// https://www.xiabingbao.com/post/crypto/js-crypto-randomuuid-qxcuqj.html
// 在此表示感謝

export default function randomUUID() {
    // crypto - 只支持在安全的上下文使用
    if (typeof crypto === 'object') {
        if (typeof crypto.randomUUID === 'function') {
            // https://developer.mozilla.org/en-US/docs/Web/API/Crypto/randomUUID
            return crypto.randomUUID()
        }
        if (typeof crypto.getRandomValues === 'function' && typeof Uint8Array === 'function') {
            // https://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid
            const callback = (c: string) => {
                const num = Number(c)
                return (num ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (num / 4)))).toString(16)
            };
            return '10000000-1000-4000-8000-100000000000'.replace(/[018]/g, callback)
        }
    }
    // 隨機數 - fallback
    let timestamp = new Date().getTime()
    let perforNow = (typeof performance !== 'undefined' && performance.now && performance.now() * 1000) || 0
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
        let random = Math.random() * 16
        if (timestamp > 0) {
            random = (timestamp + random) % 16 | 0
            timestamp = Math.floor(timestamp / 16)
        } else {
            random = (perforNow + random) % 16 | 0
            perforNow = Math.floor(perforNow / 16)
        }
        return (c === 'x' ? random : (random & 0x3) | 0x8).toString(16)
    })
}