From 07c45d84d0badb41036ca4a678f23b8035b1c229 Mon Sep 17 00:00:00 2001
From: kageru <kageru@encode.moe>
Date: Wed, 13 Nov 2019 22:06:30 +0100
Subject: [PATCH] Generify mapFirst/Second on Tuples

---
 .../kageru/kagebot/extensions/ArrowExtensions.kt | 13 ++++++-------
 .../kageru/kagebot/features/TimeoutFeature.kt    | 16 ++++++++++------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/src/main/kotlin/moe/kageru/kagebot/extensions/ArrowExtensions.kt b/src/main/kotlin/moe/kageru/kagebot/extensions/ArrowExtensions.kt
index ce3ea53..fe3d43d 100644
--- a/src/main/kotlin/moe/kageru/kagebot/extensions/ArrowExtensions.kt
+++ b/src/main/kotlin/moe/kageru/kagebot/extensions/ArrowExtensions.kt
@@ -1,11 +1,10 @@
 package moe.kageru.kagebot.extensions
 
+import arrow.Kind
 import arrow.core.Either
-import arrow.core.Option
 import arrow.core.Tuple3
 import arrow.core.getOrElse
-import arrow.optics.pFirst
-import arrow.optics.pSecond
+import arrow.typeclasses.Functor
 
 fun <L, R> Either<L, R>.on(op: (R) -> Unit): Either<L, R> {
     this.map { op(it) }
@@ -14,10 +13,10 @@ fun <L, R> Either<L, R>.on(op: (R) -> Unit): Either<L, R> {
 
 fun <T> Either<*, T>.unwrap(): T = getOrElse { error("Attempted to unwrap Either.left") }
 
-fun <A, B, C, R> Tuple3<A, B, C>.mapSecond(op: (B) -> Option<R>): Option<Tuple3<A, R, C>> {
-    return op(this.b).map { Tuple3.pSecond<A, B, C, R>().set(this, it) }
+fun <A, B, C, A2, F> Tuple3<A, B, C>.mapFirst(AP: Functor<F>, op: (A) -> Kind<F, A2>) = let { (a, b, c) ->
+    AP.run { op(a).map { Tuple3(it, b, c) } }
 }
 
-fun <A, B, C, R> Tuple3<A, B, C>.mapFirst(op: (A) -> Option<R>): Option<Tuple3<R, B, C>> {
-    return op(this.a).map { Tuple3.pFirst<A, B, C, R>().set(this, it) }
+fun <A, B, C, B2, F> Tuple3<A, B, C>.mapSecond(AP: Functor<F>, op: (B) -> Kind<F, B2>) = let { (a, b, c) ->
+    AP.run { op(b).map { Tuple3(a, it, c) } }
 }
diff --git a/src/main/kotlin/moe/kageru/kagebot/features/TimeoutFeature.kt b/src/main/kotlin/moe/kageru/kagebot/features/TimeoutFeature.kt
index 238c9a8..326ebfb 100644
--- a/src/main/kotlin/moe/kageru/kagebot/features/TimeoutFeature.kt
+++ b/src/main/kotlin/moe/kageru/kagebot/features/TimeoutFeature.kt
@@ -1,11 +1,12 @@
 package moe.kageru.kagebot.features
 
-import arrow.core.Either
-import arrow.core.Tuple3
+import arrow.Kind
+import arrow.core.*
+import arrow.core.extensions.either.applicative.applicative
 import arrow.core.extensions.either.monad.flatMap
 import arrow.core.extensions.list.monad.map
 import arrow.core.extensions.listk.functorFilter.filter
-import arrow.core.toOption
+import arrow.core.extensions.option.applicative.applicative
 import arrow.syntax.collections.destructured
 import com.fasterxml.jackson.annotation.JsonProperty
 import moe.kageru.kagebot.Log
@@ -32,13 +33,16 @@ class TimeoutFeature(@JsonProperty("role") role: String) : MessageFeature {
                 { Tuple3(args[1], args[2], args.getOrNull(3)) },
                 { "Error: expected “<command> <user> <time> [<reason>]”. If the name contains spaces, please use the user ID instead." }
             ).flatMap {
-                it.mapFirst(::findUser).toEither { "Error: User ${it.a} not found, consider using the user ID" }
+                it.mapFirst(Option.applicative(), ::findUser).fix()
+                    .toEither { "Error: User ${it.a} not found, consider using the user ID" }
             }.flatMap {
-                it.mapSecond { time -> time.toLongOrNull().toOption() }.toEither { "Error: malformed time “${it.b}”" }
+                it.mapSecond(Either.applicative()) { time ->
+                    time.toLongOrNull().rightIfNotNull { "Error: malformed time “${it.b}”" }
+                }.fix()
             }.on { (user, time, _) ->
                 applyTimeout(user, time)
             }.fold(
-                { message.channel.sendMessage(it) },
+                { error -> message.channel.sendMessage(error) },
                 { (user, time, reason) ->
                     user.sendEmbed {
                         addField("Timeout", Config.localization[LocalizationSpec.timeout].replace("@@", "$time"))