//! Local adjustments must survive the sidecar.
//!
//! The sidecar is the authoritative store (ARCH §6.1) — the catalog is a
//! disposable index and the RAW is never written. So a mask that does not
//! round-trip is not a persistence bug, it is lost work, and the tests here
//! are about the ways that happens quietly rather than loudly.

use dr_pipeline::descriptor::ParamId;
use dr_pipeline::mask::{MaskLayer, MaskSource};
use dr_pipeline::{EditGraph, Sidecar, Version};

fn regions(ids: &[u32]) -> MaskSource {
    MaskSource::Regions {
        signature: 0xdead_beef,
        level: 300,
        ids: ids.to_vec(),
    }
}

/// A graph with one masked adjustment on it.
fn graph_with_mask() -> EditGraph {
    let mut graph = EditGraph::default_chain();
    let mut layer = MaskLayer::new("m1", regions(&[3, 7, 12]));
    layer.name = "Subject".into();
    layer.set_param("exposure", ParamId("exposure"), 0.75);
    graph.masks_mut().push(layer);
    graph
}

fn round_trip(graph: &EditGraph) -> EditGraph {
    let mut sidecar = Sidecar::new();
    sidecar.put(Version::from_graph("default", "Default", graph));

    let text = sidecar.to_text();
    let parsed = Sidecar::parse(&text).expect("reparse");

    let mut restored = EditGraph::default_chain();
    parsed
        .versions
        .get("default")
        .expect("version survived")
        .apply(&mut restored);
    restored
}

#[test]
fn a_region_mask_survives_a_round_trip() {
    let graph = graph_with_mask();
    let restored = round_trip(&graph);

    let layers = restored.masks().layers();
    assert_eq!(layers.len(), 1, "the layer came back");

    let layer = &layers[0];
    assert_eq!(layer.id, "m1");
    assert_eq!(layer.name, "Subject");
    assert_eq!(layer.source, regions(&[3, 7, 12]));
    assert_eq!(
        layer
            .ops
            .iter()
            .find(|o| o.descriptor().id.0 == "exposure")
            .map(|o| o.param(ParamId("exposure"))),
        Some(0.75)
    );
}

#[test]
fn writing_the_same_state_twice_is_byte_identical() {
    // What lets a caller skip an upload by comparing content rather than
    // trusting a dirty flag — the property the whole `versions` ordering
    // exists for, now that masks are in the file too.
    let graph = graph_with_mask();
    let mut a = Sidecar::new();
    a.put(Version::from_graph("default", "Default", &graph));

    let once = a.to_text();
    let twice = Sidecar::parse(&once).expect("reparse").to_text();
    assert_eq!(once, twice);
}

#[test]
fn gradients_keep_their_geometry() {
    let mut graph = EditGraph::default_chain();

    let mut linear = MaskLayer::new(
        "m1",
        MaskSource::Linear {
            centre: (0.25, 0.75),
            angle: 1.25,
            width: 0.4,
        },
    );
    linear.set_param("exposure", ParamId("exposure"), -1.0);
    graph.masks_mut().push(linear);

    let mut radial = MaskLayer::new(
        "m2",
        MaskSource::Radial {
            centre: (0.6, 0.4),
            radii: (0.3, 0.15),
            angle: -0.5,
            feather: 0.65,
        },
    );
    radial.set_param("exposure", ParamId("exposure"), 0.5);
    graph.masks_mut().push(radial);

    let restored = round_trip(&graph);
    let layers = restored.masks().layers();
    assert_eq!(layers.len(), 2);
    assert_eq!(layers[0].source, graph.masks().layers()[0].source);
    assert_eq!(layers[1].source, graph.masks().layers()[1].source);
}

#[test]
fn flags_and_opacity_survive() {
    let mut graph = EditGraph::default_chain();
    let mut layer = MaskLayer::new("m1", regions(&[1]));
    layer.set_param("exposure", ParamId("exposure"), 1.0);
    layer.invert = true;
    layer.opacity = 0.35;
    layer.enabled = false;
    graph.masks_mut().push(layer);

    let restored = round_trip(&graph);
    let layer = &restored.masks().layers()[0];
    assert!(layer.invert);
    assert!((layer.opacity - 0.35).abs() < 1e-6);
    assert!(
        !layer.enabled,
        "a disabled layer must stay disabled, not vanish"
    );
}

/// A selection's identity is the *set*. Two files naming the same regions in
/// different orders describe one mask and must compare equal, or the two
/// devices that wrote them will fight forever over a difference that is not
/// one.
#[test]
fn region_order_is_normalised_on_read() {
    let text = "drsc 1\n\
        \n[version default]\n\
        name = Default\n\
        revision = 1\n\
        modified = 0\n\
        \n[mask default m1]\n\
        source = regions\n\
        signature = 5\n\
        level = 10\n\
        regions = 12 3 7 3\n\
        exposure.exposure = 1\n";

    let parsed = Sidecar::parse(text).expect("parse");
    let layer = &parsed.versions["default"].masks.layers()[0];
    assert_eq!(
        layer.source,
        MaskSource::Regions {
            signature: 5,
            level: 10,
            ids: vec![3, 7, 12],
        },
        "ids sort and deduplicate on the way in"
    );
}

/// The version skew case. An older build must not delete a mask type it has
/// never heard of *silently* — but neither may it apply one it cannot read.
#[test]
fn an_unknown_mask_source_is_skipped_not_guessed() {
    let text = "drsc 1\n\
        \n[version default]\n\
        name = Default\n\
        revision = 1\n\
        modified = 0\n\
        \n[mask default m1]\n\
        source = luminosity\n\
        threshold = 0.5\n\
        exposure.exposure = 1\n";

    let parsed = Sidecar::parse(text).expect("parse");
    assert!(
        parsed.versions["default"].masks.is_empty(),
        "an unreadable mask must not become a wrong one"
    );
}

#[test]
fn a_mask_naming_no_known_version_is_dropped() {
    let text = "drsc 1\n\
        \n[version default]\n\
        name = Default\n\
        revision = 1\n\
        modified = 0\n\
        \n[mask ghost m1]\n\
        source = regions\n\
        signature = 1\n\
        level = 1\n\
        regions = 1\n";

    let parsed = Sidecar::parse(text).expect("parse");
    assert!(parsed.versions["default"].masks.is_empty());
}

/// Masks name their version rather than relying on file order, so a block
/// that appears before its version still lands on it.
#[test]
fn a_mask_block_need_not_follow_its_version() {
    let text = "drsc 1\n\
        \n[mask second m1]\n\
        source = regions\n\
        signature = 1\n\
        level = 1\n\
        regions = 4 5\n\
        exposure.exposure = 1\n\
        \n[version first]\n\
        name = First\n\
        revision = 1\n\
        modified = 0\n\
        \n[version second]\n\
        name = Second\n\
        revision = 1\n\
        modified = 0\n";

    let parsed = Sidecar::parse(text).expect("parse");
    assert!(parsed.versions["first"].masks.is_empty());
    assert_eq!(
        parsed.versions["second"].masks.len(),
        1,
        "the block named its version and should have reached it"
    );
}

/// Loading is a replacement, not an overlay: opening an unedited image after
/// an edited one must not leave the previous image's masks on screen.
#[test]
fn applying_a_maskless_version_clears_existing_masks() {
    let mut graph = graph_with_mask();
    assert_eq!(graph.masks().len(), 1);

    let plain = Version::from_graph("clean", "Clean", &EditGraph::default_chain());
    plain.apply(&mut graph);
    assert!(graph.masks().is_empty());
}

#[test]
fn a_graph_with_only_a_masked_edit_is_not_neutral() {
    let graph = graph_with_mask();
    assert!(!graph.is_neutral(), "a local adjustment is still an edit");
}

/// A bare selection with nothing applied to it changes no pixel, so the image
/// is unedited — but the layer must still be written, or the selection the
/// user made is lost on reload.
#[test]
fn a_selection_with_no_adjustment_still_persists() {
    let mut graph = EditGraph::default_chain();
    graph.masks_mut().push(MaskLayer::new("m1", regions(&[9])));
    assert!(graph.is_neutral(), "no adjustment means no pixel changes");

    let restored = round_trip(&graph);
    assert_eq!(
        restored.masks().len(),
        1,
        "the selection is work and must survive even though it renders nothing"
    );
}

#[test]
fn unknown_top_level_keys_still_round_trip_alongside_masks() {
    let text = "drsc 1\n\
        \n[version default]\n\
        name = Default\n\
        revision = 1\n\
        modified = 0\n\
        future.thing = 3\n\
        \n[mask default m1]\n\
        source = regions\n\
        signature = 1\n\
        level = 1\n\
        regions = 2\n\
        exposure.exposure = 1\n";

    let out = Sidecar::parse(text).expect("parse").to_text();
    assert!(
        out.contains("future.thing"),
        "unknown keys are still preserved"
    );
    assert!(out.contains("[mask default m1]"));
}

// ---------------------------------------------------------------------------
// Brush strokes
// ---------------------------------------------------------------------------

/// One gesture to paint: whether it erases, its radius, and its path.
type Gesture = (bool, f32, Vec<(f32, f32)>);

/// Paint gestures onto a fresh brush layer.
fn brushed(id: &str, gestures: &[Gesture]) -> MaskLayer {
    let mut layer = MaskLayer::new(id, MaskSource::brush());
    layer.set_param("exposure", ParamId("exposure"), 1.0);
    for (erase, radius, path) in gestures {
        layer.begin_stroke(*erase, *radius, 0.5, 1.0);
        for &(x, y) in path {
            layer.extend_stroke(x, y);
        }
        layer.end_stroke();
    }
    layer
}

/// The whole point of storing strokes as parameters: they must come back as
/// the *same numbers*, not as numbers that render similarly. A coordinate that
/// drifts in the sixth decimal on every save is a file that never stops
/// changing, and under per-field merge that is a conflict a day.
#[test]
fn strokes_survive_a_round_trip_exactly() {
    let mut graph = EditGraph::default_chain();
    let painted = brushed(
        "m1",
        &[(
            false,
            0.0625,
            vec![(0.1234, 0.5), (0.4, 0.2), (0.8, 0.75), (0.9, 0.1)],
        )],
    );
    let expected = painted.strokes().to_vec();
    graph.masks_mut().push(painted);

    let restored = round_trip(&graph);
    let layer = &restored.masks().layers()[0];
    assert_eq!(layer.strokes(), expected.as_slice());
}

/// Order is the mask. An erase written before the add it was meant to cut into
/// would silently repaint what the user removed — the mask still looks like a
/// mask, so nothing announces it.
#[test]
fn stroke_order_and_direction_survive() {
    let mut graph = EditGraph::default_chain();
    graph.masks_mut().push(brushed(
        "m1",
        &[
            (false, 0.2, vec![(0.2, 0.5), (0.8, 0.5)]),
            (true, 0.1, vec![(0.5, 0.5)]),
        ],
    ));

    let restored = round_trip(&graph);
    let strokes = restored.masks().layers()[0].strokes();
    assert_eq!(strokes.len(), 2);
    assert!(!strokes[0].erase, "the add must still come first");
    assert!(strokes[1].erase, "and the erase second");
    assert_eq!(strokes[1].radius, 0.1, "each stroke keeps its own brush");
}

#[test]
fn a_brush_layer_writes_one_line_per_stroke() {
    let mut graph = EditGraph::default_chain();
    graph.masks_mut().push(brushed(
        "m1",
        &[
            (false, 0.05, vec![(0.2, 0.5), (0.8, 0.5)]),
            (true, 0.05, vec![(0.5, 0.5)]),
        ],
    ));

    let mut sidecar = Sidecar::new();
    sidecar.put(Version::from_graph("default", "Default", &graph));
    let text = sidecar.to_text();

    let lines: Vec<&str> = text
        .lines()
        .filter(|l| l.starts_with("stroke = "))
        .collect();
    assert_eq!(
        lines,
        [
            "stroke = add 0.05 0.5 1 0.2,0.5 0.8,0.5",
            "stroke = erase 0.05 0.5 1 0.5,0.5"
        ]
    );
}

#[test]
fn writing_a_painted_mask_twice_is_byte_identical() {
    let mut graph = EditGraph::default_chain();
    graph.masks_mut().push(brushed(
        "m1",
        &[(false, 0.05, vec![(0.2, 0.5), (0.4, 0.6), (0.8, 0.5)])],
    ));

    let mut sidecar = Sidecar::new();
    sidecar.put(Version::from_graph("default", "Default", &graph));
    let once = sidecar.to_text();
    let twice = Sidecar::parse(&once).expect("reparse").to_text();
    assert_eq!(once, twice);
}

/// One damaged line must not cost the strokes either side of it. Refusing the
/// whole layer would throw away a mask over a typo, and guessing at the missing
/// half would put paint where nobody touched.
#[test]
fn a_malformed_stroke_costs_only_that_stroke() {
    let text = "drsc 1\n\
        \n[version default]\n\
        name = Default\n\
        revision = 1\n\
        modified = 0\n\
        \n[mask default m1]\n\
        source = brush\n\
        stroke = add 0.05 0.5 1 0.2,0.5\n\
        stroke = sideways 0.05 0.5 1 0.3,0.5\n\
        stroke = add 0.05 0.5 1 0.4 0.5\n\
        stroke = add 0.05 0.5 1 0.6,0.5\n\
        exposure.exposure = 1\n";

    let parsed = Sidecar::parse(text).expect("parse");
    let strokes = parsed.versions["default"].masks.layers()[0].strokes();
    assert_eq!(strokes.len(), 2, "the two readable strokes survived");
    assert_eq!(strokes[0].points, vec![(0.2, 0.5)]);
    assert_eq!(
        strokes[1].points,
        vec![(0.6, 0.5)],
        "a point without its comma is refused rather than read as one number"
    );
}

/// A brush layer with nothing painted on it is still work — the user made the
/// layer and set its adjustment — and must not disappear because it happens to
/// render nothing yet.
#[test]
fn an_unpainted_brush_layer_still_persists() {
    let mut graph = EditGraph::default_chain();
    let mut layer = MaskLayer::new("m1", MaskSource::brush());
    layer.set_param("exposure", ParamId("exposure"), 1.0);
    graph.masks_mut().push(layer);

    let restored = round_trip(&graph);
    assert_eq!(restored.masks().len(), 1);
    assert_eq!(restored.masks().layers()[0].source, MaskSource::brush());
}

// ---------------------------------------------------------------------------
// Sync merge (FR-NC-9)
// ---------------------------------------------------------------------------

fn version_with(uuid: &str, revision: u64, build: impl FnOnce(&mut EditGraph)) -> Version {
    let mut graph = EditGraph::default_chain();
    build(&mut graph);
    let mut v = Version::from_graph(uuid, "Default", &graph);
    v.revision = revision;
    v
}

fn lit(id: &str, ids: &[u32], ev: f32) -> MaskLayer {
    let mut layer = MaskLayer::new(id, regions(ids));
    layer.set_param("exposure", ParamId("exposure"), ev);
    layer
}

/// The case the whole key-wise merge exists for, one level up: a layer added
/// on the phone and a layer added on the desktop are not a conflict.
#[test]
fn disjoint_layers_from_two_devices_both_survive() {
    let base = version_with("default", 1, |_| {});

    let mut ours = version_with("default", 2, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });
    let theirs = version_with("default", 2, |g| {
        g.masks_mut().push(lit("m2", &[2], -1.0));
    });

    let conflicts = ours.merge(&theirs, Some(&base));
    assert!(conflicts.is_empty(), "different layers are not a conflict");
    assert_eq!(ours.masks.len(), 2);
    assert!(ours.masks.get("m1").is_some());
    assert!(ours.masks.get("m2").is_some());
}

#[test]
fn a_layer_only_the_remote_added_arrives() {
    let base = version_with("default", 1, |_| {});
    let mut ours = version_with("default", 2, |_| {});
    let theirs = version_with("default", 3, |g| {
        g.masks_mut().push(lit("m1", &[5], 2.0));
    });

    assert!(ours.merge(&theirs, Some(&base)).is_empty());
    assert_eq!(ours.masks.len(), 1);
}

#[test]
fn both_editing_one_layer_is_a_conflict_resolved_by_revision() {
    let base = version_with("default", 1, |g| {
        g.masks_mut().push(lit("m1", &[1], 0.5));
    });

    let mut ours = version_with("default", 2, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });
    let theirs = version_with("default", 9, |g| {
        g.masks_mut().push(lit("m1", &[1], -1.0));
    });

    let conflicts = ours.merge(&theirs, Some(&base));
    assert_eq!(conflicts, vec![("mask".to_string(), "m1".to_string())]);

    let layer = ours.masks.get("m1").expect("layer survived");
    let ev = layer
        .ops
        .iter()
        .find(|o| o.descriptor().id.0 == "exposure")
        .map(|o| o.param(ParamId("exposure")));
    assert_eq!(ev, Some(-1.0), "the higher revision wins the layer whole");
}

/// A layer deleted on one device and untouched on the other must stay
/// deleted, or a mask the user removed reappears on every sync.
#[test]
fn a_remote_deletion_is_honoured() {
    let base = version_with("default", 1, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });
    let mut ours = version_with("default", 2, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });
    let theirs = version_with("default", 3, |_| {});

    assert!(ours.merge(&theirs, Some(&base)).is_empty());
    assert!(ours.masks.is_empty(), "the deletion should not be undone");
}

#[test]
fn an_untouched_layer_is_left_alone() {
    let base = version_with("default", 1, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });
    let mut ours = version_with("default", 2, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
        g.masks_mut().push(lit("m2", &[2], 0.5));
    });
    let theirs = version_with("default", 3, |g| {
        g.masks_mut().push(lit("m1", &[1], 1.0));
    });

    assert!(ours.merge(&theirs, Some(&base)).is_empty());
    assert_eq!(ours.masks.len(), 2, "our new layer is not a conflict");
}

/// Print a real sidecar carrying a subject mask, for eyeballing the format.
///
/// Ignored because it asserts nothing — it exists so the on-disk shape can be
/// looked at without reverse-engineering it from the writer.
///
/// ```sh
/// cargo test -p dr-pipeline --test mask_sidecar show_a_sidecar -- --ignored --nocapture
/// ```
#[test]
#[ignore = "prints the format rather than checking it"]
fn show_a_sidecar() {
    let mut graph = EditGraph::default_chain();
    graph.set_param(dr_pipeline::OpId("exposure"), ParamId("exposure"), 0.35);

    let mut subject = MaskLayer::new(
        "m1",
        MaskSource::Subject {
            signature: 0x9f2c_41aa,
            index: 0,
            class: "person".into(),
            score: 0.94,
        },
    );
    subject.name = "person".into();
    subject.invert = true;
    subject.feather = 0.02;
    subject.falloff = dr_pipeline::mask::Falloff::Gaussian;
    subject.morphology = dr_pipeline::mask::Morphology::Dilate;
    subject.morph_radius = 0.012;
    subject.set_param("saturation", ParamId("saturation"), -100.0);
    subject.set_param("exposure", ParamId("exposure"), -0.4);
    graph.masks_mut().push(subject);

    let mut grad = MaskLayer::new(
        "m2",
        MaskSource::Linear {
            centre: (0.5, 0.25),
            // The constant rather than four digits of it: clippy rejects the
            // literal, and a quarter turn written as a number is a quarter
            // turn nobody can see at a glance.
            angle: std::f32::consts::FRAC_PI_2,
            width: 0.4,
        },
    );
    grad.set_param("exposure", ParamId("exposure"), -0.6);
    graph.masks_mut().push(grad);

    let mut brush = brushed(
        "m3",
        &[
            (false, 0.06, vec![(0.31, 0.44), (0.35, 0.46), (0.4, 0.52)]),
            (true, 0.03, vec![(0.36, 0.47)]),
        ],
    );
    brush.name = "dodge".into();
    graph.masks_mut().push(brush);

    let mut sidecar = Sidecar::new();
    let mut v = Version::from_graph("default", "Default", &graph);
    v.is_default = true;
    v.rating = 4;
    sidecar.put(v);

    println!("\n{}", sidecar.to_text());
}