//! DXF output read back as group codes: versions, entities, colours, units, layers, type, images.

use std::sync::Arc;

use vectorcraft_color::{Color, Paint};
use vectorcraft_doc::{Appearance, CharStyle, Dash, Document, ImageBlob, ImageObject, Node, NodeKind, TextObject, Unit};
use vectorcraft_geom::{Affine, PathData, Point, Rect, shapes};

use crate::*;

type Pairs = Vec<(i32, String)>;

/// The `(code, value)` pairs of a DXF file.
fn pairs(dxf: &[u8]) -> Pairs {
    let text = std::str::from_utf8(dxf).expect("UTF-8");
    let lines: Vec<&str> = text.lines().collect();
    assert_eq!(lines.len() % 2, 0, "group codes and values come in pairs");
    lines.chunks(2).map(|p| (p[0].trim().parse().expect("a group code"), p[1].to_string())).collect()
}

/// The objects of section `name`: each the pairs from its `0` code on.
fn section(p: &[(i32, String)], name: &str) -> Vec<Pairs> {
    let start = p.windows(2).position(|w| w[0] == (0, "SECTION".into()) && w[1] == (2, name.into()));
    let Some(start) = start else { return vec![] };
    let mut out: Vec<Pairs> = vec![];
    for pair in &p[start + 2..] {
        if *pair == (0, "ENDSEC".into()) {
            break;
        }
        if pair.0 == 0 {
            out.push(vec![]);
        }
        if let Some(o) = out.last_mut() {
            o.push(pair.clone());
        }
    }
    out
}

fn kind(o: &[(i32, String)]) -> &str {
    o.first().map_or("", |p| p.1.as_str())
}

fn get(o: &[(i32, String)], code: i32) -> Option<&str> {
    o.iter().find(|p| p.0 == code).map(|p| p.1.as_str())
}

fn all(o: &[(i32, String)], code: i32) -> Vec<f64> {
    o.iter().filter(|p| p.0 == code).map(|p| p.1.trim().parse().expect("a number")).collect()
}

fn header(p: &[(i32, String)], var: &str) -> Option<String> {
    let i = p.iter().position(|x| *x == (9, var.into()))?;
    p.get(i + 1).map(|x| x.1.clone())
}

fn entities(out: &DxfOutput) -> Vec<Pairs> {
    section(&pairs(&out.bytes), "ENTITIES")
}

fn kinds(out: &DxfOutput) -> Vec<String> {
    entities(out).iter().map(|e| kind(e).to_string()).collect()
}

fn table(out: &DxfOutput, kind_: &str) -> Vec<Pairs> {
    section(&pairs(&out.bytes), "TABLES").into_iter().filter(|o| kind(o) == kind_).collect()
}

/// A 200 × 100 pt document whose first layer holds what `nodes` makes.
fn doc_with(nodes: impl FnOnce(&mut Document) -> Vec<Node>) -> Document {
    let mut d = Document::new(200.0, 100.0);
    let nodes = nodes(&mut d);
    let layer = d.layers[0].id;
    for n in nodes {
        d.insert(Some(layer), usize::MAX, n).unwrap();
    }
    d
}

fn path(d: &mut Document, p: PathData, fill: Paint, stroke: Paint, width: f64) -> Node {
    Node::path(d.alloc_id(), p, Appearance::basic(fill, stroke, width))
}

/// The options with the first artboard as the region, in points.
fn opts(d: &Document) -> DxfOptions {
    DxfOptions { region: d.artboards[0].rect, unit: Unit::Points, ..DxfOptions::default() }
}

/// A red-filled rectangle with a black 1 pt stroke, and an unfilled blue 2 pt ellipse.
fn shapes_doc() -> Document {
    doc_with(|d| {
        vec![
            path(d, shapes::rectangle(Rect::new(10.0, 10.0, 110.0, 60.0)), Paint::solid(Color::rgb(1.0, 0.0, 0.0)), Paint::solid(Color::BLACK), 1.0),
            path(d, shapes::ellipse(Rect::new(120.0, 20.0, 180.0, 80.0)), Paint::None, Paint::solid(Color::rgb(0.0, 0.0, 1.0)), 2.0),
        ]
    })
}

#[test]
fn every_version_declares_its_acadver_and_is_well_formed() {
    let d = shapes_doc();
    for v in DxfVersion::ALL {
        let out = export(&d, &DxfOptions { version: v, ..opts(&d) }).unwrap();
        let p = pairs(&out.bytes);
        assert_eq!(header(&p, "$ACADVER").as_deref(), Some(v.acadver()), "{v:?}");
        assert_eq!(p.last(), Some(&(0, "EOF".to_string())), "{v:?}");
        let opened = p.iter().filter(|x| **x == (0, "SECTION".into())).count();
        assert_eq!(opened, p.iter().filter(|x| **x == (0, "ENDSEC".into())).count(), "{v:?}: balanced sections");
        assert!(!entities(&out).is_empty(), "{v:?}");
        if v >= DxfVersion::R13 {
            // Every handle is unique and below $HANDSEED.
            let body = &p[p.iter().position(|x| *x == (0, "ENDSEC".into())).unwrap()..];
            let handles: Vec<u32> = body.iter().filter(|x| x.0 == 5 || x.0 == 105).map(|x| u32::from_str_radix(&x.1, 16).unwrap()).collect();
            let unique: std::collections::HashSet<_> = handles.iter().collect();
            assert_eq!(unique.len(), handles.len(), "{v:?}: unique handles");
            let seed = u32::from_str_radix(&header(&p, "$HANDSEED").unwrap(), 16).unwrap();
            assert!(handles.iter().all(|h| *h < seed), "{v:?}: handles below the seed");
            assert!(section(&p, "OBJECTS").iter().any(|o| kind(o) == "DICTIONARY"), "{v:?}: root dictionary");
        } else {
            assert!(header(&p, "$HANDSEED").is_none());
        }
    }
    assert_eq!(DxfVersion::from_id("r2013"), Some(DxfVersion::R2013));
    assert_eq!(DxfVersion::from_id("AC1009"), Some(DxfVersion::R12));
    assert_eq!(DxfVersion::from_id("2019"), None);
}

#[test]
fn lines_are_lwpolylines_curves_splines_and_fills_hatches() {
    let d = shapes_doc();
    let out = export(&d, &opts(&d)).unwrap();
    assert_eq!(kinds(&out), ["HATCH", "LWPOLYLINE", "SPLINE"], "fill, then stroke, then the ellipse's stroke");
    let e = entities(&out);
    // The rectangle, y up from the artboard's bottom-left corner: 10..110 × 40..90.
    let poly = &e[1];
    assert_eq!(get(poly, 70), Some("1"), "closed");
    let mut xs = all(poly, 10);
    xs.sort_by(f64::total_cmp);
    assert_eq!(xs, [10.0, 10.0, 110.0, 110.0]);
    let mut ys = all(poly, 20);
    ys.sort_by(f64::total_cmp);
    assert_eq!(ys, [40.0, 40.0, 90.0, 90.0]);
    let hatch = &e[0];
    assert_eq!((get(hatch, 2), get(hatch, 70), get(hatch, 91), get(hatch, 93)), (Some("SOLID"), Some("1"), Some("1"), Some("4")));
    // The ellipse: four cubics through clamped knots.
    let spline = &e[2];
    assert_eq!((get(spline, 71), get(spline, 73)), (Some("3"), Some("13")));
    assert_eq!(all(spline, 40), [0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 2.0, 2.0, 2.0, 3.0, 3.0, 3.0, 4.0, 4.0, 4.0, 4.0]);
    // R14 has lightweight polylines but no lineweights: the stroke is a polyline width.
    let r14 = export(&d, &DxfOptions { version: DxfVersion::R14, ..opts(&d) }).unwrap();
    assert_eq!(get(&entities(&r14)[1], 43), Some("1"));
    assert_eq!(get(&entities(&r14)[1], 370), None);
    // R13 has splines and hatches, and polylines of vertices.
    let r13 = export(&d, &DxfOptions { version: DxfVersion::R13, ..opts(&d) }).unwrap();
    assert_eq!(kinds(&r13), ["HATCH", "POLYLINE", "VERTEX", "VERTEX", "VERTEX", "VERTEX", "SEQEND", "SPLINE"]);
    // R12: polylines only; the fill is its outline, the ellipse flattened.
    let r12 = export(&d, &DxfOptions { version: DxfVersion::R12, ..opts(&d) }).unwrap();
    let k = kinds(&r12);
    assert!(k.iter().all(|k| matches!(k.as_str(), "POLYLINE" | "VERTEX" | "SEQEND")), "{k:?}");
    assert_eq!(k.iter().filter(|k| *k == "POLYLINE").count(), 3);
    assert!(k.iter().filter(|k| *k == "VERTEX").count() > 20, "the ellipse is flattened");
    assert!(r12.warnings.iter().any(|w| w.contains("R12 has no fills")), "{:?}", r12.warnings);
}

#[test]
fn colours_map_to_the_index_palette_or_true_colour() {
    let d = shapes_doc();
    let style = |o: &DxfOutput, i: usize| {
        let e = &entities(o)[i];
        (get(e, 62).map(str::to_string), get(e, 420).map(str::to_string))
    };
    let out = export(&d, &opts(&d)).unwrap();
    assert_eq!(style(&out, 0), (Some("1".into()), Some("16711680".into())), "red: index 1, true colour 0xFF0000");
    assert_eq!(style(&out, 1), (Some("7".into()), Some("0".into())), "black is index 7");
    assert_eq!(style(&out, 2), (Some("5".into()), Some("255".into())));
    for depth in [ColorDepth::Aci8, ColorDepth::Aci16, ColorDepth::Aci256] {
        let o = export(&d, &DxfOptions { colors: depth, ..opts(&d) }).unwrap();
        assert_eq!(style(&o, 0), (Some("1".into()), None), "{depth:?}");
    }
    let orange = doc_with(|d| {
        vec![path(d, shapes::rectangle(Rect::new(0.0, 0.0, 10.0, 10.0)), Paint::solid(Color::from_hex("#ff8000").unwrap()), Paint::None, 0.0)]
    });
    let aci = |depth| get(&entities(&export(&orange, &DxfOptions { colors: depth, ..opts(&orange) }).unwrap())[0], 62).unwrap().to_string();
    assert_eq!(
        (aci(ColorDepth::Aci256), aci(ColorDepth::Aci16), aci(ColorDepth::Aci8)),
        ("30".into(), "30".into(), "2".into()),
        "8 colours: yellow is nearest"
    );
    // True colour needs 2004: earlier versions fall back to indices, and say so.
    let old = export(&d, &DxfOptions { version: DxfVersion::R2000, ..opts(&d) }).unwrap();
    assert_eq!(style(&old, 0), (Some("1".into()), None));
    assert!(old.warnings.iter().any(|w| w.contains("true colour")));
}

#[test]
fn units_scale_coordinates_and_set_insunits() {
    let d = shapes_doc();
    let insunits = |o: &DxfOutput| header(&pairs(&o.bytes), "$INSUNITS");
    let max_x = |o: &DxfOutput| all(&entities(o)[1], 10).into_iter().fold(f64::MIN, f64::max);
    let mm = export(&d, &DxfOptions { unit: Unit::Millimeters, ..opts(&d) }).unwrap();
    assert_eq!(insunits(&mm).as_deref(), Some("4"));
    assert!((max_x(&mm) - 110.0 * 25.4 / 72.0).abs() < 1e-5);
    assert_eq!(header(&pairs(&mm.bytes), "$MEASUREMENT").as_deref(), Some("1"));
    let inches = export(&d, &DxfOptions { unit: Unit::Inches, ..opts(&d) }).unwrap();
    assert_eq!(insunits(&inches).as_deref(), Some("1"));
    // 1 in = 10 units: unitless, coordinates ten times larger.
    let scaled = export(&d, &DxfOptions { unit: Unit::Inches, scale: 10.0, ..opts(&d) }).unwrap();
    assert_eq!(insunits(&scaled).as_deref(), Some("0"));
    assert!((max_x(&scaled) - 110.0 / 72.0 * 10.0).abs() < 1e-5);
    // Lineweights: 1 pt is 0.35 mm, scaled with the drawing only when asked.
    assert_eq!(get(&entities(&scaled)[1], 370), Some("35"));
    let heavy = export(&d, &DxfOptions { unit: Unit::Inches, scale: 2.0, scale_lineweights: true, ..opts(&d) }).unwrap();
    assert_eq!(get(&entities(&heavy)[1], 370), Some("70"));
    assert!(export(&d, &DxfOptions { scale: 0.0, ..opts(&d) }).is_err());
    assert!(export(&d, &DxfOptions { scale: f64::NAN, ..opts(&d) }).is_err());
}

#[test]
fn layers_become_dxf_layers() {
    let mut d = shapes_doc();
    let second = d.add_layer(Some("Dims: <top>"));
    let hidden = d.add_layer(Some("Notes"));
    let template = d.add_layer(Some("Tracing"));
    for l in [second, hidden, template] {
        let n = path(&mut d, shapes::rectangle(Rect::new(0.0, 0.0, 5.0, 5.0)), Paint::solid(Color::BLACK), Paint::None, 0.0);
        d.insert(Some(l), 0, n).unwrap();
    }
    if let Some(n) = d.node_mut(hidden) {
        n.visible = false;
    }
    if let Some(NodeKind::Layer { template, .. }) = d.node_mut(template).map(|n| &mut n.kind) {
        *template = true;
    }
    let out = export(&d, &opts(&d)).unwrap();
    let layers: Vec<(String, String)> =
        table(&out, "LAYER").iter().map(|o| (get(o, 2).unwrap().to_string(), get(o, 62).unwrap().to_string())).collect();
    let names: Vec<&str> = layers.iter().map(|l| l.0.as_str()).collect();
    assert_eq!(names, ["0", "Layer 1", "Dims_ _top_", "Notes"], "the template layer is left out");
    assert!(layers[3].1.starts_with('-'), "a hidden layer is switched off");
    let on: Vec<String> = entities(&out).iter().map(|e| get(e, 8).unwrap().to_string()).collect();
    assert_eq!(on, ["Layer 1", "Layer 1", "Layer 1", "Dims_ _top_", "Notes"]);
    // Before 2000: capitals, letters, digits and $-_ only.
    let r12 = export(&d, &DxfOptions { version: DxfVersion::R12, ..opts(&d) }).unwrap();
    let names: Vec<String> = table(&r12, "LAYER").iter().map(|o| get(o, 2).unwrap().to_string()).collect();
    assert_eq!(names, ["0", "LAYER_1", "DIMS___TOP_", "NOTES"]);
}

#[test]
fn dashes_become_linetypes_and_opacity_transparency() {
    let d = doc_with(|d| {
        let mut n = path(d, shapes::line(Point::new(0.0, 50.0), Point::new(100.0, 50.0)), Paint::None, Paint::solid(Color::BLACK), 1.0);
        if let Some(st) = n.appearance.stroke_mut() {
            st.dash = Some(Dash { pattern: vec![6.0, 3.0], offset: 0.0, align_corners: false });
        }
        n.opacity = 0.5;
        vec![n]
    });
    let out = export(&d, &opts(&d)).unwrap();
    let e = &entities(&out)[0];
    let alpha = (0x0200_0000 | 128).to_string();
    assert_eq!((get(e, 6), get(e, 440)), (Some("DASHED1"), Some(alpha.as_str())));
    let lt = table(&out, "LTYPE").into_iter().find(|o| get(o, 2) == Some("DASHED1")).unwrap();
    assert_eq!(all(&lt, 49), [6.0, -3.0]);
    let old = export(&d, &DxfOptions { version: DxfVersion::R2000, ..opts(&d) }).unwrap();
    assert!(get(&entities(&old)[0], 440).is_none());
    assert!(old.warnings.iter().any(|w| w.contains("transparency")));
}

#[test]
fn alter_paths_writes_strokes_as_filled_outlines() {
    let d = shapes_doc();
    let out = export(&d, &DxfOptions { alter_paths: true, ..opts(&d) }).unwrap();
    assert_eq!(kinds(&out), ["HATCH", "HATCH", "HATCH"]);
    // The rectangle's stroke: an outer and an inner boundary.
    assert_eq!(get(&entities(&out)[1], 91), Some("2"));
    // Preserve Appearance outlines only the strokes a line can't draw.
    let mut d = shapes_doc();
    let rect = d.layers[0].children().and_then(|c| c.first()).map(|n| n.id).unwrap();
    if let Some(st) = d.node_mut(rect).and_then(|n| n.appearance.stroke_mut()) {
        st.align = vectorcraft_doc::StrokeAlign::Outside;
    }
    assert_eq!(kinds(&export(&d, &opts(&d)).unwrap()), ["HATCH", "HATCH", "SPLINE"]);
    let editable = export(&d, &DxfOptions { preserve: Preserve::Editability, ..opts(&d) }).unwrap();
    assert_eq!(kinds(&editable), ["HATCH", "LWPOLYLINE", "SPLINE"]);
    assert!(editable.warnings.iter().any(|w| w.contains("stroke alignment")));
}

fn text_doc(text: &str, size: f64) -> Document {
    doc_with(|d| {
        let style = CharStyle { size, fill: Paint::solid(Color::rgb(0.0, 0.5, 0.0)), ..CharStyle::default() };
        let t = TextObject::point(Point::new(10.0, 50.0), text, style);
        vec![Node::new(d.alloc_id(), NodeKind::Text(Box::new(t)))]
    })
}

#[test]
fn type_is_text_or_outlines() {
    let d = text_doc("Plan A", 20.0);
    let editable = export(&d, &DxfOptions { preserve: Preserve::Editability, ..opts(&d) }).unwrap();
    let e = entities(&editable);
    assert_eq!(e.len(), 1);
    assert_eq!((kind(&e[0]), get(&e[0], 1)), ("TEXT", Some("Plan A")));
    assert!((all(&e[0], 40)[0] - 14.0).abs() < 1e-6, "the cap height of 20 pt type");
    assert_eq!((all(&e[0], 10)[0], all(&e[0], 20)[0]), (10.0, 50.0), "the baseline start, y up");
    let family = CharStyle::default().font_family;
    let style = table(&editable, "STYLE").into_iter().find(|o| get(o, 3) == Some(&*format!("{family}.ttf"))).unwrap();
    assert_eq!(get(&e[0], 7), get(&style, 2));
    // Outline Text, and Preserve Appearance: the glyphs as filled outlines.
    for o in [DxfOptions { preserve: Preserve::Editability, outline_text: true, ..opts(&d) }, opts(&d)] {
        let k = kinds(&export(&d, &o).unwrap());
        assert!(!k.is_empty() && k.iter().all(|k| k == "HATCH"), "{k:?}");
    }
}

#[test]
fn text_outside_ascii_is_escaped_before_2007() {
    let d = text_doc("Größe", 12.0);
    let text = |v| {
        let out = export(&d, &DxfOptions { version: v, preserve: Preserve::Editability, ..opts(&d) }).unwrap();
        get(&entities(&out)[0], 1).unwrap().to_string()
    };
    assert_eq!(text(DxfVersion::R2004), "Gr\\U+00F6\\U+00DFe");
    assert_eq!(text(DxfVersion::R2018), "Größe");
}

#[test]
fn images_link_png_or_jpeg_files() {
    let mut png = vec![];
    image::RgbaImage::from_pixel(4, 2, image::Rgba([255, 0, 0, 128])).write_to(&mut std::io::Cursor::new(&mut png), image::ImageFormat::Png).unwrap();
    let mut d = doc_with(|d| {
        let im = ImageObject {
            key: "raster-1".into(),
            width: 4,
            height: 2,
            xf: Affine::translate((10.0, 20.0)) * Affine::scale(5.0),
            link: None,
            placement: Default::default(),
        };
        vec![Node::new(d.alloc_id(), NodeKind::Image(im))]
    });
    d.images.insert("raster-1".into(), ImageBlob { mime: "image/png".into(), bytes: Arc::new(png), proxy: None });
    let out = export(&d, &opts(&d)).unwrap();
    let e = entities(&out);
    assert_eq!(kind(&e[0]), "IMAGE");
    // The bottom-left corner (10, 30) is (10, 70) y up; a pixel is 5 units.
    assert_eq!((all(&e[0], 10)[0], all(&e[0], 20)[0]), (10.0, 70.0));
    assert_eq!((all(&e[0], 11)[0], all(&e[0], 22)[0], all(&e[0], 13)[0], all(&e[0], 23)[0]), (5.0, 5.0, 4.0, 2.0));
    assert_eq!(out.images.len(), 1);
    assert!(out.images[0].name.ends_with(".png") && out.images[0].bytes.starts_with(b"\x89PNG"));
    let p = pairs(&out.bytes);
    let objects = section(&p, "OBJECTS");
    let def = objects.iter().find(|o| kind(o) == "IMAGEDEF").unwrap();
    assert_eq!(get(def, 1), Some(out.images[0].name.as_str()));
    assert_eq!(get(&e[0], 340), get(def, 5), "the image points at its definition");
    assert!(objects.iter().any(|o| kind(o) == "IMAGEDEF_REACTOR"));
    assert!(section(&p, "CLASSES").iter().any(|o| get(o, 1) == Some("IMAGE")));
    let jpeg = export(&d, &DxfOptions { raster: RasterFormat::Jpeg, ..opts(&d) }).unwrap();
    assert!(jpeg.images[0].name.ends_with(".jpg") && jpeg.images[0].bytes.starts_with(&[0xFF, 0xD8]));
    let r12 = export(&d, &DxfOptions { version: DxfVersion::R12, ..opts(&d) }).unwrap();
    assert!(entities(&r12).is_empty() && r12.images.is_empty());
    assert!(r12.warnings.iter().any(|w| w.contains("no images")));
}

#[test]
fn crop_leaves_out_art_outside_the_region() {
    let d = shapes_doc();
    // Only the ellipse (120..180) reaches into 115..200.
    let o = DxfOptions { region: Rect::new(115.0, 0.0, 200.0, 100.0), crop: true, ..opts(&d) };
    assert_eq!(kinds(&export(&d, &o).unwrap()), ["SPLINE"]);
    assert_eq!(kinds(&export(&d, &DxfOptions { crop: false, ..o }).unwrap()).len(), 3);
}