Geolocation: Custom Styling

export default {
  async fetch(request): Promise<Response> {
    let grads = [
      [
        { color: "00000c", position: 0 },
        { color: "00000c", position: 0 },
      ],
      [
        { color: "020111", position: 85 },
        { color: "191621", position: 100 },
      ],
      [
        { color: "020111", position: 60 },
        { color: "20202c", position: 100 },
      ],
      [
        { color: "020111", position: 10 },
        { color: "3a3a52", position: 100 },
      ],
      [
        { color: "20202c", position: 0 },
        { color: "515175", position: 100 },
      ],
      [
        { color: "40405c", position: 0 },
        { color: "6f71aa", position: 80 },
        { color: "8a76ab", position: 100 },
      ],
      [
        { color: "4a4969", position: 0 },
        { color: "7072ab", position: 50 },
        { color: "cd82a0", position: 100 },
      ],
      [
        { color: "757abf", position: 0 },
        { color: "8583be", position: 60 },
        { color: "eab0d1", position: 100 },
      ],
      [
        { color: "82addb", position: 0 },
        { color: "ebb2b1", position: 100 },
      ],
      [
        { color: "94c5f8", position: 1 },
        { color: "a6e6ff", position: 70 },
        { color: "b1b5ea", position: 100 },
      ],
      [
        { color: "b7eaff", position: 0 },
        { color: "94dfff", position: 100 },
      ],
      [
        { color: "9be2fe", position: 0 },
        { color: "67d1fb", position: 100 },
      ],
      [
        { color: "90dffe", position: 0 },
        { color: "38a3d1", position: 100 },
      ],
      [
        { color: "57c1eb", position: 0 },
        { color: "246fa8", position: 100 },
      ],
      [
        { color: "2d91c2", position: 0 },
        { color: "1e528e", position: 100 },
      ],
      [
        { color: "2473ab", position: 0 },
        { color: "1e528e", position: 70 },
        { color: "5b7983", position: 100 },
      ],
      [
        { color: "1e528e", position: 0 },
        { color: "265889", position: 50 },
        { color: "9da671", position: 100 },
      ],
      [
        { color: "1e528e", position: 0 },
        { color: "728a7c", position: 50 },
        { color: "e9ce5d", position: 100 },
      ],
      [
        { color: "154277", position: 0 },
        { color: "576e71", position: 30 },
        { color: "e1c45e", position: 70 },
        { color: "b26339", position: 100 },
      ],
      [
        { color: "163C52", position: 0 },
        { color: "4F4F47", position: 30 },
        { color: "C5752D", position: 60 },
        { color: "B7490F", position: 80 },
        { color: "2F1107", position: 100 },
      ],
      [
        { color: "071B26", position: 0 },
        { color: "071B26", position: 30 },
        { color: "8A3B12", position: 80 },
        { color: "240E03", position: 100 },
      ],
      [
        { color: "010A10", position: 30 },
        { color: "59230B", position: 80 },
        { color: "2F1107", position: 100 },
      ],
      [
        { color: "090401", position: 50 },
        { color: "4B1D06", position: 100 },
      ],
      [
        { color: "00000c", position: 80 },
        { color: "150800", position: 100 },
      ],
    ];
    async function toCSSGradient(hour) {
      let css = "linear-gradient(to bottom,";
      const data = grads[hour];
      const len = data.length;
      for (let i = 0; i < len; i++) {
        const item = data[i];
        css += ` #${item.color} ${item.position}%`;
        if (i < len - 1) css += ",";
      }
      return css + ")";
    }
    let html_content = "";
    let html_style = `
			html{width:100vw; height:100vh;}
			body{padding:0; margin:0 !important;height:100%;}
			#container {
				display: flex;
				flex-direction:column;
				align-items: center;
				justify-content: center;
				height: 100%;
				color:white;
				font-family:sans-serif;
			}`;
    const timezone = request.cf.timezone;
    console.log(timezone);
    let localized_date = new Date(
      new Date().toLocaleString("en-US", { timeZone: timezone })
    );
    let hour = localized_date.getHours();
    let minutes = localized_date.getMinutes();
    html_content += "<h1>" + hour + ":" + minutes + "</h1>";
    html_content += "<p>" + timezone + "<br/></p>";
    html_style += "body{background:" + (await toCSSGradient(hour)) + ";}";
    let html = `
			<!DOCTYPE html>
			<head>
				<title>Geolocation: Customized Design</title>
			</head>
			<body>
				<style> ${html_style}</style>
				<div id="container">
					${html_content}
				</div>
			</body>`;
    return new Response(html, {
      headers: { "content-type": "text/html;charset=UTF-8" },
    });
  },
} satisfies ExportedHandler;