// GoatCounter: https://www.goatcounter.com
// This file is released under the ISC license: https://opensource.org/licenses/ISC
;(function() {
	'use strict';

	window.goatcounter = window.goatcounter || {}

	// Load settings from data-goatcounter-settings.
	var s = document.querySelector('script[data-goatcounter]')
	if (s && s.dataset.goatcounterSettings) {
		try         { var set = JSON.parse(s.dataset.goatcounterSettings) }
		catch (err) { console.error('invalid JSON in data-goatcounter-settings: ' + err) }
		for (var k in set)
			if (['no_onload', 'no_events', 'allow_local', 'allow_frame', 'path', 'title', 'referrer', 'event'].indexOf(k) > -1)
				window.goatcounter[k] = set[k]
	}

	var enc = encodeURIComponent

	// Get all data we're going to send off to the counter endpoint.
	window.goatcounter.get_data = function(vars) {
		vars = vars || {}
		var data = {
			p: (vars.path     === undefined ? goatcounter.path     : vars.path),
			r: (vars.referrer === undefined ? goatcounter.referrer : vars.referrer),
			t: (vars.title    === undefined ? goatcounter.title    : vars.title),
			e: !!(vars.event || goatcounter.event),
			s: window.screen.width,
			b: is_bot(),
			q: location.search,
		}

		var rcb, pcb, tcb  // Save callbacks to apply later.
		if (typeof(data.r) === 'function') rcb = data.r
		if (typeof(data.t) === 'function') tcb = data.t
		if (typeof(data.p) === 'function') pcb = data.p

		if (is_empty(data.r)) data.r = document.referrer
		if (is_empty(data.t)) data.t = document.title
		if (is_empty(data.p)) data.p = get_path()

		if (rcb) data.r = rcb(data.r)
		if (tcb) data.t = tcb(data.t)
		if (pcb) data.p = pcb(data.p)
		return data
	}

	// Check if a value is "empty" for the purpose of get_data().
	var is_empty = function(v) { return v === null || v === undefined || typeof(v) === 'function' }

	// See if this looks like a bot; there is some additional filtering on the
	// backend, but these properties can't be fetched from there.
	var is_bot = function() {
		// Headless browsers are probably a bot.
		var w = window, d = document
		if (w.callPhantom || w._phantom || w.phantom)
			return 150
		if (w.__nightmare)
			return 151
		if (d.__selenium_unwrapped || d.__webdriver_evaluate || d.__driver_evaluate)
			return 152
		if (navigator.webdriver)
			return 153
		return 0
	}

	// Object to urlencoded string, starting with a ?.
	var urlencode = function(obj) {
		var p = []
		for (var k in obj)
			if (obj[k] !== '' && obj[k] !== null && obj[k] !== undefined && obj[k] !== false)
				p.push(enc(k) + '=' + enc(obj[k]))
		return '?' + p.join('&')
	}

	// Show a warning in the console.
	var warn = function(msg) {
		if (console && 'warn' in console)
			console.warn('goatcounter: ' + msg)
	}

	// Get the endpoint to send requests to.
	var get_endpoint = function() {
		var s = document.querySelector('script[data-goatcounter]')
		return (s && s.dataset.goatcounter) ? s.dataset.goatcounter : goatcounter.endpoint
	}

	// Get current path.
	var get_path = function() {
		var loc = location,
			c = document.querySelector('link[rel="canonical"][href]')
		if (c) {  // May be relative or point to different domain.
			var a = document.createElement('a')
			a.href = c.href
			if (a.hostname.replace(/^www\./, '') === location.hostname.replace(/^www\./, ''))
				loc = a
		}
		return (loc.pathname + loc.search) || '/'
	}

	// Run function after DOM is loaded.
	var on_load = function(f) {
		if (document.body === null)
			document.addEventListener('DOMContentLoaded', function() { f() }, false)
		else
			f()
	}

	// Filter some requests that we (probably) don't want to count.
	window.goatcounter.filter = function() {
		if ('visibilityState' in document && document.visibilityState === 'prerender')
			return 'visibilityState'
		if (!goatcounter.allow_frame && location !== parent.location)
			return 'frame'
		if (!goatcounter.allow_local && location.hostname.match(/(localhost$|^127\.|^10\.|^172\.(1[6-9]|2[0-9]|3[0-1])\.|^192\.168\.|^0\.0\.0\.0$)/))
			return 'localhost'
		if (!goatcounter.allow_local && location.protocol === 'file:')
			return 'localfile'
		if (localStorage && localStorage.getItem('skipgc') === 't')
			return 'disabled with #toggle-goatcounter'
		return false
	}

	// Get URL to send to GoatCounter.
	window.goatcounter.url = function(vars) {
		var data = window.goatcounter.get_data(vars || {})
		if (data.p === null)  // null from user callback.
			return
		data.rnd = Math.random().toString(36).substr(2, 5)  // Browsers don't always listen to Cache-Control.

		var endpoint = get_endpoint()
		if (!endpoint)
			return warn('no endpoint found')

		return endpoint + urlencode(data)
	}

	// Count a hit.
	window.goatcounter.count = function(vars) {
		var f = goatcounter.filter()
		if (f)
			return warn('not counting because of: ' + f)
		var url = goatcounter.url(vars)
		if (!url)
			return warn('not counting because path callback returned null')

		if (!navigator.sendBeacon(url)) {
			// This mostly fails due to being blocked by CSP; try again with an
			// image-based fallback.
			var img = document.createElement('img')
			img.src = url
			img.style.position = 'absolute'  // Affect layout less.
			img.style.bottom = '0px'
			img.style.width = '1px'
			img.style.height = '1px'
			img.loading = 'eager'
			img.setAttribute('alt', '')
			img.setAttribute('aria-hidden', 'true')

			var rm = function() { if (img && img.parentNode) img.parentNode.removeChild(img) }
			img.addEventListener('load', rm, false)
			document.body.appendChild(img)
		}
	}

	// Get a query parameter.
	window.goatcounter.get_query = function(name) {
		var s = location.search.substr(1).split('&')
		for (var i = 0; i < s.length; i++)
			if (s[i].toLowerCase().indexOf(name.toLowerCase() + '=') === 0)
				return s[i].substr(name.length + 1)
	}

	// Track click events.
	window.goatcounter.bind_events = function() {
		if (!document.querySelectorAll)  // Just in case someone uses an ancient browser.
			return

		var send = function(elem) {
			return function() {
				goatcounter.count({
					event:    true,
					path:     (elem.dataset.goatcounterClick || elem.name || elem.id || ''),
					title:    (elem.dataset.goatcounterTitle || elem.title || (elem.innerHTML || '').substr(0, 200) || ''),
					referrer: (elem.dataset.goatcounterReferrer || elem.dataset.goatcounterReferral || ''),
				})
			}
		}

		Array.prototype.slice.call(document.querySelectorAll("*[data-goatcounter-click]")).forEach(function(elem) {
			if (elem.dataset.goatcounterBound)
				return
			var f = send(elem)
			elem.addEventListener('click', f, false)
			elem.addEventListener('auxclick', f, false)  // Middle click.
			elem.dataset.goatcounterBound = 'true'
		})
	}

	// Add a "visitor counter" frame or image.
	window.goatcounter.visit_count = function(opt) {
		on_load(function() {
			opt        = opt        || {}
			opt.type   = opt.type   || 'html'
			opt.append = opt.append || 'body'
			opt.path   = opt.path   || get_path()
			opt.attr   = opt.attr   || {width: '200', height: (opt.no_branding ? '60' : '80')}

			opt.attr['src'] = get_endpoint() + 'er/' + enc(opt.path) + '.' + enc(opt.type) + '?'
			if (opt.no_branding) opt.attr['src'] += '&no_branding=1'
			if (opt.style)       opt.attr['src'] += '&style=' + enc(opt.style)
			if (opt.start)       opt.attr['src'] += '&start=' + enc(opt.start)
			if (opt.end)         opt.attr['src'] += '&end='   + enc(opt.end)

			var tag = {png: 'img', svg: 'img', html: 'iframe'}[opt.type]
			if (!tag)
				return warn('visit_count: unknown type: ' + opt.type)

			if (opt.type === 'html') {
				opt.attr['frameborder'] = '0'
				opt.attr['scrolling']   = 'no'
			}

			var d = document.createElement(tag)
			for (var k in opt.attr)
				d.setAttribute(k, opt.attr[k])

			var p = document.querySelector(opt.append)
			if (!p)
				return warn('visit_count: element to append to not found: ' + opt.append)
			p.appendChild(d)
		})
	}

	// Make it easy to skip your own views.
	if (location.hash === '#toggle-goatcounter') {
		if (localStorage.getItem('skipgc') === 't') {
			localStorage.removeItem('skipgc', 't')
			alert('GoatCounter tracking is now ENABLED in this browser.')
		}
		else {
			localStorage.setItem('skipgc', 't')
			alert('GoatCounter tracking is now DISABLED in this browser until ' + location + ' is loaded again.')
		}
	}

	if (!goatcounter.no_onload)
		on_load(function() {
			// 1. Page is visible, count request.
			// 2. Page is not yet visible; wait until it switches to 'visible' and count.
			// See #487
			if (!('visibilityState' in document) || document.visibilityState === 'visible')
				goatcounter.count()
			else {
				var f = function(e) {
					if (document.visibilityState !== 'visible')
						return
					document.removeEventListener('visibilitychange', f)
					goatcounter.count()
				}
				document.addEventListener('visibilitychange', f)
			}

			if (!goatcounter.no_events)
				goatcounter.bind_events()
		})
})();
