/* engram_geometry.c — M9 FOUNDATION: relational-neighborhood geometry descriptor.
 * See engram_geometry.h. Pure C11, stdlib + libm. READ-ONLY over store + vindex.
 */
#include "engram_geometry.h"

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdio.h>
#include <stdarg.h>
#include <time.h>

/* Must match ENGRAM_HEBB_GAIN in el_runtime.c (eff = weight*(1+GAIN*hebb)). */
#define GEO_HEBB_GAIN 0.5
/* Internal cap on the m×m Jacobi eigensolve: above this we still give centroid +
 * radius but skip principal axes (honest degradation, not a lie). */
#define GEO_EIG_CAP 512

/* ───────────────────────── small dynamic member table ──────────────────────
 * Neighborhoods are small (tens..few hundred), so linear-scan dedup is fine. */
typedef struct {
    char** id;          /* strdup'd ids                                        */
    double* memb;       /* provisional membership                              */
    float** emb;        /* L2-normalized emb copy (dim floats) or NULL         */
    double* sal;        /* stored salience                                     */
    int   n, cap, dim;
} MemSet;

static int ms_init(MemSet* s, int dim){
    s->n=0; s->cap=16; s->dim=dim;
    s->id=calloc(s->cap,sizeof*s->id); s->memb=calloc(s->cap,sizeof*s->memb);
    s->emb=calloc(s->cap,sizeof*s->emb); s->sal=calloc(s->cap,sizeof*s->sal);
    return (s->id&&s->memb&&s->emb&&s->sal)?0:-1;
}
static int ms_find(const MemSet* s, const char* id){
    for(int i=0;i<s->n;i++) if(strcmp(s->id[i],id)==0) return i;
    return -1;
}
/* Insert or bump membership (keep the max). Returns member index or <0 on OOM. */
static int ms_upsert(MemSet* s, const char* id, double memb){
    int i=ms_find(s,id);
    if(i>=0){ if(memb>s->memb[i]) s->memb[i]=memb; return i; }
    if(s->n==s->cap){
        int nc=s->cap*2;
        char** a=realloc(s->id,nc*sizeof*a); if(!a) return -1; s->id=a;
        double* b=realloc(s->memb,nc*sizeof*b); if(!b) return -1; s->memb=b;
        float** c=realloc(s->emb,nc*sizeof*c); if(!c) return -1; s->emb=c;
        double* d=realloc(s->sal,nc*sizeof*d); if(!d) return -1; s->sal=d;
        s->cap=nc;
    }
    s->id[s->n]=strdup(id); if(!s->id[s->n]) return -1;
    s->memb[s->n]=memb; s->emb[s->n]=NULL; s->sal[s->n]=0.0;
    return s->n++;
}
static void ms_free(MemSet* s){
    for(int i=0;i<s->n;i++){ free(s->id[i]); free(s->emb[i]); }
    free(s->id); free(s->memb); free(s->emb); free(s->sal);
}

/* L2-normalize a copy of v into out (dim floats). Returns 0, or -1 if ~zero. */
static int normcopy(const float* v, int dim, float* out){
    double s=0; for(int i=0;i<dim;i++) s+=(double)v[i]*v[i];
    double n=sqrt(s); if(n<1e-12) return -1;
    for(int i=0;i<dim;i++) out[i]=(float)(v[i]/n);
    return 0;
}
/* ── mean-centered cosine geometry (whitening the anisotropic emb space) ──────
 * All three operate on RAW (unnormalized-here, but member embs are already unit)
 * vectors, subtracting the global-mean offset `gm` on the fly. With gm all-zeros
 * they reduce EXACTLY to the raw unit-space cosine — so the same code path serves
 * both the centered and legacy-raw modes. */
static double cnorm2(const float* a, const float* gm, int dim){
    double s=0; for(int d=0;d<dim;d++){ double v=(double)a[d]-gm[d]; s+=v*v; } return s;
}
static double cdot(const float* a, const float* b, const float* gm, int dim){
    double s=0; for(int d=0;d<dim;d++){ double av=(double)a[d]-gm[d], bv=(double)b[d]-gm[d]; s+=av*bv; }
    return s;
}
static double ccos(const float* a, const float* b, const float* gm, int dim){
    double na=sqrt(cnorm2(a,gm,dim)), nb=sqrt(cnorm2(b,gm,dim));
    if(na<1e-12||nb<1e-12) return 0.0;
    double c=cdot(a,b,gm,dim)/(na*nb); if(c>1)c=1; if(c<-1)c=-1; return c;
}
/* cosine of (a-gm) against a pre-centered UNIT direction `dir`. */
static double ccos_dir(const float* a, const float* gm, const float* dir, int dim){
    double na=sqrt(cnorm2(a,gm,dim)); if(na<1e-12) return 0.0;
    double s=0; for(int d=0;d<dim;d++) s+=((double)a[d]-gm[d])*(double)dir[d];
    double c=s/na; if(c>1)c=1; if(c<-1)c=-1; return c;
}

/* ───────────────────────── global-mean cache ───────────────────────────────
 * Store-derived centering offset: the mean of the L2-normalized embeddings over
 * the embed-eligible set. See engram_geometry.h for the anisotropy rationale. */
struct GeoMeanCache { float* mean; int dim; uint64_t n; };

typedef struct { double* sum; int dim; uint64_t n; int err; } GeoMeanAcc;
/* The reified records (Neighborhood / GeoMeanFrame) carry an emb (centroid / mean)
 * but are STRUCTURE, not corpus content — they must never pollute the store-wide
 * mean, the hub scan, or the descriptor. One predicate, used everywhere. */
static int geo_is_reified_type(const char* nt){
    return nt && (strcmp(nt,ENGRAM_GEO_NBHD_TYPE)==0 ||
                  strcmp(nt,ENGRAM_GEO_MEANFRAME_TYPE)==0);
}
/* Identify a structural record by its id convention (no store read needed), so the
 * descriptor never admits a reified Neighborhood / GeoMeanFrame as a neighborhood
 * MEMBER even when the ANN index or adjacency still references it (re-reify/refresh
 * on a store that already holds reified records; ad-hoc descriptors alike). */
static int geo_is_structural_id(const char* id){
    if(!id) return 0;
    if(strcmp(id,ENGRAM_GEO_MEANFRAME_ID)==0) return 1;
    size_t p=strlen(ENGRAM_GEO_NBHD_ID_PREFIX);
    return strncmp(id,ENGRAM_GEO_NBHD_ID_PREFIX,p)==0;
}
static void geo_mean_cb(const StoreNode* n, void* ctx){
    GeoMeanAcc* a=ctx; if(a->err) return;
    if(geo_is_reified_type(n->node_type)) return;       /* skip structural records */
    if(!(n->emb && n->emb_dim>0)) return;               /* skip unembedded */
    if(a->dim==0){
        a->dim=n->emb_dim;
        a->sum=calloc((size_t)a->dim,sizeof(double));
        if(!a->sum){ a->err=1; return; }
    }
    if(n->emb_dim!=a->dim) return;                      /* skip off-dim */
    double s=0; for(int d=0;d<a->dim;d++) s+=(double)n->emb[d]*n->emb[d];
    double nn=sqrt(s); if(nn<1e-12) return;             /* skip ~zero */
    for(int d=0;d<a->dim;d++) a->sum[d]+=(double)n->emb[d]/nn;
    a->n++;
}
typedef struct { uint64_t n; } GeoCntAcc;
static void geo_cnt_cb(const StoreNode* n, void* ctx){
    if(n->emb && n->emb_dim>0) ((GeoCntAcc*)ctx)->n++;
}

GeoMeanCache* engram_geo_mean_build(EngramPagedStore* store){
    if(!store) return NULL;
    GeoMeanAcc a; memset(&a,0,sizeof a);
    if(store_scan_nodes(store,geo_mean_cb,&a)<0){ free(a.sum); return NULL; }
    if(a.err || a.n==0 || !a.sum){ free(a.sum); return NULL; }
    GeoMeanCache* c=calloc(1,sizeof*c);
    if(!c){ free(a.sum); return NULL; }
    c->mean=malloc((size_t)a.dim*sizeof(float));
    if(!c->mean){ free(a.sum); free(c); return NULL; }
    for(int d=0;d<a.dim;d++) c->mean[d]=(float)(a.sum[d]/(double)a.n);
    c->dim=a.dim; c->n=a.n; free(a.sum);
    return c;
}
const float* engram_geo_mean_vec(const GeoMeanCache* c){ return c?c->mean:NULL; }
int          engram_geo_mean_dim(const GeoMeanCache* c){ return c?c->dim:0; }
uint64_t     engram_geo_mean_count(const GeoMeanCache* c){ return c?c->n:0; }

int engram_geo_mean_maybe_refresh(GeoMeanCache* c, EngramPagedStore* store, double frac){
    if(!c||!store) return -1;
    GeoCntAcc cn={0};
    if(store_scan_nodes(store,geo_cnt_cb,&cn)<0) return -1;
    double base=(double)(c->n?c->n:1);
    double drift=fabs((double)cn.n-(double)c->n)/base;
    if(drift<=frac) return 0;                            /* no significant change */
    GeoMeanAcc a; memset(&a,0,sizeof a);
    if(store_scan_nodes(store,geo_mean_cb,&a)<0){ free(a.sum); return -1; }
    if(a.err || a.n==0 || !a.sum){ free(a.sum); return -1; }
    float* nm=malloc((size_t)a.dim*sizeof(float));
    if(!nm){ free(a.sum); return -1; }
    for(int d=0;d<a.dim;d++) nm[d]=(float)(a.sum[d]/(double)a.n);
    free(a.sum); free(c->mean);
    c->mean=nm; c->dim=a.dim; c->n=a.n;
    return 1;
}
void engram_geo_mean_free(GeoMeanCache* c){ if(c){ free(c->mean); free(c); } }

/* Attach a member's emb (normalized) + salience by point-reading the store. */
static void ms_load_node(MemSet* s, int i, EngramPagedStore* st){
    StoreNode nn; memset(&nn,0,sizeof nn);
    if(store_get_node(st, s->id[i], &nn)!=1){ return; }
    s->sal[i]=nn.salience;
    if(nn.emb && nn.emb_dim==s->dim){
        float* e=malloc((size_t)s->dim*sizeof(float));
        if(e && normcopy(nn.emb,s->dim,e)==0) s->emb[i]=e; else free(e);
    }
    store_node_free(&nn);
}

/* ───────────────────────── Jacobi symmetric eigensolver ─────────────────────
 * Cyclic Jacobi on a dense symmetric m×m matrix A (row-major, overwritten).
 * Eigenvalues -> w[m]; eigenvectors (columns) -> V[m*m]. Robust, libm-only. */
static void jacobi_sym(double* A, int m, double* w, double* V){
    for(int i=0;i<m;i++){ for(int j=0;j<m;j++) V[i*m+j]=(i==j)?1.0:0.0; }
    for(int sweep=0; sweep<100; sweep++){
        double off=0; for(int p=0;p<m;p++) for(int q=p+1;q<m;q++) off+=A[p*m+q]*A[p*m+q];
        if(off < 1e-18) break;
        for(int p=0;p<m;p++) for(int q=p+1;q<m;q++){
            double apq=A[p*m+q]; if(fabs(apq)<1e-300) continue;
            double app=A[p*m+p], aqq=A[q*m+q];
            double phi=0.5*atan2(2*apq, aqq-app);
            double c=cos(phi), sn=sin(phi);
            for(int k=0;k<m;k++){
                double akp=A[k*m+p], akq=A[k*m+q];
                A[k*m+p]=c*akp - sn*akq; A[k*m+q]=sn*akp + c*akq;
            }
            for(int k=0;k<m;k++){
                double apk=A[p*m+k], aqk=A[q*m+k];
                A[p*m+k]=c*apk - sn*aqk; A[q*m+k]=sn*apk + c*aqk;
            }
            for(int k=0;k<m;k++){
                double vkp=V[k*m+p], vkq=V[k*m+q];
                V[k*m+p]=c*vkp - sn*vkq; V[k*m+q]=sn*vkp + c*vkq;
            }
        }
    }
    for(int i=0;i<m;i++) w[i]=A[i*m+i];
}

void engram_geo_default_params(GeoParams* p){
    if(!p) return;
    p->ann_k=24; p->hop_relational=1; p->edge_min_weight=0.05;
    p->kcore_k=0; p->top_axes=8; p->max_members=400;
}

/* Effective hebb-weighted edge strength, matching eg_edge_eff_weight. */
static double eff_w(double weight, double hebb){
    double w = weight * (1.0 + GEO_HEBB_GAIN*hebb);
    if(w>1.0) w=1.0; if(w<0.0) w=0.0; return w;
}

GeoDescriptor* engram_geometry_descriptor(
    EngramPagedStore* store, VIndex* vindex,
    char** vids, int n_vids,
    const char* const* seed_ids, size_t n_seeds,
    const GeoParams* params,
    const float* global_mean)
{
    if(!store || !seed_ids || n_seeds==0) return NULL;
    GeoParams P; if(params) P=*params; else engram_geo_default_params(&P);

    int dim = 0;
    /* infer dim from the first embedded seed */
    for(size_t i=0;i<n_seeds && dim==0;i++){
        StoreNode nn; memset(&nn,0,sizeof nn);
        if(store_get_node(store, seed_ids[i], &nn)==1){
            if(nn.emb && nn.emb_dim>0) dim=nn.emb_dim;
        }
        store_node_free(&nn);
    }
    if(dim==0) dim = 768; /* no embedded seed: still build the relational side */

    /* Centering offset. When a global_mean is supplied the semantic cosine math
     * runs in mean-centered (isotropic) space; otherwise GM is an all-zeros
     * vector so the identical code path reproduces raw unit-space cosines. */
    int centered = (global_mean != NULL);
    float* zeros = NULL;
    const float* GM;
    if(centered) GM = global_mean;
    else { zeros = calloc((size_t)dim,sizeof(float));
           if(!zeros) return NULL; GM = zeros; }

    MemSet ms; if(ms_init(&ms,dim)!=0){ ms_free(&ms); free(zeros); return NULL; }

    /* 1. seeds (membership 1.0) */
    for(size_t i=0;i<n_seeds;i++) ms_upsert(&ms, seed_ids[i], 1.0);
    int n_seed_members = ms.n;
    for(int i=0;i<ms.n;i++) ms_load_node(&ms,i,store);

    /* provisional centroid from seed embeddings (for the ANN query) */
    float* prov = calloc((size_t)dim,sizeof(float));
    int prov_n=0;
    for(int i=0;i<n_seed_members;i++) if(ms.emb[i]){
        for(int d=0;d<dim;d++) prov[d]+=ms.emb[i][d]; prov_n++;
    }
    if(prov_n){ for(int d=0;d<dim;d++) prov[d]/=(float)prov_n; }

    /* 2. semantic expansion via vindex ANN around the provisional centroid */
    if(vindex && vids && P.ann_k>0 && prov_n>0){
        int k=P.ann_k*(int)n_seeds; if(k<P.ann_k) k=P.ann_k; if(k>n_vids) k=n_vids;
        uint64_t* rids=malloc((size_t)k*sizeof(uint64_t));
        float* dd=malloc((size_t)k*sizeof(float));
        if(rids&&dd){
            int got=vindex_search(vindex, prov, k, 0, rids, dd);
            for(int r=0;r<got;r++){
                if(rids[r]>=(uint64_t)n_vids) continue;
                if(geo_is_structural_id(vids[rids[r]])) continue; /* never a member */
                double memb = 1.0 - (double)dd[r]; /* cosine sim in [-1,1] */
                if(memb<0) memb=0;
                int mi=ms_upsert(&ms, vids[rids[r]], memb*0.9); /* <1: not a seed */
                if(mi>=0 && !ms.emb[mi]) ms_load_node(&ms,mi,store);
            }
        }
        free(rids); free(dd);
    }
    free(prov);

    /* 3. relational expansion: seeds' hebb neighbors become members */
    if(P.hop_relational){
        for(int i=0;i<n_seed_members;i++){
            StoreEdge* es=NULL; size_t ne=0;
            if(store_get_edges_from(store, ms.id[i], &es, &ne)==0 && es){
                for(size_t e=0;e<ne;e++){
                    if(es[e].tombstoned || es[e].inhibitory) continue;
                    if(es[e].relation && strcmp(es[e].relation,ENGRAM_GEO_MEMBER_RELATION)==0) continue;
                    if(geo_is_structural_id(es[e].to_id)) continue;
                    double w=eff_w(es[e].weight, es[e].hebb);
                    if(w < P.edge_min_weight) continue;
                    int mi=ms_upsert(&ms, es[e].to_id, w);
                    if(mi>=0 && !ms.emb[mi]) ms_load_node(&ms,mi,store);
                }
            }
            store_edges_free(es,ne);
            es=NULL; ne=0;
            if(store_get_edges_to(store, ms.id[i], &es, &ne)==0 && es){
                for(size_t e=0;e<ne;e++){
                    if(es[e].tombstoned || es[e].inhibitory) continue;
                    if(es[e].relation && strcmp(es[e].relation,ENGRAM_GEO_MEMBER_RELATION)==0) continue;
                    if(geo_is_structural_id(es[e].from_id)) continue;
                    double w=eff_w(es[e].weight, es[e].hebb);
                    if(w < P.edge_min_weight) continue;
                    int mi=ms_upsert(&ms, es[e].from_id, w);
                    if(mi>=0 && !ms.emb[mi]) ms_load_node(&ms,mi,store);
                }
            }
            store_edges_free(es,ne);
        }
    }

    /* optional cap: keep the highest-membership members (guards eigensolve) */
    if(P.max_members>0 && ms.n>P.max_members){
        /* simple selection: repeatedly drop the min-membership non-seed member */
        while(ms.n>P.max_members){
            int worst=-1; double wv=1e30;
            for(int i=n_seed_members;i<ms.n;i++) if(ms.memb[i]<wv){wv=ms.memb[i];worst=i;}
            if(worst<0) break;
            free(ms.id[worst]); free(ms.emb[worst]);
            ms.id[worst]=ms.id[ms.n-1]; ms.emb[worst]=ms.emb[ms.n-1];
            ms.memb[worst]=ms.memb[ms.n-1]; ms.sal[worst]=ms.sal[ms.n-1];
            ms.n--;
        }
    }

    int M = ms.n;
    /* ── final centroid over all embedded members ── */
    float* centroid=calloc((size_t)dim,sizeof(float));
    int nemb=0; int* eidx=malloc((size_t)M*sizeof(int));
    for(int i=0;i<M;i++) if(ms.emb[i]){ eidx[nemb++]=i;
        for(int d=0;d<dim;d++) centroid[d]+=ms.emb[i][d]; }
    if(nemb){ for(int d=0;d<dim;d++) centroid[d]/=(float)nemb; }

    /* ── radius + per-member cosine distance to centroid (CENTERED frame) ── */
    double total_var=0;
    double* distc=calloc((size_t)M,sizeof(double));
    /* centered centroid (= raw centroid - global mean) and its unit direction */
    float* ccen=malloc((size_t)dim*sizeof(float));
    for(int d=0;d<dim;d++) ccen[d]=centroid[d]-GM[d];
    float* cdir=malloc((size_t)dim*sizeof(float));
    int have_cdir = (nemb>0 && normcopy(ccen,dim,cdir)==0);
    for(int i=0;i<M;i++){
        if(ms.emb[i] && have_cdir){
            double cs=ccos_dir(ms.emb[i],GM,cdir,dim);
            distc[i]=1.0-cs;
        } else distc[i]=-1.0; /* unknown */
    }
    /* variance = mean squared Euclid distance of normalized embs to centroid */
    for(int j=0;j<nemb;j++){
        int i=eidx[j]; double s=0;
        for(int d=0;d<dim;d++){ double df=(double)ms.emb[i][d]-centroid[d]; s+=df*df; }
        total_var+=s;
    }
    if(nemb) total_var/=nemb;
    double radius=sqrt(total_var>0?total_var:0);

    /* ── principal axes via dual PCA (Jacobi on the m×m Gram of centered embs) ──
     * Skipped entirely when top_axes==0: the eigensolve is the dominant cost, and
     * priming needs only members+membership, so reified records that don't want the
     * ellipsoid pass top_axes=0 and pay nothing here (centroid+radius still filled). */
    int n_axes=0; GeoAxis* axes=NULL;
    if(P.top_axes>0 && nemb>=2 && nemb<=GEO_EIG_CAP){
        int m=nemb;
        /* centered, row-major m×dim */
        float* Xc=malloc((size_t)m*dim*sizeof(float));
        for(int j=0;j<m;j++){ int i=eidx[j];
            for(int d=0;d<dim;d++) Xc[(size_t)j*dim+d]=ms.emb[i][d]-centroid[d]; }
        double* G=malloc((size_t)m*m*sizeof(double));
        for(int a=0;a<m;a++) for(int b=a;b<m;b++){
            double s=0; for(int d=0;d<dim;d++) s+=(double)Xc[(size_t)a*dim+d]*Xc[(size_t)b*dim+d];
            G[a*m+b]=s; G[b*m+a]=s;
        }
        double* w=malloc((size_t)m*sizeof(double));
        double* V=malloc((size_t)m*m*sizeof(double));
        jacobi_sym(G,m,w,V);
        /* sort eigenvalue indices descending */
        int* ord=malloc((size_t)m*sizeof(int));
        for(int i=0;i<m;i++) ord[i]=i;
        for(int a=0;a<m;a++) for(int b=a+1;b<m;b++) if(w[ord[b]]>w[ord[a]]){int t=ord[a];ord[a]=ord[b];ord[b]=t;}
        int keep=P.top_axes; if(keep>m) keep=m; if(keep<0) keep=0;
        axes=calloc((size_t)keep,sizeof(GeoAxis));
        for(int t=0;t<keep;t++){
            int c=ord[t];
            double lam=w[c]; if(lam<0) lam=0;
            double eigcov = lam/(double)(m-1);   /* covariance eigenvalue */
            /* principal axis in R^dim: a = Xc^T u_c, then unit-normalize */
            float* ax=calloc((size_t)dim,sizeof(float));
            for(int d=0;d<dim;d++){ double s=0;
                for(int j=0;j<m;j++) s+=(double)V[j*m+c]*Xc[(size_t)j*dim+d];
                ax[d]=(float)s; }
            double nn=0; for(int d=0;d<dim;d++) nn+=(double)ax[d]*ax[d]; nn=sqrt(nn);
            if(nn>1e-12) for(int d=0;d<dim;d++) ax[d]=(float)(ax[d]/nn);
            axes[t].axis=ax; axes[t].extent=sqrt(eigcov);
            n_axes++;
        }
        free(Xc); free(G); free(w); free(V); free(ord);
    }

    /* ── skeleton: internal hebb edges among members + centrality gradient ── */
    GeoEdge* edges=NULL; int n_edges=0, cap_e=0;
    double* centrality=calloc((size_t)M,sizeof(double));
    int* degree=calloc((size_t)M,sizeof(int));
    /* co-registration accumulators */
    double cr_n=0, cr_sx=0, cr_sy=0, cr_sxx=0, cr_syy=0, cr_sxy=0;
    for(int i=0;i<M;i++){
        StoreEdge* es=NULL; size_t ne=0;
        if(store_get_edges_from(store, ms.id[i], &es, &ne)==0 && es){
            for(size_t e=0;e<ne;e++){
                if(es[e].tombstoned || es[e].inhibitory) continue;
                int j=ms_find(&ms, es[e].to_id);
                if(j<0 || j<=i) continue; /* internal, undirected, i<j only */
                double w=eff_w(es[e].weight, es[e].hebb);
                if(w < P.edge_min_weight) continue;
                if(n_edges==cap_e){ cap_e=cap_e?cap_e*2:32;
                    GeoEdge* t=realloc(edges,(size_t)cap_e*sizeof(GeoEdge)); if(!t) break; edges=t; }
                edges[n_edges].a=(uint32_t)i; edges[n_edges].b=(uint32_t)j;
                edges[n_edges].eff_weight=w; edges[n_edges].hebb=es[e].hebb;
                n_edges++;
                centrality[i]+=w; centrality[j]+=w; degree[i]++; degree[j]++;
                /* co-registration: relational strength vs semantic proximity
                 * (semantic proximity measured in the CENTERED frame). */
                if(ms.emb[i] && ms.emb[j]){
                    double cs=ccos(ms.emb[i],ms.emb[j],GM,dim);
                    double x=w, y=cs;
                    cr_n++; cr_sx+=x; cr_sy+=y; cr_sxx+=x*x; cr_syy+=y*y; cr_sxy+=x*y;
                }
            }
        }
        store_edges_free(es,ne);
    }
    double co_reg=0;
    if(cr_n>=2){
        double cov=cr_sxy - cr_sx*cr_sy/cr_n;
        double vx=cr_sxx - cr_sx*cr_sx/cr_n, vy=cr_syy - cr_sy*cr_sy/cr_n;
        if(vx>1e-12 && vy>1e-12) co_reg=cov/sqrt(vx*vy);
    }

    /* ── k-core: peel members by internal degree to get core numbers ── */
    int* core=calloc((size_t)M,sizeof(int));
    {
        int* deg=malloc((size_t)M*sizeof(int));
        int* removed=calloc((size_t)M,sizeof(int));
        for(int i=0;i<M;i++) deg[i]=degree[i];
        int level=0, remaining=M;
        while(remaining>0){
            int progressed=0;
            for(int i=0;i<M;i++){
                if(!removed[i] && deg[i]<=level){
                    core[i]=level; removed[i]=1; remaining--; progressed=1;
                    /* decrement neighbors' working degree */
                    for(int e=0;e<n_edges;e++){
                        int o=-1;
                        if((int)edges[e].a==i && !removed[edges[e].b]) o=edges[e].b;
                        else if((int)edges[e].b==i && !removed[edges[e].a]) o=edges[e].a;
                        if(o>=0) deg[o]--;
                    }
                }
            }
            if(!progressed) level++;
        }
        free(deg); free(removed);
    }
    int k_core=0; for(int i=0;i<M;i++) if(core[i]>k_core) k_core=core[i];

    /* hub = highest centrality (tie-break salience) */
    int hub=-1; double hv=-1;
    for(int i=0;i<M;i++){ double v=centrality[i]+1e-6*ms.sal[i];
        if(v>hv){hv=v;hub=i;} }
    if(hub<0) hub=0;

    /* ── assemble descriptor ── */
    GeoDescriptor* g=calloc(1,sizeof(GeoDescriptor));
    g->dim=dim;
    g->hub_id = strdup(ms.id[hub]);
    g->centroid = ccen;          /* CENTERED centroid; transfer ownership */
    free(centroid);
    if(centered){
        g->global_mean = malloc((size_t)dim*sizeof(float));
        if(g->global_mean) memcpy(g->global_mean, GM, (size_t)dim*sizeof(float));
    } else g->global_mean = NULL;
    g->n_axes=n_axes; g->axes=axes;
    g->total_variance=total_var; g->radius=radius;
    g->n_members=M; g->n_embedded=nemb;
    g->members=calloc((size_t)M,sizeof(GeoMember));
    for(int i=0;i<M;i++){
        g->members[i].id=strdup(ms.id[i]);
        g->members[i].membership=ms.memb[i];
        g->members[i].centrality=centrality[i];
        g->members[i].salience=ms.sal[i];
        g->members[i].core=core[i];
        g->members[i].dist_centroid=distc[i];
        g->members[i].embedded=ms.emb[i]?1:0;
    }
    g->n_edges=n_edges; g->edges=edges;
    g->k_core=(P.kcore_k>0?P.kcore_k:k_core);
    g->co_registration=co_reg;

    free(centrality); free(degree); free(core); free(distc); free(eidx);
    free(cdir); free(zeros);
    ms_free(&ms);
    return g;
}

void engram_geo_free(GeoDescriptor* g){
    if(!g) return;
    free(g->hub_id); free(g->centroid); free(g->global_mean);
    for(int i=0;i<g->n_axes;i++) free(g->axes[i].axis);
    free(g->axes);
    for(int i=0;i<g->n_members;i++) free(g->members[i].id);
    free(g->members); free(g->edges);
    free(g);
}

/* ═══════════════════════════════════════════════════════════════════════════
 * M10 — REIFICATION: persist / load / lookup first-class neighborhood records.
 * ═══════════════════════════════════════════════════════════════════════════ */

static int64_t geo_now_ms(void){
    struct timespec ts;
    if(clock_gettime(CLOCK_REALTIME,&ts)==0)
        return (int64_t)ts.tv_sec*1000 + ts.tv_nsec/1000000;
    return (int64_t)time(NULL)*1000;
}

void engram_geo_reify_default_params(GeoReifyParams* p){
    if(!p) return;
    p->min_weighted_degree=0;
    p->max_neighborhoods=128;
    p->cover_membership=0.5;
    p->persist_member_edges=1;
    engram_geo_default_params(&p->descriptor);
    p->descriptor.top_axes=4;      /* keep a small ellipsoid summary; cheap */
    p->descriptor.max_members=256; /* reified neighborhoods stay compact       */
}

/* ── tiny growable string builder ─────────────────────────────────────────── */
typedef struct { char* s; size_t n, cap; } SB;
static int sb_reserve(SB* b, size_t add){
    if(b->n+add+1<=b->cap) return 0;
    size_t nc=b->cap?b->cap:256; while(nc<b->n+add+1) nc*=2;
    char* t=realloc(b->s,nc); if(!t) return -1; b->s=t; b->cap=nc; return 0;
}
static int sb_puts(SB* b, const char* s){
    size_t l=strlen(s); if(sb_reserve(b,l)) return -1;
    memcpy(b->s+b->n,s,l); b->n+=l; b->s[b->n]=0; return 0;
}
static int sb_fmt(SB* b, const char* fmt, ...){
    char tmp[512]; va_list ap; va_start(ap,fmt);
    int k=vsnprintf(tmp,sizeof tmp,fmt,ap); va_end(ap);
    if(k<0) return -1; if(k>=(int)sizeof tmp) k=sizeof tmp-1;
    return sb_puts(b,tmp);
}

/* Serialize a descriptor's DURABLE geometry into the GEO1 metadata schema.
 * (The raw centroid is stored separately as the record's emb.) */
static char* geo_nbhd_metadata(const GeoDescriptor* g, const char* hub,
                               const char* meanid){
    SB b={0};
    if(sb_puts(&b,"GEO1\n")) { free(b.s); return NULL; }
    sb_fmt(&b,"hub %s\n", hub?hub:"");
    sb_fmt(&b,"mean %s\n", meanid?meanid:"");
    sb_fmt(&b,"s %.9g %.9g %d %.9g %d %d\n",
           g->radius, g->total_variance, g->k_core, g->co_registration,
           g->n_embedded, g->n_members);
    sb_puts(&b,"e");
    for(int i=0;i<g->n_axes;i++) sb_fmt(&b," %.9g", g->axes[i].extent);
    sb_puts(&b,"\n");
    for(int i=0;i<g->n_members;i++){
        sb_fmt(&b,"m %s %.9g %.9g %d\n",
               g->members[i].id, g->members[i].membership,
               g->members[i].centrality, g->members[i].core);
    }
    return b.s; /* caller frees */
}

/* ── string set (greedy-cover claimed ids) + string→id list (hub→old nbhd) ──── */
static uint64_t geo_djb2(const char* s){
    uint64_t h=5381; for(;*s;s++) h=((h<<5)+h)^(unsigned char)*s; return h;
}
typedef struct SSNode { char* key; struct SSNode* next; } SSNode;
typedef struct { SSNode** b; size_t nb; } SSet;
static void ss_init(SSet* s, size_t nb){ s->nb=nb; s->b=calloc(nb,sizeof*s->b); }
static int  ss_has(const SSet* s, const char* k){
    if(!s->b) return 0; SSNode* n=s->b[geo_djb2(k)%s->nb];
    for(;n;n=n->next) if(strcmp(n->key,k)==0) return 1; return 0;
}
static void ss_add(SSet* s, const char* k){
    if(!s->b||ss_has(s,k)) return; size_t i=geo_djb2(k)%s->nb;
    SSNode* n=malloc(sizeof*n); if(!n) return; n->key=strdup(k); n->next=s->b[i]; s->b[i]=n;
}
static void ss_free(SSet* s){
    if(!s->b) return;
    for(size_t i=0;i<s->nb;i++){ SSNode* n=s->b[i]; while(n){ SSNode* x=n->next; free(n->key); free(n); n=x; } }
    free(s->b); s->b=NULL;
}

typedef struct { char** id; int n, cap; } StrVec;
static void sv_push(StrVec* v, const char* s){
    if(v->n==v->cap){ v->cap=v->cap?v->cap*2:64; v->id=realloc(v->id,(size_t)v->cap*sizeof*v->id); }
    v->id[v->n++]=strdup(s);
}
static void sv_free(StrVec* v){ for(int i=0;i<v->n;i++) free(v->id[i]); free(v->id); }

/* pass 1 collector: all non-structural node ids; also record existing Neighborhood
 * records as (hub -> old_id) so a re-reify supersedes the prior version. */
typedef struct {
    StrVec cand;                    /* candidate node ids (content nodes)   */
    StrVec old_hub, old_id;         /* parallel: existing nbhd hub + its id */
} ReifyScan;
static void geo_reify_scan_cb(const StoreNode* n, void* ctx){
    ReifyScan* rs=ctx; if(!n->id||!n->node_type) { if(n->id) sv_push(&rs->cand,n->id); return; }
    if(strcmp(n->node_type,ENGRAM_GEO_NBHD_TYPE)==0){
        /* parse hub from metadata GEO1 (line "hub <id>") for supersede lineage */
        const char* md=n->metadata?n->metadata:"";
        const char* p=strstr(md,"hub ");
        if(p && (p==md || p[-1]=='\n')){
            p+=4; const char* e=p; while(*e && *e!='\n') e++;
            char* hub=strndup(p,(size_t)(e-p));
            sv_push(&rs->old_hub,hub); sv_push(&rs->old_id,n->id); free(hub);
        }
        return; /* structural: not a candidate */
    }
    if(strcmp(n->node_type,ENGRAM_GEO_MEANFRAME_TYPE)==0) return;
    sv_push(&rs->cand,n->id);
}

/* weighted strong-edge degree of a node (from+to), matching eff_w/threshold. */
static double geo_weighted_degree(EngramPagedStore* st, const char* id, double emin){
    double deg=0; StoreEdge* es=NULL; size_t ne=0;
    if(store_get_edges_from(st,id,&es,&ne)==0 && es){
        for(size_t e=0;e<ne;e++){ if(es[e].tombstoned||es[e].inhibitory) continue;
            double w=eff_w(es[e].weight,es[e].hebb); if(w>=emin) deg+=w; }
    }
    store_edges_free(es,ne); es=NULL; ne=0;
    if(store_get_edges_to(st,id,&es,&ne)==0 && es){
        for(size_t e=0;e<ne;e++){ if(es[e].tombstoned||es[e].inhibitory) continue;
            double w=eff_w(es[e].weight,es[e].hebb); if(w>=emin) deg+=w; }
    }
    store_edges_free(es,ne);
    return deg;
}

int engram_geo_reify_store(EngramPagedStore* store, VIndex* vindex,
                           char** vids, int n_vids,
                           const GeoReifyParams* params){
    if(!store) return -1;
    GeoReifyParams P; if(params) P=*params; else engram_geo_reify_default_params(&P);

    /* 1. true store-wide mean → persist the GeoMeanFrame record (once). */
    GeoMeanCache* mc=engram_geo_mean_build(store);
    if(!mc) return -2;
    int dim=engram_geo_mean_dim(mc);
    const float* mean=engram_geo_mean_vec(mc);
    int64_t now=geo_now_ms();
    { StoreNode mf; memset(&mf,0,sizeof mf);
      mf.id=(char*)ENGRAM_GEO_MEANFRAME_ID; mf.node_type=(char*)ENGRAM_GEO_MEANFRAME_TYPE;
      mf.content=(char*)"geo-mean-frame"; mf.tier=(char*)"Semantic"; mf.metadata=(char*)"{}";
      mf.emb=(float*)mean; mf.emb_dim=dim; mf.created_at=now; mf.updated_at=now;
      if(store_put_node(store,&mf)<0){ engram_geo_mean_free(mc); return -3; }
    }

    /* 2. scan: candidate ids + existing (hub→old id) for supersede. */
    ReifyScan rs; memset(&rs,0,sizeof rs);
    if(store_scan_nodes(store,geo_reify_scan_cb,&rs)<0){
        sv_free(&rs.cand); sv_free(&rs.old_hub); sv_free(&rs.old_id);
        engram_geo_mean_free(mc); return -4;
    }

    /* 3. weighted degree per candidate; sort desc. */
    int N=rs.cand.n;
    double* deg=malloc((size_t)N*sizeof(double));
    int* ord=malloc((size_t)N*sizeof(int));
    for(int i=0;i<N;i++){ deg[i]=geo_weighted_degree(store,rs.cand.id[i],P.descriptor.edge_min_weight); ord[i]=i; }
    /* simple insertion-ish selection sort by degree desc (N a few thousand, one-time) */
    for(int a=0;a<N;a++){ int best=a; for(int b=a+1;b<N;b++) if(deg[ord[b]]>deg[ord[best]]) best=b;
        int t=ord[a]; ord[a]=ord[best]; ord[best]=t; }

    /* 4. greedy non-redundant cover: reify each qualifying hub once. */
    SSet claimed; ss_init(&claimed, (size_t)(N>16?N:16));
    int persisted=0;
    for(int oi=0; oi<N && persisted<P.max_neighborhoods; oi++){
        int i=ord[oi]; const char* hub=rs.cand.id[i];
        if(P.min_weighted_degree>0 && deg[i]<(double)P.min_weighted_degree) break; /* sorted: rest smaller */
        if(ss_has(&claimed,hub)) continue;
        const char* seeds[1]={hub};
        GeoDescriptor* g=engram_geometry_descriptor(store,vindex,vids,n_vids,
                                                    seeds,1,&P.descriptor,mean);
        if(!g || g->n_members<=0){ if(g) engram_geo_free(g); continue; }
        /* claim members above cover threshold (incl. the hub itself) */
        for(int m=0;m<g->n_members;m++)
            if(g->members[m].membership>=P.cover_membership) ss_add(&claimed,g->members[m].id);

        /* build record: id = nbhd-<hub>-<now>, emb = RAW centroid = centered+mean */
        char nid[512]; snprintf(nid,sizeof nid,"%s%s-%lld",ENGRAM_GEO_NBHD_ID_PREFIX,hub,(long long)now);
        float* raw=NULL;
        if(g->n_embedded>0 && g->centroid && g->global_mean){
            raw=malloc((size_t)dim*sizeof(float));
            if(raw) for(int d=0;d<dim;d++) raw[d]=g->centroid[d]+g->global_mean[d];
        }
        char* md=geo_nbhd_metadata(g,hub,ENGRAM_GEO_MEANFRAME_ID);
        StoreNode nn; memset(&nn,0,sizeof nn);
        nn.id=nid; nn.node_type=(char*)ENGRAM_GEO_NBHD_TYPE;
        nn.content=(char*)"reified-neighborhood"; nn.tier=(char*)"Semantic";
        nn.metadata=md?md:(char*)"{}"; nn.emb=raw; nn.emb_dim=raw?dim:0;
        nn.created_at=now; nn.updated_at=now;
        int wrc=store_put_node(store,&nn);
        free(raw); free(md);
        if(wrc<0){ engram_geo_free(g); continue; }

        /* provenance: supersede any prior neighborhood for this hub. */
        for(int k=0;k<rs.old_hub.n;k++) if(strcmp(rs.old_hub.id[k],hub)==0){
            store_supersede(store, rs.old_id.id[k], nid);
        }

        /* member links (durable, but inert to activation — runtime skips them). */
        if(P.persist_member_edges){
            for(int m=0;m<g->n_members;m++){
                char eid[600]; snprintf(eid,sizeof eid,"%s->%s",nid,g->members[m].id);
                StoreEdge se; memset(&se,0,sizeof se);
                se.id=eid; se.from_id=nid; se.to_id=g->members[m].id;
                se.relation=(char*)ENGRAM_GEO_MEMBER_RELATION;
                se.metadata=(char*)"{}"; se.weight=g->members[m].membership;
                se.confidence=1.0; se.created_at=now; se.updated_at=now;
                store_put_edge(store,&se);
            }
        }
        engram_geo_free(g);
        persisted++;
    }

    ss_free(&claimed);
    free(deg); free(ord);
    sv_free(&rs.cand); sv_free(&rs.old_hub); sv_free(&rs.old_id);
    engram_geo_mean_free(mc);
    return persisted;
}

/* ═══════════════ resident loaded form + hot-path lookup ═════════════════════ */

typedef struct {
    char*   id;
    char*   hub_id;
    int     n_members;
    char**  member_ids;
    double* member_w;
    double  radius, co_reg;
    int     k_core, n_embedded;
    float*  centroid_raw;   /* dim floats or NULL   */
    float*  centroid_unit;  /* centered+normalized (finalize) or NULL */
    int     dim;
    GeoNeighborhood view;
} RNbhd;

typedef struct RE { char* id; int nbhd; double w; struct RE* next; } RE;

struct GeoReifyIndex {
    RNbhd* nb; int n, cap;
    float* mean; int mean_dim;
    RE**   buckets; size_t nbuckets;
    double* score;    /* scratch[n], reused per lookup */
};

GeoReifyIndex* engram_geo_reify_index_new(void){
    GeoReifyIndex* ix=calloc(1,sizeof*ix); return ix;
}

/* parse a GEO1 metadata blob into an RNbhd (members + scalars). */
static int geo_parse_nbhd(const char* md, RNbhd* r){
    if(!md) return -1;
    if(strncmp(md,"GEO1",4)!=0) return -1;
    /* count member lines to size arrays */
    int cap=0; for(const char* p=md; (p=strstr(p,"\nm ")); p+=3) cap++;
    r->member_ids=cap?calloc((size_t)cap,sizeof(char*)):NULL;
    r->member_w  =cap?calloc((size_t)cap,sizeof(double)):NULL;
    r->n_members=0;
    const char* line=md;
    while(line && *line){
        const char* nl=strchr(line,'\n');
        size_t len= nl? (size_t)(nl-line) : strlen(line);
        char buf[600]; if(len>=sizeof buf) len=sizeof buf-1;
        memcpy(buf,line,len); buf[len]=0;
        if(buf[0]=='h'&&buf[1]=='u'&&buf[2]=='b'&&buf[3]==' '){
            free(r->hub_id); r->hub_id=strdup(buf+4);
        } else if(buf[0]=='s'&&buf[1]==' '){
            int kc=0,ne=0,nm=0; double rad=0,tv=0,cr=0;
            sscanf(buf+2,"%lf %lf %d %lf %d %d",&rad,&tv,&kc,&cr,&ne,&nm);
            r->radius=rad; r->co_reg=cr; r->k_core=kc; r->n_embedded=ne;
        } else if(buf[0]=='m'&&buf[1]==' '){
            char mid[512]; double w=0,c=0; int core=0;
            if(sscanf(buf+2,"%511s %lf %lf %d",mid,&w,&c,&core)>=2 && r->member_ids){
                r->member_ids[r->n_members]=strdup(mid);
                r->member_w[r->n_members]=w;
                r->n_members++;
            }
        }
        line = nl? nl+1 : NULL;
    }
    return 0;
}

int engram_geo_reify_index_add(GeoReifyIndex* ix, const StoreNode* n){
    if(!ix||!n||!n->node_type) return 0;
    if(strcmp(n->node_type,ENGRAM_GEO_MEANFRAME_TYPE)==0){
        if(n->emb && n->emb_dim>0){
            free(ix->mean);
            ix->mean=malloc((size_t)n->emb_dim*sizeof(float));
            if(ix->mean){ memcpy(ix->mean,n->emb,(size_t)n->emb_dim*sizeof(float)); ix->mean_dim=n->emb_dim; }
        }
        return 0;
    }
    if(strcmp(n->node_type,ENGRAM_GEO_NBHD_TYPE)!=0) return 0;
    if(ix->n==ix->cap){ ix->cap=ix->cap?ix->cap*2:16;
        RNbhd* t=realloc(ix->nb,(size_t)ix->cap*sizeof*t); if(!t) return -1; ix->nb=t; }
    RNbhd* r=&ix->nb[ix->n]; memset(r,0,sizeof*r);
    r->id=strdup(n->id?n->id:"");
    if(geo_parse_nbhd(n->metadata,r)!=0){ free(r->id); return 0; } /* skip malformed */
    if(n->emb && n->emb_dim>0){
        r->dim=n->emb_dim;
        r->centroid_raw=malloc((size_t)n->emb_dim*sizeof(float));
        if(r->centroid_raw) memcpy(r->centroid_raw,n->emb,(size_t)n->emb_dim*sizeof(float));
    }
    ix->n++;
    return 0;
}

int engram_geo_reify_index_finalize(GeoReifyIndex* ix){
    if(!ix) return -1;
    /* member → neighborhood hash */
    size_t total=0; for(int i=0;i<ix->n;i++) total+=(size_t)ix->nb[i].n_members;
    ix->nbuckets = total? (total*2+1) : 1;
    ix->buckets=calloc(ix->nbuckets,sizeof(RE*));
    if(!ix->buckets) return -1;
    for(int i=0;i<ix->n;i++){
        RNbhd* r=&ix->nb[i];
        for(int m=0;m<r->n_members;m++){
            size_t b=geo_djb2(r->member_ids[m])%ix->nbuckets;
            RE* e=malloc(sizeof*e); if(!e) continue;
            e->id=r->member_ids[m]; e->nbhd=i; e->w=r->member_w[m]; e->next=ix->buckets[b]; ix->buckets[b]=e;
        }
        /* centered, normalized centroid for the nearest-fallback */
        if(r->centroid_raw && ix->mean && ix->mean_dim==r->dim){
            r->centroid_unit=malloc((size_t)r->dim*sizeof(float));
            if(r->centroid_unit){
                double nrm=0; for(int d=0;d<r->dim;d++){ double v=(double)r->centroid_raw[d]-ix->mean[d]; r->centroid_unit[d]=(float)v; nrm+=v*v; }
                nrm=sqrt(nrm); if(nrm>1e-12) for(int d=0;d<r->dim;d++) r->centroid_unit[d]=(float)(r->centroid_unit[d]/nrm);
                else { free(r->centroid_unit); r->centroid_unit=NULL; }
            }
        }
        /* fill the borrowed view */
        r->view.id=r->id; r->view.hub_id=r->hub_id; r->view.n_members=r->n_members;
        r->view.member_ids=r->member_ids; r->view.member_w=r->member_w;
        r->view.radius=r->radius; r->view.co_registration=r->co_reg;
        r->view.k_core=r->k_core; r->view.n_embedded=r->n_embedded;
    }
    ix->score=ix->n?calloc((size_t)ix->n,sizeof(double)):NULL;
    return 0;
}

static void geo__reify_load_cb(const StoreNode* n, void* ctx){
    engram_geo_reify_index_add((GeoReifyIndex*)ctx, n);
}
GeoReifyIndex* engram_geo_reify_load(EngramPagedStore* store){
    if(!store) return NULL;
    GeoReifyIndex* ix=engram_geo_reify_index_new(); if(!ix) return NULL;
    store_scan_nodes(store, geo__reify_load_cb, ix);
    if(ix->n==0 && ix->mean==NULL){ engram_geo_reify_index_free(ix); return NULL; }
    engram_geo_reify_index_finalize(ix);
    return ix;
}

const GeoNeighborhood* engram_geo_reify_lookup(
    const GeoReifyIndex* ix,
    const char* const* seed_ids, size_t n_seeds,
    const float* q_emb, int q_dim){
    if(!ix||ix->n<=0) return NULL;
    /* (a) membership route: score each neighborhood by summed seed membership. */
    if(ix->score && ix->buckets && seed_ids && n_seeds>0){
        for(int i=0;i<ix->n;i++) ((GeoReifyIndex*)ix)->score[i]=0.0;
        int any=0;
        for(size_t s=0;s<n_seeds;s++){
            const char* id=seed_ids[s]; if(!id) continue;
            for(RE* e=ix->buckets[geo_djb2(id)%ix->nbuckets]; e; e=e->next)
                if(strcmp(e->id,id)==0){ ((GeoReifyIndex*)ix)->score[e->nbhd]+=e->w; any=1; }
        }
        if(any){
            int best=-1; double bv=-1;
            for(int i=0;i<ix->n;i++) if(ix->score[i]>bv){ bv=ix->score[i]; best=i; }
            if(best>=0 && bv>0) return &ix->nb[best].view;
        }
    }
    /* (b) centroid-nearest fallback (centered query vs centered centroids). */
    if(q_emb && q_dim>0 && ix->mean && ix->mean_dim==q_dim){
        double nq=0; float* cq=malloc((size_t)q_dim*sizeof(float));
        if(!cq) return NULL;
        for(int d=0;d<q_dim;d++){ double v=(double)q_emb[d]-ix->mean[d]; cq[d]=(float)v; nq+=v*v; }
        nq=sqrt(nq);
        if(nq>1e-12){
            int best=-1; double bc=-1e9;
            for(int i=0;i<ix->n;i++){ RNbhd* r=&ix->nb[i]; if(!r->centroid_unit) continue;
                double s=0; for(int d=0;d<q_dim;d++) s+=(double)cq[d]*r->centroid_unit[d];
                s/=nq; if(s>bc){ bc=s; best=i; } }
            free(cq);
            if(best>=0) return &ix->nb[best].view;
        } else free(cq);
    }
    return NULL;
}

int engram_geo_reify_count(const GeoReifyIndex* ix){ return ix?ix->n:0; }
const float* engram_geo_reify_mean(const GeoReifyIndex* ix, int* dim){
    if(!ix||!ix->mean){ if(dim)*dim=0; return NULL; }
    if(dim)*dim=ix->mean_dim; return ix->mean;
}

void engram_geo_reify_index_free(GeoReifyIndex* ix){
    if(!ix) return;
    if(ix->buckets){
        for(size_t b=0;b<ix->nbuckets;b++){ RE* e=ix->buckets[b]; while(e){ RE* x=e->next; free(e); e=x; } }
        free(ix->buckets);
    }
    for(int i=0;i<ix->n;i++){ RNbhd* r=&ix->nb[i];
        free(r->id); free(r->hub_id);
        for(int m=0;m<r->n_members;m++) free(r->member_ids[m]);
        free(r->member_ids); free(r->member_w);
        free(r->centroid_raw); free(r->centroid_unit);
    }
    free(ix->nb); free(ix->score); free(ix->mean);
    free(ix);
}