#!/bin/bash
set -euo pipefail

SCRIPT_DIRECTORY="$(cd "$(dirname "$0")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIRECTORY/.." && pwd)"
FFMPEG_ROOT="$PROJECT_ROOT/ThirdParty/FFmpeg"
SOURCE_ARCHIVE="$FFMPEG_ROOT/Source/ffmpeg-8.1.2.tar.xz"
OUTPUT_BINARY="$FFMPEG_ROOT/macOS/ffmpeg"
EXPECTED_SHA256="464beb5e7bf0c311e68b45ae2f04e9cc2af88851abb4082231742a74d97b524c"
BUILD_ROOT="$(mktemp -d /tmp/projectquint-ffmpeg-build.XXXXXX)"
BUILD_JOBS="$(sysctl -n hw.ncpu)"

cleanup() {
    rm -rf "$BUILD_ROOT"
}
trap cleanup EXIT

if [[ ! -f "$SOURCE_ARCHIVE" ]]; then
    echo "Missing pinned source archive: $SOURCE_ARCHIVE" >&2
    exit 1
fi

ACTUAL_SHA256="$(shasum -a 256 "$SOURCE_ARCHIVE" | awk '{print $1}')"
if [[ "$ACTUAL_SHA256" != "$EXPECTED_SHA256" ]]; then
    echo "FFmpeg source hash mismatch: $ACTUAL_SHA256" >&2
    exit 1
fi

tar -xf "$SOURCE_ARCHIVE" -C "$BUILD_ROOT"
SOURCE_ROOT="$BUILD_ROOT/ffmpeg-8.1.2"

COMMON_OPTIONS=(
    --target-os=darwin
    --cc=clang
    --disable-everything
    --disable-autodetect
    --disable-doc
    --disable-debug
    --disable-network
    --disable-x86asm
    --enable-small
    --enable-ffmpeg
    --disable-ffprobe
    --disable-ffplay
    --enable-avcodec
    --enable-avformat
    --enable-avfilter
    --enable-swscale
    --enable-protocol=file
    --enable-demuxer=asf,avi
    --enable-decoder=wmv1,wmv2,wmv3,vc1,mpeg4,msmpeg4v1,msmpeg4v2,msmpeg4v3,mjpeg,h263,h264,rawvideo
    --enable-parser=vc1,mpeg4video,mjpeg,h263,h264
    --enable-encoder=h264_videotoolbox
    --enable-muxer=mp4
    --enable-filter=format,scale
    --enable-videotoolbox
)

build_architecture() {
    local architecture="$1"
    local build_directory="$BUILD_ROOT/build-$architecture"
    local install_directory="$BUILD_ROOT/install-$architecture"
    mkdir -p "$build_directory" "$install_directory"
    (
        cd "$build_directory"
        "$SOURCE_ROOT/configure" \
            "--prefix=$install_directory" \
            "--arch=$architecture" \
            "--extra-cflags=-arch $architecture -mmacosx-version-min=12.0" \
            "--extra-ldflags=-arch $architecture -mmacosx-version-min=12.0" \
            "${COMMON_OPTIONS[@]}"
        make -j"$BUILD_JOBS"
        make install
    )
}

build_architecture arm64
build_architecture x86_64

mkdir -p "$(dirname "$OUTPUT_BINARY")"
lipo -create \
    "$BUILD_ROOT/install-arm64/bin/ffmpeg" \
    "$BUILD_ROOT/install-x86_64/bin/ffmpeg" \
    -output "$OUTPUT_BINARY"
chmod 755 "$OUTPUT_BINARY"
lipo "$OUTPUT_BINARY" -verify_arch arm64 x86_64

VERSION_OUTPUT="$($OUTPUT_BINARY -version)"
if [[ "$VERSION_OUTPUT" == *"--enable-gpl"* ||
      "$VERSION_OUTPUT" == *"--enable-nonfree"* ||
      "$VERSION_OUTPUT" == *"libx264"* ]]; then
    echo "Refusing non-LGPL FFmpeg configuration." >&2
    exit 1
fi

echo "Built Universal LGPL FFmpeg: $OUTPUT_BINARY"