From a545cf2b1c992cb9aba6d2b3e2d0f9f3880afbfa Mon Sep 17 00:00:00 2001
From: Xevion <xevion@xevion.dev>
Date: Sun, 24 Dec 2023 21:59:03 -0600
Subject: [PATCH] Add structhash, hash command definition with xxhash, store &
 compare with redis

---
 go.mod  |  1 +
 go.sum  |  2 ++
 main.go | 55 +++++++++++++++++++++++++++++++++++++++++++------------
 3 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/go.mod b/go.mod
index de542b4..6b3f0b5 100644
--- a/go.mod
+++ b/go.mod
@@ -8,6 +8,7 @@ require github.com/joho/godotenv v1.5.1
 
 require (
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/cnf/structhash v0.0.0-20201127153200-e1b16c1ebc08 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
diff --git a/go.sum b/go.sum
index f17a5e5..a864793 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,8 @@ github.com/bwmarrin/discordgo v0.27.1 h1:ib9AIc/dom1E/fSIulrBwnez0CToJE113ZGt4Ho
 github.com/bwmarrin/discordgo v0.27.1/go.mod h1:NJZpH+1AfhIcyQsPeuBKsUtYrRnjkyu0kIVMCHkZtRY=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cnf/structhash v0.0.0-20201127153200-e1b16c1ebc08 h1:ox2F0PSMlrAAiAdknSRMDrAr8mfxPCfSZolH+/qQnyQ=
+github.com/cnf/structhash v0.0.0-20201127153200-e1b16c1ebc08/go.mod h1:pCxVEbcm3AMg7ejXyorUXi6HQCzOIBf7zEDVPtw0/U4=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
diff --git a/main.go b/main.go
index af37361..0885094 100644
--- a/main.go
+++ b/main.go
@@ -1,13 +1,18 @@
 package main
 
 import (
+	"context"
+	"encoding/base64"
 	"flag"
+	"fmt"
 	"net/http"
 	"net/http/cookiejar"
 	"os"
 	"os/signal"
 
 	"github.com/bwmarrin/discordgo"
+	"github.com/cespare/xxhash/v2"
+	"github.com/cnf/structhash"
 	"github.com/joho/godotenv"
 	"github.com/redis/go-redis/v9"
 	"github.com/rs/zerolog"
@@ -20,6 +25,7 @@ var (
 	baseURL        string
 	client         http.Client
 	kv             *redis.Client
+	ctx            context.Context
 	cookies        http.CookieJar
 	session        *discordgo.Session
 	RemoveCommands = flag.Bool("rmcmd", true, "Remove all commands after shutdowning or not")
@@ -50,6 +56,8 @@ func (l logOut) WriteLevel(level zerolog.Level, p []byte) (n int, err error) {
 }
 
 func init() {
+	ctx = context.Background()
+
 	// Try to grab the environment variable, or default to development
 	env := os.Getenv("ENVIRONMENT")
 	if env == "" {
@@ -83,6 +91,13 @@ func main() {
 	}
 	kv = redis.NewClient(options)
 
+	// Test the redis instance
+	pong, err := kv.Ping(ctx).Result()
+	if err != nil {
+		log.Fatal().Err(err).Msg("Cannot connect to redis")
+	}
+	log.Debug().Str("ping", pong).Msg("Redis connection successful")
+
 	// Create cookie jar
 	cookies, err = cookiejar.New(nil)
 	if err != nil {
@@ -128,14 +143,39 @@ func main() {
 	// Register commands
 	registeredCommands := make([]*discordgo.ApplicationCommand, len(commandDefinitions))
 	for i, cmdDefinition := range commandDefinitions {
-		cmdInstance, err := session.ApplicationCommandCreate(session.State.User.ID, os.Getenv("BOT_TARGET_GUILD"), cmdDefinition)
+		// Compare the hash to the hash stored in redis
+		hash := xxhash.Sum64(structhash.Dump(cmdDefinition, 1))
+		key := fmt.Sprintf("command:%s:xxhash", cmdDefinition.Name)
+		keyB64 := base64.StdEncoding.EncodeToString([]byte(key))
+		storedHash, err := kv.Get(ctx, key).Uint64()
 		if err != nil {
-			log.Panic().Err(err).Str("name", cmdDefinition.Name).Msgf("Cannot register command")
+			if err != redis.Nil {
+				log.Err(err).Msg("Cannot get command hash from redis")
+			} else {
+				log.Debug().Str("command", cmdDefinition.Name).Str("key", keyB64).Msg("Command hash not found in redis")
+			}
+		}
+
+		// If the hash is the same, skip registering the command
+		if hash == storedHash {
+			log.Debug().Str("command", cmdDefinition.Name).Str("key", keyB64).Msg("Command hash matches, skipping registration")
+			continue
+		}
+
+		// Register the command
+		cmdInstance, err := session.ApplicationCommandCreate(session.State.User.ID, "", cmdDefinition)
+		if err != nil {
+			log.Panic().Err(err).Str("name", cmdDefinition.Name).Str("key", keyB64).Msg("Cannot register command")
+		}
+		err = kv.Set(ctx, key, hash, 0).Err()
+		if err != nil {
+			log.Err(err).Str("name", cmdDefinition.Name).Str("key", keyB64).Msg("Cannot set command hash in redis")
 		}
 		registeredCommands[i] = cmdInstance
+		log.Info().Str("name", cmdDefinition.Name).Str("key", keyB64).Msg("Registered command")
 	}
 
-	// Cloes session, ensure
+	// Cloes session, ensure http client closes idle connections
 	defer session.Close()
 	defer client.CloseIdleConnections()
 
@@ -144,15 +184,6 @@ func main() {
 	log.Info().Msg("Press Ctrl+C to exit")
 	<-stop
 
-	if *RemoveCommands {
-		for _, cmd := range registeredCommands {
-			err := session.ApplicationCommandDelete(session.State.User.ID, os.Getenv("BOT_TARGET_GUILD"), cmd.ID)
-			if err != nil {
-				log.Err(err).Str("command", cmd.Name)
-			}
-		}
-	}
-
 	log.Warn().Msg("Gracefully shutting down")
 
 }