//! TRACES: FR-DEV-8 | FR-NC-9
//! Repairs must survive the sidecar, and survive two devices.
//!
//! The sidecar is the authoritative store (ARCH §6.12), so a spot that does not
//! round-trip is not a persistence bug but lost work — and a spot that
//! round-trips *nearly* is worse than one that fails, because a disc copied
//! from slightly the wrong place looks like a damaged file rather than like a
//! feature that did not run.

use dr_pipeline::spot::{Spot, SpotMode, DEFAULT_RADIUS};
use dr_pipeline::{EditGraph, Sidecar, Version};

fn spot_at(centre: (f32, f32), offset: (f32, f32)) -> Spot {
    Spot::new(centre, offset, DEFAULT_RADIUS)
}

/// A graph carrying three repairs: the default kind, a clone, and one switched
/// off — which between them cover every field the line format carries.
fn graph_with_spots() -> EditGraph {
    let mut graph = EditGraph::default_chain();

    graph
        .spots_mut()
        .place(spot_at((0.25, 0.75), (0.08, -0.02)));

    let mut cloned = spot_at((0.6, 0.4), (-0.12, 0.05));
    cloned.mode = SpotMode::Clone;
    cloned.set_feather(0.0);
    cloned.set_opacity(0.5);
    graph.spots_mut().place(cloned);

    let mut off = spot_at((0.1, 0.1), (0.2, 0.2));
    off.enabled = false;
    graph.spots_mut().place(off);

    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)
        .expect_no_film();
    restored
}

#[test]
fn every_field_of_every_repair_comes_back() {
    let graph = graph_with_spots();
    let restored = round_trip(&graph);

    assert_eq!(
        restored.spots().spots(),
        graph.spots().spots(),
        "a repair is eight numbers and every one of them matters"
    );
}

/// The order is the order they were made in, which decides which repair lands
/// on top where two overlap and which of them may share a pass. Sorting by id
/// on the way out would look tidier and would reorder the photograph.
#[test]
fn the_order_they_were_made_in_survives() {
    let graph = graph_with_spots();
    let ids: Vec<&str> = graph
        .spots()
        .spots()
        .iter()
        .map(|s| s.id.as_str())
        .collect();
    let restored = round_trip(&graph);
    let back: Vec<&str> = restored
        .spots()
        .spots()
        .iter()
        .map(|s| s.id.as_str())
        .collect();

    assert_eq!(ids, back);
}

/// What lets a caller skip an upload by comparing content: the same edit must
/// produce the same bytes, or every save looks like a change to sync.
#[test]
fn writing_the_same_repairs_twice_is_byte_identical() {
    let graph = graph_with_spots();

    let mut a = Sidecar::new();
    a.put(Version::from_graph("default", "Default", &graph));
    let mut b = Sidecar::new();
    b.put(Version::from_graph("default", "Default", &graph));

    assert_eq!(a.to_text(), b.to_text());
}

/// A frame nobody has repaired must not grow a line, in the same way an
/// operation at neutral contributes nothing.
#[test]
fn an_unrepaired_frame_writes_no_spot_lines() {
    let mut sidecar = Sidecar::new();
    sidecar.put(Version::from_graph(
        "default",
        "Default",
        &EditGraph::default_chain(),
    ));

    assert!(!sidecar.to_text().contains("spot."));
}

/// The file is meant to be readable by a human debugging an edit that went
/// wrong, and hand-editable by one who knows what they are doing.
#[test]
fn a_hand_written_line_loads() {
    let text = "drsc 1\n\
        \n\
        [version default]\n\
        name = Default\n\
        default = 1\n\
        revision = 1\n\
        spot.abc123 = 0.4 0.6 0.02 0.5 0.1 -0.05 1 heal\n";

    let sidecar = Sidecar::parse(text).expect("parse");
    let spots = &sidecar.versions["default"].spots;

    assert_eq!(spots.len(), 1);
    let spot = &spots.spots()[0];
    assert_eq!(spot.id, "abc123");
    assert_eq!(spot.centre, (0.4, 0.6));
    assert_eq!(spot.radius, 0.02);
    assert_eq!(spot.feather, 0.5);
    assert_eq!(spot.offset, (0.1, -0.05));
    assert_eq!(spot.mode, SpotMode::Heal);
    assert!(spot.enabled);
}

/// A truncated or hand-mangled line costs that repair and not the file. The
/// alternative — refusing the version — throws away every other repair, the
/// crop and the exposure over one bad line.
#[test]
fn a_malformed_line_costs_one_repair() {
    let text = "drsc 1\n\
        \n\
        [version default]\n\
        revision = 1\n\
        exposure.exposure = 0.75\n\
        spot.good11 = 0.4 0.6 0.02 0.5 0.1 -0.05 1 heal\n\
        spot.short1 = 0.4 0.6 0.02\n\
        spot.nomode = 0.4 0.6 0.02 0.5 0.1 -0.05 1 smudge\n\
        spot.notnum = x y 0.02 0.5 0.1 -0.05 1 heal\n";

    let sidecar = Sidecar::parse(text).expect("parse");
    let version = &sidecar.versions["default"];

    assert_eq!(version.spots.len(), 1);
    assert_eq!(version.spots.spots()[0].id, "good11");
    assert_eq!(
        version.params.get(&("exposure".into(), "exposure".into())),
        Some(&0.75),
        "the rest of the edit still loaded"
    );
}

/// A field a newer build added must not cost the repair. The disc is complete
/// without it, and refusing would be a device running behind deleting work it
/// merely does not understand.
#[test]
fn a_trailing_field_from_a_newer_build_is_ignored_not_refused() {
    let text = "drsc 1\n\
        \n\
        [version default]\n\
        revision = 1\n\
        spot.abc123 = 0.4 0.6 0.02 0.5 0.1 -0.05 1 heal rotation=0.5\n";

    let sidecar = Sidecar::parse(text).expect("parse");
    assert_eq!(sidecar.versions["default"].spots.len(), 1);
}

/// A spot switched off is state the photographer set, not an absence.
#[test]
fn a_disabled_repair_stays_disabled() {
    let graph = graph_with_spots();
    let restored = round_trip(&graph);
    let off = restored.spots().spots().last().expect("three repairs");

    assert!(!off.enabled);
}

// ---------------------------------------------------------------------------
// 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
}

/// The case the id derivation exists for. Two devices, offline, each removing a
/// different mark: with counted ids both would be `spot3` and one would be
/// lost here without a word.
#[test]
fn repairs_from_two_devices_both_survive() {
    let base = version_with("default", 1, |_| {});

    let mut ours = version_with("default", 2, |g| {
        g.spots_mut().place(spot_at((0.2, 0.2), (0.05, 0.0)));
    });
    let theirs = version_with("default", 2, |g| {
        g.spots_mut().place(spot_at((0.8, 0.8), (-0.05, 0.0)));
    });

    let conflicts = ours.merge(&theirs, Some(&base));

    assert!(conflicts.is_empty(), "different marks are not a conflict");
    assert_eq!(ours.spots.len(), 2);
}

/// And the other half of that: two devices that removed *the same* piece of
/// dust agree on the id, so the merge sees one repair — which is right, because
/// it is one repair, and the alternative is the same disc drawn twice.
#[test]
fn the_same_mark_removed_on_both_devices_stays_one_repair() {
    let base = version_with("default", 1, |_| {});
    let mut ours = version_with("default", 2, |g| {
        g.spots_mut().place(spot_at((0.5, 0.5), (0.06, 0.0)));
    });
    let theirs = version_with("default", 3, |g| {
        g.spots_mut().place(spot_at((0.5, 0.5), (0.06, 0.0)));
    });

    let conflicts = ours.merge(&theirs, Some(&base));

    assert!(
        conflicts.is_empty(),
        "the same repair is not a disagreement"
    );
    assert_eq!(ours.spots.len(), 1);
}

/// Both devices dragging one repair's source is genuinely ambiguous: the two
/// offsets cannot be averaged into a third that either photographer wanted, so
/// the higher revision takes the spot whole.
#[test]
fn both_moving_one_repair_is_a_conflict_resolved_by_revision() {
    let placed = spot_at((0.5, 0.5), (0.06, 0.0));
    let id = placed.id.clone();

    let base = version_with("default", 1, |g| {
        g.spots_mut().place(placed.clone());
    });
    let mut ours = version_with("default", 2, |g| {
        g.spots_mut().place(placed.clone());
        g.spots_mut().get_mut(&id).unwrap().set_offset((0.2, 0.0));
    });
    let theirs = version_with("default", 5, |g| {
        g.spots_mut().place(placed.clone());
        g.spots_mut().get_mut(&id).unwrap().set_offset((0.0, -0.2));
    });

    let conflicts = ours.merge(&theirs, Some(&base));

    assert_eq!(conflicts, vec![("spot".to_string(), id.clone())]);
    assert_eq!(
        ours.spots.get(&id).map(|s| s.offset),
        Some((0.0, -0.2)),
        "the higher revision wins the repair whole"
    );
}

/// A repair deleted on one device and untouched on the other stays deleted —
/// the disjoint case again, in the direction that is easy to get backwards.
#[test]
fn a_deletion_propagates() {
    let placed = spot_at((0.5, 0.5), (0.06, 0.0));
    let id = placed.id.clone();

    let base = version_with("default", 1, |g| {
        g.spots_mut().place(placed.clone());
    });
    let mut ours = version_with("default", 2, |g| {
        g.spots_mut().place(placed.clone());
    });
    let theirs = version_with("default", 3, |_| {});

    assert!(ours.merge(&theirs, Some(&base)).is_empty());
    assert!(ours.spots.get(&id).is_none());
}