add core func

go.mod

@@ -0,0 +1,3 @@
+module jar-dedup
+
+go 1.20

main.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"archive/zip"
+	"encoding/json"
+	"io/ioutil"
+	"log"
+	"os"
+)
+
+// Fabric/Quilt Mod Json
+type FabricModJson struct {
+	ID      string `json:"id"`
+	Version string `json:"version"`
+	Name    string `json:"name"`
+}
+type QuiltModJson struct {
+	QuiltLoader struct {
+		ID       string `json:"id"`
+		Version  string `json:"version"`
+		Metadata struct {
+			Name string `json:"name"`
+		} `json:"metadata"`
+	} `json:"quilt_loader"`
+}
+
+var (
+	fabricMods []FabricModJson
+	quiltMods  []QuiltModJson
+)
+
+// deduplicate mod jars based off the name of the jar
+// if the jar name is the same, then we will only keep the one with the highest version
+// or the latest modified date
+func main() {
+	// get list of jars in ./mods
+	files, err := ioutil.ReadDir("./mods")
+	if err != nil {
+		log.Fatalln("[READ DIR]", err)
+	}
+
+	// for modjars,
+	for _, file := range files {
+		// read the mod.json file and return the name, version, and filename
+		name, version, loader := readMod("./mods/" + file.Name())
+		if loader != "" {
+			// rename the file to Name-Version.jar
+			err := os.Rename("./mods/"+file.Name(), "./mods/"+name+"-"+version+".jar")
+			if err != nil {
+				log.Fatalln("[RENAME MOD]", err)
+			}
+			log.Println(loader, name, version)
+		} else {
+			log.Println("Unsupported Loader", file.Name())
+		}
+	}
+	for _, mod := range fabricMods {
+		// check if there is a duplicate in the list
+		for _, mod2 := range fabricMods {
+			if mod.Name == mod2.Name && mod.Version != mod2.Version {
+				// if there is a duplicate, delete the one with the lower semver version
+				if mod.Version < mod2.Version {
+					err := os.Remove("./mods/" + mod.Name + "-" + mod.Version + ".jar")
+					if err != nil {
+						log.Fatalln("[REMOVE MOD]", err)
+					}
+				}
+			}
+		}
+	}
+
+}
+
+// read the mod.json file and return the name, version, and filename
+
+func readMod(filename string) (string, string, string) {
+	var fabricJson FabricModJson
+	var quiltJson QuiltModJson
+	var loader string
+	zipReader, err := zip.OpenReader(filename)
+	if err != nil {
+		log.Fatalln("[READ ZIP]", err)
+	}
+	defer zipReader.Close()
+	for _, file := range zipReader.File {
+		contents, _ := file.Open()
+		if file.Name == "fabric.mod.json" {
+			loader = "fabric"
+			// add to fabric list
+			json.NewDecoder(contents).Decode(&fabricJson)
+		}
+		if file.Name == "quilt.mod.json" {
+			loader = "quilt"
+			json.NewDecoder(contents).Decode(&quiltJson)
+		}
+	}
+
+	if loader == "fabric" {
+		fabricMods = append(fabricMods, fabricJson)
+		return fabricJson.Name, fabricJson.Version, loader
+	}
+	if loader == "quilt" {
+		quiltMods = append(quiltMods, quiltJson)
+		return quiltJson.QuiltLoader.Metadata.Name, quiltJson.QuiltLoader.Version, loader
+	}
+	return "", "", ""
+}