package utils

import (
	"errors"
	"strings"
	"testing"
)

func TestSanitizeMessageText_TrimsWhitespace(t *testing.T) {
	got, err := SanitizeMessageText("  سلام دوست من  ")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if got != "سلام دوست من" {
		t.Fatalf("expected trimmed text, got %q", got)
	}
}

func TestSanitizeMessageText_EmptyAfterTrim(t *testing.T) {
	_, err := SanitizeMessageText("     ")
	if !errors.Is(err, ErrMessageEmpty) {
		t.Fatalf("expected ErrMessageEmpty, got %v", err)
	}
}

func TestSanitizeMessageText_StripsControlChars(t *testing.T) {
	got, err := SanitizeMessageText("سلام\x00\x07دنیا")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if got != "سلامدنیا" {
		t.Fatalf("expected control chars stripped, got %q", got)
	}
}

func TestSanitizeMessageText_KeepsNewlinesAndTabs(t *testing.T) {
	got, err := SanitizeMessageText("خط اول\nخط دوم\tبا تب")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if got != "خط اول\nخط دوم\tبا تب" {
		t.Fatalf("expected newline/tab preserved, got %q", got)
	}
}

func TestSanitizeMessageText_InvalidUTF8(t *testing.T) {
	invalid := string([]byte{0xff, 0xfe, 0xfd})
	_, err := SanitizeMessageText(invalid)
	if !errors.Is(err, ErrInvalidMessageEncoding) {
		t.Fatalf("expected ErrInvalidMessageEncoding, got %v", err)
	}
}

func TestSanitizeMessageText_TooLong(t *testing.T) {
	long := strings.Repeat("a", MaxMessageLength+1)
	_, err := SanitizeMessageText(long)
	if !errors.Is(err, ErrMessageTooLong) {
		t.Fatalf("expected ErrMessageTooLong, got %v", err)
	}
}

func TestSanitizeMessageText_ExactlyMaxLength(t *testing.T) {
	exact := strings.Repeat("a", MaxMessageLength)
	got, err := SanitizeMessageText(exact)
	if err != nil {
		t.Fatalf("unexpected error at exact max length: %v", err)
	}
	if len(got) != MaxMessageLength {
		t.Fatalf("expected length %d, got %d", MaxMessageLength, len(got))
	}
}