package com.cxz.wanandroid.http.function

import io.reactivex.Observable
import io.reactivex.functions.BiFunction
import io.reactivex.functions.Function
import retrofit2.HttpException
import java.net.ConnectException
import java.net.SocketTimeoutException
import java.util.concurrent.TimeUnit
import java.util.concurrent.TimeoutException

/**
 * @author chenxz
 * @date 2018/8/21
 * @desc 请求重连
 */
class RetryWithDelay : Function<Observable<out Throwable>, Observable<*>> {

    private var maxRetryCount = 3 // 可重试次数
    private var retryDelayMillis: Long = 3000 // 重试等待时间

    constructor() {}

    constructor(retryDelayMillis: Long) {
        this.retryDelayMillis = retryDelayMillis
    }

    constructor(maxRetryCount: Int, retryDelayMillis: Long) {
        this.maxRetryCount = maxRetryCount
        this.retryDelayMillis = retryDelayMillis
    }

    @Throws(Exception::class)
    override fun apply(observable: Observable<out Throwable>): Observable<*> {
        return observable
                .zipWith(Observable.range(1, maxRetryCount + 1),
                        BiFunction<Throwable, Int, Wrapper> { t1, t2 -> Wrapper(t2, t1) })
                .flatMap { wrapper ->
                    val t = wrapper.throwable
                    if ((t is ConnectException
                                    || t is SocketTimeoutException
                                    || t is TimeoutException
                                    || t is HttpException)
                            && wrapper.index < maxRetryCount + 1) {
                        Observable.timer(retryDelayMillis * wrapper.index, TimeUnit.MILLISECONDS)
                    } else Observable.error<Any>(wrapper.throwable)
                }
    }

    private inner class Wrapper(val index: Int, val throwable: Throwable)

}