Refactor: split monolith into cmd/palette + internal/{store,api,web,lang} (#35)

internal/api/guess.go

@@ -0,0 +1,26 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"palette/internal/lang"
+)
+
+// handleGuessLang serves POST /api/guess-language.
+func (a *apiServer) handleGuessLang(w http.ResponseWriter, r *http.Request) {
+	setRateLimitHeaders(w, 1, 5)
+	if !rateLimitGuess(r) {
+		writeRateLimited(w, 1)
+		return
+	}
+	var req struct {
+		Content string `json:"content"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeErr(w, http.StatusBadRequest, "invalid json body")
+		return
+	}
+	l := lang.GuessLang(req.Content)
+	writeJSON(w, http.StatusOK, map[string]any{"language": l})
+}