//! Effect menu commands (live effects) and Object → Expand Appearance.
//!
//! Effects are stored on the object's appearance (`appearance.effects`) and evaluated at render
//! time by `vectorcraft-effects` (re-exported by the renderer). The commands edit the objects'
//! own stacks, groups and layers included (layers through `ids`), or with `target: "contents"`
//! the objects inside them (see `appearance`).

use std::sync::Arc;

use serde_json::{Value, json};
use vectorcraft_doc::{Effect, Node, NodeKind};
use vectorcraft_geom::{FillRule, PathData};
use vectorcraft_render::effects;

use super::appearance::{ItemTarget, appearance_targets, index_param, item_target, item_target_at};
use super::*;

pub fn specs() -> Vec<CommandSpec> {
    vec![
        cmd!(
            "effect.apply",
            "Apply Effect",
            [],
            None,
            "{effect: id (see effect.list, e.g. \"stylize.dropShadow\", \"distort.roughen\", \"warp.arc\"), params?: {…} (missing keys take the dialog defaults), item?: appearance item index|null (apply to that fill/stroke only; omitted: the Appearance panel's active item, else the whole object), ids?: [..] (layers too), target?: \"object\"|\"contents\" (contents: the objects inside groups and layers)} append a live effect to each selected object's appearance (a group's or layer's apply to its members as one piece: one combined shadow) → {ids, index, item}",
            has_doc,
            apply
        ),
        cmd!(
            query "effect.list",
            "Effects",
            [],
            None,
            "{} → {catalog: [{id, label, menu, params, defaults, raster}], applied: [{id, effects, items: [{index, kind: fill|stroke, effects}]}], activeItem} for the selection",
            always,
            list
        ),
        cmd!(
            "effect.remove",
            "Remove Effect",
            [],
            None,
            "{index: int (position in the effect list), item?: appearance item index|null (that fill/stroke's effects; omitted: the active item, else the object's), ids?: [..]} → {ids}",
            has_doc,
            remove
        ),
        cmd!(
            "effect.setParams",
            "Effect Options",
            [],
            None,
            "{index: int, params?: {…} (merged into the current parameters), visible?: bool, item?: appearance item index|null (as effect.remove), ids?: [..]} → {ids}",
            has_doc,
            set_params
        ),
        cmd!(
            "effect.expandAppearance",
            "Expand Appearance",
            ["Object"],
            None,
            "{ids?: [..], target?} bake geometry effects into the paths and drop them (raster effects stay live); a group's or layer's own fills and strokes become paths among its members → {ids}",
            has_doc,
            expand_appearance
        ),
        cmd!(
            "effect.duplicate",
            "Duplicate Effect",
            [],
            None,
            "{index: int, item?: appearance item index|null (as effect.remove), ids?: [..]} insert a copy of the effect right after it → {ids}",
            has_doc,
            duplicate
        ),
        cmd!(
            "effect.move",
            "Move Effect",
            [],
            None,
            "{from: int (position in the source list), to: int (its position in the destination list afterwards), fromItem?: appearance item index|null (the source list: that fill/stroke's effects, null the object's; omitted: the active item, else the object's), toItem?: item index|null (the destination list; default: the source list), copy?: bool (copy instead of move, as Alt-dragging the row), ids?: [..]} reorder an effect or move it between the object and its fills/strokes, as one undo step → {ids, index, item}",
            has_doc,
            move_effect
        ),
    ]
}

fn ids_json(ids: &[NodeId]) -> Value {
    json!(ids.iter().map(|i| i.0).collect::<Vec<_>>())
}

/// One undo step (`label`) running `f` on the effect list `item` addresses on each target (an
/// appearance item's own effects, or the object's). Errors with `none` when `f` changed no object;
/// returns the changed ids.
fn edit_effects(
    s: &mut Session,
    p: &Value,
    item: ItemTarget,
    cmd: &str,
    label: &str,
    none: &str,
    mut f: impl FnMut(&mut Vec<Effect>) -> bool,
) -> Result<Vec<NodeId>> {
    let roots = appearance_targets(s, p)?;
    s.edit(label, |d, _| {
        let mut done = vec![];
        for id in &roots {
            let Some(n) = d.node_mut(*id) else { continue };
            let index = item.effects_item(&n.appearance, cmd)?;
            if n.appearance.effects_mut(index).is_some_and(&mut f) {
                done.push(*id);
            }
        }
        if done.is_empty() {
            return Err(EngineError::Other(none.into()));
        }
        Ok(done)
    })
}

pub(crate) fn apply(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "effect.apply";
    let id = str_param(p, "effect").or_else(|| str_param(p, "id")).ok_or_else(|| bad(C, "missing `effect` id"))?;
    let params = p.get("params").cloned().unwrap_or(Value::Null);
    if !params.is_null() && !params.is_object() {
        return Err(bad(C, "`params` must be an object"));
    }
    let effect = effects::new_effect(id, &params).ok_or_else(|| bad(C, format!("unknown effect `{id}`")))?;
    let label = effects::effect_info(id).map(|e| e.label.trim_end_matches('…').to_string()).unwrap_or_default();
    let item = item_target(s, p, C)?;
    let mut index = 0;
    let ids = edit_effects(s, p, item, C, &label, "Apply Effect: select objects", |fx| {
        fx.push(effect.clone());
        index = fx.len() - 1;
        true
    })?;
    // The item the effect landed on in the first object (the active item applies where it fits).
    let first = ids.first().and_then(|id| s.doc().ok()?.doc.node(*id));
    let landed = first.and_then(|n| item.effects_item(&n.appearance, C).ok().flatten());
    Ok(json!({ "ids": ids_json(&ids), "index": index, "item": landed }))
}

fn list(s: &mut Session, p: &Value) -> Result<Value> {
    let catalog: Vec<Value> = effects::effect_catalog()
        .into_iter()
        .map(|e| json!({"id": e.id, "label": e.label, "menu": e.menu, "params": e.params, "defaults": e.defaults, "raster": e.raster}))
        .collect();
    let mut applied = vec![];
    if s.active().is_some() {
        let fx = |e: &[Effect]| serde_json::to_value(e).unwrap_or(Value::Null);
        for id in appearance_targets(s, p)? {
            if let Some(n) = s.doc()?.doc.node(id) {
                let items: Vec<Value> = n
                    .appearance
                    .items
                    .iter()
                    .enumerate()
                    .map(|(i, it)| json!({"index": i, "kind": it.kind_name(), "effects": fx(it.effects())}))
                    .collect();
                applied.push(json!({"id": id.0, "effects": fx(&n.appearance.effects), "items": items}));
            }
        }
    }
    Ok(json!({ "catalog": catalog, "applied": applied, "activeItem": s.appearance_item() }))
}

fn remove(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "effect.remove";
    let index = index_param(p, "index", C)?;
    let item = item_target(s, p, C)?;
    let ids = edit_effects(s, p, item, C, "Remove Effect", &format!("{C}: no effect at index {index}"), |fx| {
        (index < fx.len()).then(|| fx.remove(index)).is_some()
    })?;
    Ok(json!({ "ids": ids_json(&ids) }))
}

fn duplicate(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "effect.duplicate";
    let index = index_param(p, "index", C)?;
    let item = item_target(s, p, C)?;
    let ids = edit_effects(s, p, item, C, "Duplicate Effect", &format!("{C}: no effect at index {index}"), |fx| match fx.get(index).cloned() {
        Some(e) => {
            fx.insert(index + 1, e);
            true
        }
        None => false,
    })?;
    Ok(json!({ "ids": ids_json(&ids) }))
}

fn move_effect(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "effect.move";
    let from = index_param(p, "from", C)?;
    let to = index_param(p, "to", C)?;
    let src = item_target_at(s, p, "fromItem", C)?;
    let dst = if p.get("toItem").is_some() { item_target_at(s, p, "toItem", C)? } else { src };
    let copy = p.get("copy").and_then(Value::as_bool).unwrap_or(false);
    let roots = appearance_targets(s, p)?;
    // Where the effect landed in the first object.
    let mut landed = None;
    let ids = s.edit(if copy { "Duplicate Effect" } else { "Move Effect" }, |d, _| {
        let mut done = vec![];
        for id in &roots {
            let Some(n) = d.node_mut(*id) else { continue };
            let (si, di) = (src.effects_item(&n.appearance, C)?, dst.effects_item(&n.appearance, C)?);
            let Some(fx) = n.appearance.effects_mut(si).filter(|fx| from < fx.len()) else { continue };
            let e = if copy { fx[from].clone() } else { fx.remove(from) };
            let Some(fx) = n.appearance.effects_mut(di) else { continue };
            let at = to.min(fx.len());
            fx.insert(at, e);
            landed.get_or_insert((at, di));
            done.push(*id);
        }
        if done.is_empty() {
            return Err(EngineError::Other(format!("{C}: no effect at index {from}")));
        }
        Ok(done)
    })?;
    let (index, item) = landed.unzip();
    Ok(json!({ "ids": ids_json(&ids), "index": index, "item": item.flatten() }))
}

fn set_params(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "effect.setParams";
    let index = index_param(p, "index", C)?;
    let params = p.get("params").cloned().unwrap_or(Value::Null);
    if !params.is_null() && !params.is_object() {
        return Err(bad(C, "`params` must be an object"));
    }
    let visible = p.get("visible").and_then(Value::as_bool);
    let item = item_target(s, p, C)?;
    let ids = edit_effects(s, p, item, C, "Effect Options", &format!("{C}: no effect at index {index}"), |fx| {
        let Some(e) = fx.get_mut(index) else { return false };
        if let (Value::Object(new), cur) = (&params, &mut e.params) {
            if !cur.is_object() {
                *cur = effects::merged_params(&e.id, &Value::Null);
            }
            if let Value::Object(m) = cur {
                for (k, v) in new {
                    m.insert(k.clone(), v.clone());
                }
            }
        }
        if let Some(v) = visible {
            e.visible = v;
        }
        true
    })?;
    Ok(json!({ "ids": ids_json(&ids) }))
}

/// Geometry of a path or compound path node.
fn node_geometry(n: &Node) -> Option<(PathData, FillRule)> {
    match &n.kind {
        NodeKind::Path { path, rule, guide: false, .. } => Some((path.clone(), *rule)),
        NodeKind::Compound { children, rule } => {
            Some((PathData::new(children.iter().filter_map(|c| c.path_data()).flat_map(|p| p.subpaths.iter().cloned()).collect()), *rule))
        }
        _ => None,
    }
}

/// Bake the object-level geometry effects of `id` (and, recursively, of group members). A group's
/// or layer's Pathfinder and geometry effects and its own fills and strokes become its members.
fn expand_node(d: &mut vectorcraft_doc::Document, id: NodeId, out: &mut Vec<NodeId>) {
    let Some(n) = d.node(id).cloned() else { return };
    if matches!(n.kind, NodeKind::Group { .. } | NodeKind::Layer { .. }) {
        if let Some(mut m) = effects::evaluate_container(&n) {
            let mut seen = std::collections::HashSet::from([m.id]);
            for c in m.children_mut().into_iter().flatten() {
                effects::fresh_ids(d, Arc::make_mut(c), &mut seen);
            }
            let Some(slot) = d.node_mut(id) else { return };
            *slot = m;
            out.push(id);
        }
        let children: Vec<NodeId> = d.node(id).and_then(|n| n.children()).map(|c| c.iter().map(|c| c.id).collect()).unwrap_or_default();
        for c in children {
            expand_node(d, c, out);
        }
        return;
    }
    if !effects::has_geometry(&n.appearance.effects) {
        return;
    }
    let Some((path, rule)) = node_geometry(&n) else { return };
    let Some(bounds) = path.bounds() else { return };
    let baked = effects::apply_geometry_with(&n.appearance.effects, &path, bounds, &effects::GeomContext::of(&n));
    let kind = if matches!(n.kind, NodeKind::Compound { .. }) || baked.subpaths.len() > 1 {
        let children = baked
            .subpaths
            .into_iter()
            .map(|sp| {
                let cid = d.alloc_id();
                Arc::new(Node::path(cid, PathData::single(sp), Default::default()))
            })
            .collect();
        NodeKind::Compound { children, rule }
    } else {
        NodeKind::Path { path: baked, rule, live: None, clipping: false, guide: false }
    };
    let Some(m) = d.node_mut(id) else { return };
    m.kind = kind;
    m.appearance.effects.retain(|e| !effects::is_geometry(&e.id));
    out.push(id);
}

fn expand_appearance(s: &mut Session, p: &Value) -> Result<Value> {
    let roots = appearance_targets(s, p)?;
    let ids = s.edit("Expand Appearance", |d, _| {
        let mut out = vec![];
        for id in &roots {
            expand_node(d, *id, &mut out);
        }
        if out.is_empty() {
            return Err(EngineError::Other("Expand Appearance: no geometry effects to expand".into()));
        }
        Ok(out)
    })?;
    Ok(json!({ "ids": ids_json(&ids) }))
}

#[cfg(test)]
mod tests {
    use serde_json::json;
    use vectorcraft_doc::NodeKind;

    use crate::{NodeId, Session};

    fn session_with_rect() -> (Session, NodeId) {
        let mut s = Session::new();
        s.execute("file.new", &json!({"width": 400, "height": 400})).unwrap();
        let r = s.execute("shape.rectangle", &json!({"x": 100, "y": 100, "width": 100, "height": 100})).unwrap();
        (s, NodeId(r["id"].as_u64().unwrap()))
    }

    fn node(s: &Session, id: NodeId) -> vectorcraft_doc::Node {
        s.doc().unwrap().doc.node(id).cloned().unwrap()
    }

    #[test]
    fn apply_uses_catalog_defaults_and_undoes() {
        let (mut s, id) = session_with_rect();
        let r = s.execute("effect.apply", &json!({"effect": "stylize.dropShadow", "params": {"x": 3}})).unwrap();
        assert_eq!(r["index"], json!(0));
        let n = node(&s, id);
        assert_eq!(n.appearance.effects.len(), 1);
        assert_eq!(n.appearance.effects[0].params["x"], json!(3));
        assert_eq!(n.appearance.effects[0].params["opacity"], json!(75.0));
        s.execute("edit.undo", &json!({})).unwrap();
        assert!(node(&s, id).appearance.effects.is_empty());
        assert!(s.execute("effect.apply", &json!({"effect": "nope"})).is_err());
    }

    #[test]
    fn list_remove_and_set_params() {
        let (mut s, id) = session_with_rect();
        s.execute("effect.apply", &json!({"effect": "distort.twist"})).unwrap();
        s.execute("effect.apply", &json!({"effect": "stylize.outerGlow"})).unwrap();
        let l = s.execute("effect.list", &json!({})).unwrap();
        assert!(l["catalog"].as_array().unwrap().len() >= 34);
        assert_eq!(l["applied"][0]["effects"].as_array().unwrap().len(), 2);
        s.execute("effect.setParams", &json!({"index": 0, "params": {"angle": 45}, "visible": false})).unwrap();
        let e = &node(&s, id).appearance.effects[0];
        assert_eq!(e.params["angle"], json!(45));
        assert!(!e.visible);
        s.execute("effect.remove", &json!({"index": 0})).unwrap();
        let n = node(&s, id);
        assert_eq!(n.appearance.effects.len(), 1);
        assert_eq!(n.appearance.effects[0].id, "stylize.outerGlow");
        assert!(s.execute("effect.remove", &json!({"index": 5})).is_err());
    }

    #[test]
    fn expand_appearance_bakes_geometry_and_keeps_raster() {
        let (mut s, id) = session_with_rect();
        s.execute("effect.apply", &json!({"effect": "path.offsetPath", "params": {"offset": 10}})).unwrap();
        s.execute("effect.apply", &json!({"effect": "stylize.dropShadow"})).unwrap();
        s.execute("effect.expandAppearance", &json!({})).unwrap();
        let n = node(&s, id);
        let b = n.geometric_bounds().unwrap();
        assert!((b.width() - 120.0).abs() < 0.1, "{b:?}");
        assert_eq!(n.appearance.effects.len(), 1);
        assert_eq!(n.appearance.effects[0].id, "stylize.dropShadow");
        assert!(matches!(n.kind, NodeKind::Path { live: None, .. }));
        // Nothing left to expand.
        assert!(s.execute("effect.expandAppearance", &json!({})).is_err());
    }

    #[test]
    fn expand_transform_copies_makes_compound() {
        let (mut s, id) = session_with_rect();
        s.execute("effect.apply", &json!({"effect": "distort.transform", "params": {"moveH": 120, "copies": 1}})).unwrap();
        s.execute("effect.expandAppearance", &json!({})).unwrap();
        let n = node(&s, id);
        assert!(matches!(n.kind, NodeKind::Compound { .. }));
        let b = n.geometric_bounds().unwrap();
        assert!((b.x1 - 320.0).abs() < 1e-6, "{b:?}");
    }

    #[test]
    fn pathfinder_effect_on_a_group_renders_live_and_expands() {
        let (mut s, a) = session_with_rect();
        let b = s.execute("shape.rectangle", &json!({"x": 150, "y": 100, "width": 100, "height": 100})).unwrap();
        s.execute("select.set", &json!({"ids": [a.0, b["id"]]})).unwrap();
        let g = NodeId(s.execute("object.group", &json!({})).unwrap()["id"].as_u64().unwrap());
        s.execute("effect.apply", &json!({"effect": "pathfinder.subtract"})).unwrap();
        // Live: the renderer shows only the back square minus the front one.
        let doc = s.doc().unwrap().doc.clone();
        let img = vectorcraft_render::Renderer::new().render(&doc, 400, 400, vectorcraft_geom::Affine::IDENTITY, &Default::default());
        assert!(img.pixel(125, 150)[3] > 0);
        assert_eq!(img.pixel(200, 150)[3], 0);
        s.execute("effect.expandAppearance", &json!({})).unwrap();
        let n = node(&s, g);
        assert!(n.appearance.effects.is_empty());
        let ch = n.children().unwrap();
        assert_eq!(ch.len(), 1);
        assert!((ch[0].geometric_bounds().unwrap().width() - 50.0).abs() < 1e-6);
    }
}