From f6c11b54f31634d19317269562d1fb03dd361a2e Mon Sep 17 00:00:00 2001
From: Benjamin Loison <Benjamin_Loison@users.noreply.gitea.lemnoslife.com>
Date: Sat, 14 Jan 2023 15:14:24 +0100
Subject: [PATCH] Fix #26: Keep efficient search algorithm while keeping order
 (notably of the starting set)

---
 main.cpp | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/main.cpp b/main.cpp
index 67dfa97..7fee7fd 100644
--- a/main.cpp
+++ b/main.cpp
@@ -36,8 +36,10 @@ bool doesFileExist(string filePath),
 mutex printMutex,
       channelsAlreadyTreatedAndToTreatMutex,
       quotaMutex;
-set<string> channelsAlreadyTreated,
-    channelsToTreat;
+set<string> channelsAlreadyTreated;
+// Two `map`s to simulate a bidirectional map.
+map<unsigned int, string> channelsToTreat;
+map<string, unsigned int> channelsToTreatRev;
 vector<string> keys;
 unsigned int commentsCount = 0,
              commentsPerSecondCount = 0,
@@ -76,10 +78,14 @@ int main(int argc, char *argv[])
 
     // The starting set should be written to `CHANNELS_FILE_PATH`.
     // To resume this algorithm after a shutdown, just restart it after having deleted the last channel folders in `CHANNELS_DIRECTORY` being treated.
-    // On a restart, `CHANNELS_FILE_PATH` is read and every channel not found in `CHANNELS_DIRECTORY` is added to `channelsToTreat` or `channelsToTreat` otherwise before continuing, as if `CHANNELS_FILE_PATH` was containing a **treated** starting set.
+    // On a restart, `CHANNELS_FILE_PATH` is read and every channel not found in `CHANNELS_DIRECTORY` is added to `channelsToTreat*` or `channelsToTreat*` otherwise before continuing, as if `CHANNELS_FILE_PATH` was containing a **treated** starting set.
     vector<string> channelsVec = getFileContent(CHANNELS_FILE_PATH);
-    // Note that using `set`s makes the search faster but we lose the `channels.txt` lines order.
-    channelsToTreat = setFromVector(channelsVec);
+    for(unsigned int channelsVecIndex = 0; channelsVecIndex < channelsVec.size(); channelsVecIndex++)
+    {
+        string channel = channelsVec[channelsVecIndex];
+        channelsToTreat[channelsVecIndex] = channel;
+        channelsToTreatRev[channel] = channelsVecIndex;
+    }
 
     keys = getFileContent(KEYS_FILE_PATH);
     apiKey = keys[0];
@@ -90,7 +96,10 @@ int main(int argc, char *argv[])
     {
         string fileName = entry.path().filename(),
                channelId = fileName.substr(0, fileName.length() - 4);
-        channelsToTreat.erase(channelId);
+
+        channelsToTreat.erase(channelsToTreatRev[channelId]);
+        channelsToTreatRev.erase(channelId);
+
         channelsAlreadyTreated.insert(channelId);
     }
 
@@ -132,11 +141,13 @@ void treatChannels(unsigned short threadId)
             continue;
         }
 
-        string channelToTreat = *channelsToTreat.begin();
+        string channelToTreat = channelsToTreat.begin()->second;
 
         PRINT(threadId, "Treating channel " << channelToTreat << " (treated: " << channelsAlreadyTreated.size() << ", to treat: " << channelsToTreat.size() << ")")
 
-        channelsToTreat.erase(channelToTreat);
+        channelsToTreat.erase(channelsToTreatRev[channelToTreat]);
+        channelsToTreatRev.erase(channelToTreat);
+
         channelsAlreadyTreated.insert(channelToTreat);
 
         channelsAlreadyTreatedAndToTreatMutex.unlock();
@@ -285,9 +296,12 @@ void treatComment(unsigned short threadId, json comment, string channelId)
     {
         string channelId = snippet["authorChannelId"]["value"];
         channelsAlreadyTreatedAndToTreatMutex.lock();
-        if(channelsAlreadyTreated.find(channelId) == channelsAlreadyTreated.end() && channelsToTreat.find(channelId) == channelsToTreat.end())
+        if(channelsAlreadyTreated.find(channelId) == channelsAlreadyTreated.end() && channelsToTreatRev.find(channelId) == channelsToTreatRev.end())
         {
-            channelsToTreat.insert(channelId);
+            unsigned int channelsToTreatIndex = channelsToTreat.end()->first + 1;
+            channelsToTreat[channelsToTreatIndex] = channelId;
+            channelsToTreatRev[channelId] = channelsToTreatIndex;
+
             channelsAlreadyTreatedAndToTreatMutex.unlock();
 
             writeFile(threadId, CHANNELS_FILE_PATH, "a", "\n" + channelId);