. "$BST_LIB"

# libopus 1.5.2 (meta-oe recipes-multimedia/libopus) -- the Opus interactive
# audio codec of RFC 6716, with upstream's reference driver opus_demo and its
# conformance comparator opus_compare, both installed by this layer's
# libopus_%.bbappend (upstream builds them as noinst_PROGRAMS and discards them).
#
# HOW A LOSSY CODEC IS CHECKED OFFLINE, WHICH IS THE WHOLE PROBLEM HERE. flac is
# easy: losslessness is an exact property, so `cmp` of input against output is
# the gate. Opus throws information away by design, so that assertion does not
# exist and the naive alternative -- "it ran and printed a banner" -- says
# nothing about whether the arithmetic on this arm is right. Two properties
# replace it, and between them they pin the codec without asserting anything a
# lossy codec cannot promise:
#
#   1. DETERMINISM AND A DIGEST. For a fixed build, a fixed configuration and a
#      fixed input, opus_demo's decoded output is a fixed byte string. Two
#      independent runs must therefore agree byte for byte, and the digest of
#      the decoded PCM is a constant this file pins. The decoder half of that is
#      guaranteed by the specification rather than by luck -- RFC 6716 defines
#      Opus decoding bit-exactly, which is why the split -e/-d path below
#      re-decodes the same bitstream twice and demands identity.
#   2. BOUNDED DEVIATION FROM THE INPUT. opus_compare is upstream's own
#      comparator: it scores the weighted spectral distance between a reference
#      and a test signal and exits non-zero once the result exceeds the
#      threshold it defines conformance at. Running it over (fixture, round trip)
#      is the bounded-deviation criterion computed by upstream's code rather than
#      by an assertion of ours.
#
# opus_compare IS NOT A GENERAL PCM DIFFER, AND ITS CONTRACT DICTATES THE SHAPE OF
# THE SECOND HALF. Three constraints come straight out of src/opus_compare.c and
# are the reason the deviation case below runs at 48 kHz stereo while everything
# else runs at 8 kHz mono:
#
#   - It ALWAYS reads the reference with `read_pcm16(&x,fin1,2)` -- two channels,
#     48 kHz assumed -- and reads the test file at the rate `-r` names, then
#     requires `xlength == ylength*(48000/rate)` exactly. Handing it an 8 kHz mono
#     pair cannot satisfy that: the reference is reinterpreted as 48 kHz stereo and
#     the counts come out 8192 against 98304. Matching rate and channels on both
#     sides at 48 kHz is the only invocation whose assumptions are the truth.
#   - Its verdict is Q = 100*(1 - 0.5*log(1+err)/log(1.13)), failing at Q<0, i.e.
#     err > 0.2769. That is a quality bar, not a bit-exactness bar, so the signal
#     has to be one Opus can actually carry.
#   - A PURE TONE IS THE WRONG PROBE, MEASURED RATHER THAN ASSUMED. The metric
#     normalises error per band, so a signal with energy in one band lets tiny
#     absolute differences in the near-empty bands dominate: a 750 Hz sine scored
#     err 0.92 at 96 kb/s and got WORSE with more bits (1.10 at 256 kb/s, 1.15 at
#     510 kb/s). The broadband sawtooth scores 0.125 at 256 kb/s and 0.125 at
#     510 kb/s -- better than 2x inside the threshold, and flat in the bitrate,
#     which is the signature of having reached the codec's fidelity ceiling rather
#     than of starving it. 510 kb/s is used so the number below reports this arm's
#     arithmetic and not a bitrate choice.
#
# WHAT A GREEN HERE SAYS ABOUT wasm32. meta-oe passes --enable-asm and
# --enable-intrinsics, both of which are auto-detected per architecture and
# neither of which recognises wasm32: configure answers no to every SSE and NEON
# probe, so celt/ and silk/ contribute their portable C and nothing else. A
# round trip that lands on the pinned digest is therefore a statement about this
# arm's integer and floating-point arithmetic, not about a SIMD path that was
# skipped.
#
# EVERY CASE IS OFFLINE AND DEVICE-FREE. No sound card, no /dev/dsp, no network
# and no peer -- the fixture is generated by shell arithmetic, and the codec
# reads and writes plain files.
#
# THE FIXTURE IS BUILT WITHOUT FORKING, for the reason 57-flac.test states at
# length: on this arm each exec is a fresh wasm module instantiation and guest
# memory is not returned on process exit, so a `printf '%03o'` subshell per byte
# would cost 256 forks before the first case. Every byte here comes out of
# arithmetic expansion and the printf builtin.

require opus_demo libopus/present

tmp=${TMPDIR:-/tmp}/bst-libopus.$$
mkdir -p "$tmp" 2>/dev/null
pcm=$tmp/tone.pcm
rt1=$tmp/rt1.pcm
rt2=$tmp/rt2.pcm
bit=$tmp/tone.opus
dec1=$tmp/dec1.pcm
dec2=$tmp/dec2.pcm
pcm48=$tmp/s48.pcm
rt48=$tmp/s48.rt.pcm

# The digest of the decoded PCM from the single-run round trip below, observed on
# the wasm32-hwjs glibc image at port time. It is pinned, not derived: opus_demo
# is deterministic for a fixed build, so a change here means the encoder's or
# decoder's arithmetic moved -- a finding worth a look, not automatically a bug,
# since a libopus version bump or a toolchain change to the floating-point path
# legitimately moves it. The determinism and bounded-deviation cases stay valid
# either way, which is why this is one case rather than the gate.
OPUS_RT_MD5=f78327987246b5c87508f11e77afee8d

# ------------------------------------------------------------------ fixture ---
# A 256-sample sawtooth, 16-bit signed little-endian mono, repeated 64 times:
# 16384 samples / 32768 bytes / 2.048 s at 8 kHz. opus_demo reads and writes
# native-endian 16-bit PCM and wasm32 is little-endian, so the bytes below are
# read back as the samples they were written as. Sawtooth rather than silence
# because a constant signal is carried by SILK's lowest rate and would exercise
# almost nothing; the low byte is held at zero so the waveform is a clean ramp in
# the high byte.
i=0; esc=""
while [ $i -lt 256 ]; do
  esc="$esc\\000\\$((i/64))$((i/8%8))$((i%8))"
  i=$((i+1))
done
j=0
while [ $j -lt 64 ]; do printf "$esc"; j=$((j+1)); done > "$pcm"

nbytes=$(wc -c < "$pcm" 2>/dev/null | tr -d ' ')
check_eq libopus/fixture-size 32768 "$nbytes"

# A fixture the shell failed to write would make every case below fail for a
# reason that has nothing to do with libopus, so stop here rather than emit a
# dozen misleading reds against the wrong subject.
if [ "$nbytes" != "32768" ]; then
  bst_notok libopus/fixture "the shell could not emit the 32768-byte PCM fixture -- remaining cases not run"
  rm -rf "$tmp"
  exit 0
fi

# opus_demo with no arguments prints its usage and exits non-zero, which is the
# cheapest proof that the binary is a real executable on this arm and got as far
# as its own argument parser.
usage=$(opus_demo 2>&1)
if bst_execfail "$usage"; then
  bst_unrun libopus/usage "$usage"
else
  case "$usage" in
    *[Uu]sage*) bst_ok libopus/usage ;;
    *) bst_notok libopus/usage "opus_demo printed no usage: $(_bst_1line "$usage")" ;;
  esac
fi

# --------------------------------------------- the ticket's own criterion ----
# One run, encode and decode together, exactly as the ticket describes it:
# `opus_demo <application> <rate> <channels> <bitrate> <in> <out>` with neither
# -e nor -d. voip is the application SILK serves at 8 kHz; 24000 bit/s is well
# inside its range, so the deviation below is a statement about the codec rather
# than about starving it.
check libopus/roundtrip opus_demo voip 8000 1 24000 "$pcm" "$rt1"

rtbytes=$(wc -c < "$rt1" 2>/dev/null | tr -d ' ')
if [ -n "$rtbytes" ] && [ "$rtbytes" -gt 0 ]; then
  bst_ok libopus/roundtrip-nonempty
else
  bst_notok libopus/roundtrip-nonempty "the round trip produced ${rtbytes:-no} bytes of decoded PCM"
fi

# The decoder emits whole frames, so the output is the input rounded up to a
# frame multiple -- never shorter than the input, and never more than one 20 ms
# frame (320 samples / 640 bytes at 8 kHz) longer. Bounding it both ways catches
# a truncated decode without pinning a number that a default frame-size change
# would move.
if [ -n "$rtbytes" ] && [ "$rtbytes" -ge 32768 ] && [ "$rtbytes" -le 33408 ]; then
  bst_ok libopus/roundtrip-length
else
  bst_notok libopus/roundtrip-length "decoded $rtbytes bytes from a 32768-byte fixture; want 32768..33408"
fi

# Determinism: same binary, same input, same options, twice. This is the property
# the pinned digest below rests on, and it is asserted separately so that a
# digest change can be read as "the arithmetic moved" rather than "the codec is
# no longer reproducible" -- two very different findings.
check libopus/roundtrip-again opus_demo voip 8000 1 24000 "$pcm" "$rt2"
check libopus/deterministic cmp "$rt1" "$rt2"

if command -v md5sum >/dev/null 2>&1; then
  check_eq libopus/decoded-digest "$OPUS_RT_MD5" "$(md5sum < "$rt1" 2>/dev/null | cut -d' ' -f1)"
else
  bst_skip libopus/decoded-digest "md5sum not installed on this image"
fi

# ------------------------------------------------------ bounded deviation ----
# 48 kHz stereo, because that is the only shape opus_compare's reference reader
# agrees with (see the header). 256 frames of sawtooth -- left ramping up, right
# offset by half a period so the two channels are not identical -- repeated 180
# times: 46080 frames / 184320 bytes / 0.96 s, a whole number of 20 ms frames so
# the decoder returns exactly what it was given and the length check below is an
# equality rather than a range.
i=0; esc=""
while [ $i -lt 256 ]; do
  r=$(( (i+128) % 256 ))
  esc="$esc\\000\\$((i/64))$((i/8%8))$((i%8))\\000\\$((r/64))$((r/8%8))$((r%8))"
  i=$((i+1))
done
j=0
while [ $j -lt 180 ]; do printf "$esc"; j=$((j+1)); done > "$pcm48"

check_eq libopus/fixture48-size 184320 "$(wc -c < "$pcm48" 2>/dev/null | tr -d ' ')"

check libopus/roundtrip48 opus_demo audio 48000 2 510000 "$pcm48" "$rt48"

# opus_compare refuses a pair whose sample counts disagree, and reports that as
# "Sample counts do not match" -- a message that reads like a codec fault when it
# is really a fixture fault. Asserting the equality here means a length drift is
# named for what it is instead of surfacing as a confusing deviation red.
rt48bytes=$(wc -c < "$rt48" 2>/dev/null | tr -d ' ')
if [ "$rt48bytes" = "184320" ]; then
  bst_ok libopus/roundtrip48-length
else
  bst_notok libopus/roundtrip48-length "decoded $rt48bytes bytes from a 184320-byte fixture; opus_compare requires the two to match exactly"
fi

# upstream's own comparator, over the fixture and its round trip. A pass is
# agreement inside the threshold opus_compare defines; a fail prints the weighted
# error it measured, so a red here carries the number rather than just the verdict.
if command -v opus_compare >/dev/null 2>&1; then
  check libopus/bounded-deviation opus_compare -s "$pcm48" "$rt48"
else
  bst_notok libopus/bounded-deviation "opus_compare is not in /usr/bin, though it is packaged with opus_demo"
fi

# ------------------------------------------------------- the split -e/-d path ---
# The single run above proves the pair; this proves each half separately, and it
# is where the bitstream itself becomes observable. It is also the only place
# RFC 6716's bit-exactness clause can be asserted directly: the decoder is
# specified exactly, so decoding one fixed bitstream twice must give identical
# bytes on any conforming implementation, this arm included.
check libopus/encode opus_demo -e voip 8000 1 24000 "$pcm" "$bit"

encbytes=$(wc -c < "$bit" 2>/dev/null | tr -d ' ')
if [ -n "$encbytes" ] && [ "$encbytes" -gt 0 ] && [ "$encbytes" -lt 32768 ]; then
  bst_ok libopus/compresses
else
  bst_notok libopus/compresses "encoded ${encbytes:-no} bytes from a 32768-byte fixture -- no compression"
fi

check libopus/decode opus_demo -d 8000 1 "$bit" "$dec1"
check libopus/decode-again opus_demo -d 8000 1 "$bit" "$dec2"
check libopus/decode-bit-exact cmp "$dec1" "$dec2"

# ----------------------------------------------------------- the payload ------
# The library half of the port. libopus ships no shared object on a distro that
# configures --disable-shared image-wide; one appearing here would mean the
# static-only rule silently stopped holding.
if [ -e /usr/lib/libopus.so ] || [ -e /usr/lib/libopus.so.0 ]; then
  bst_notok libopus/static-only "a shared libopus shipped on a --disable-shared distro"
else
  bst_ok libopus/static-only
fi

for f in /usr/lib/libopus.a /usr/include/opus/opus.h /usr/lib/pkgconfig/opus.pc; do
  if [ -s "$f" ]; then
    bst_ok "libopus/payload$(printf '%s' "$f" | tr / -)"
  else
    bst_notok "libopus/payload$(printf '%s' "$f" | tr / -)" "$f is missing or empty"
  fi
done

rm -rf "$tmp"