/** 按并发限制执行一个函数数组，同时只能运行限制数量的异步函数
 * @example
 * ```ts
 *  const funcs = list.map((item) => async () => {})
 *  runWithLimit(funcs, 3).then(() => { console.log("done") })
 * ```
 * @param funcs 要执行的函数数组，函数必须返回 Promise
 * @param limit 并发限制数量
 *
 *  */
export function runWithLimit(funcs: (() => Promise<any | void>)[], limit: number) {
    return new Promise((resolve) => {
        let doneList: any[] = []
        let runningList: any[] = []
        let waitList: any[] = funcs.slice(0)
        tick()

        function tick() {
            let readyList: any[] = []
            while (waitList.length > 0 && readyList.length + runningList.length < limit) {
                let func = waitList.shift()
                readyList.push(func)
            }
            // console.log("[runWithLimit] tick", { limit, readyListLength: readyList.length })
            for (const func of readyList) {
                let promise: Promise<any> = func()
                runningList.push(promise)
                promise.finally(() => {
                    doneList.push(promise)
                    runningList.splice(runningList.indexOf(promise), 1)
                    tick()
                })
            }
            if (runningList.length == 0 && waitList.length == 0) {
                // console.log("[runWithLimit] done", doneList)
                resolve(doneList)
            }
        }
    })
}