#!/bin/bash
# Copyright 2020 Google LLC
#
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

set -ex

BASE_DIR=`cd $(dirname ${BASH_SOURCE[0]}) && pwd`
# This expects the environment variable EMSDK to be set
if [[ ! -d $EMSDK ]]; then
  cat >&2 << "EOF"
Be sure to set the EMSDK environment variable to the location of Emscripten SDK:

    https://emscripten.org/docs/getting_started/downloads.html
EOF
  exit 1
fi

# Navigate to SKIA_HOME from where this file is located.
pushd $BASE_DIR/../..

source $EMSDK/emsdk_env.sh
EMCC=`which emcc`
EMCXX=`which em++`
EMAR=`which emar`

RELEASE_CONF="-O3 -DSK_RELEASE --pre-js $BASE_DIR/release.js \
              -DGR_GL_CHECK_ALLOC_WITH_GET_ERROR=0 -DGR_TEST_UTILS"
EXTRA_CFLAGS="\"-DSK_RELEASE\", \"-DGR_GL_CHECK_ALLOC_WITH_GET_ERROR=0\", \"-DGR_TEST_UTILS\", "
IS_OFFICIAL_BUILD="false"

BUILD_DIR=${BUILD_DIR:="out/wasm_gm_tests"}

mkdir -p $BUILD_DIR
# sometimes the .a files keep old symbols around - cleaning them out makes sure
# we get a fresh build.
rm -f $BUILD_DIR/*.a

GN_GPU="skia_enable_gpu=true skia_gl_standard = \"webgl\""
GN_GPU_FLAGS="\"-DSK_DISABLE_LEGACY_SHADERCONTEXT\","
WASM_GPU="-lGL -DSK_SUPPORT_GPU=1 -DSK_GL \
          -DSK_DISABLE_LEGACY_SHADERCONTEXT --pre-js $BASE_DIR/cpu.js --pre-js $BASE_DIR/gpu.js\
          -s USE_WEBGL2=1"

GM_LIB="$BUILD_DIR/libgm_wasm.a"

GN_FONT="skia_enable_fontmgr_custom_directory=false "
BUILTIN_FONT="$BASE_DIR/fonts/NotoMono-Regular.ttf.cpp"
# Generate the font's binary file (which is covered by .gitignore)
python tools/embed_resources.py \
      --name SK_EMBEDDED_FONTS \
      --input $BASE_DIR/fonts/NotoMono-Regular.ttf \
      --output $BASE_DIR/fonts/NotoMono-Regular.ttf.cpp \
      --align 4
GN_FONT+="skia_enable_fontmgr_custom_embedded=true skia_enable_fontmgr_custom_empty=false"


GN_SHAPER="skia_use_icu=true skia_use_system_icu=false skia_use_harfbuzz=true skia_use_system_harfbuzz=false"

# Turn off exiting while we check for ninja (which may not be on PATH)
set +e
NINJA=`which ninja`
if [[ -z $NINJA ]]; then
  git clone "https://chromium.googlesource.com/chromium/tools/depot_tools.git" --depth 1 $BUILD_DIR/depot_tools
  NINJA=$BUILD_DIR/depot_tools/ninja
fi
# Re-enable error checking
set -e

./bin/fetch-gn

echo "Compiling bitcode"

# Inspired by https://github.com/Zubnix/skia-wasm-port/blob/master/build_bindings.sh
./bin/gn gen ${BUILD_DIR} \
  --args="cc=\"${EMCC}\" \
  cxx=\"${EMCXX}\" \
  ar=\"${EMAR}\" \
  extra_cflags_cc=[\"-frtti\"] \
  extra_cflags=[\"-s\", \"WARN_UNALIGNED=1\", \"-s\", \"MAIN_MODULE=1\",
    \"-DSKNX_NO_SIMD\", \"-DSK_DISABLE_AAA\",
    \"-DSK_FORCE_8_BYTE_ALIGNMENT\",
    ${GN_GPU_FLAGS}
    ${EXTRA_CFLAGS}
  ] \
  is_debug=false \
  is_official_build=${IS_OFFICIAL_BUILD} \
  is_component_build=false \
  werror=true \
  target_cpu=\"wasm\" \
  \
  skia_use_angle=false \
  skia_use_dng_sdk=false \
  skia_use_webgl=true \
  skia_use_fontconfig=false \
  skia_use_freetype=true \
  skia_use_libheif=true \
  skia_use_libjpeg_turbo_decode=true \
  skia_use_libjpeg_turbo_encode=true \
  skia_use_libpng_decode=true \
  skia_use_libpng_encode=true \
  skia_use_libwebp_decode=true \
  skia_use_libwebp_encode=true \
  skia_use_lua=false \
  skia_use_piex=true \
  skia_use_system_freetype2=false \
  skia_use_system_libjpeg_turbo=false \
  skia_use_system_libpng=false \
  skia_use_system_libwebp=false \
  skia_use_system_zlib=false\
  skia_use_vulkan=false \
  skia_use_wuffs=true \
  skia_use_zlib=true \
  \
  ${GN_SHAPER} \
  ${GN_GPU} \
  ${GN_FONT} \
  skia_use_expat=true \
  skia_enable_ccpr=false \
  skia_enable_svg=true \
  skia_enable_skshaper=true \
  skia_enable_nvpr=false \
  skia_enable_skparagraph=true \
  skia_enable_pdf=false"

# Build all the libs we will need below
parse_targets() {
  for LIBPATH in $@; do
    basename $LIBPATH
  done
}
${NINJA} -C ${BUILD_DIR} libskia.a libskshaper.a \
  $(parse_targets $SHAPER_LIB $GM_LIB)

echo "Generating final wasm"

# Disable '-s STRICT=1' outside of Linux until
# https://github.com/emscripten-core/emscripten/issues/12118 is resovled.
STRICTNESS="-s STRICT=1"
if [[ `uname` != "Linux" ]]; then
  echo "Disabling '-s STRICT=1'. See: https://github.com/emscripten-core/emscripten/issues/12118"
  STRICTNESS=""
fi

GMS_TO_BUILD="gm/*.cpp"
# When developing locally, it can be faster to focus only on the gms or tests you care about
# (since they all have to be recompiled/relinked) every time. To do so, mark the following as true
if false; then
   GMS_TO_BUILD="gm/beziereffects.cpp gm/gm.cpp"
fi

# These gms do not compile or link with the WASM code. Thus, we omit them.
GLOBIGNORE="gm/cgms.cpp:"\
"gm/compressed_textures.cpp:"\
"gm/fiddle.cpp:"\
"gm/xform.cpp:"\
"gm/video_decoder.cpp"

# Emscripten prefers that the .a files go last in order, otherwise, it
# may drop symbols that it incorrectly thinks aren't used. One day,
# Emscripten will use LLD, which may relax this requirement.
EMCC_DEBUG=1 ${EMCXX} \
    $RELEASE_CONF \
    -I. \
    -DSK_DISABLE_AAA \
    -DSK_FORCE_8_BYTE_ALIGNMENT \
    -DGR_OP_ALLOCATE_USE_NEW \
    $WASM_GPU \
    -std=c++17 \
    --bind \
    --no-entry \
    --pre-js $BASE_DIR/gm.js \
    tools/Resources.cpp \
    $BASE_DIR/gm_bindings.cpp \
    $GMS_TO_BUILD \
    $GM_LIB \
    $BUILD_DIR/libskshaper.a \
    $BUILD_DIR/libsvg.a \
    $BUILD_DIR/libskia.a \
    $BUILTIN_FONT \
    -s LLD_REPORT_UNDEFINED \
    -s ALLOW_MEMORY_GROWTH=1 \
    -s EXPORT_NAME="InitWasmGMTests" \
    -s EXPORTED_FUNCTIONS=['_malloc','_free'] \
    -s FORCE_FILESYSTEM=0 \
    -s FILESYSTEM=0 \
    -s MODULARIZE=1 \
    -s NO_EXIT_RUNTIME=1 \
    -s INITIAL_MEMORY=256MB \
    -s WASM=1 \
    $STRICTNESS \
    -o $BUILD_DIR/wasm_gm_tests.js