/** 跨上下文快速调用 */
export class Calls {
    idpool = 0
    callMap: any = {}
    onMap: any = {}
    constructor(public target: any) {
        target.addEventListener(
            "message",
            async (e: any) => {
                if (e.data.__isResult) {
                    let resolve = this.callMap[e.data.__callId]
                    resolve(e.data.__re)
                } else {
                    let method = e.data.method
                    let onFunc = this.onMap[method]
                    if (onFunc) {
                        let re

                        try {
                            re = await onFunc(e.data.data)
                        } catch (e) {
                            re = { error: e }
                        }
                        let id = e.data.__callId

                        this.target.postMessage({ __re: re, __isResult: true, __callId: <any>id })
                    }
                }
            },
            false
        )
    }

    async post<T = any>(method: string, data: any, transferable?: any): Promise<T> {
        let id = this.idpool++
        let payload = Object.assign({}, { data, method, __callId: id })
        this.target.postMessage(payload, transferable)

        return new Promise((resolve, reject) => {
            this.callMap[id] = resolve
        })
    }

    async on(method: string, func: (data: any) => any) {
        this.onMap[method] = func
    }
}