package service

import (
	"bytes"
	"image/png"
	"strings"
	"testing"
)

func TestRandomCaptcha(t *testing.T) {
	code := randomCaptcha(4)
	if len(code) != 4 {
		t.Fatalf("len = %d", len(code))
	}
	for _, r := range code {
		if !strings.ContainsRune(captchaAlphabet, r) {
			t.Fatalf("unexpected char %q", r)
		}
		if _, ok := captchaFont[r]; !ok {
			t.Fatalf("missing glyph %q", r)
		}
	}
}

func TestCaptchaPNG(t *testing.T) {
	raw := captchaPNG("W8K2")
	img, err := png.Decode(bytes.NewReader(raw))
	if err != nil {
		t.Fatal(err)
	}
	if img.Bounds().Dx() < 40 || img.Bounds().Dy() < 20 {
		t.Fatalf("image too small: %v", img.Bounds())
	}
}

func TestCaptchaFontCoversAlphabet(t *testing.T) {
	for _, r := range captchaAlphabet {
		if _, ok := captchaFont[r]; !ok {
			t.Fatalf("alphabet char %q has no glyph", r)
		}
	}
}