#!/usr/bin/env bash
set -euo pipefail

FFMPEG_VERSION="8.1.2"
FFMPEG_SHA256="464beb5e7bf0c311e68b45ae2f04e9cc2af88851abb4082231742a74d97b524c"
DEPLOYMENT_TARGET="12.0"

HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DEST="${HERE}/ffmpeg"
WORK="${KV_FFMPEG_WORKDIR:-$(mktemp -d)}"

echo "==================================================="
echo " Building LGPL ffmpeg ${FFMPEG_VERSION} (arm64, decode-only)"
echo " work : ${WORK}"
echo " dest : ${DEST}"
echo "==================================================="

command -v curl >/dev/null || { echo "ERROR: curl not found"; exit 1; }
command -v make >/dev/null || { echo "ERROR: make not found (xcode-select --install)"; exit 1; }

TARBALL="${WORK}/ffmpeg-${FFMPEG_VERSION}.tar.xz"
SRC="${WORK}/ffmpeg-${FFMPEG_VERSION}"
STAGE="${WORK}/stage"

echo "[1/5] Fetching source..."
if [[ ! -f "$TARBALL" ]]; then
    curl -sSL -o "$TARBALL" "https://ffmpeg.org/releases/ffmpeg-${FFMPEG_VERSION}.tar.xz"
fi
ACTUAL="$(shasum -a 256 "$TARBALL" | awk '{print $1}')"
[[ "$ACTUAL" == "$FFMPEG_SHA256" ]] || {
    echo "ERROR: sha256 mismatch for the ffmpeg tarball"
    echo "  expected $FFMPEG_SHA256"
    echo "  got      $ACTUAL"
    exit 1
}
rm -rf "$SRC" "$STAGE"
tar -xf "$TARBALL" -C "$WORK"

# LGPL only: no --enable-gpl, no --enable-nonfree, no external codec library. Bundling the Homebrew
# ffmpeg instead would drag x264/x265 in and relicense the whole app under the GPL.
#
# The player only ever opens a local file (the timelapse is downloaded to a temp path first), so the
# network stack, the protocols and every encoder are compiled out. --install-name-dir=@rpath is what
# makes the dylibs relocatable inside Contents/Frameworks instead of hardcoding an absolute path.
echo "[2/5] configure..."
cd "$SRC"
./configure \
    --prefix="$STAGE" \
    --arch=arm64 \
    --extra-cflags="-mmacosx-version-min=${DEPLOYMENT_TARGET}" \
    --extra-ldflags="-mmacosx-version-min=${DEPLOYMENT_TARGET}" \
    --install-name-dir="@rpath" \
    --enable-shared \
    --disable-static \
    --enable-pic \
    --disable-programs \
    --disable-doc \
    --disable-autodetect \
    --disable-everything \
    --disable-avdevice \
    --disable-avfilter \
    --disable-swresample \
    --disable-network \
    --disable-gpl \
    --disable-nonfree \
    --enable-videotoolbox \
    --enable-decoder=h264,hevc,mjpeg,mjpegb \
    --enable-hwaccel=h264_videotoolbox,hevc_videotoolbox \
    --enable-parser=h264,hevc,mjpeg \
    --enable-demuxer=mov,matroska,avi,flv,mpegts,h264,hevc,mjpeg,image2 \
    --enable-protocol=file \
    --enable-bsf=h264_mp4toannexb,hevc_mp4toannexb,extract_extradata

echo "[3/5] make..."
make -j"$(sysctl -n hw.ncpu)"
make install

echo "[4/5] Staging into ${DEST}..."
rm -rf "$DEST"
mkdir -p "${DEST}/include" "${DEST}/lib"
cp -R "${STAGE}/include/"* "${DEST}/include/"
# `make install` lays out libavcodec.62.28.102.dylib + a libavcodec.62.dylib symlink, but a symlink does
# not survive a git checkout on every machine. Copy the real file under its soname instead, which is
# also the name dyld looks up at runtime (the install name is @rpath/libavcodec.62.dylib).
for f in "${STAGE}/lib/"*.dylib; do
    [[ -L "$f" ]] && continue
    cp "$f" "${DEST}/lib/$(basename "$(otool -D "$f" | tail -1)")"
done
chmod u+w "${DEST}/lib/"*.dylib

echo "[5/5] Verifying install names..."
FAIL=0
for f in "${DEST}/lib/"*.dylib; do
    ID="$(otool -D "$f" | tail -1)"
    [[ "$ID" == @rpath/* ]] || { echo "  BAD id: $f -> $ID"; FAIL=1; }
    while read -r dep; do
        case "$dep" in
            /usr/lib/*|/System/*|@rpath/*) ;;
            *) echo "  BAD dep in $(basename "$f"): $dep"; FAIL=1 ;;
        esac
    done < <(otool -L "$f" | tail -n +2 | awk '{print $1}')
done
[[ "$FAIL" -eq 0 ]] || { echo "ERROR: absolute paths left in the dylibs"; exit 1; }

echo ""
echo "Done. Vendored:"
ls -lh "${DEST}/lib/"
echo ""
echo "Now rebuild the app and check that nothing points at Homebrew:"
echo "  otool -L build/macos/Build/Products/Release-beta/*.app/Contents/Frameworks/krevoxa_video.framework/Versions/A/krevoxa_video"