use super::align::choice;
use super::{Document, EngineError, Node, NodeId, NodeKind, Result, Session, Value, bad, id_param, json, ok, selected_roots};

pub(super) enum Arrange {
    Front,
    Forward,
    Backward,
    Back,
}

pub(super) fn arrange(s: &mut Session, how: Arrange) -> Result<Value> {
    let mut ids = selected_roots(s)?;
    if matches!(how, Arrange::Forward | Arrange::Front) {
        ids.reverse();
    }
    let label = match how {
        Arrange::Front => "Bring to Front",
        Arrange::Forward => "Bring Forward",
        Arrange::Backward => "Send Backward",
        Arrange::Back => "Send to Back",
    };
    // When nothing changes order, the document and its undo history stay as they are.
    crate::cmd::overprint::edit_counted(s, label, |d| {
        let mut moved = 0;
        // Arrange within each parent independently (selections may span layers/groups).
        let mut by_parent: Vec<(Option<vectorcraft_doc::NodeId>, Vec<vectorcraft_doc::NodeId>)> = vec![];
        for id in &ids {
            let par = d.parent_of(*id);
            match by_parent.iter_mut().find(|(p, _)| *p == par) {
                Some((_, v)) => v.push(*id),
                None => by_parent.push((par, vec![*id])),
            }
        }
        for (par, mut group) in by_parent {
            // In a clip group or a clipping layer the bottom child is the clipping path: it stays
            // there, and the art above it never goes below it (#3188).
            let floor = usize::from(par.and_then(|p| d.node(p)).is_some_and(vectorcraft_doc::Node::clips));
            if floor > 0 {
                group.retain(|id| d.position(*id).is_some_and(|(_, idx, _)| idx >= floor));
            }
            for (k, id) in group.iter().enumerate() {
                let Some((_, idx, len)) = d.position(*id) else { continue };
                if len <= floor {
                    continue;
                }
                let last = len - 1;
                let to = match how {
                    Arrange::Front => last.saturating_sub(k).max(floor),
                    Arrange::Back => (floor + k).min(last),
                    Arrange::Forward => (idx + 1).min(last.saturating_sub(k)).max(idx),
                    Arrange::Backward => idx.saturating_sub(1).max(floor + k.min(idx.saturating_sub(floor))),
                };
                if to != idx {
                    d.move_node(*id, par, to)?;
                    moved += 1;
                }
            }
        }
        Ok(moved)
    })?;
    ok()
}

pub(super) fn send_to_current_layer(s: &mut Session, _: &Value) -> Result<Value> {
    let ids = selected_roots(s)?;
    // Ids are reused after undo: the remembered current layer must still be a layer.
    let st = s.doc()?;
    let layer = st.current_layer().or_else(|| st.doc.default_layer()).ok_or_else(|| EngineError::Other("no current layer".into()))?;
    // When the current layer is hidden or locked, or is inside a hidden or locked layer, the
    // command fails with the error that `DocState::target_parent` gives for new art.
    if !st.doc.is_editable(layer) {
        return Err(EngineError::Other("the target layer is locked or hidden".into()));
    }
    // When the selected objects are already the topmost in the current layer, in paint order, the
    // document and its undo history stay as they are.
    if st.doc.children(Some(layer)).is_some_and(|c| c.iter().rev().map(|n| n.id).take(ids.len()).eq(ids.iter().rev().copied())) {
        return ok();
    }
    s.edit("Send to Current Layer", |d, _| {
        let moved = d.remove_many(&ids)?;
        d.children_mut(Some(layer))?.extend(moved);
        Ok(())
    })?;
    ok()
}

pub(super) fn group(s: &mut Session, _: &Value) -> Result<Value> {
    let ids = selected_roots(s)?;
    let gid = s.edit("Group", |d, sel| {
        let gid = group_nodes(d, &ids)?;
        sel.set([gid]);
        Ok(gid)
    })?;
    Ok(json!({ "id": gid.0 }))
}

/// Put `ids` (top-level objects, in paint order) in a new group where the front-most one was.
pub(crate) fn group_nodes(d: &mut Document, ids: &[NodeId]) -> Result<NodeId> {
    if ids.is_empty() {
        return Err(EngineError::Other("nothing selected".into()));
    }
    let gid = d.alloc_id();
    Ok(d.wrap(ids, |children| Node::group(gid, children))?)
}

pub(super) fn ungroup(s: &mut Session, _: &Value) -> Result<Value> {
    let ids = selected_roots(s)?;
    // With no group selected, the document, the selection and the undo history stay as they are.
    let d = &s.doc()?.doc;
    if !ids.iter().any(|id| d.node(*id).is_some_and(|n| matches!(n.kind, NodeKind::Group { .. }))) {
        return ok();
    }
    s.edit("Ungroup", |d, sel| {
        let mut new_sel = vec![];
        let mut ungrouped = vec![];
        for id in &ids {
            let Some(n) = d.node(*id) else { continue };
            let NodeKind::Group { children, clip } = &n.kind else {
                new_sel.push(*id);
                continue;
            };
            let mut out = Vec::with_capacity(children.len());
            for (k, c) in children.iter().enumerate() {
                let mut c = (**c).clone();
                // The clipping path keeps its paint (none, unless painted after Make).
                if *clip
                    && k == 0
                    && let NodeKind::Path { clipping, .. } = &mut c.kind
                {
                    *clipping = false;
                }
                // Each member keeps its own opacity; the group's opacity goes with the group.
                new_sel.push(c.id);
                out.push(c);
            }
            ungrouped.push((*id, out));
        }
        d.insert_beside(ungrouped, true)?;
        sel.set(new_sel);
        Ok(())
    })?;
    ok()
}

pub(super) fn lock(s: &mut Session, _: &Value) -> Result<Value> {
    let ids = selected_lock_hide_roots(s)?;
    // With every selected object already locked, the document and its undo history stay as they
    // are, and the objects are deselected.
    let d = &s.doc()?.doc;
    if ids.iter().all(|id| d.node(*id).is_none_or(|n| n.locked)) {
        s.select(|_, sel| sel.clear())?;
        return ok();
    }
    s.edit("Lock", |d, sel| {
        for id in &ids {
            if let Some(n) = d.node_mut(*id) {
                n.locked = true;
            }
        }
        sel.clear();
        Ok(())
    })?;
    ok()
}

/// The selected objects ([`selected_roots`]) that Lock › Selection and Hide › Selection change: in
/// isolation mode, only those inside the isolated object, where a path of the isolated compound
/// path is an object of its own.
fn selected_lock_hide_roots(s: &Session) -> Result<Vec<NodeId>> {
    match crate::cmd::ordinary_isolation(s.doc()?) {
        Some(root) => crate::cmd::edit::selected_roots_inside(s, root, false),
        None => selected_roots(s),
    }
}

fn collect_flag(d: &Document, f: impl Fn(&Node) -> bool) -> Vec<NodeId> {
    let mut v = vec![];
    d.walk(|n| {
        if !n.is_layer() && f(n) {
            v.push(n.id)
        }
    });
    v
}

/// The objects that `f` picks for `object.unlockAll` and `object.showAll` (`cmd`): in the whole
/// document, inside the isolated object in isolation mode, or with `scope: "group"` inside the
/// groups that hold the selected objects (in isolation mode, only the objects of those groups
/// that are inside the isolated object). A selected group is the group that holds its own
/// members, and the objects of a group inside another such group are taken once. With
/// `scope: "group"` and no selected object in a group, it returns an error.
fn collect_flag_in_scope(s: &Session, cmd: &str, p: &Value, f: impl Fn(&Node) -> bool) -> Result<Vec<NodeId>> {
    let st = s.doc()?;
    let d = &st.doc;
    if choice(p, cmd, "scope", &["document", "group"])? != Some("group") {
        if let Some(root) = crate::cmd::ordinary_isolation(st) {
            let mut ids = vec![];
            if let Some(node) = d.node(root) {
                for child in node.children().into_iter().flatten() {
                    child.walk(&mut |n| {
                        if !n.is_layer() && f(n) {
                            ids.push(n.id);
                        }
                    });
                }
            }
            return Ok(ids);
        }
        return Ok(collect_flag(d, f));
    }
    let is_group = |id: &NodeId| d.node(*id).is_some_and(|n| matches!(n.kind, NodeKind::Group { .. }));
    let mut groups: Vec<NodeId> = st.selection.objects.iter().filter_map(|id| d.ancestry(*id)?.into_iter().rev().find(is_group)).collect();
    groups.sort();
    groups.dedup();
    if groups.is_empty() {
        return Err(EngineError::Other("nothing selected is in a group".into()));
    }
    let mut v = vec![];
    for g in &groups {
        if d.ancestry(*g).is_some_and(|a| a.iter().any(|up| up != g && groups.contains(up))) {
            continue;
        }
        for c in d.node(*g).and_then(Node::children).into_iter().flatten() {
            c.walk(&mut |n| {
                if !n.is_layer() && f(n) {
                    v.push(n.id)
                }
            });
        }
    }
    // In isolation mode only the objects inside the isolated object are taken.
    if let Some(root) = crate::cmd::ordinary_isolation(st) {
        v.retain(|id| crate::cmd::inside_isolation(d, root, *id));
    }
    Ok(v)
}

pub(super) fn unlock_all(s: &mut Session, p: &Value) -> Result<Value> {
    let ids = collect_flag_in_scope(s, "object.unlockAll", p, |n| n.locked)?;
    // With nothing locked, the document, the selection and the undo history stay as they are.
    if ids.is_empty() {
        return Ok(json!({ "count": 0 }));
    }
    s.edit("Unlock All", |d, sel| {
        for id in &ids {
            if let Some(n) = d.node_mut(*id) {
                n.locked = false;
            }
        }
        sel.set(ids.iter().copied());
        Ok(())
    })?;
    Ok(json!({ "count": ids.len() }))
}

pub(super) fn hide(s: &mut Session, _: &Value) -> Result<Value> {
    let ids = selected_lock_hide_roots(s)?;
    // With every selected object already hidden, the document and its undo history stay as they
    // are, and the objects are deselected.
    let d = &s.doc()?.doc;
    if ids.iter().all(|id| d.node(*id).is_none_or(|n| !n.visible)) {
        s.select(|_, sel| sel.clear())?;
        return ok();
    }
    s.edit("Hide", |d, sel| {
        for id in &ids {
            if let Some(n) = d.node_mut(*id) {
                n.visible = false;
            }
        }
        sel.clear();
        Ok(())
    })?;
    ok()
}

pub(super) fn show_all(s: &mut Session, p: &Value) -> Result<Value> {
    let ids = collect_flag_in_scope(s, "object.showAll", p, |n| !n.visible)?;
    // With nothing hidden, the document, the selection and the undo history stay as they are.
    if ids.is_empty() {
        return Ok(json!({ "count": 0 }));
    }
    s.edit("Show All", |d, sel| {
        for id in &ids {
            if let Some(n) = d.node_mut(*id) {
                n.visible = true;
            }
        }
        sel.set(ids.iter().copied());
        Ok(())
    })?;
    Ok(json!({ "count": ids.len() }))
}

pub(super) fn isolate(s: &mut Session, p: &Value) -> Result<Value> {
    let id = id_param(p, "id")
        .or_else(|| s.active().and_then(|d| d.selection.objects.first().copied()))
        .ok_or_else(|| bad("object.isolate", "missing id"))?;
    let guides_locked = s.menu.guides_locked;
    let (isolation, prev) = {
        let st = s.doc_mut()?;
        // Groups, layers and single objects (a path, a compound path, an image…); type isn't
        // isolated: a double-click on it edits its text.
        if matches!(st.doc.node(id).ok_or(EngineError::NoNode(id))?.kind, NodeKind::Text(_)) {
            return Err(bad("object.isolate", "type objects can't be isolated"));
        }
        let isolation =
            st.doc.node(id).filter(|n| n.extras().shaper.is_some()).and_then(|n| n.children()).and_then(|c| c.first()).map_or(id, |n| n.id);
        // A hidden or locked object, one in a hidden or locked group or layer, and a guide path while
        // Lock Guides is on aren't isolated either: a click with the Selection tool doesn't select them.
        // A Shaper Group isolates its source group, so that group is the one checked.
        if !st.doc.is_editable(isolation) {
            return Err(bad("object.isolate", "the object is hidden or locked"));
        }
        if guides_locked && crate::is_guide_path(&st.doc, isolation) {
            return Err(EngineError::Other("guides are locked".into()));
        }
        (isolation, st.isolation)
    };
    if let Some(prev) = prev
        && prev != isolation
    {
        crate::cmd::settle_interaction(s)?;
        let st = s.doc_mut()?;
        crate::cmd::distortcmds::finish_edit_text(st, prev);
    }
    let st = s.doc_mut()?;
    st.isolation = Some(isolation);
    st.selection.clear();
    // New art on a locked artboard, now deselected, is protected.
    st.sync_new_art();
    st.revision += 1;
    ok()
}

pub(super) fn exit_isolation(s: &mut Session, p: &Value) -> Result<Value> {
    // Opacity mask editing, pattern editing and symbol editing isolate their editing layer. Leaving
    // isolation mode then leaves that mode, as Stop Editing Opacity Mask and the isolation bar's
    // Done do. A group isolated inside the symbol's art goes back to the symbol's layer.
    let st = s.doc()?;
    if let Some(layer) = st.doc.symbol_edit.as_ref().map(|e| e.layer)
        && let Some(inner) = st.isolation.filter(|i| *i != layer)
    {
        crate::cmd::settle_interaction(s)?;
        let st = s.doc_mut()?;
        crate::cmd::distortcmds::finish_edit_text(st, inner);
        st.isolation = Some(layer);
        st.selection.set([inner]);
        st.revision += 1;
        return ok();
    }
    let leave_mode: Option<fn(&mut Session, &Value) -> Result<Value>> = if st.doc.mask_edit.is_some() {
        Some(crate::cmd::maskedit::leave)
    } else if st.doc.pattern_edit.is_some() {
        Some(crate::cmd::patterncmds::pattern_done)
    } else if st.doc.symbol_edit.is_some() {
        Some(crate::cmd::symboledit::leave)
    } else {
        None
    };
    if let Some(leave_mode) = leave_mode {
        if let Some(i) = st.isolation {
            crate::cmd::distortcmds::finish_edit_text(s.doc_mut()?, i);
        }
        leave_mode(s, p)?;
        return ok();
    }
    let menu = s.menu.clone();
    let prev = s.active().and_then(|d| d.isolation);
    if let Some(i) = prev {
        crate::cmd::settle_interaction(s)?;
        let st = s.doc_mut()?;
        st.isolation = None;
        crate::cmd::distortcmds::finish_edit_text(st, i);
        let target = st.doc.parent_of(i).filter(|p| st.doc.node(*p).is_some_and(|n| n.extras().shaper.is_some())).unwrap_or(i);
        st.selection.set([target]);
        // A guide path isolated while Lock Guides is on isn't selected (#1534).
        crate::deselect_hidden(&menu, &st.doc, &mut st.selection);
        // The art on a locked artboard can't be selected.
        st.protect_locked_artboards(&[], &Default::default(), None);
    }
    let st = s.doc_mut()?;
    st.revision += 1;
    ok()
}