From 01af48aadfe79e954c93163776a915602cbed1fc Mon Sep 17 00:00:00 2001
From: Damon Stephenson <me@xixora.net>
Date: Sun, 4 Jul 2021 23:41:56 +0000
Subject: [PATCH] Add basic custom player UI

---
 src/app.css                |   2 +
 src/lib/Player.svelte      | 316 +++++++++++++++++++++++++++++++++++--
 src/lib/table/Play.svelte  |  26 ++-
 src/lib/table/Table.svelte |   1 -
 src/routes/__layout.svelte |   1 -
 5 files changed, 326 insertions(+), 20 deletions(-)

diff --git a/src/app.css b/src/app.css
index 14d12b1..76e3ce3 100644
--- a/src/app.css
+++ b/src/app.css
@@ -30,6 +30,8 @@ body {
 	font-family: 'Maven Pro';
 	color: var(--black);
 	background: var(--gray);
+	padding: 0;
+	margin: 0;
 }
 
 a {
diff --git a/src/lib/Player.svelte b/src/lib/Player.svelte
index c432f05..abedd19 100644
--- a/src/lib/Player.svelte
+++ b/src/lib/Player.svelte
@@ -1,36 +1,236 @@
 <script context="module" type="ts">
 	import { writable } from 'svelte/store';
 
-	export const currentTrack = writable();
+	interface StereoMix {
+		vorbis: string;
+		mp3?: string;
+	}
+
+	interface Track {
+		title: string;
+		data_folder: string;
+		stereo_mix: StereoMix;
+		isPlaying: boolean;
+	}
+
+	export const currentTrack = writable<Track>();
 </script>
 
 <script lang="ts">
 	import { root } from '$lib/ipfs';
 
-	const autoplay = (audio: HTMLAudioElement, currentTrack) => {
-		const play = (currentTrack) => {
-			if (currentTrack) {
+	let time = 0;
+	let maxTime = 0;
+	let formattedElapsed = '-';
+	let formattedDuration = '-';
+	let controller: AbortController;
+	let previousTrack: Track;
+
+	let canvas: HTMLCanvasElement;
+	let audioContext: AudioContext;
+	let source: MediaElementAudioSourceNode;
+	let audioElement: HTMLAudioElement;
+
+	const autoplay = (audio: HTMLAudioElement, current: Track) => {
+		audioElement = audio;
+		audio.crossOrigin = 'anonymous';
+		const play = async (track: Track) => {
+			if (track == previousTrack) {
+				if (!track.isPlaying) {
+					audio.pause();
+				} else {
+					await audio.play();
+				}
+
+				return;
+			}
+			controller?.abort();
+			if (track) {
 				audio.load();
-				audio.play();
+				await audio.play();
+
+				// This will need to be replaced with non-existant api to get audio buffer from element… or better yet pre-computed values.
+				controller = new AbortController();
+				fetch(audio.currentSrc, { signal: controller.signal })
+					.then((response) => response.arrayBuffer())
+					.then((arrayBuffer) => audioContext.decodeAudioData(arrayBuffer))
+					.then((audioBuffer) => draw(normalizeData(filterData(audioBuffer))));
 			}
+
+			previousTrack = track;
+		};
+
+		audio.addEventListener('timeupdate', function () {
+			const currentTime = Math.floor(audio.currentTime);
+			if (time != currentTime) {
+				time = currentTime;
+				formattedElapsed = formatTimespan(currentTime);
+			}
+		});
+		audio.addEventListener('loadedmetadata', function () {
+			maxTime = Math.floor(audio.duration);
+			formattedDuration = formatTimespan(maxTime);
+		});
+		audio.addEventListener('play', () => {
+			// $currentTrack.isPlaying = true;
+			audioContext = audioContext || new (window.AudioContext || window.webkitAudioContext)();
+			source = source || audioContext.createMediaElementSource(audio);
+
+			source.connect(audioContext.destination);
+		});
+
+		const filterData = (audioBuffer: AudioBuffer): number[] => {
+			const rawData = audioBuffer.getChannelData(0);
+			const samples = Math.floor(canvas.offsetWidth / 5);
+			const blockSize = Math.floor(rawData.length / samples);
+			const filteredData: number[] = [];
+			for (let i = 0; i < samples; i++) {
+				let blockStart = blockSize * i;
+				let sum = 0;
+				for (let j = 0; j < blockSize; j++) {
+					sum = sum + Math.abs(rawData[blockStart + j]);
+				}
+				filteredData.push(sum / blockSize);
+			}
+
+			return filteredData;
+		};
+
+		const normalizeData = (filteredData: number[]): number[] => {
+			const multiplier = Math.pow(Math.max(...filteredData), -1);
+
+			return filteredData.map((n) => n * multiplier);
+		};
+
+		const draw = (normalizedData: number[]) => {
+			// setup
+			const dpr = window.devicePixelRatio || 1;
+			const padding = 0;
+			canvas.width = canvas.offsetWidth * dpr;
+			canvas.height = (canvas.offsetHeight + padding * 2) * dpr;
+			const ctx = canvas.getContext('2d');
+			ctx.scale(dpr, dpr);
+
+			// reset
+			ctx.clearRect(0, 0, canvas.width, canvas.height);
+			ctx.translate(0, canvas.offsetHeight / 2 + padding);
+
+			// draw the segments
+			const width = canvas.offsetWidth / normalizedData.length;
+			for (let i = 0; i < normalizedData.length; i++) {
+				const x = width * i;
+				let height = normalizedData[i] * canvas.offsetHeight - padding;
+				if (height < 0) {
+					height = 0;
+				} else if (height > canvas.offsetHeight / 2) {
+					height = canvas.offsetHeight / 2;
+				}
+				drawLineSegment(ctx, x, height, width);
+			}
+		};
+
+		const drawLineSegment = (
+			ctx: CanvasRenderingContext2D,
+			x: number,
+			height: number,
+			width: number
+		) => {
+			// skew
+			const dpr = window.devicePixelRatio || 1;
+			const origx = 10;
+			const origy = 30 * dpr;
+			const rotation = 0;
+			const skewx = 10;
+			const skewy = 0;
+			const scalex = 0.95 * dpr;
+			const scaley = 1 * dpr;
+			const anglex = rotation + skewy;
+			const angley = rotation + skewx;
+			const rx = (Math.PI * anglex) / 180;
+			const ry = (Math.PI * angley) / 180;
+			ctx.setTransform(
+				scalex * Math.cos(rx),
+				scalex * Math.sin(rx),
+				-scaley * Math.sin(ry),
+				scaley * Math.cos(ry),
+				origx,
+				origy
+			);
+
+			// background gutters
+			ctx.lineWidth = 2;
+			ctx.strokeStyle = '#eee';
+			ctx.beginPath();
+			ctx.moveTo(x, -canvas.offsetHeight / 2);
+			ctx.lineTo(x, canvas.offsetHeight / 2);
+			ctx.closePath();
+			ctx.stroke();
+
+			// analysed sound
+			ctx.strokeStyle = '#000';
+			// ctx.strokeStyle = '#ccc';
+			ctx.beginPath();
+			ctx.moveTo(x, -1 * height);
+			ctx.lineTo(x, height);
+			ctx.closePath();
+			ctx.stroke();
+
+			// played
+			// ctx.strokeStyle = '#000';
+			// ctx.beginPath();
+			// ctx.moveTo(x, -1 * height);
+			// ctx.lineTo(x, height);
+			// ctx.closePath();
+			// ctx.stroke();
 		};
 
-		play(currentTrack);
+		function formatTimespan(time: number): string {
+			const minuteValue = Math.floor(time / 60);
+			const minutes = minuteValue.toString().padStart(2, '0');
+			const secondValue = time - minuteValue * 60;
+			const seconds = secondValue.toString().padStart(2, '0');
+
+			return `${minutes}:${seconds}`;
+		}
+
+		play(current);
 
 		return {
 			update: play
 		};
 	};
 
+	function handlePlay() {
+		if (audioContext.state === 'suspended') {
+			audioContext.resume();
+		}
+
+		if ($currentTrack.isPlaying) {
+			audioElement.pause();
+			$currentTrack.isPlaying = false;
+		} else {
+			audioElement.play();
+			$currentTrack.isPlaying = true;
+		}
+	}
+
+	function changeSeek(e: { target: HTMLInputElement }) {
+		audioElement.currentTime = parseInt(e.target.value);
+	}
+
+	$: {
+		console.log($currentTrack);
+	}
+
 	$: baseSrc = $currentTrack && `https://ipfs.io${$root}/${$currentTrack.data_folder}`;
 	$: vorbis =
 		baseSrc && $currentTrack.stereo_mix.vorbis && `${baseSrc}/${$currentTrack.stereo_mix.vorbis}`;
 	$: mp3 = baseSrc && $currentTrack.stereo_mix.mp3 && `${baseSrc}/${$currentTrack.stereo_mix.mp3}`;
 </script>
 
-<article>
-	{#if $currentTrack}
-		<audio use:autoplay={$currentTrack} controls>
+{#if $currentTrack}
+	<article>
+		<audio use:autoplay={$currentTrack} preload="metadata">
 			<track kind="captions" src="data:%5b%e2%99%ab music %e2%99%ab%5d" />
 
 			{#if vorbis}
@@ -43,11 +243,103 @@
 
 			Your browser does not support the <code>audio</code> element.
 		</audio>
-	{/if}
-</article>
+		<div class="controls">
+			<div>
+				<button id="play" class="icon" on:click={handlePlay}>
+					{#if $currentTrack.isPlaying}
+						pause
+					{:else}
+						play_arrow
+					{/if}
+				</button>
+			</div>
+			<div class="seek">
+				<span>{$currentTrack.title}</span>
+				<canvas bind:this={canvas} />
+				<input id="seek" type="range" on:change={changeSeek} value={time} max={maxTime} />
+			</div>
+			<div class="duration">{formattedElapsed}/{formattedDuration}</div>
+		</div>
+	</article>
+{/if}
 
 <style>
-	audio {
+	article {
 		width: 100%;
+		height: 64px;
+		background-color: var(--gray-light);
+		padding-bottom: env(safe-area-inset-bottom);
+		padding-left: env(safe-area-inset-left);
+		padding-right: env(safe-area-inset-right);
+	}
+
+	.controls {
+		display: grid;
+		grid-template-columns: 64px 1fr 128px;
+		width: 100%;
+		height: 64px;
+	}
+
+	button {
+		margin: 4px;
+		padding: 0;
+		width: 56px;
+		height: 56px;
+	}
+
+	.seek {
+		position: relative;
+	}
+
+	span {
+		background-color: rgba(255, 255, 255, 0.9);
+		color: var(--black);
+		display: inline;
+		z-index: 200;
+		position: absolute;
+		user-select: none;
+		top: 8px;
+		left: 8px;
+		max-width: calc(100% - 8px);
+		height: 1em;
+		line-height: 1;
+		text-overflow: ellipsis;
+		white-space: nowrap;
+		overflow: hidden;
+	}
+
+	canvas {
+		position: absolute;
+		width: 100%;
+		height: 56px;
+		margin: 4px;
+		z-index: 1;
+	}
+
+	input[type='range'] {
+		-webkit-appearance: none;
+		appearance: none;
+		height: 100%;
+		width: 100%;
+		margin: 0;
+		background-color: transparent;
+		border: none;
+		z-index: 10;
+		position: absolute;
+	}
+
+	input[type='range']::-webkit-slider-thumb {
+		-webkit-appearance: none;
+		appearance: none;
+		background-color: black;
+		display: block;
+		width: 16px;
+		height: 16px;
+		margin-top: 38px;
+		border-radius: 50%;
+	}
+
+	.duration {
+		padding: 8px;
 	}
 </style>
diff --git a/src/lib/table/Play.svelte b/src/lib/table/Play.svelte
index 0f113f8..043da00 100644
--- a/src/lib/table/Play.svelte
+++ b/src/lib/table/Play.svelte
@@ -2,14 +2,28 @@
 	import { currentTrack } from '$lib/Player.svelte';
 
 	export let track;
+
+	function handlePlay() {
+		if ($currentTrack) {
+			$currentTrack.isPlaying = !$currentTrack.isPlaying;
+		}
+
+		if ($currentTrack != track) {
+			if ($currentTrack) {
+				$currentTrack.isPlaying = false;
+			}
+			$currentTrack = track;
+			$currentTrack.isPlaying = true;
+		}
+	}
 </script>
 
-<button
-	class:playing={$currentTrack === track}
-	class="icon"
-	on:click|stopPropagation={() => ($currentTrack = track)}
->
-	play_arrow
+<button class:playing={$currentTrack === track} class="icon" on:click|stopPropagation={handlePlay}>
+	{#if track.isPlaying}
+		pause
+	{:else}
+		play_arrow
+	{/if}
 </button>
 
 <style>
diff --git a/src/lib/table/Table.svelte b/src/lib/table/Table.svelte
index 1592e34..0ef56f0 100644
--- a/src/lib/table/Table.svelte
+++ b/src/lib/table/Table.svelte
@@ -63,7 +63,6 @@
 		border-collapse: collapse;
 		width: 100%;
 		width: calc(100% + 16px);
-		margin: 8px -8px;
 		box-sizing: border-box;
 	}
 
diff --git a/src/routes/__layout.svelte b/src/routes/__layout.svelte
index 65ddaad..fcc54be 100644
--- a/src/routes/__layout.svelte
+++ b/src/routes/__layout.svelte
@@ -29,7 +29,6 @@
 		height: 5rem;
 		padding: calc(5px + env(safe-area-inset-top)) calc(5px + env(safe-area-inset-right)) 5px
 			calc(5px + env(safe-area-inset-left));
-		margin: -8px;
 
 		background: var(--gray);
 		border-bottom: 5px solid var(--black);