//! Gradient swatches and gradient stops linked to global and spot swatches: the recorded links,
//! stops following swatch edits, spot stops on their plate and as Separation shadings in PDF.

use serde_json::{Value, json};
use vectorcraft_color::{Color, GradientPaint, GradientStop, Paint};
use vectorcraft_render::proof;

use super::*;

fn session() -> Session {
    let mut s = Session::new();
    s.execute("file.new", &json!({"width": 100, "height": 100})).unwrap();
    s
}

fn run(s: &mut Session, id: &str, p: Value) -> Value {
    s.execute(id, &p).unwrap_or_else(|e| panic!("{id} {p}: {e}"))
}

fn doc(s: &Session) -> &vectorcraft_doc::Document {
    &s.doc().unwrap().doc
}

const INK: Color = Color::Cmyk { c: 0.0, m: 1.0, y: 0.0, k: 0.0 };

/// A document with spot swatch "Ink" and a selected rectangle.
fn setup() -> (Session, NodeId) {
    let mut s = session();
    run(&mut s, "swatch.new", json!({"name": "Ink", "color": INK, "spot": true}));
    let id = NodeId(run(&mut s, "shape.rectangle", json!({"x": 10, "y": 10, "width": 30, "height": 30}))["id"].as_u64().unwrap());
    run(&mut s, "select.set", json!({"ids": [id.0]}));
    (s, id)
}

fn gradient(s: &Session, id: NodeId) -> GradientPaint {
    match doc(s).node(id).unwrap().appearance.fill_paint() {
        Paint::Gradient(g) => *g,
        p => panic!("not a gradient: {p:?}"),
    }
}

/// Ink at `tint` % → white.
fn ink_to_white(tint: f64) -> Value {
    json!({"stops": [{"offset": 0, "swatch": "Ink", "tint": tint}, {"offset": 1, "color": "#ffffff"}]})
}

#[test]
fn applying_a_gradient_swatch_records_the_link_until_the_stops_change() {
    let (mut s, id) = setup();
    run(&mut s, "paint.setFill", json!({"swatch": "Sunset"}));
    assert_eq!(gradient(&s, id).swatch.as_deref(), Some("Sunset"));
    let used = run(&mut s, "swatch.unused", json!({}));
    assert!(!used["names"].as_array().unwrap().contains(&json!("Sunset")));
    run(&mut s, "paint.editGradient", json!({"angle": 45}));
    assert_eq!(gradient(&s, id).swatch.as_deref(), Some("Sunset"), "moving the vector keeps it");
    run(&mut s, "paint.editGradient", ink_to_white(100.0));
    assert_eq!(gradient(&s, id).swatch, None, "new stops are another gradient");
}

#[test]
fn stops_link_to_swatches_and_follow_their_edits() {
    let (mut s, id) = setup();
    run(&mut s, "paint.editGradient", ink_to_white(50.0));
    let st = gradient(&s, id).gradient.stops[0].clone();
    assert_eq!((st.swatch.as_deref(), st.tint, st.color), (Some("Ink"), 0.5, INK.tinted(0.5)), "the colour comes from the swatch");
    assert_eq!(gradient(&s, id).gradient.stops[1].swatch, None);
    // A tint swatch links the stop to its base at its tint; a process swatch just gives its colour.
    run(&mut s, "paint.setFill", json!({"swatch": "Ink", "tint": 40}));
    run(&mut s, "swatch.new", json!({}));
    run(&mut s, "paint.setFill", json!({"gradient": {"stops": [{"offset": 0, "swatch": "Ink 40%"}, {"offset": 1, "swatch": "Black"}]}}));
    let stops = gradient(&s, id).gradient.stops;
    assert_eq!((stops[0].swatch.as_deref(), stops[0].tint), (Some("Ink"), 0.4));
    assert_eq!((stops[1].swatch.as_deref(), stops[1].tint), (None, 1.0));
    assert!(s.execute("paint.editGradient", &json!({"stops": [{"offset": 0, "swatch": "Nope"}, {"offset": 1, "color": "#fff"}]})).is_err());
    // Editing the swatch recolours the stops (and the tint swatch) as one undo step.
    let undo = s.doc().unwrap().history.undo.len();
    run(&mut s, "swatch.edit", json!({"name": "Ink", "color": {"c": 1, "m": 0, "y": 0, "k": 0}}));
    let cyan = Color::cmyk(1.0, 0.0, 0.0, 0.0);
    assert_eq!(gradient(&s, id).gradient.stops[0].color, cyan.tinted(0.4));
    assert_eq!(s.doc().unwrap().history.undo.len(), undo + 1);
    // Global mode of Adjust Color Balance shifts stop tints too.
    run(&mut s, "edit.colors.adjustBalance", json!({"tint": 60}));
    assert_eq!(gradient(&s, id).gradient.stops[0].color, cyan);
    // Recolouring a stop unlinks it; deleting the swatch unlinks the rest, which keep their colour.
    run(&mut s, "paint.editGradient", ink_to_white(25.0));
    run(&mut s, "swatch.delete", json!({"name": "Ink"}));
    let st = gradient(&s, id).gradient.stops[0].clone();
    assert_eq!((st.swatch, st.tint, st.color), (None, 1.0, cyan.tinted(0.25)));
}

#[test]
fn gradient_swatches_keep_their_stop_links_and_follow_edits() {
    let (mut s, id) = setup();
    run(&mut s, "swatch.new", json!({"name": "Glow", "gradient": ink_to_white(100.0)}));
    run(&mut s, "paint.setFill", json!({"swatch": "Glow"}));
    run(&mut s, "swatch.edit", json!({"name": "Ink", "color": {"c": 0, "m": 0, "y": 1, "k": 0}}));
    let yellow = Color::cmyk(0.0, 0.0, 1.0, 0.0);
    let Paint::Gradient(sw) = doc(&s).swatch("Glow").unwrap().paint.clone() else { panic!() };
    assert_eq!(sw.gradient.stops[0].color, yellow, "the gradient swatch's stop follows");
    let g = gradient(&s, id);
    assert_eq!((g.gradient.stops[0].color, g.swatch.as_deref()), (yellow, Some("Glow")), "so does the art, still linked to its swatch");
    assert_eq!(g.gradient, sw.gradient);
}

#[test]
fn spot_stops_separate_on_their_plate() {
    let (mut s, id) = setup();
    run(&mut s, "paint.editGradient", ink_to_white(60.0));
    let mut node = doc(&s).node(id).unwrap().clone();
    let mut links = vec![];
    proof::map_node_colors(&mut node, &mut |c, link| {
        links.push(link.map(|(n, t)| (n.to_string(), t)));
        *c
    });
    assert!(links.contains(&Some(("Ink".to_string(), 0.6))), "{links:?}");
    let c = vectorcraft_color::cms::active();
    let st = gradient(&s, id).gradient.stops[0].clone();
    let ink = proof::inks(doc(&s), &c, &st.color, Some(("Ink", st.tint)), proof::Intent::RelativeColorimetric);
    assert_eq!((ink.cmyk, ink.spot), ([0.0; 4], Some(("Ink".to_string(), 0.6))));
}

fn pdf_of(s: &Session) -> (String, Vec<String>) {
    let opts = vectorcraft_pdf::PdfOptions { created: Some(0), ..vectorcraft_pdf::PdfOptions::uncompressed() };
    let r = vectorcraft_pdf::export_with_report(doc(s), &opts).unwrap();
    (String::from_utf8_lossy(&r.bytes).into_owned(), r.warnings)
}

#[test]
fn spot_gradients_export_as_separation_shadings() {
    let (mut s, _) = setup();
    run(&mut s, "paint.editGradient", ink_to_white(80.0));
    let (pdf, _) = pdf_of(&s);
    assert!(pdf.contains("/ShadingType 2") && pdf.contains("/Separation/Ink/DeviceCMYK"), "an Ink → paper gradient is a Separation shading");
    // Its function runs over the tints: 80 % (204 / 255) to 0 %.
    assert!(pdf.contains("/C0[0.8]/C1[0]"), "the shading's tints");
    // Mixing the spot ink with another colour falls back to process colours, with a warning.
    run(&mut s, "paint.editGradient", json!({"stops": [{"offset": 0, "swatch": "Ink"}, {"offset": 1, "color": "#00ff00"}]}));
    let (pdf, warnings) = pdf_of(&s);
    assert!(!pdf.contains("/Separation"), "no Separation for a mixed gradient");
    assert!(warnings.iter().any(|w| w.contains("spot")), "{warnings:?}");
}

#[test]
fn linked_stops_round_trip() {
    let (mut s, id) = setup();
    run(&mut s, "paint.editGradient", ink_to_white(30.0));
    let d = doc(&s).clone();
    let back = vectorcraft_format::load(&vectorcraft_format::save(&d, false)).unwrap();
    assert_eq!(back.node(id).unwrap().appearance.fill_paint(), d.node(id).unwrap().appearance.fill_paint());
    // Stops from before links read as unlinked.
    let old: GradientStop = serde_json::from_value(json!({"offset": 0.5, "color": {"model": "rgb", "r": 1, "g": 0, "b": 0}})).unwrap();
    assert_eq!(old, GradientStop::new(0.5, Color::rgb(1.0, 0.0, 0.0)));
    assert!(!serde_json::to_string(&old).unwrap().contains("tint"));
}