/*
 * ============LICENSE_START=======================================================
 * dcaegen2-collectors-veshv
 * ================================================================================
 * Copyright (C) 2018 NOKIA
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */

@file:Suppress("TooManyFunctions")

package org.onap.dcae.collectors.veshv.utils.arrow

import arrow.core.Either
import arrow.core.ForOption
import arrow.core.Option
import arrow.core.Try
import arrow.core.extensions.option.monad.monad
import arrow.core.fix
import arrow.core.identity
import arrow.syntax.collections.firstOption
import arrow.typeclasses.MonadContinuation
import reactor.core.publisher.Flux
import reactor.core.publisher.Mono
import java.util.concurrent.atomic.AtomicReference

/**
 * @author Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
 * @since July 2018
 */


object OptionUtils {
    fun <A> binding(c: suspend MonadContinuation<ForOption, *>.() -> A)
            : Option<A> = Option.monad().binding(c).fix()
}

fun <A> Either<A, A>.flatten() = fold(::identity, ::identity)

fun <B> Either<Throwable, B>.rightOrThrow() = fold({ throw it }, ::identity)

fun <A, B> Either<A, B>.rightOrThrow(mapper: (A) -> Throwable) = fold({ throw mapper(it) }, ::identity)

fun <A : Exception, B> Flux<Either<A, B>>.throwOnLeft(): Flux<B> = map { it.rightOrThrow() }

fun <A, B> Flux<Either<A, B>>.throwOnLeft(f: (A) -> Exception): Flux<B> = map { it.rightOrThrow(f) }

fun <A, B> Mono<Either<A, B>>.throwOnLeft(f: (A) -> Exception): Mono<B> = map { it.rightOrThrow(f) }

fun <A> AtomicReference<A>.getOption() = Option.fromNullable(get())

fun <A> Option.Companion.fromNullablesChain(firstValue: A?, vararg nextValues: () -> A?): Option<A> =
        if (firstValue != null)
            Option.just(firstValue)
        else nextValues.asSequence()
                .map { it() }
                .filter { it != null }
                .firstOption()


fun <A, B> Either<A, B>.doOnLeft(action: () -> Unit): Either<A, B> = apply { if (isLeft()) action() }

fun <A> Option<A>.doOnEmpty(action: () -> Unit): Option<A> = apply { if (isEmpty()) action() }

fun <A> Try<A>.doOnFailure(action: (Throwable) -> Unit): Try<A> = apply {
    if (this is Try.Failure) {
        action(exception)
    }
}

fun <A, B> A.mapBinding(c: suspend MonadContinuation<ForOption, *>.(A) -> B)
        : Option<B> = let { OptionUtils.binding { c(it) } }

fun <T> Option<Boolean>.flatFold(ifEmptyOrFalse: () -> T, ifTrue: () -> T) =
        fold({
            ifEmptyOrFalse()
        }, {
            if (it) {
                ifTrue()
            } else {
                ifEmptyOrFalse()
            }
        })