use golang flag instead of external getopt library

aplus.go

@@ -63,7 +63,7 @@ func submit_code(course_code int, attendance_code string) {
 func launch_aplus(course_code int) string {
 	err := init_aplus_toolid(course_code)
 	if err != nil {
-		fmt.Println("Failed to get A+ base URL and tool ID")
+		fmt.Println("Failed to get A+ base URL and tool ID. Try again with a different course code.")
 		os.Exit(1)
 	}
 

go.mod

@@ -1,7 +1,5 @@
 module codeberg.org/flpolyaplus/aplus
 
-go 1.21.3
+go 1.21.1
 
 require golang.org/x/net v0.18.0
-
-require github.com/pborman/getopt v1.1.0 // indirect

go.sum

@@ -1,4 +1,2 @@
-github.com/pborman/getopt v1.1.0 h1:eJ3aFZroQqq0bWmraivjQNt6Dmm5M0h2JcDW38/Azb0=
-github.com/pborman/getopt v1.1.0/go.mod h1:FxXoW1Re00sQG/+KIkuSqRL/LwQgSkv7uyac+STFsbk=
 golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
 golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=

main.go

@@ -1,43 +1,74 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"net/http"
 	"os"
-
-	"github.com/pborman/getopt"
 )
 
 var base_link string
+var base_aplus_link string
+var external_tools_code int
 var token string
 var client http.Client
 
+func usage() {
+	fmt.Println("Usage: aplus [--code attendance_code --course course_code] [--list] [--listfav] [--help]")
+}
+
 func main() {
 	initialize()
 
-	code := getopt.StringLong("code", 'c', "", "Code to enter")
-	course := getopt.IntLong("course", 'C', -1, "Canvas course number")
-	list_all := getopt.BoolLong("list-all", 'L', "List all courses")
-	list_favorites := getopt.BoolLong("list-favorites", 'F', "List favorite courses")
-	help := getopt.BoolLong("help", 'h', "Help")
+	var code string
+	var course int
+	var listall bool
+	var listfav bool
+	var help bool
 
-	getopt.Parse()
+	flag.StringVar(&code, "code", "", "5 character attendance code")
+	flag.StringVar(&code, "c", "", "5 character attendance code")
+	flag.IntVar(&course, "course", -1, "canvas course code")
+	flag.IntVar(&course, "C", -1, "canvas course code")
+	flag.BoolVar(&listall, "list", false, "list all canvas courses")
+	flag.BoolVar(&listall, "L", false, "list all canvas courses")
+	flag.BoolVar(&listfav, "listfav", false, "list favorited canvas courses")
+	flag.BoolVar(&listfav, "F", false, "list favorited canvas courses")
+	flag.BoolVar(&help, "help", false, "view usage message")
+	flag.BoolVar(&help, "h", false, "view usage message")
 
-	if *help || (*list_all == false && *list_favorites == false && *code == "" && *course == -1) {
-		getopt.Usage()
+	flag.Parse()
+
+	if (code == "" && course == -1 && !listall && !listfav) {
+		usage()
+		os.Exit(1)
+	}
+
+	if (listall) {
+		list_all_courses()
 		os.Exit(0)
 	}
 
-	if *list_all {
-		list_all_courses()
-	}
-
-	if *list_favorites {
+	if (listfav) {
 		list_favorite_courses()
+		os.Exit(0)
 	}
 
-	if *code != "" && *course != -1 {
-		fmt.Printf("%d %s", *course, *code)
-		submit_code(*course, *code)
+	if (help) {
+		usage()
+		os.Exit(0)
+	}
+
+	if (len(code) != 5) {
+		fmt.Println("Attendance code must be 5 characters long")
+		os.Exit(1)
+	}
+
+	if code != "" && course != -1 {
+		fmt.Printf("%d %s\n", course, code)
+		submit_code(course, code)
+	} else {
+		usage()
+		os.Exit(1)
 	}
 }