feat: show random cat picture on results page based on score

internal/handlers/test.go

@@ -7,7 +7,9 @@ import (
 	"log/slog"
 	"math/rand"
 	"net/http"
+	"os"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/go-chi/chi/v5"
@@ -18,6 +20,9 @@ import (
 	"qbank/internal/sampling"
 )
 
+// happyCatThreshold is the minimum score percentage to show a happy cat.
+const happyCatThreshold = 60
+
 type TestHandler struct {
 	auth   *auth.Manager
 	repo   *db.Repo
@@ -302,11 +307,18 @@ func (h *TestHandler) ResultsGet(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	mood := "sad"
+	if test.NQuestions > 0 && nCorrect*100/test.NQuestions >= happyCatThreshold {
+		mood = "happy"
+	}
+	catURL := randomCatURL(mood)
+
 	data := BaseData(h.auth, r)
 	data["Test"] = test
 	data["Items"] = items
 	data["NCorrect"] = nCorrect
 	data["TimeTaken"] = timeTaken
+	data["CatURL"] = catURL
 	h.render.Render(w, http.StatusOK, "test_results", data)
 }
 
@@ -342,6 +354,32 @@ func (h *TestHandler) loadTestAndN(w http.ResponseWriter, r *http.Request) (int,
 	return n, test, true
 }
 
+// randomCatURL picks a random image from web/static/cats/<mood>/ and returns
+// its URL path, or an empty string if the folder is missing or empty.
+func randomCatURL(mood string) string {
+	dir := "web/static/cats/" + mood
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return ""
+	}
+	var images []string
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		n := strings.ToLower(e.Name())
+		if strings.HasSuffix(n, ".jpg") || strings.HasSuffix(n, ".jpeg") ||
+			strings.HasSuffix(n, ".png") || strings.HasSuffix(n, ".gif") ||
+			strings.HasSuffix(n, ".webp") {
+			images = append(images, e.Name())
+		}
+	}
+	if len(images) == 0 {
+		return ""
+	}
+	return "/static/cats/" + mood + "/" + images[rand.Intn(len(images))]
+}
+
 // deterministicShuffle returns a copy of answers shuffled by a seed derived
 // from the test ID and question ID, so the order is stable across page reloads.
 func deterministicShuffle(answers []*models.Answer, testID int64, questionID string) []*models.Answer {