First not working app skeleton with nix support and dependency setup and generated logo not final structure

src/utils.go

@@ -0,0 +1,132 @@
+package src
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"log"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func mustRandToken(n int) string {
+	b := make([]byte, n)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+	return hex.EncodeToString(b)
+}
+
+func now() time.Time { return time.Now().UTC() }
+
+func defaultUsername() string {
+	// io-game style: adjective-animal-xxxx
+	adjectives := []string{"swift", "brave", "mighty", "cheeky", "sneaky", "zippy", "bouncy", "crispy", "fuzzy", "spicy", "snappy", "jazzy", "spry", "bold", "witty"}
+	animals := []string{"otter", "panda", "falcon", "lynx", "badger", "tiger", "koala", "yak", "gecko", "eagle", "mamba", "fox", "yak", "whale", "rhino"}
+	a := adjectives[int(time.Now().UnixNano())%len(adjectives)]
+	an := animals[int(time.Now().UnixNano()/17)%len(animals)]
+	return a + "-" + an + "-" + strings.ToLower(mustRandToken(2))
+}
+
+func slugify(s string) string {
+	s = strings.ToLower(s)
+	s = strings.TrimSpace(s)
+	s = strings.ReplaceAll(s, " ", "-")
+	// keep alnum and - only
+	var b strings.Builder
+	for _, r := range s {
+		if (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '-' {
+			b.WriteRune(r)
+		}
+	}
+	out := b.String()
+	if out == "" {
+		out = "user-" + mustRandToken(2)
+	}
+	return out
+}
+
+func ensureUniqueUsernameAndSlug(u *User) error {
+	// try to keep username/slug unique by appending short token if needed
+	baseU := u.Username
+	baseS := slugify(u.Username)
+	for i := 0; i < 5; i++ {
+		candU := baseU
+		candS := baseS
+		if i > 0 {
+			suffix := "-" + mustRandToken(1)
+			candU = baseU + suffix
+			candS = baseS + suffix
+		}
+		var cnt int64
+		db.Model(&User{}).Where("username = ?", candU).Count(&cnt)
+		if cnt == 0 {
+			db.Model(&User{}).Where("slug = ?", candS).Count(&cnt)
+			if cnt == 0 {
+				u.Username = candU
+				u.Slug = candS
+				return nil
+			}
+		}
+	}
+	return errors.New("cannot create unique username/slug")
+}
+
+func userByEmail(email string) (*User, error) {
+	var u User
+	tx := db.Where("email = ?", strings.ToLower(email)).First(&u)
+	if tx.Error != nil {
+		return nil, tx.Error
+	}
+	return &u, nil
+}
+
+func userBySlug(slug string) (*User, error) {
+	var u User
+	tx := db.Where("slug = ?", slug).First(&u)
+	if tx.Error != nil {
+		return nil, tx.Error
+	}
+	return &u, nil
+}
+
+func atoiSafe(s string) int {
+	var n int
+	for _, r := range s {
+		if r < '0' || r > '9' {
+			return 0
+		}
+	}
+	_, _ = fmtSscanf(s, "%d", &n)
+	return n
+}
+
+// minimal sscanf to avoid fmt import just for one call
+func fmtSscanf(s, format string, a *int) (int, error) {
+	// Only supports "%d"
+	n := 0
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if c < '0' || c > '9' {
+			break
+		}
+		n = n*10 + int(c-'0')
+	}
+	*a = n
+	return 1, nil
+}
+
+func render(c *gin.Context, name string, data ctxData) {
+	u := getSessionUser(c)
+	if data == nil {
+		data = ctxData{}
+	}
+	log.Println("tpl error:", name)
+	data["CurrentUser"] = u
+	if err := tpl.ExecuteTemplate(c.Writer, name, data); err != nil {
+		log.Println("tpl error:", err)
+		c.Status(500)
+	}
+}