package ocr

import (
	"context"
	"image"
	"image/color"
	"testing"
)

func TestPreprocessScaleThresholdAndLimit(t *testing.T) {
	source := image.NewRGBA(image.Rect(4, 5, 6, 6))
	source.SetRGBA(4, 5, color.RGBA{R: 20, G: 20, B: 20, A: 255})
	source.SetRGBA(5, 5, color.RGBA{R: 220, G: 220, B: 220, A: 255})
	processed, err := Preprocess(context.Background(), source, Options{Scale: 2, BlackWhite: true, Threshold: 200})
	if err != nil {
		t.Fatal(err)
	}
	if processed.Bounds() != image.Rect(0, 0, 4, 2) {
		t.Fatal(processed.Bounds())
	}
	for x := 0; x < 4; x++ {
		r, _, _, _ := processed.At(x, 0).RGBA()
		want := uint32(0)
		if x >= 2 {
			want = 0xffff
		}
		if r != want {
			t.Fatalf("pixel %d = %d", x, r)
		}
	}
	if _, err := Preprocess(context.Background(), source, Options{Scale: 5}); err != ErrLimit {
		t.Fatal(err)
	}
}

func TestPreprocessInversion(t *testing.T) {
	source := image.NewRGBA(image.Rect(0, 0, 1, 1))
	source.SetRGBA(0, 0, color.RGBA{R: 10, G: 20, B: 30, A: 255})
	processed, err := Preprocess(context.Background(), source, Options{Invert: true})
	if err != nil {
		t.Fatal(err)
	}
	r, g, b, _ := processed.At(0, 0).RGBA()
	if r != 245*257 || g != 235*257 || b != 225*257 {
		t.Fatalf("inverted pixel %d %d %d", r, g, b)
	}
}