#!/usr/bin/env python3
"""Export every reconstructed ORCASat component and solid as binary glTF 2.0.

glTF: metres, +Y along ram, +Z nadir, -X starboard. Right-handed rotation.
Standalone part/solid geometry is centred; manifest preserves satellite placement.
Assembly and module geometry use the satellite origin, not individual origins.
"""
from pathlib import Path
import csv, hashlib, json, struct
import numpy as np
import cadquery as cq
import build_orcasat as b

TOLERANCE_MM=.08
ANGULAR_TOLERANCE_RAD=.30


def vector_glb(v):
    x,y,z=v
    return np.array([-x,z,y],dtype=float)*.001


def point_glb(v):
    return vector_glb((v[0],v[1],v[2]-113.5))


def tessellate_absolute(shape):
    # Absolute linear deflection prevents sub-millimetre spline wires from
    # receiving hundreds of thousands of triangles under relative meshing.
    from OCP.BRepTools import BRepTools
    from OCP.BRepMesh import BRepMesh_IncrementalMesh
    from OCP.BRep import BRep_Tool
    from OCP.TopLoc import TopLoc_Location
    from OCP.TopAbs import TopAbs_Orientation
    if not BRepTools.Triangulation_s(shape.wrapped,TOLERANCE_MM):
        mesher=BRepMesh_IncrementalMesh(shape.wrapped,TOLERANCE_MM,False,ANGULAR_TOLERANCE_RAD,True)
        assert mesher.IsDone(), 'Triangulation failed'
    verts=[];tris=[];offset=0
    for face in shape.Faces():
        location=TopLoc_Location();poly=BRep_Tool.Triangulation_s(face.wrapped,location)
        if poly is None:continue
        transform=location.Transformation()
        verts.extend(cq.Vector(poly.Node(i).Transformed(transform)) for i in range(1,poly.NbNodes()+1))
        reverse=face.wrapped.Orientation()==TopAbs_Orientation.TopAbs_REVERSED
        for triangle in poly.Triangles():
            a,c,d=triangle.Get()
            tris.append((a+offset-1,d+offset-1,c+offset-1) if reverse else (a+offset-1,c+offset-1,d+offset-1))
        offset+=poly.NbNodes()
    return verts,tris


def triangulate(shape):
    verts,tris=tessellate_absolute(shape)
    v=np.array([[q.x,q.y,q.z] for q in verts],dtype=np.float64)
    t=np.array(tris,dtype=np.uint32)
    if not len(t):raise ValueError('Solid has no triangulation')
    face=np.cross(v[t[:,1]]-v[t[:,0]],v[t[:,2]]-v[t[:,0]])
    good=np.linalg.norm(face,axis=1)>1e-12
    t=t[good];face=face[good]
    n=np.zeros_like(v)
    for k in range(3):np.add.at(n,t[:,k],face)
    ll=np.linalg.norm(n,axis=1)
    n[ll<1e-15]=(0,0,1);ll[ll<1e-15]=1
    n/=ll[:,None]
    # Drop unused vertices left by zero-area OCCT seam triangles.
    used,inv=np.unique(t,return_inverse=True)
    return v[used],n[used],inv.reshape(-1,3).astype(np.uint32)


def convert_mesh(v,n,t,centre):
    q=v-centre
    pos=np.column_stack((-q[:,0],q[:,2],q[:,1]))*.001
    nor=np.column_stack((-n[:,0],n[:,2],n[:,1]))
    return pos.astype('<f4'),nor.astype('<f4'),t.astype('<u4')


class GLB:
    def __init__(self,title):
        self.bin=bytearray();self.doc={'asset':{'version':'2.0','generator':'ORCASat reference reconstruction '+b.VERSION+' / CadQuery 2.7','extras':{'units':'metres','upAxis':'+Y','referenceModel':True}},'scene':0,'scenes':[{'name':title,'nodes':[0]}],'nodes':[{'name':title,'children':[]}],'meshes':[],'materials':[],'accessors':[],'bufferViews':[],'buffers':[]}
        self.materials={}
    def array(self,arr,target,kind):
        while len(self.bin)%4:self.bin.append(0)
        offset=len(self.bin);raw=arr.tobytes();self.bin.extend(raw)
        vi=len(self.doc['bufferViews']);self.doc['bufferViews'].append({'buffer':0,'byteOffset':offset,'byteLength':len(raw),'target':target})
        ac={'bufferView':vi,'componentType':5126 if arr.dtype.kind=='f' else 5125,'count':len(arr),'type':kind}
        if kind=='VEC3':ac.update({'min':arr.min(0).astype(float).tolist(),'max':arr.max(0).astype(float).tolist()})
        ai=len(self.doc['accessors']);self.doc['accessors'].append(ac);return ai
    def material(self,col):
        if col in self.materials:return self.materials[col]
        metal=.7 if col in ['al','bright','gold','copper','copperback','battery'] else .05
        rgb=b.COL[col];mat={'name':col,'pbrMetallicRoughness':{'baseColorFactor':[float(c) for c in rgb]+[1.0],'metallicFactor':metal,'roughnessFactor':.45 if metal>.5 else .72}}
        idx=len(self.doc['materials']);self.doc['materials'].append(mat);self.materials[col]=idx;return idx
    def node(self,name,parent=0,extras=None):
        idx=len(self.doc['nodes']);d={'name':name,'children':[]}
        if extras:d['extras']=extras
        self.doc['nodes'].append(d);self.doc['nodes'][parent]['children'].append(idx);return idx
    def mesh(self,name,arrays,col,parent=0,translation=None,extras=None):
        pos,nor,tri=arrays
        pa=self.array(pos,34962,'VEC3');na=self.array(nor,34962,'VEC3');ia=self.array(tri.reshape(-1),34963,'SCALAR')
        idx=len(self.doc['meshes']);self.doc['meshes'].append({'name':name,'primitives':[{'attributes':{'POSITION':pa,'NORMAL':na},'indices':ia,'material':self.material(col),'mode':4}]})
        n=self.node(name,parent,extras);self.doc['nodes'][n]['mesh']=idx
        if translation is not None:self.doc['nodes'][n]['translation']=[float(x) for x in translation]
    def save(self,path):
        path=Path(path);path.parent.mkdir(parents=True,exist_ok=True)
        self.doc['buffers']=[{'byteLength':len(self.bin)}]
        for node in self.doc['nodes']:
            if not node.get('children'):node.pop('children',None)
        raw=json.dumps(self.doc,separators=(',',':'),ensure_ascii=True).encode()
        raw+=b' '*((-len(raw))%4);self.bin.extend(b'\0'*((-len(self.bin))%4))
        total=12+8+len(raw)+8+len(self.bin)
        with path.open('wb') as f:
            f.write(struct.pack('<4sII',b'glTF',2,total));f.write(struct.pack('<I4s',len(raw),b'JSON'));f.write(raw);f.write(struct.pack('<I4s',len(self.bin),b'BIN\0'));f.write(self.bin)


def export_all(target):
    target=Path(target);target.mkdir(parents=True,exist_ok=True)
    cache={};rows=[];files=[];source_count=0
    def finish(path,kind,components,solid_count):
        raw=path.read_bytes();files.append({'path':str(path.relative_to(target)),'kind':kind,'components':components,'solids':solid_count,'bytes':len(raw),'sha256':hashlib.sha256(raw).hexdigest()})
    for pi,p in enumerate(b.PARTS):
        solids=p.shape.Solids();vv=[];nn=[];tt=[];base=0
        bb=p.shape.BoundingBox();centre=np.array([(bb.xmin+bb.xmax)/2,(bb.ymin+bb.ymax)/2,(bb.zmin+bb.zmax)/2])
        extra={'module':p.group,'state':p.state,'dimensional_status':p.note}
        for si,solid in enumerate(solids):
            v,n,t=triangulate(solid);vv.append(v);nn.append(n);tt.append(t+base);base+=len(v)
            # All physical solids have their own file, including compound contacts.
            own=(v.min(0)+v.max(0))/2
            arr=convert_mesh(v,n,t,own)
            name=p.name+f'__Solid_{si+1:03d}'
            path=target/'solids'/p.group/(name+'.glb')
            g=GLB(name);g.mesh(name,arr,p.colour,extras=extra);g.save(path);finish(path,'solid',1,1)
            rows.append({'module':p.group,'component':p.name,'state':p.state,'solid':si+1,'path':str(path.relative_to(target)),'origin_gltf_m':point_glb(own).tolist(),'triangles':len(t),'kind':'solid'})
        arr=convert_mesh(np.concatenate(vv),np.concatenate(nn),np.concatenate(tt),centre)
        cache[pi]=(arr,centre)
        path=target/'parts'/p.group/(p.name+'.glb')
        g=GLB(p.name);g.mesh(p.name,arr,p.colour,extras=extra);g.save(path);finish(path,'part',1,len(solids))
        rows.append({'module':p.group,'component':p.name,'state':p.state,'solid':None,'path':str(path.relative_to(target)),'origin_gltf_m':point_glb(centre).tolist(),'triangles':len(arr[2]),'kind':'part'})
        if pi%50==0:print('GLB components',pi+1,'/',len(b.PARTS),flush=True)
    def scene(name,state,view,group=None,face=None):
        g=GLB(name);groups={};count=0;ns=0
        for pi,p in enumerate(b.PARTS):
            if not b.visible(p,state,view) or (group and p.group!=group):continue
            if face and not (p.name.startswith(face+'_') and p.group in ['07_Exterior_Panels','08_Sensors_Deployables']):continue
            if p.group not in groups:groups[p.group]=g.node(p.group)
            arr,centre=cache[pi]
            # Exploded placement is a translation; use actual CAD view transform.
            original=p.shape.BoundingBox();moved=b.moved(p,view).BoundingBox()
            delta=np.array([moved.xmin-original.xmin,moved.ymin-original.ymin,moved.zmin-original.zmin])
            g.mesh(p.name,arr,p.colour,groups[p.group],point_glb(centre+delta),{'state':p.state,'dimensional_status':p.note,'solids':len(p.shape.Solids())})
            count+=1;ns+=len(p.shape.Solids())
        folder='modules' if group else 'panels' if face else 'assemblies'
        path=target/folder/(name+'.glb');g.save(path);finish(path,'module' if group else 'panel' if face else 'assembly',count,ns)
    for name,state,view in [('ORCASat_Stowed','stowed','full'),('ORCASat_Deployed','deployed','full'),('ORCASat_Internal','stowed','internal'),('ORCASat_Exploded','deployed','exploded')]:scene(name,state,view)
    for group in sorted({p.group for p in b.PARTS}):
        scene(group,'stowed','full',group=group)
        if any(p.group==group and p.state=='deployed' for p in b.PARTS):scene(group+'_Deployed','deployed','full',group=group)
    for face in ['Starboard','Port','Nadir','Zenith','Ram','Wake']:
        scene(face+'_Panel','stowed','full',face=face)
    manifest={'version':b.VERSION,'units':'metres','up_axis':'+Y','coordinate_mapping_from_STEP_body':'glTF=( -STEP_Y, STEP_X, STEP_Z ) / 1000','standalone_origin':'Each part or solid is centred. origin_gltf_m restores the stowed/deployed model placement of that source geometry. Assembly/module/panel scenes already use spacecraft-centred positions.','tessellation':{'absolute_linear_deflection_mm':TOLERANCE_MM,'angular_deflection_radians':ANGULAR_TOLERANCE_RAD},'components_defined':len(b.PARTS),'solids_defined':sum(len(p.shape.Solids()) for p in b.PARTS),'files':files,'items':rows}
    (target/'manifest.json').write_text(json.dumps(manifest,indent=2))
    with (target/'placement_manifest.csv').open('w',newline='') as f:
        w=csv.writer(f);w.writerow(['kind','module','component','state','solid','path','origin_X_m','origin_Y_m','origin_Z_m','triangles'])
        for row in rows:w.writerow([row[k] for k in ['kind','module','component','state','solid','path']]+row['origin_gltf_m']+[row['triangles']])
    print('GLB export complete:',len(files),'files',flush=True)
    return manifest


if __name__=='__main__':
    import argparse
    ap=argparse.ArgumentParser();ap.add_argument('--out',type=Path,default=Path(__file__).resolve().parent.parent/'EXPORT');args=ap.parse_args()
    b.build();export_all(args.out)