# syntax=docker/dockerfile:1
#
# FFmpeg's AAC decoder compiled to WebAssembly for johnmcm.com's Video Repair
# (/repair-video): it tells the page how many bytes each raw AAC frame takes,
# so the sound of a recording cut off before its index can be found and
# copied without a working clip. FFmpeg 5.1.6 (LGPL-2.1-or-later), the same
# release and tarball as the site's FFmpeg (wasm-src/ffmpeg/, published at
# /source/ffmpeg/), built with the AAC decoder and nothing else; the glue is
# src/aacscan.c. The Emscripten image is pinned by version and digest.
#
# Built from wasm-src/ so the FFmpeg tarball is shared, not copied:
#   ./build.ps1     (or, in wasm-src)   docker build -f aacscan/Dockerfile --target export --output type=local,dest=aacscan/dist .

ARG EMSDK_IMAGE=emscripten/emsdk:6.0.10@sha256:e077d54e2b8970575ebc4f185ac1de0b95c05f2b266134d4ba27449af7aebf65
FROM ${EMSDK_IMAGE} AS build

ARG FFMPEG_SHA256=f4fa066278f7a47feab316fef905f4db0d5e9b589451949740f83972b30901bd
COPY ffmpeg/source/ffmpeg-5.1.6.tar.xz /src/
RUN cd /src \
 && echo "${FFMPEG_SHA256}  ffmpeg-5.1.6.tar.xz" | sha256sum -c - \
 && tar xf ffmpeg-5.1.6.tar.xz

RUN cd /src/ffmpeg-5.1.6 \
 && emconfigure ./configure \
      --target-os=none --arch=x86_32 --enable-cross-compile \
      --cc=emcc --cxx=em++ --ar=emar --ranlib=emranlib --nm=emnm --objcc=emcc --dep-cc=emcc \
      --extra-cflags="-O3" \
      --disable-asm --disable-x86asm --disable-inline-asm --disable-stripping --disable-runtime-cpudetect \
      --disable-autodetect --disable-network --disable-doc --disable-debug \
      --disable-pthreads --disable-w32threads --disable-os2threads \
      --disable-programs --disable-everything \
      --disable-avdevice --disable-avformat --disable-avfilter --disable-swscale --disable-swresample --disable-postproc \
      --enable-decoder=aac \
 && emmake make -j"$(nproc)" libavcodec/libavcodec.a libavutil/libavutil.a

WORKDIR /build
COPY aacscan/src/aacscan.c .
RUN mkdir -p /out \
 && emcc -O3 -I/src/ffmpeg-5.1.6 aacscan.c /src/ffmpeg-5.1.6/libavcodec/libavcodec.a /src/ffmpeg-5.1.6/libavutil/libavutil.a -o /out/aacscan.mjs \
    -sMODULARIZE=1 -sEXPORT_ES6=1 -sEXPORT_NAME=createAacScan \
    -sENVIRONMENT=web,worker,node \
    -sALLOW_MEMORY_GROWTH=1 \
    -sFILESYSTEM=0 \
    -sDYNAMIC_EXECUTION=0 \
    -sINCOMING_MODULE_JS_API=print,printErr,locateFile \
    -sEXPORTED_FUNCTIONS=_aacs_alloc,_aacs_free,_aacs_open,_aacs_close,_aacs_frame,_aacs_samples,_aacs_channels \
    -sEXPORTED_RUNTIME_METHODS=HEAPU8

FROM scratch AS export
COPY --from=build /out/ /