implemented guess endpoint

internal/rest_handler/guess_letter.go

@@ -0,0 +1,47 @@
+package rest_handler
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+
+	"gitea.elara.ws/Hazel/hangman/internal/game"
+	"github.com/labstack/echo/v4"
+)
+
+func GuessLetter(c echo.Context) error {
+	session := game.GetSession(c.Param("session"))
+
+	sig := c.Request().Header.Get("signature")
+	body, _ := io.ReadAll(c.Request().Body)
+
+	u := session.VerifySignature(sig, body)
+	if u == nil {
+		return c.String(http.StatusBadRequest, "This user was not fount in the current session.")
+	}
+
+	if !session.CurrentUser.PublicKey.Equal(u.PublicKey) {
+		return c.String(http.StatusBadRequest, "It's not the turn of user "+u.Name+". It's the turn of "+session.CurrentUser.Name+".")
+	}
+
+	c.Request().Body = io.NopCloser(bytes.NewBuffer(body))
+
+	type BodyContent struct {
+		Guess string
+	}
+	var bodyContent BodyContent
+
+	err := c.Bind(&bodyContent)
+	if err != nil {
+		fmt.Println(err)
+		return c.String(http.StatusBadRequest, err.Error())
+	}
+
+	_, err = session.GuessLetter(bodyContent.Guess)
+	if err != nil {
+		return c.String(http.StatusBadRequest, err.Error())
+	}
+
+	return c.JSON(http.StatusOK, session)
+}