"""Plateau-less elements whose LAST keyframe is visible -- do they contradict
the entry->hold->exit model, or are they 'slides in and stops'?"""
import struct, zlib, glob, os, collections
DECL_AT, DECL_ENTRY, KEYFRAME = 0x20, 60, 40
def entries(base):
    stub=open(base+".pak","rb").read()
    if stub[:4]!=b"IPFB": return
    n=struct.unpack_from(">I",stub,4)[0]
    segs=sorted(glob.glob(base+".p[0-9][0-9]"))
    if not segs: return
    blob=b"".join(open(s,"rb").read() for s in segs)
    for i in range(n):
        h,off,sz=struct.unpack_from(">III",stub,0x10+12*i)
        st=blob[off:off+sz]
        if len(st)<10: continue
        try: yield (zlib.decompress(st[10:]) if st[:2]==b"Z1" else st)
        except Exception: continue
def elements(d):
    if d[:4]!=b"RATC": return []
    count=struct.unpack_from(">I",d,0x14)[0]
    if not (0<count<4096): return []
    names=[]
    for i in range(count):
        o=DECL_AT+i*DECL_ENTRY
        if o+DECL_ENTRY>len(d): return []
        names.append(d[o:o+28].split(b"\0")[0].decode("ascii","replace"))
    out,pos=[],DECL_AT+count*DECL_ENTRY
    while True:
        if pos+8>len(d): break
        idx,frames=struct.unpack_from(">II",d,pos)
        if idx>=count or frames==0 or frames>4096: break
        first=pos+12; end=first+frames*KEYFRAME-4
        poses=[]
        for k in range(frames):
            b=first+k*KEYFRAME
            if b+36>len(d) or b+36>end: break
            poses.append(struct.unpack_from(">I",d,b)+struct.unpack_from(">II",d,b+16)+struct.unpack_from(">ii",d,b+28))
        if poses: out.append((names[idx],poses))
        pos=end
    return out
alpha=lambda q:(q[0]>>24)&0xff
mono=stuck=other=0
ex=[]
for pak in sorted(glob.glob("/work/sylph_extract/dat/GP_*.pak")):
    for d in entries(pak[:-4]):
        for nm,p in elements(d):
            if len(p)==1: continue
            if any(p[i]==p[i+1] for i in range(len(p)-1)): continue
            if alpha(p[-1])==0: continue                       # ends invisible: transient
            a=[alpha(q) for q in p]
            if all(a[i]<=a[i+1] for i in range(len(a)-1)):      # alpha never decreases
                mono+=1
                if len(ex)<8: ex.append((os.path.basename(pak), nm, a, [(q[1],q[2]) for q in p]))
            elif a[-1]==max(a): stuck+=1
            else: other+=1
tot=mono+stuck+other
print(f"plateau-less, multi-keyframe, ending VISIBLE: {tot}")
print(f"  alpha never decreases (a fade/slide IN that stops): {mono}  ({100*mono/max(tot,1):.1f} %)")
print(f"  ends at its maximum alpha but dips on the way     : {stuck}  ({100*stuck/max(tot,1):.1f} %)")
print(f"  ends visible but NOT at maximum alpha             : {other}  ({100*other/max(tot,1):.1f} %)")
print("\nexamples of the monotone kind (alpha sequence, then scale pairs):")
for e in ex: print("  ", e[0], e[1], e[2], e[3])