);
			gotoSourceUrl();
		});
		$('#GM_done').fadeIn(1000).fadeOut(1000);
		$('#GM_reset').click(function(){
			$('#clientId').val('');
			$('#clientSecret').val('');
			GM_deleteValue("clientId");
			GM_deleteValue("clientSecret");
			$('#GM_reset').fadeTo(1000,0.01).fadeTo(1000,1);
			gotoSourceUrl();
		});
	} else {
		saveSourceUrl();
	}
}

function getCurrentUserProjectUrlPart() {
	var splittedPath = window.location.pathname.split('/');
	if(splittedPath.length >= 3) {
		return splittedPath[1] + '/' + splittedPath[2];
	}
}

function getDownloadCount(userProjectUserPart) {
	var url = "https://api.github.com/repos/" + userProjectUserPart + "/releases";
	var headers = {
		"Cache-Control": "no-cache"
	}
	if(isTokenSet()) {
		headers.Authorization = "Basic " + btoa(GM_getValue("clientId")+":"+GM_getValue("clientSecret"));
	}
	GM_xmlhttpRequest({
	  method: "GET",
	  headers: headers,
	  url: url,
	  onload: parseDownloadStatsReponse
	});
}

function parseDownloadStatsReponse(response) {
	var status = response.status;
	var data = $.parseJSON(response.responseText);
	// Check if login credentials are accepted
	if(status == 401) {
		onUnauthorized();
	} else if(data.message && data.message.indexOf("API rate limit exceeded") >-1) {
		// Credentials are requested
		accessTokenNeeded();
	} else {
		// Parsing of the response only if some data are present.
		if(data && data.length > 0) {
			parseLastReleaseDownloadCount(data);
			parseTotalDownloadCount(data);
		} else {
			lastReleaseItemList.append("No release<br>");
		}
	
		if(isTokenSet()) {
			lastReleaseItemList.append("Change/Clear your <a href='https://github.com/settings/tokens'>Gihtub login credentials</a>");
		}
	}
}

function parseLastReleaseDownloadCount(data) {
	var releaseName = data[0].name;
	var htmlUrl = data[0].html_url;
	lastReleaseItemList.append($('<a/>').attr({
		href: htmlUrl
	}).append(releaseName));
	if(data[0].assets && data[0].assets.length > 0) {
		for(var i = 0 ; i < data[0].assets.length ; i++) {
			var assetName = data[0].assets[i].name;
			var assetDlCount = data[0].assets[i].download_count;
			var assetUrl = data[0].assets[i].browser_download_url;
			appendAssetDlItem(assetName, assetDlCount, assetUrl);
		}
	} else {
		lastReleaseItemList.append("<br>No binaries in the last release<br>");
	}
}

function parseTotalDownloadCount(data) {
	var totalDownloadCount = 0;
	for(var i = 0 ; i < data.length ; i++) {
		if(data[i].assets && data[i].assets.length > 0) {
			for(var j = 0 ; j < data[i].assets.length ; j++) {
				totalDownloadCount += data[i].assets[j].download_count;
			}
		}
	}
	lastReleaseItemList.append("All releases download count: " + totalDownloadCount + "<br>");
}

function appendAssetDlItem(assetName, assetDlCount, assetUrl) {
	lastReleaseItemList.append($('<li/>').attr({
		style: "margin-left: 20px;"
	}).append("<b>Name:</b> <a href='" + assetUrl + "'>" + assetName + '</a>, <b>Dl Count:</b> ' + assetDlCount));
}


function accessTokenNeeded() {
	lastReleaseItemList.append($('<li/>').attr({
		style: "margin-left: 20px;"
	}).append("Your api limit has been hit. Please add a <a href='https://github.com/settings/tokens'>Gihtub login credentials</a>"));
}

function onUnauthorized() {
	lastReleaseItemList.append($('<li/>').attr({
		style: "margin-left: 20px;"
	}).append("Bad credentials. Please check your <a href='https://github.com/settings/tokens'>Gihtub login credentials</a>"));
}

function isTokenSet() {
	return GM_getValue("clientId","") && GM_getValue("clientSecret","");
}

function saveSourceUrl() {
	GM_setValue("sourceUrl", window.location.href);
}
	
function gotoSourceUrl() {
	var sourceUrl = GM_getValue("sourceUrl", "");
	console.log("Restore location: " + sourceUrl);
	if(sourceUrl) {
		window.location.href = sourceUrl;
	}
}