#!/usr/bin/env python3
"""Everything tools/bench/packed.lua needs to know about a DLXP container.

    python3 tools/bench/prep_packed.py <in.dlxp>   -> tmp/packed_meta.lua

THERE IS NO BLOB TO PREPARE, and that is the whole difference from
`prep_stream.py`.  The codec's rig has to hand the machine expanded codebooks, a
packed palette and a record index, because a DLX record cannot be found or drawn
without them; `prep_dlx.py` and `prep_stream.py` exist for that and FINDINGS
49.7.5 records what it cost to have two copies of one of those transforms.  A
packed container carries no such thing: record `i` is at sector 1 + i*97 by
geometry and its bytes are already in the order GVRAM wants them (dlxp.py).  So
this file emits METADATA ONLY -- six numbers the rig would otherwise have to
hard-code, every one of them read out of the container's own header.

The volume is the container itself; tools/bench/mkvol.sh copies it.
"""
import os, sys
sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                "..", "encoder"))
from dlxp import DLXP, SECTOR

if len(sys.argv) != 2:
    sys.exit(__doc__)
d = DLXP(sys.argv[1])

# The record's sector count, and the array chain's entry count, DERIVED here and
# asserted by the 68000 (PG_ARRN).  Two independent statements of one geometry
# is the only way a container and a player can be caught disagreeing about it --
# a chain one entry short delivers a picture with its last row missing, which
# looks like a decode bug and is a layout bug.
recs = d.rec_bytes // SECTOR
rows = d.H
entries = rows + (1 if d.has_palette else 0)

out = "tmp/packed_meta.lua"
with open(out, "w") as fh:
    fh.write("-- generated by tools/bench/prep_packed.py; do not edit\n")
    fh.write("return {\n")
    for k, v in [("W", d.W), ("H", d.H), ("fps", d.fps), ("nframes", d.nframes),
                 ("rec_bytes", d.rec_bytes), ("rec_sectors", recs),
                 ("pal_bytes", d.pal_bytes), ("pic_bytes", d.pic_bytes),
                 ("lba0", d.off_frm // SECTOR),
                 ("palette_last", int(d.palette_last)),
                 ("has_palette", int(d.has_palette)),
                 # DLXP2. Zero in a silent container, and the player branches on
                 # the zero rather than being built two ways.
                 ("cad_f", d.cad_f), ("cad_a", d.cad_a),
                 ("has_audio", int(d.has_audio)),
                 ("aud_bytes", d.aud_bytes), ("aud_hz", d.aud_hz),
                 ("n_lumps", d.n_lumps),
                 ("entries", entries)]:
        fh.write(f"  {k} = {v},\n")
    fh.write("}\n")

print(f"{sys.argv[1]}: DLXP{d.version} {d.W}x{d.H} {d.fps}fps {d.nframes} frames"
      + (f", AUDIO F={d.cad_f} A={d.cad_a}" if d.has_audio else ", silent"))
print(f"  record {d.rec_bytes:,} B = {recs} sectors, palette "
      f"{'LAST' if d.palette_last else 'FIRST'}, {d.pal_bytes} B")
cad = (f" + (i//{d.cad_f})*{d.cad_a}" if d.has_audio else "")
print(f"  record i is at LBA {d.off_frm // SECTOR} + i*{recs}{cad} -- ARITHMETIC. "
      f"There is no index in this container and none can be needed.")
print(f"  the chain the 68000 must build: {entries} entries "
      f"({rows} rows{' + 1 palette' if d.has_palette else ''})")
print(f"  wire {d.video_kbps():.1f}"
      + (f" + {d.audio_kbps():.2f} = {d.kbps():.1f}" if d.has_audio else "")
      + f" KB/s, FIXED by geometry -> {out}")