#!/bin/bash
# Build OpenCASCADE Technology (OCCT) for WebAssembly
# OCCT provides 3D geometry kernel for STEP file import/export

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/../common/env.sh"
source "${SCRIPT_DIR}/../common/versions.sh"
source "${SCRIPT_DIR}/../common/functions.sh"

OCC_DIR="${DEPS_ROOT}/opencascade-${OCC_VERSION}"
OCC_BUILD="${BUILD_ROOT}/deps/opencascade"
OCC_STAMP="${BUILD_ROOT}/stamps/opencascade.stamp"

# Parse arguments
CLEAN=0
for arg in "$@"; do
    case $arg in
        --clean)
            CLEAN=1
            shift
            ;;
    esac
done

if [ $CLEAN -eq 1 ]; then
    log_info "Cleaning OpenCASCADE build..."
    rm -rf "${OCC_BUILD}" "${OCC_STAMP}"
fi

# Check if already built
if check_stamp "${OCC_STAMP}"; then
    log_info "OpenCASCADE already built, skipping..."
    exit 0
fi

# Download if needed
if [ ! -d "${OCC_DIR}" ]; then
    log_info "Downloading OpenCASCADE ${OCC_VERSION}..."
    mkdir -p "${DEPS_ROOT}"
    cd "${DEPS_ROOT}"

    # OpenCASCADE releases are on GitHub
    OCC_URL="https://github.com/Open-Cascade-SAS/OCCT/archive/refs/tags/V${OCC_VERSION//./_}.tar.gz"
    download_file "${OCC_URL}" "opencascade-${OCC_VERSION}.tar.gz"
    tar -xzf "opencascade-${OCC_VERSION}.tar.gz"
    # Directory name in tarball is OCCT-7_8_0 (without V prefix)
    mv "OCCT-${OCC_VERSION//./_}" "opencascade-${OCC_VERSION}"
    rm "opencascade-${OCC_VERSION}.tar.gz"
fi

# RapidJSON (header-only): required by OCC's glTF/GLB writer — without it the
# writer compiles out (HAVE_RAPIDJSON undefined) and GLB export fails at
# runtime with "glTF writer is unavailable". Pinned to the vcpkg master
# snapshot (see versions.sh) — a commit archive extracts as rapidjson-<sha>,
# so rename to the dated version dir.
RAPIDJSON_DIR="${DEPS_ROOT}/rapidjson-${RAPIDJSON_VERSION}"
if [ ! -d "${RAPIDJSON_DIR}" ]; then
    log_info "Downloading RapidJSON ${RAPIDJSON_VERSION} (master snapshot ${RAPIDJSON_COMMIT:0:12})..."
    mkdir -p "${DEPS_ROOT}"
    cd "${DEPS_ROOT}"
    download_file "${RAPIDJSON_URL}" "rapidjson-${RAPIDJSON_VERSION}.tar.gz"
    tar -xzf "rapidjson-${RAPIDJSON_VERSION}.tar.gz"
    mv "rapidjson-${RAPIDJSON_COMMIT}" "rapidjson-${RAPIDJSON_VERSION}"
    rm "rapidjson-${RAPIDJSON_VERSION}.tar.gz"
fi

log_info "Building OpenCASCADE ${OCC_VERSION} for WASM..."
log_warn "This is a large library and may take a while..."

mkdir -p "${OCC_BUILD}"
cd "${OCC_BUILD}"

# OpenCASCADE build configuration for WASM
# Disable GUI, visualization that needs X11/OpenGL native
# Enable core geometry and data exchange modules only
#
# OCC's CMake unconditionally adds -DOCC_CONVERT_SIGNALS (occt_defs_flags.cmake), which turns the
# OCC_CATCH_SIGNALS macro into setjmp(handler.Label()). The STEP read/write code
# (STEPControl_Reader/ActorRead, ...) uses OCC_CATCH_SIGNALS pervasively. Under -fwasm-exceptions that
# setjmp is lowered (emscripten's LowerEmscriptenEHSjLj) into a wasm-SjLj state-machine br_table whose
# branch targets are inconsistently typed -> INVALID wasm that V8, wabt AND Binaryen all reject (this
# is the "popping from empty stack" / br_table type-mismatch that blocks pcbnew's OCC link). WASM has
# no POSIX signals, so OCC_CONVERT_SIGNALS (signal->exception conversion) is meaningless here anyway;
# OCC's normal C++ Standard_Failure throw/catch is unaffected. Disabling it means OCC_CATCH_SIGNALS
# expands to nothing (clang) -> no setjmp -> no wasm-SjLj -> valid native-EH wasm.
_occ_defs="${OCC_DIR}/adm/cmake/occt_defs_flags.cmake"
if grep -q '^[[:space:]]*add_definitions(-DOCC_CONVERT_SIGNALS)' "${_occ_defs}" 2>/dev/null; then
  sed -i 's|add_definitions(-DOCC_CONVERT_SIGNALS)|# add_definitions(-DOCC_CONVERT_SIGNALS) # disabled for native wasm-EH by build-opencascade.sh (no POSIX signals in WASM; setjmp breaks -fwasm-exceptions)|' "${_occ_defs}"
  log_info "Disabled OCC_CONVERT_SIGNALS for native wasm-EH (avoids invalid wasm-SjLj br_table)"
fi
emcmake cmake "${OCC_DIR}" \
    -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
    -DCMAKE_BUILD_TYPE=${BUILD_TYPE:-Debug} \
    -DCMAKE_INSTALL_PREFIX="${SYSROOT}" \
    -DCMAKE_CXX_FLAGS="${DEBUG_CFLAGS:--g -O0} -pthread -matomics -mbulk-memory ${DEPS_EH_FLAGS}" \
    -DCMAKE_C_FLAGS="${DEBUG_CFLAGS:--g -O0} -pthread -matomics -mbulk-memory ${DEPS_EH_FLAGS}" \
    -DBUILD_LIBRARY_TYPE=Static \
    -DBUILD_MODULE_ApplicationFramework=OFF \
    -DBUILD_MODULE_Draw=OFF \
    -DBUILD_MODULE_Visualization=OFF \
    -DBUILD_MODULE_DETools=OFF \
    -DBUILD_MODULE_FoundationClasses=ON \
    -DBUILD_MODULE_ModelingData=ON \
    -DBUILD_MODULE_ModelingAlgorithms=ON \
    -DBUILD_MODULE_DataExchange=ON \
    -DUSE_FREETYPE=OFF \
    -DUSE_FREEIMAGE=OFF \
    -DUSE_OPENVR=OFF \
    -DUSE_FFMPEG=OFF \
    -DUSE_TBB=OFF \
    -DUSE_VTK=OFF \
    -DUSE_TCL=OFF \
    -DUSE_TK=OFF \
    -DUSE_GLES2=OFF \
    -DUSE_OPENGL=OFF \
    -DUSE_D3D=OFF \
    -DUSE_RAPIDJSON=ON \
    -D3RDPARTY_RAPIDJSON_DIR="${RAPIDJSON_DIR}" \
    -DUSE_DRACO=OFF \
    -DBUILD_DOC_Overview=OFF \
    -DINSTALL_SAMPLES=OFF \
    -DINSTALL_TEST_CASES=OFF

emmake make -j${JOBS}
emmake make install

create_stamp "${OCC_STAMP}"
log_info "OpenCASCADE build complete!"
