package project

import (
	"fmt"
	"image"
	"image/png"
	"log"
	"os"
	"testing"
)

func SavePNG(img image.Image, filename string) error {
	if img == nil {
		return nil
	}
	// Save the image to a file
	file, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer file.Close()
	return png.Encode(file, img)
}

func TestNewIterator(t *testing.T) {
	i, err := NewIterator("../../IMG_2399_1024.MOV")
	if err != nil {
		t.Fatalf("NewIterator() error = %v", err)
	}
	defer i.Close()
	os.Mkdir("testdata", 0755)

	n := 0
	for i.Next() && n < 10 {
		log.Printf("Next() returned true for frame %d err:%s", i.Frame(), i.Error())
		n++
		frame := i.Frame()
		img := i.Image()
		log.Printf("Frame %d: Img:%T img.bounds=%#v duration=%s", frame, img, img.Bounds(), i.Duration())
		// write out to testdata/%d.png
		if img != nil {
			err = SavePNG(img, fmt.Sprintf("testdata/%d.png", frame))
			if err != nil {
				t.Errorf("SavePNG() error = %v", err)
			}
		} else {
			log.Printf("No image at frame %d", frame)
		}
	}
}