From 8d030f738675c72dcd7949b76a197bbfb892791b Mon Sep 17 00:00:00 2001
From: milarin <milaring@proton.me>
Date: Thu, 19 Jan 2023 10:16:43 +0100
Subject: [PATCH] telegram message send offset introduced

---
 envvars.go  |  1 +
 telegram.go |  5 +----
 utils.go    | 15 +++++++++++++++
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/envvars.go b/envvars.go
index dece52c..133fcb1 100644
--- a/envvars.go
+++ b/envvars.go
@@ -22,6 +22,7 @@ var (
 	TelegramOrganizeMessagePattern       = template.Must(template.New("TELEGRAM_ORGANIZE_MESSAGE_PATTERN").Parse(TelegramOrganizeMessagePatternStr))
 	TelegramOrganizeMessageSendCondition = envvars.ObjectSlice("TELEGRAM_ORGANIZE_MESSAGE_SEND_CONDITION", ",", []SendCondition{SendConditionAlways}, SendConditionFromString)
 	TelegramOrganizeMessageSendInterval  = envvars.Duration("TELEGRAM_ORGANIZE_MESSAGE_SEND_INTERVAL", 0)
+	TelegramOrganizeMessageSendOffset    = envvars.Duration("TELEGRAM_ORGANIZE_MESSAGE_SEND_OFFSET", 0)
 
 	Uid = envvars.Object("UID", 1000, func(s string) (int, error) {
 		if uid, err := strconv.Atoi(s); err == nil {
diff --git a/telegram.go b/telegram.go
index 9640f51..e77f7c2 100644
--- a/telegram.go
+++ b/telegram.go
@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"strings"
-	"time"
 
 	"git.milar.in/milarin/adverr"
 	"git.milar.in/milarin/anilist"
@@ -33,9 +32,7 @@ func SendMessagePeriodically() {
 	var messagesPerInterval <-chan []model.AnimeEpisode
 
 	if TelegramOrganizeMessageSendInterval > 0 {
-		lastCycle := time.Now().Truncate(TelegramOrganizeMessageSendInterval)
-		nextCycle := lastCycle.Add(TelegramOrganizeMessageSendInterval)
-		time.Sleep(time.Until(nextCycle))
+		WaitForNextTelegramSendCycle()
 		sendAllQueuedAnimeEpisodes()
 
 		grouperFunc := func(current []model.AnimeEpisode, value model.AnimeEpisode) []model.AnimeEpisode {
diff --git a/utils.go b/utils.go
index 8f254ef..8c8778e 100644
--- a/utils.go
+++ b/utils.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"time"
 
 	"git.milar.in/milarin/channel"
 	"git.milar.in/milarin/gmath"
@@ -48,3 +49,17 @@ func PrintFileHandle(fh *FileHandle) {
 		panic(err) // TODO error handling
 	}
 }
+
+func WaitForNextTelegramSendCycle() {
+	now := time.Now()
+	_, offset := now.Zone()
+	offsetDuration := time.Duration(offset) * time.Second
+	lastCycle := now.Truncate(TelegramOrganizeMessageSendInterval).Add(-offsetDuration).Add(TelegramOrganizeMessageSendOffset)
+
+	if durationUntilLastCycle := time.Until(lastCycle); durationUntilLastCycle > 0 {
+		time.Sleep(durationUntilLastCycle)
+	} else {
+		nextCycle := lastCycle.Add(TelegramOrganizeMessageSendInterval)
+		time.Sleep(time.Until(nextCycle))
+	}
+}