// Group a node's sub-objects by KIND (the SLOT side of SLOT.SUBTYPE in the AST).
// Per the editor design: items sharing a kind share one pane; different kinds
// produce separate panes whose handles render in the AppShell bottom bar.
// Each group is { kind, items: [{ kind, node, label, hasChildren, readOnly? }] }.
// The returned order is the display order for the handle bar.

export const KIND_LABEL = {
    tuning:     'TU',
    stage:      'ST',
    instrument: 'IN',
    articles:   'AR',
    bar:        'BA',
    variation:  'VR',
    label_spec: 'LA',
    voice:      'VO',
    motif:      'MO',
    offset:     'OF',
    stem_note:  'SN',
};

export function getKindGroups(node) {
    if (!node) return [];

    if (node.type === 'score') {
        const groups = [];

        if (node.tuning) {
            groups.push({ kind: 'tuning', items: [
                { kind: 'tuning', node: node.tuning, label: `base ${node.tuning.base ?? '?'}`, hasChildren: false },
            ]});
        }

        const stage = [];
        if (node.stageCone) stage.push({ kind: 'stage', node: node.stageCone, label: 'cone (orchestra)', hasChildren: false });
        for (const sv of (node.stageVoices ?? []))
            stage.push({ kind: 'stage', node: sv, label: sv.name, hasChildren: false });
        if (stage.length) groups.push({ kind: 'stage', items: stage });

        if (node.instruments.length) {
            groups.push({ kind: 'instrument', items: node.instruments.map(i => ({
                kind: 'instrument', node: i, label: i.name, hasChildren: !i.isLinked, readOnly: i.isLinked,
            }))});
        }

        if ((node.articles ?? []).length) {
            groups.push({ kind: 'articles', items: node.articles.map(a => ({
                kind: 'articles', node: a, label: `${a.subtype}: ${a.name}`, hasChildren: false,
            }))});
        }

        if (node.bars.length) {
            groups.push({ kind: 'bar', items: node.bars.map(b => ({
                kind: 'bar', node: b, label: b.id, hasChildren: Object.keys(b.voices).length > 0,
            }))});
        }

        return groups;
    }

    if (node.type === 'instrument') {
        if (!node.variations.length) return [];
        return [{ kind: 'variation', items: node.variations.map((v, idx) => ({
            kind: 'variation', node: v,
            label: `variation ${idx + 1}${v.dependsOn ? ` (${v.dependsOn})` : ''}`,
            hasChildren: true,
        }))}];
    }

    if (node.type === 'variation') {
        const groups = [];
        if (node.labelSpecs.length) {
            groups.push({ kind: 'label_spec', items: node.labelSpecs.map(ls => ({
                kind: 'label_spec', node: ls, label: ls.label ?? '(no label)', hasChildren: false,
            }))});
        }
        if (node.subvariations.length) {
            groups.push({ kind: 'variation', items: node.subvariations.map((sv, idx) => {
                const dep = sv.dependsOn;
                const label = dep == null ? `subvariation ${idx + 1}`
                    : isNaN(Number(dep)) ? `ATTR: ${dep}`
                    : String(dep);
                return { kind: 'variation', node: sv, label, hasChildren: true };
            })});
        }
        return groups;
    }

    if (node.type === 'bar') {
        const entries = Object.entries(node.voices);
        if (!entries.length) return [];
        return [{ kind: 'voice', items: entries.map(([name, v]) => ({
            kind: 'voice', node: v, label: name,
            hasChildren: v.offsets.length > 0 || v.motifs.some(m => m.isStatic),
        }))}];
    }

    if (node.type === 'voice') {
        const groups = [];
        const staticMotifs = node.motifs.filter(m => m.isStatic);
        if (staticMotifs.length) {
            groups.push({ kind: 'motif', items: staticMotifs.map(m => ({
                kind: 'motif', node: m, label: m.label, hasChildren: m.stemNotes.length > 0,
            }))});
        }
        if (node.offsets.length) {
            groups.push({ kind: 'offset', items: node.offsets.map((o, idx) => ({
                kind: 'offset', node: o, label: `tick ${o.tick ?? idx}`, hasChildren: o.stemNotes.length > 0,
            }))});
        }
        return groups;
    }

    if (node.type === 'motif' || node.type === 'offset') {
        if (!node.stemNotes.length) return [];
        return [{ kind: 'stem_note', items: node.stemNotes.map(sn => ({
            kind: 'stem_note', node: sn,
            label: `pitch ${sn.pitch}${sn.clauses.length ? ` (${sn.clauses.length} clause${sn.clauses.length > 1 ? 's' : ''})` : ''}`,
            hasChildren: false,
        }))}];
    }

    return [];
}