From bb4816c4b39c06e587762cae5aa764932c466827 Mon Sep 17 00:00:00 2001
From: Cadence Ember <cadence@disroot.org>
Date: Thu, 14 Jan 2021 00:55:31 +1300
Subject: [PATCH] Support t parameter using media fragments

---
 api/video.js        |  9 ++++++---
 pug/video.pug       |  2 +-
 utils/converters.js | 49 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/api/video.js b/api/video.js
index bee1df4..401a3d6 100644
--- a/api/video.js
+++ b/api/video.js
@@ -122,20 +122,23 @@ module.exports = [
 		route: "/watch", methods: ["GET", "POST"], upload: true, code: async ({req, url, body}) => {
 			const user = getUser(req)
 			const settings = user.getSettingsOrDefaults()
+			const id = url.searchParams.get("v")
 			if (req.method === "GET") {
-				const id = url.searchParams.get("v")
+				const t = url.searchParams.get("t")
+				let mediaFragment = converters.tToMediaFragment(t)
 				if (!settings.local) {
 					const instanceOrigin = settings.instance
 					const outURL = `${instanceOrigin}/api/v1/videos/${id}`
 					const videoPromise = request(outURL).then(res => res.json())
-					return renderVideo(videoPromise, {user, id, instanceOrigin})
+					return renderVideo(videoPromise, {user, id, instanceOrigin}, {mediaFragment})
 				} else {
 					return render(200, "pug/local-video.pug", {id})
 				}
 			} else { // req.method === "POST"
 				const video = JSON.parse(new URLSearchParams(body.toString()).get("video"))
 				const videoPromise = Promise.resolve(video)
-				return renderVideo(videoPromise, {user})
+				const instanceOrigin = "http://localhost:3000"
+				return renderVideo(videoPromise, {user, id, instanceOrigin})
 			}
 		}
 	}
diff --git a/pug/video.pug b/pug/video.pug
index cfe444a..4a38c2c 100644
--- a/pug/video.pug
+++ b/pug/video.pug
@@ -22,7 +22,7 @@ block content
           - const format = sortedFormatStreams[0]
           if format
             video(controls preload="auto" poster=`/vi/${video.videoId}/maxresdefault.jpg` width=format.second__width height=format.second__height data-itag=format.itag)#video.video
-              source(src=format.url type=format.type)
+              source(src=format.url+mediaFragment type=format.type)
           else
             video(src="")#video.video
             .stream-notice The server provided no playback streams.
diff --git a/utils/converters.js b/utils/converters.js
index 5f54680..f1b61bd 100644
--- a/utils/converters.js
+++ b/utils/converters.js
@@ -47,6 +47,55 @@ function normaliseVideoInfo(video) {
 	}
 }
 
+/**
+ * YT supports a time parameter t in these possible formats:
+ * - [digits] -> seconds
+ * - ([digits]:)?[digits]:[digits] -> hours?, minutes, seconds
+ * - ([digits]h)?([digits]m)?([digits]s)? -> hours?, minutes?, seconds
+ *
+ * Try our best to get something suitable out. Fail by returning empty
+ * string, meaning nothing suitable was recognised.
+ */
+function tToMediaFragment(t) {
+	let resolved = ""
+
+	console.log(t)
+	if (!t || t.length > 10) { // don't parse missing values, don't pass too long strings
+		// skip processing
+	} else if (t.match(/^[0-9.,]+$/)) {
+		resolved = t
+	} else if (t.includes(":")) {
+		resolved = t.split(":").map(s => s.padStart(2, "0")).join(":") // need to pad each to length 2 for npt
+	} else if (t.match(/[hms]/)) {
+		let buffer = ""
+		let sum = 0
+		const multipliers = new Map([
+			["h", 60*60],
+			["m", 60],
+			["s", 1]
+		])
+		for (const char of t) {
+			console.log(char)
+			if (char.match(/[0-9]/)) {
+				buffer += char
+			} else if (char.match(/[hms]/)) {
+				sum += +buffer * multipliers.get(char)
+				buffer = ""
+			} else {
+				buffer = ""
+			}
+		}
+		resolved = String(sum)
+	}
+
+	if (resolved) {
+		return "#t=npt:" + resolved
+	} else {
+		return ""
+	}
+}
+
 module.exports.timeToPastText = timeToPastText
 module.exports.lengthSecondsToLengthText = lengthSecondsToLengthText
 module.exports.normaliseVideoInfo = normaliseVideoInfo
+module.exports.tToMediaFragment = tToMediaFragment