nigig-org/crates/apps/pdf/pdf-graphics/tests/codec_port.rs

//! 1:1 port of `dart-pdf/packages/pdf_graphics/test/render_command_codec_test.dart`
//! (tranche 1: synthetic round-trip, overprint tag, corpus round-trip, and
//! the f32 path precision contract).
//!
//! Codec fidelity is compared at the command level (`format_commands`):
//! a buffer that survives the wire byte-identical replays identically.
//! Replay itself is covered by `render_command_port.rs`.
//!
//! Not ported: worker state-scope compaction, image offload/placeholders
//! (nigig's wire always carries image bytes — no decline model), glyph
//! outline deduplication, decode regions, resolution caps, page budgets,
//! and raster-pixel helpers. Those are the background-worker render
//! pipeline, which nigig does not have.

use nigig_pdf_document::PdfDocument;
use nigig_pdf_graphics::content::parse_content_stream;
use nigig_pdf_graphics::path::PdfPathBuilder;
use nigig_pdf_graphics::recording::{format_commands, RecordingDevice, RenderCommand};
use nigig_pdf_graphics::wire::{decode, encode};

fn roundtrip(cmds: &[RenderCommand]) -> Vec<RenderCommand> {
    let bytes = encode(cmds);
    decode(&bytes).expect("decodes")
}

fn record(content: &str) -> Vec<RenderCommand> {
    let ops = parse_content_stream(content.as_bytes()).expect("content parses");
    RecordingDevice::from_ops(&ops)
}

#[test]
fn synthetic_buffers_round_trip() {
    let cases = [
        "q 2 0 0 2 10 10 cm 0 0 1 rg 5 5 20 30 re f 1 0 0 RG 4 w 0 0 10 10 re S Q",
        "[3 2] 1.5 d 1 w 10 10 m 90 90 l S",
        "0 0 5 5 re W n 0 0 1 rg 0 0 10 10 re f",
        "BT /F1 24 Tf 72 720 Td (Hello, world!) Tj ET",
        // Word spacing (Tw) with char spacing exercises kern-adjusted runs.
        "BT /F1 10 Tf 5 Tw 0.2 Tc 72 700 Td ( ab ) Tj ET",
        "q q 0 0 1 1 re f Q q 1 1 2 2 re f Q Q",
        "10 10 m 20 30 40 30 50 10 c f",
        "0 0 10 10 re 2 2 6 6 re f*",
    ];
    for content in cases {
        let original = record(content);
        assert!(!original.is_empty(), "fixture should paint something");
        let restored = roundtrip(&original);
        assert_eq!(
            format_commands(&restored),
            format_commands(&original),
            "round-trip diverged for {content:?}"
        );
    }
}

#[test]
fn byte_output_is_stable_across_two_serializations() {
    let original =
        record("q 0 0 1 rg 5 5 20 30 re f Q BT /F1 12 Tf 10 10 Td (hi) Tj ET");
    let a = encode(&original);
    let b = encode(&original);
    assert_eq!(a, b);
}

#[test]
fn overprint_state_round_trips_fill_stroke_mode() {
    let commands = vec![
        RenderCommand::SetOverprint { fill: true, stroke: false, mode: 1 },
        RenderCommand::SetOverprint { fill: false, stroke: true, mode: 0 },
    ];
    let restored = roundtrip(&commands);
    assert_eq!(restored.len(), 2);
    assert!(
        matches!(
            &restored[0],
            RenderCommand::SetOverprint { fill: true, stroke: false, mode: 1 }
        ),
        "got {:?}",
        restored[0]
    );
    assert!(
        matches!(
            &restored[1],
            RenderCommand::SetOverprint { fill: false, stroke: true, mode: 0 }
        ),
        "got {:?}",
        restored[1]
    );
}

#[test]
fn path_coordinates_survive_at_f32_precision() {
    // Geometry rides the wire as f32 (dart's Float32List exactness): the
    // codec promises the f32 image, not the f64 original.
    let mut b = PdfPathBuilder::new();
    b.move_to(0.1, 0.2);
    b.line_to(0.3, 1.0 / 3.0);
    let path = b.take_path();
    let restored = roundtrip(&[RenderCommand::Path(path)]);
    assert_eq!(restored.len(), 1);
    let RenderCommand::Path(back) = &restored[0] else {
        panic!("expected a Path");
    };
    // Decoded coords equal the f32 truncation of the inputs, exactly.
    let coords: Vec<f64> = back
        .segments()
        .iter()
        .flat_map(|s| match *s {
            nigig_pdf_graphics::path::PdfPathSegment::MoveTo { x, y }
            | nigig_pdf_graphics::path::PdfPathSegment::LineTo { x, y } => vec![x, y],
            nigig_pdf_graphics::path::PdfPathSegment::CubicTo { x1, y1, x2, y2, x3, y3 } => {
                vec![x1, y1, x2, y2, x3, y3]
            }
            nigig_pdf_graphics::path::PdfPathSegment::Close => Vec::new(),
        })
        .collect();
    for (got, want) in coords.iter().zip([0.1, 0.2, 0.3, 1.0 / 3.0]) {
        assert_eq!(*got as f32, want as f32, "f32 image must match");
        assert!(
            (*got - want).abs() < 1e-6,
            "f32 rounding only, got {got} want {want}"
        );
    }
}

// Real pages exercise the fragile callbacks. Nigig's wire always carries
// image bytes (no decline/placeholder model — a documented deviation from
// dart's cos-gated serialization), so every parseable page must round-trip.
const GHENT: &str = "/Users/aok/Projects/rustdev/CratesCode/dart-pdf/test_corpora/ghent/1-CMYK";

#[test]
fn corpus_buffers_round_trip() {
    let files = [
        "GWG168_Softmasks_Vector_part1_X4.pdf",
        "GWG1610_Softmasks_Text_part1_X4.pdf",
        "GWG160_Transp_Basic_BM_DeviceCMYK_Non-knockout_X4.pdf",
        "GWG161_Transp_Basic_BM_DeviceCMYK_Knockout_X4.pdf",
        "GWG060_Shading_x1a.pdf",
        "GWG061_Shading_x1a.pdf",
    ];
    let mut ran = 0;
    for name in files {
        let path = format!("{GHENT}/{name}");
        let Ok(bytes) = std::fs::read(&path) else {
            eprintln!("SKIP (missing corpus file): {path}");
            continue;
        };
        let Ok(mut doc) = PdfDocument::parse(&bytes) else {
            eprintln!("SKIP (unparseable — likely compressed xref): {path}");
            continue;
        };
        for i in 0..doc.page_count() {
            let Ok(page) = doc.page(i) else { continue };
            let Ok(ops) = parse_content_stream(&page.content_data) else { continue };
            let original = RecordingDevice::from_ops(&ops);
            if original.is_empty() {
                continue;
            }
            let restored = roundtrip(&original);
            ran += 1;
            assert_eq!(
                format_commands(&restored),
                format_commands(&original),
                "{name} page {i} diverged after round-trip"
            );
        }
    }
    eprintln!("corpus_buffers_round_trip compared {ran} pages");
    assert!(ran > 0, "no corpus pages ran — checkout missing?");
}