feat: add CLI to use it every day

cmd/pwgen/main.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"code.icb4dc0.de/prskr/go-pwgen"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+// although there might be terminals where it's less, let's be pessimistic
+const tabWidth = 8
+
+var (
+	length           uint
+	count            int
+	letters          uint
+	lowercase        uint
+	uppercase        uint
+	digits           uint
+	specials         uint
+	specialsAlphabet string
+)
+
+func main() {
+	flags := flag.NewFlagSet("pwgen", flag.ExitOnError)
+	flags.IntVar(&count, "count", 20, "Number of passwords to generate")
+	flags.UintVar(&length, "length", 20, "Length of each password to generate")
+	flags.UintVar(&letters, "letters", 0, "Number of letters to include at least")
+	flags.UintVar(&lowercase, "lowercase", 3, "Number of lowercase characters to include at least")
+	flags.UintVar(&uppercase, "uppercase", 3, "Number of uppercase characters to include at least")
+	flags.UintVar(&digits, "digits", 3, "Number of digits to include at least")
+	flags.UintVar(&specials, "specials", 0, "Number of special characters to include at least")
+	flags.StringVar(&specialsAlphabet, "specials-alphabet", pwgen.DefaultSpecialsAlphabet, "Special characters to include as special characters")
+
+	if err := flags.Parse(os.Args[1:]); err != nil {
+		log.Fatalf("Failed to parse arguments: %v", err)
+	}
+
+	terminalWidth := getWidth()
+
+	passwordsPerRow := int(terminalWidth / (length + tabWidth))
+
+	builder := strings.Builder{}
+	for i := 0; i < count; i += passwordsPerRow {
+		for j := 0; j < passwordsPerRow && i+j < count; j++ {
+			pw, err := pwgen.Generate(
+				pwgen.WithLength(length),
+				pwgen.WithLetters(letters),
+				pwgen.WithLowercase(lowercase),
+				pwgen.WithUppercase(uppercase),
+				pwgen.WithDigits(digits),
+				pwgen.WithSpecials(specials),
+				pwgen.WithSpecialsAlphabet(specialsAlphabet),
+			)
+			if err != nil {
+				log.Fatalf("Error occurred generating password: %v", err)
+			}
+
+			builder.WriteString(pw)
+			builder.WriteRune('\t')
+		}
+
+		fmt.Println(strings.TrimSuffix(builder.String(), "\t"))
+		builder.Reset()
+	}
+}

cmd/pwgen/terminal.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+type winsize struct {
+	Row    uint16
+	Col    uint16
+	Xpixel uint16
+	Ypixel uint16
+}
+
+func getWidth() uint {
+	ws := &winsize{}
+	retCode, _, errno := syscall.Syscall(syscall.SYS_IOCTL,
+		uintptr(syscall.Stdin),
+		uintptr(syscall.TIOCGWINSZ),
+		uintptr(unsafe.Pointer(ws)))
+
+	if int(retCode) == -1 {
+		panic(errno)
+	}
+	return uint(ws.Col)
+}