use std::fs;
use std::io::Read;

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

#[test]
fn pdf_writer_writes_valid_pdf_header() {
    // Build a simple 2x2 red image page
    let mut img = image::DynamicImage::new_rgb8(2, 2).to_rgb8();
    for p in img.pixels_mut() {
        *p = image::Rgb([255, 0, 0]);
    }
    let page = ImagePage {
        name: "page1.jpg".to_string(),
        image: image::DynamicImage::ImageRgb8(img),
        jpeg_dct: None,
    };
    let doc = Document::new(vec![page]);

    let temp_dir = tempfile::tempdir().expect("create temp dir");
    let output = temp_dir.path().join("out.pdf");

    let writer = PdfWriter;
    writer.write(&doc, &output).expect("failed to write PDF");

    // Assert file exists and has PDF header
    let mut f = fs::File::open(&output).expect("pdf not created");
    let mut header = [0u8; 5];
    f.read_exact(&mut header).expect("cannot read header");
    assert_eq!(&header, b"%PDF-", "missing PDF header");

    let meta = fs::metadata(&output).unwrap();
    assert!(meta.len() > 0, "empty pdf");

    // temp_dir cleans up automatically on drop
}