implement check word

.golangci.yaml

@@ -25,8 +25,4 @@ linters:
 linters-settings:
   varnamelen:
     ignore-names:
-      - id
-      - db
-    ignore-decls:
-      - w http.ResponseWriter
-      - r *http.Request
+      - i

lib/gordle/gordle.go

@@ -10,6 +10,14 @@ import (
 
 var ErrWordNotFound = errors.New("word not found with requested length")
 
+const (
+	FeedbackNotInWord  = Feedback("N")
+	FeedbackWrongPlace = Feedback("W")
+	FeedbackCorrect    = Feedback("C")
+)
+
+type Feedback string
+
 func GetWord(reader *strings.Reader, wordLength int) (string, error) {
 	var candidates []string
 
@@ -34,3 +42,37 @@ func GetWord(reader *strings.Reader, wordLength int) (string, error) {
 
 	return candidates[rnd], nil
 }
+
+func CheckWord(word, input string) []Feedback {
+	wordRunes := []rune(word)
+	inputRunes := []rune(input)
+	res := []Feedback{}
+
+	counter := map[rune]int{}
+
+	for _, r := range wordRunes {
+		counter[r]++
+	}
+
+	for i, wordRune := range wordRunes {
+		if i >= len(inputRunes) {
+			res = append(res, FeedbackNotInWord)
+			continue
+		}
+
+		inputRune := inputRunes[i]
+
+		switch {
+		case wordRune == inputRune:
+			res = append(res, FeedbackCorrect)
+			counter[wordRune]--
+		case counter[inputRune] > 0:
+			res = append(res, FeedbackWrongPlace)
+			counter[inputRune]--
+		default:
+			res = append(res, FeedbackNotInWord)
+		}
+	}
+
+	return res
+}

lib/gordle/gordle_test.go

@@ -2,6 +2,7 @@ package gordle_test
 
 import (
 	"errors"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -36,3 +37,45 @@ func TestGetWord(t *testing.T) {
 		})
 	}
 }
+
+func TestTryWord(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		word  string
+		input string
+		want  []gordle.Feedback
+	}{
+		{"empty", "", "", []gordle.Feedback{}},
+		{"missing input", "i", "", []gordle.Feedback{gordle.FeedbackNotInWord}},
+		{"correct single", "i", "i", []gordle.Feedback{gordle.FeedbackCorrect}},
+		{"incorrect place", "ab", "ba", []gordle.Feedback{gordle.FeedbackWrongPlace, gordle.FeedbackWrongPlace}},
+		{
+			"some correct some incorrect", "aba", "baa",
+			[]gordle.Feedback{gordle.FeedbackWrongPlace, gordle.FeedbackWrongPlace, gordle.FeedbackCorrect},
+		},
+		{
+			"complex", "testing", "xsesing",
+			[]gordle.Feedback{
+				gordle.FeedbackNotInWord,
+				gordle.FeedbackWrongPlace,
+				gordle.FeedbackWrongPlace,
+				gordle.FeedbackNotInWord,
+				gordle.FeedbackCorrect,
+				gordle.FeedbackCorrect,
+				gordle.FeedbackCorrect,
+			},
+		},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			got := gordle.CheckWord(test.word, test.input)
+			if !reflect.DeepEqual(got, test.want) {
+				t.Errorf("got %q, want %q", got, test.want)
+			}
+		})
+	}
+}