init

.gitignore

@@ -0,0 +1 @@
+bin

Makefile

@@ -0,0 +1,17 @@
+.PHONY: default b build i install r release
+
+default: build
+
+b build:
+	go build
+
+i install:
+	go install
+
+r release:
+	mkdir -p bin
+	CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build -o bin/genpno-macos-arm64
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o bin/genpno-linux-amd64
+	CGO_ENABLED=0 GOOS=linux GOARCH=386 go build -o bin/genpno-linux-386
+	CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build -o bin/genpno-windows-amd64.exe
+	CGO_ENABLED=0 GOOS=windows GOARCH=386 go build -o bin/genpno-windows-386.exe

README.md

@@ -0,0 +1,55 @@
+# Swedish Personnummer Generator
+
+A simple command-line interface (CLI) application written in Go that generates valid [Swedish "Personnummer" (personal identification numbers)](https://en.wikipedia.org/wiki/Personal_identity_number_(Sweden)).
+
+## Usage
+
+a) Download the binary from the releases page or
+
+b) Build the binary from source
+```bash
+go install github.com/dominikwinter/genpno@latest
+
+genpno
+```
+
+## Development
+
+1. Clone the repository:
+
+```bash
+git clone https://github.com/dominikwinter/genpno.git
+```
+
+2. Navigate to the project directory:
+
+```bash
+cd genpno
+```
+
+3. Build and install the application:
+
+```bash
+make
+make install
+```
+
+4. Run the application:
+
+```bash
+genpno
+```
+
+## Features
+
+- **Easy to Use:** Simply execute the binary in the CLI to generate a valid Swedish "Personnummer."
+- **Planned Flags:** Future updates will include optional flags to specify gender, birthdate, and output format.
+
+## How to Contribute
+
+If you'd like to contribute to the project, feel free to fork the repository and submit a pull request. Contributions are welcome!
+
+
+## License
+
+This project is licensed under the [MIT License](LICENSE).

go.mod

@@ -0,0 +1,3 @@
+module genpno
+
+go 1.21.6

main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"time"
+)
+
+func main() {
+	date := getRandomDate()
+	three := getRandomThreeDigits(true)
+	checksum := getChecksum(&date, &three)
+
+	fmt.Println(date + three + checksum)
+}
+
+func getRandomDate() string {
+	now := time.Now()
+
+	min := now.AddDate(-100, 0, 0).Unix()
+	max := now.AddDate(-18, 0, 0).Unix()
+
+	delta := max - min
+	sec := rand.Int63n(delta) + min
+
+	return time.Unix(sec, 0).Format("20060102")
+}
+
+func getRandomThreeDigits(male bool) string {
+	two := rand.Intn(99)
+	one := rand.Intn(9)
+
+	var last int
+
+	if male {
+		if one%2 == 1 {
+			last = one
+		} else {
+			last = (one + 1) % 10
+		}
+	} else {
+		if one%2 == 0 {
+			last = one
+		} else {
+			last = (one + 1) % 10
+		}
+	}
+
+	return fmt.Sprintf("%02d%d", two, last)
+}
+
+func getChecksum(date *string, three *string) string {
+	short_date := (*date)[len(*date)-6:]
+	short_checksum := short_date + *three
+
+	sum := 0
+	m := 2
+
+	for i := 0; i < len(short_checksum); i++ {
+		num, _ := strconv.Atoi(string(short_checksum[i]))
+		num = num * m
+
+		if num >= 10 {
+			sum += (num % 10) + 1
+		} else {
+			sum += num
+		}
+
+		if m == 2 {
+			m = 1
+		} else {
+			m = 2
+		}
+	}
+
+	checksum := 10 - (sum % 10)
+
+	if checksum == 10 {
+		checksum = 0
+	}
+
+	return strconv.Itoa(checksum)
+}