use cbz2pdf::formats::pdf::{PdfReader, PdfWriter};
use cbz2pdf::formats::{FormatReader, FormatWriter};
use cbz2pdf::model::{Document, ImagePage};

fn make_small_jpeg(w: u32, h: u32, rgb: [u8; 3]) -> (Vec<u8>, image::DynamicImage) {
    let mut img = image::ImageBuffer::<image::Rgb<u8>, _>::new(w, h);
    for p in img.pixels_mut() {
        *p = image::Rgb(rgb);
    }
    let dynimg = image::DynamicImage::ImageRgb8(img);

    let mut buf = Vec::new();
    {
        let mut cursor = std::io::Cursor::new(&mut buf);
        let mut enc = image::codecs::jpeg::JpegEncoder::new_with_quality(&mut cursor, 85);
        let rgb8 = dynimg.to_rgb8();
        enc.encode(&rgb8, w, h, image::ColorType::Rgb8.into())
            .unwrap();
    }
    (buf, dynimg)
}

#[test]
fn pdf_reader_extracts_jpeg_xobject_and_preserves_dct() {
    // Build a PDF with one JPEG-backed page
    let (jpeg_dct, dynimg) = make_small_jpeg(3, 2, [10, 20, 30]);
    let page = ImagePage {
        name: "p1.jpg".into(),
        image: dynimg.clone(),
        jpeg_dct: Some(jpeg_dct.clone()),
    };
    let doc = Document::new(vec![page]);

    let temp_dir = tempfile::tempdir().expect("tmpdir");
    let pdf_path = temp_dir.path().join("in.pdf");

    PdfWriter.write(&doc, &pdf_path).expect("write pdf");

    // Read back with PdfReader
    let out = PdfReader.read(&pdf_path).expect("read pdf");
    assert_eq!(out.pages.len(), 1, "should have one page extracted");
    let p = &out.pages[0];
    assert_eq!(p.image.width(), dynimg.width());
    assert_eq!(p.image.height(), dynimg.height());
    assert!(p.jpeg_dct.is_some(), "should preserve DCT for JPEG images");
    assert_eq!(
        p.jpeg_dct.as_ref().unwrap(),
        &jpeg_dct,
        "JPEG bytes should match"
    );
}