Generate a chartd chart with Swift

chartd.swift

import Foundation

let b62 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

func encode(data: [Double], min: Double, max: Double) -> String {
	let r = max - min
	var bs = [Character](repeating: b62.first!, count: data.count)
	if r == 0 {
		for i in 0..<data.count {
			bs[i] = b62.first!
		}
		return String(bs)
	}
	let enclen = Double(b62.count - 1)
	for (i, y) in data.enumerated() {
		let index = Int(enclen * (y - min) / r)
		if index >= 0 && index < b62.count {
			bs[i] = b62[b62.index(b62.startIndex, offsetBy: index)]
		} else {
			bs[i] = b62.first!
		}
	}
	return String(bs)
}
// http://chartd.co/a.svg?w=580&h=180&d0=caaageehox301yusuurywwqmjdghhhjmrt0yywwuqrs2yslkgfahnomqux666zzvttv0wsmkgdbhmnlrsz6795420xtvtrnjgdadkopqqv256520zxsssokfdZZbeffjltwzzzxussuywrmgbYWaeefjmu100ywsqqrvuoidb&ymin=0&ymax=160000000&t=1+week+@+1+hour&step=1"

let data0 = [1.0, 0.99, 0.9869, 0.95, 0.88]
let data1 = [0.0, 0.01, 0.02, 0.05, 0.12]
let encoded0 = encode(data: data0, min: 0.0, max: 1.0)
let encoded1 = encode(data: data1, min: 0.0, max: 1.0)
let minTime = Date().timeIntervalSince1970 - Double(data0.count * 24 * 60 * 60)
let maxTime = Date().timeIntervalSince1970

var components = URLComponents(string: "https://chartd.co/a.svg")
components?.queryItems = [
	.init(name: "w", value: "600"),
	.init(name: "h", value: "200"),
	.init(name: "d0", value: encoded0),
	.init(name: "d1", value: encoded1),
	.init(name: "ymin", value: "0.0"),
	.init(name: "ymax", value: "1.0"),
	.init(name: "step", value: "0"),
	.init(name: "xmin", value: "\(Int(minTime))"),
	.init(name: "xmax", value: "\(Int(maxTime))"),
]

print(components!.url)