From 78fb5e122ca2c25cab92d47e3697752edaef8874 Mon Sep 17 00:00:00 2001
From: William Perron <hey@wperron.io>
Date: Sun, 19 Nov 2023 16:36:37 -0500
Subject: [PATCH] wip: add scheduled message every Saturday 5pm

---
 .gitignore                |  3 +++
 cmd/themis-server/main.go | 28 ++++++++++++++++++++
 fly.toml                  |  1 +
 notify.go                 | 56 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+)
 create mode 100644 notify.go

diff --git a/.gitignore b/.gitignore
index ee4d410..6647a79 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,3 +19,6 @@ bin/
 *.db
 *.db-shm
 *.db-wal
+
+# local env files
+env.sh
diff --git a/cmd/themis-server/main.go b/cmd/themis-server/main.go
index 292efae..589af62 100644
--- a/cmd/themis-server/main.go
+++ b/cmd/themis-server/main.go
@@ -17,6 +17,7 @@ import (
 
 	"github.com/bwmarrin/discordgo"
 	_ "github.com/mattn/go-sqlite3"
+	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 
 	"go.wperron.io/themis"
@@ -38,6 +39,9 @@ func main() {
 	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGTERM, syscall.SIGKILL, syscall.SIGINT)
 	defer cancel()
 
+	// TODO(wperron) remove before merging
+	zerolog.SetGlobalLevel(zerolog.DebugLevel)
+
 	flag.Parse()
 
 	err := touchDbFile(*dbFile)
@@ -53,6 +57,10 @@ func main() {
 	}
 	defer store.Close()
 
+	notifChan := make(chan struct{})
+	notifier := themis.NewNotifier(notifChan)
+	go notifier.Start(ctx)
+
 	authToken, ok := os.LookupEnv("DISCORD_TOKEN")
 	if !ok {
 		log.Fatal().Err(err).Msg("no auth token found at DISCORD_TOKEN env var")
@@ -68,6 +76,11 @@ func main() {
 		log.Fatal().Err(err).Msg("no guild id found at DISCORD_GUILD_ID env var")
 	}
 
+	channelId, ok := os.LookupEnv("DISCORD_BOT_CHANNEL_ID")
+	if !ok {
+		log.Fatal().Err(err).Msg("no channel id found at DISCORD_BOT_CHANNEL_ID env var")
+	}
+
 	discord, err := discordgo.New(fmt.Sprintf("Bot %s", authToken))
 	if err != nil {
 		log.Fatal().Err(err).Msg("failed to initialize discord session")
@@ -511,6 +524,21 @@ func main() {
 		cancel()
 	}()
 
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-notifChan:
+				_, err := discord.ChannelMessageSend(channelId, "don't forget we have a session next %s!")
+				if err != nil {
+					log.Error().Err(err).Msg("failed to send scheduled notification")
+				}
+			}
+			time.Sleep(5 * time.Minute)
+		}
+	}()
+
 	<-ctx.Done()
 	log.Info().Msg("context cancelled, exiting")
 
diff --git a/fly.toml b/fly.toml
index 0421d03..bf05045 100644
--- a/fly.toml
+++ b/fly.toml
@@ -8,6 +8,7 @@ processes = []
 [env]
 DISCORD_APP_ID = "1014881815921705030"
 DISCORD_GUILD_ID = "375417755777892353"
+DISCORD_BOT_CHANNEL_ID = "1018997240968265768"
 
 [experimental]
   allowed_public_ports = []
diff --git a/notify.go b/notify.go
new file mode 100644
index 0000000..0f1398d
--- /dev/null
+++ b/notify.go
@@ -0,0 +1,56 @@
+package themis
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+var loc *time.Location
+
+func init() {
+	loc, _ = time.LoadLocation("America/Toronto")
+}
+
+type Notifier struct {
+	c chan struct{}
+}
+
+func NewNotifier(c chan struct{}) *Notifier {
+	return &Notifier{
+		c: c,
+	}
+}
+
+func (n *Notifier) Start(ctx context.Context) {
+	m := NextMonday()
+	sat := m.AddDate(0, 0, -2)
+	if sat.Before(time.Now()) {
+		sat = sat.AddDate(0, 0, 7)
+	}
+
+	t, err := time.ParseInLocation(time.DateTime, fmt.Sprintf("%s 16:35:00", sat.Format(time.DateOnly)), loc)
+	if err != nil {
+		panic("failed to parse next monday notif time. this is likely a bug.")
+	}
+
+	first := time.NewTimer(time.Until(t))
+	<-first.C
+	select {
+	case <-ctx.Done():
+		return
+	default:
+		n.c <- struct{}{}
+	}
+
+	ticker := time.NewTicker(time.Hour * 24 * 7)
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			n.c <- struct{}{}
+		}
+		time.Sleep(time.Hour)
+	}
+}