From becf67a286eacd311e1adce1118a6bf8b9fec2eb Mon Sep 17 00:00:00 2001
From: Yuta Koshizawa <koher@koherent.org>
Date: Sat, 30 Dec 2017 01:41:48 +0900
Subject: [PATCH] Implement tweet chains by replies

---
 Sources/TweetupKit/Async.swift   | 18 ++++++++++++------
 Sources/TweetupKit/Speaker.swift |  6 +++---
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/Sources/TweetupKit/Async.swift b/Sources/TweetupKit/Async.swift
index 70fc351..bacac33 100644
--- a/Sources/TweetupKit/Async.swift
+++ b/Sources/TweetupKit/Async.swift
@@ -28,27 +28,33 @@ public func sync<T, R>(operation: (@escaping (T, @escaping (() throws -> R) -> (
     }
 }
 
+internal func repeated<T, R1, R2>(operation: @escaping (T, R1?) -> Promise<() throws -> R2>, convert: @escaping (R2) -> R1, interval: TimeInterval? = nil) -> ([T]) -> Promise<() throws -> [R2]> {
+    return { values in
+        _repeat(operation: operation, for: values[...], convert: convert, interval: interval)
+    }
+}
+
 internal func repeated<T, R>(operation: @escaping (T) -> Promise<() throws -> R>, interval: TimeInterval? = nil) -> ([T]) -> Promise<() throws -> [R]> {
     return { values in
-        _repeat(operation: operation, for: values[...], interval: interval)
+        _repeat(operation: { r, _ in operation(r) }, for: values[...], convert: { $0 }, interval: interval)
     }
 }
 
-private func _repeat<T, R>(operation: @escaping (T) -> Promise<() throws -> R>, for values: ArraySlice<T>, interval: TimeInterval?, results: [R] = []) -> Promise<() throws -> [R]> {
+private func _repeat<T, R1, R2>(operation: @escaping (T, R1?) -> Promise<() throws -> R2>, for values: ArraySlice<T>, convert: @escaping (R2) -> R1, interval: TimeInterval?, results: [R2] = []) -> Promise<() throws -> [R2]> {
     let (headOrNil, tail) = values.headAndTail
     guard let head = headOrNil else {
         return Promise { results }
     }
     
-    let resultPromise: Promise<() throws -> R>
+    let resultPromise: Promise<() throws -> R2>
     if let interval = interval, !tail.isEmpty {
-        resultPromise = wait(operation(head), for: interval)
+        resultPromise = wait(operation(head, results.last.map(convert)), for: interval)
     } else {
-        resultPromise = operation(head)
+        resultPromise = operation(head, results.last.map(convert))
     }
     
     return resultPromise.flatMap { getResult in
-        _repeat(operation: operation, for: tail, interval: interval, results: results + [try getResult()])
+        _repeat(operation: operation, for: tail, convert: convert, interval: interval, results: results + [try getResult()])
     }
 }
 
diff --git a/Sources/TweetupKit/Speaker.swift b/Sources/TweetupKit/Speaker.swift
index 110817b..97bc9fd 100644
--- a/Sources/TweetupKit/Speaker.swift
+++ b/Sources/TweetupKit/Speaker.swift
@@ -43,10 +43,10 @@ public struct Speaker {
     }
     
     public func post(tweets: [Tweet], interval: TimeInterval?) -> Promise<() throws -> [PostResponse]> {
-        return repeated(operation: post, interval: interval)(tweets)
+        return repeated(operation: post, convert: { $0.statusId }, interval: interval)(tweets)
     }
     
-    public func post(tweet: Tweet) -> Promise<() throws -> PostResponse> {
+    public func post(tweet: Tweet, replyingTo statusId: String?) -> Promise<() throws -> PostResponse> {
         guard let twitterCredential = twitterCredential else {
             return Promise { throw SpeakerError.noTwitterCredential }
         }
@@ -76,7 +76,7 @@ public struct Speaker {
                 } else {
                     mediaId = nil
                 }
-                return Twitter.update(status: status, mediaId: mediaId, credential: twitterCredential).map { PostResponse(try $0()) }
+                return Twitter.update(status: status, mediaId: mediaId, inReplyToStatusId: statusId, credential: twitterCredential).map { PostResponse(try $0()) }
             }.map { getResponse in
                 try getResponse()
             }