1 files changed, 171 insertions, 0 deletions
diff --git a/go/makepass.go b/go/makepass.go
new file mode 100644
index 0000000..542b63e
--- /dev/null
+++ b/go/makepass.go
@@ -0,0 +1,171 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"golang.org/x/term"
+	"math/rand"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Basic constant definitions
+const (
+	normNum = 10 // Number of normal passwords
+	specNum = 6  // Number of special passwords
+	passNum = 6  // Number of passphrases
+
+	maxLength = 255 // Maximum length of passwords
+	rangeMax  = 42  // Maximum range for password length
+	rangeMin  = 8   // Minimum range for password length
+	passWords = 8   // Number of words in passphrases
+
+	lower = "abcdefghijklmnopqrstuvwxyz"
+	upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	digit = "0123456789"
+	other = "!$%&#/()=?+-_,.;:<>[]{}|@*" // Special characters for special passwords
+
+	defaultFile = "/usr/share/dict/words" // Default path to the file of words used for passphrases
+)
+
+// Variables for different types of passwords
+var (
+	alpha    []string = strings.Split(lower+upper, "")             // Array of alphabets (lowercase and uppercase)
+	alnum    []string = append(alpha, strings.Split(digit, "")...) // Array of alphanumeric characters
+	every    []string = append(alnum, strings.Split(other, "")...) // Array of all characters (alphabet, digit and special)
+	normal   []string = append(alnum, "-", "_")                    // Characters for normal passwords
+	special  []string = every                                      // Characters for special passwords
+	wordlist string   = defaultFile                                // Path to a dictionary to use for passphrases
+	length   int      = 0                                          // Length of passwords
+)
+
+func main() {
+	//
+	// Error handling
+	//
+	var err error
+
+	// Checking command line argument and environment variable for password length
+	if len(os.Args) == 2 {
+		length, err = strconv.Atoi(os.Args[1])
+	} else if len(os.Getenv("MAKEPASS_DEFAULT_LENGTH")) > 0 {
+		length, err = strconv.Atoi(os.Getenv("MAKEPASS_DEFAULT_LENGTH"))
+	}
+
+	// If there is an error in conversion, or if the length is not within limits, exit the program with an error message
+	if err != nil || (length > maxLength || length < 0) {
+		fmt.Printf("Error: Argument must be a whole number between 0 and %d.\n", maxLength)
+		os.Exit(1)
+	}
+
+	// Get wordlist from env
+	if len(os.Getenv("MAKEPASS_WORDLIST")) > 0 {
+		wordlist = os.Getenv("MAKEPASS_WORDLIST")
+	}
+
+	// Check if the wordlist file exists
+	if _, err := os.Stat(wordlist); os.IsNotExist(err) {
+		fmt.Println("The file", wordlist, "does not exist")
+		os.Exit(1)
+	}
+
+	//
+	// move on
+	//
+
+	// initialise the random seed
+	// TODO: Get seed from /dev/random, like we do in the perl- and zsh-versions?
+	rand.Seed(time.Now().UnixNano())
+
+	// get screen width
+	termWidth, _, err := term.GetSize(0)
+
+	// Read wordlist from file
+	file, err := os.Open(wordlist)
+	if err != nil {
+		fmt.Printf("failed to open file: %s", err)
+	}
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+	var text []string
+	for scanner.Scan() {
+		text = append(text, scanner.Text())
+	}
+	file.Close()
+
+	//
+	// print passwords
+	//
+
+	// Generate and print normal and special passwords
+	printColumns("Normal passwords:", 10, normal, termWidth)
+	fmt.Println("")
+	printColumns("Passwords with special characters:", 6, special, termWidth)
+	fmt.Println("")
+
+	// Generate and print passphrases
+	for i := 0; i < passNum; i++ {
+		fmt.Println(passphrase(&text))
+	}
+}
+
+// Function to generate a random string of given length from given characters
+func randstring(chars []string) string {
+	l := length
+	if length == 0 { // Random length if not specified
+		l = rand.Intn(rangeMax-rangeMin) + rangeMin
+	}
+	var str strings.Builder
+
+	// Add random characters to str
+	for i := 1; i <= l; i++ {
+		if i == 1 || i == l { // don't want passwords to start or end with special characters
+			str.WriteString(alnum[rand.Intn(len(alnum))])
+		} else {
+			str.WriteString(chars[rand.Intn(len(chars))])
+		}
+	}
+	return str.String()
+}
+
+// Function to generate and print passwords
+func printColumns(title string, num int, chars []string, termWidth int) {
+
+	// column width
+	colWidth := rangeMax + 2
+	if length > 0 {
+		colWidth = length + 2
+	}
+
+	// number of colums
+	columns := termWidth / colWidth
+	if columns == 0 {
+		columns = 1
+	}
+
+	// Print title
+	fmt.Println(title)
+
+	// Print passwords in columns
+	for i := 1; i <= num; i++ {
+		fmt.Printf("%-[1]*[2]s", colWidth, randstring(chars))
+		if i%columns == 0 || (i == num && i%columns > 0) { // Add newlines
+			fmt.Println("")
+		}
+	}
+}
+
+// Function to generate passphrases
+func passphrase(arrh *[]string) string {
+	text := *arrh
+	var str strings.Builder
+	for i := 0; i < passWords; i++ {
+		str.WriteString(text[rand.Intn(len(text))]) // Write a random word to the passphrase
+		if i != passWords-1 {
+			str.WriteString("-") // Add hyphen between words
+		}
+	}
+	return str.String()
+}