#!/usr/bin/env bash
# Build the open MPEG / 3GPP reference codecs that act as the *sink* decoders
# for the volumetric and immersive-audio rows of tools/wai_carriage_demo.sh.
# WAI never bundles a decoder — it carries bytes and dispatches. These are the
# field's own reference tools; this script just fetches and builds them at the
# exact versions verified for the demo, so the "real+decode" / "real+parse"
# rows reproduce without the ad-hoc /tmp builds.
#
# Builds (each pinned to a verified tag/ref):
#   - G-PCC  : MPEG mpeg-pcc-tmc13  release-v23.0-rc2   -> tmc3
#   - V-PCC  : MPEG mpeg-pcc-tmc2   release-v25.0       -> PccApp{Encoder,Parser,VideoEncoder,...}
#   - IVAS   : 3GPP ivas-codec      main @ 3882460      -> IVAS_cod / IVAS_dec
#
# (JPEG 2000 / IAMF / Draco come from OpenJPEG / ffmpeg / draco, installed via a
#  package manager — not built here.)
#
# Usage:
#   ./tools/build_reference_decoders.sh [PREFIX] [-j N]
#     PREFIX  install/checkout root (default: ./.reference-tools, gitignored)
#     -j N    parallel build jobs (default: CPU count)
#
# On success it prints the exact `export PATH=… TMC2_CFG=…` line to source
# before running ./tools/wai_carriage_demo.sh.
#
# Toolchain notes (verified on macOS arm64, the platform clang 21, cmake 4.3.3):
#   * tmc2/tmc13 ship a build.sh that rejects cmake major != 3; we invoke cmake
#     directly with -DCMAKE_POLICY_VERSION_MINIMUM=3.5 so cmake 4.x accepts the
#     pre-3.5 minimums the reference CMakeLists still declare.
#   * Both MPEG trees vendor their video/HEVC dependencies, so no external
#     HM/HEVC fetch is needed for the encode + parse paths the demo uses.

set -euo pipefail

PREFIX="${1:-$(cd "$(dirname "$0")/.." && pwd)/.reference-tools}"
[ "${PREFIX:0:1}" = "-" ] && PREFIX="$(cd "$(dirname "$0")/.." && pwd)/.reference-tools"
JOBS="$(getconf _NPROCESSORS_ONLN 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 4)"
# allow `-j N` anywhere
prev=""; for a in "$@"; do [ "$prev" = "-j" ] && JOBS="$a"; prev="$a"; done

mkdir -p "$PREFIX"
PREFIX="$(cd "$PREFIX" && pwd)"
echo "reference-tool prefix: $PREFIX  (jobs: $JOBS)"

need() { command -v "$1" >/dev/null 2>&1 || { echo "missing required tool: $1"; exit 1; }; }
need git; need cmake; need make

# clone_pinned <url> <ref> <dir>
clone_pinned() {
  local url="$1" ref="$2" dir="$3"
  if [ -d "$dir/.git" ]; then echo "  exists: $dir"; return; fi
  echo "  cloning $url @ $ref"
  git clone --branch "$ref" --depth 1 "$url" "$dir" 2>/dev/null \
    || git clone "$url" "$dir"   # fall back to full clone if --branch ref isn't a branch/tag head
  ( cd "$dir" && git checkout -q "$ref" 2>/dev/null || true )
}

# ---------------------------------------------------------------- G-PCC (tmc13)
echo "== G-PCC: mpeg-pcc-tmc13 =="
GPCC="$PREFIX/mpeg-pcc-tmc13"
clone_pinned https://github.com/MPEGGroup/mpeg-pcc-tmc13.git release-v23.0-rc2 "$GPCC"
if [ ! -x "$GPCC/build/tmc3/tmc3" ]; then
  mkdir -p "$GPCC/build"
  ( cd "$GPCC/build" && cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
      && cmake --build . -j"$JOBS" )
fi
[ -x "$GPCC/build/tmc3/tmc3" ] && echo "  -> $GPCC/build/tmc3/tmc3"

# ---------------------------------------------------------------- V-PCC (tmc2)
echo "== V-PCC: mpeg-pcc-tmc2 =="
VPCC="$PREFIX/mpeg-pcc-tmc2"
clone_pinned https://github.com/MPEGGroup/mpeg-pcc-tmc2.git release-v25.0 "$VPCC"
if [ ! -x "$VPCC/bin/PccAppEncoder" ]; then
  mkdir -p "$VPCC/build"
  ( cd "$VPCC/build" && cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
      && cmake --build . -j"$JOBS" )
fi
[ -x "$VPCC/bin/PccAppEncoder" ] && echo "  -> $VPCC/bin/  (cfg: $VPCC/cfg/)"

# ---------------------------------------------------------------- IVAS (3GPP)
echo "== IVAS: 3GPP ivas-codec =="
IVAS="$PREFIX/ivas-codec"
clone_pinned https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec.git main "$IVAS"
# Pin the exact verified commit when present (main moves).
( cd "$IVAS" && git checkout -q 3882460b6c65 2>/dev/null || true )
if [ ! -x "$IVAS/IVAS_cod" ]; then
  ( cd "$IVAS" && make -j"$JOBS" )
fi
[ -x "$IVAS/IVAS_cod" ] && echo "  -> $IVAS/IVAS_cod  $IVAS/IVAS_dec"

# ---------------------------------------------------------------- summary
echo
echo "done. To reproduce the volumetric + immersive-audio decode rows, run:"
echo
echo "  export PATH=\"$VPCC/bin:$IVAS:$GPCC/build/tmc3:\$PATH\""
echo "  export TMC2_CFG=\"$VPCC/cfg\""
echo "  ./tools/wai_carriage_demo.sh"
echo
echo "Expected: wai.image.jp2 / wai.audio.iamf / wai.audio.ivas / wai.mesh.draco"
echo "/ wai.pc.gpcc -> real+decode; wai.pc.vpcc -> real+parse; all byte-exact."