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

cd "$(dirname "$0")"

# LinuxCNC source basis: this probe derives required Python C API exports from
# RS274 Python/remap sources in src/emc/rs274ngc and from
# src/emc/pythonplugin/python_plugin.cc initialization/configuration paths,
# while compiling only the RS274 binding objects that need wasm-safe symbols.
linuxcnc_root=${LINUXCNC_ROOT:-../linuxcnc}
cxx=${CXX:-g++}
if [[ -z ${CXX:-} ]] && command -v ccache >/dev/null 2>&1; then
    cxx="ccache $cxx"
fi
build_jobs=${CNC_SIM_BUILD_JOBS:-8}
if ! [[ "$build_jobs" =~ ^[1-9][0-9]*$ ]]; then
    echo "CNC_SIM_BUILD_JOBS must be a positive integer: $build_jobs" >&2
    exit 1
fi
build_dir=${CNC_SIM_WASM_PYTHON_C_API_BUILD_DIR-build/wasm-python-c-api-symbols}
if [[ -z "$build_dir" ]]; then
    echo "CNC_SIM_WASM_PYTHON_C_API_BUILD_DIR must not be empty" >&2
    exit 1
fi
if [[ "$build_dir" =~ [[:space:]] ]]; then
    echo "CNC_SIM_WASM_PYTHON_C_API_BUILD_DIR must not contain whitespace: $build_dir" >&2
    exit 1
fi
mkdir -p "$build_dir"
build_dir=$(cd "$build_dir" && pwd)
if [[ "$build_dir" == "/" ]]; then
    echo "CNC_SIM_WASM_PYTHON_C_API_BUILD_DIR must not be the filesystem root" >&2
    exit 1
fi
exec 9>"$build_dir/python-c-api.lock"
flock 9

preflight_cache_dir=${CNC_SIM_PREFLIGHT_CACHE_DIR:-"$build_dir/preflight-cache"}
LINUXCNC_ROOT="$linuxcnc_root" ./check-linuxcnc-inputs-cached.sh --cache-dir "$preflight_cache_dir" --root-only
linuxcnc_root=$(cd "$linuxcnc_root" && pwd)

python_c_api_shim=$(./list-linuxcnc-wasm-safe-shims.sh python_c_api_shim.cc)
runtime_shim=$(./list-linuxcnc-wasm-safe-shims.sh linuxcnc_runtime_shim.cc)
linuxcnc_source_output=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh \
    src/emc/rs274ngc/interp_namedparams.cc \
    src/emc/rs274ngc/interp_o_word.cc \
    src/emc/rs274ngc/interp_python.cc \
    src/emc/rs274ngc/interp_remap.cc \
    src/emc/rs274ngc/interp_setup.cc \
    src/emc/rs274ngc/rs274ngc_pre.cc \
    src/emc/rs274ngc/pyarrays.cc \
    src/emc/rs274ngc/pyblock.cc \
    src/emc/rs274ngc/pyemctypes.cc \
    src/emc/rs274ngc/pyinterp1.cc \
    src/emc/rs274ngc/pyparamclass.cc \
    src/emc/rs274ngc/canonmodule.cc \
    src/emc/rs274ngc/interpmodule.cc \
    src/emc/rs274ngc/gcodemodule.cc)
mapfile -t linuxcnc_sources <<<"$linuxcnc_source_output"
python_binding_sources=("${linuxcnc_sources[@]:6}")
python_plugin_source_output=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh \
    src/emc/pythonplugin/python_plugin.cc)
mapfile -t python_plugin_sources <<<"$python_plugin_source_output"
python_token_sources=("${linuxcnc_sources[@]}" "${python_plugin_sources[@]}")

common_flag_output=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-wasm-common-cxxflags.sh)
mapfile -t common_flags <<<"$common_flag_output"

objects=(
    "$build_dir/python_c_api_shim.o"
    "$build_dir/runtime_shim.o"
)
object_sources=(
    "$python_c_api_shim"
    "$runtime_shim"
)
probe_objects=(
    "$build_dir/python_c_api_probe_main.o"
)
probe_sources=(
    core/wasm_shims/python_c_api_probe_main.cc
)
for source in "${python_binding_sources[@]}"; do
    object_name=$(basename "$source" .cc)
    objects+=("$build_dir/$object_name.o")
    object_sources+=("$source")
done

signature="$build_dir/python-c-api.signature"
next_signature="$build_dir/python-c-api.signature.next"
{
    printf 'CXX=%s\n' "$cxx"
    printf 'PWD=%s\n' "$PWD"
    printf 'LINUXCNC_ROOT=%s\n' "$linuxcnc_root"
    printf 'BUILD_RULE_VERSION=1\n'
    printf 'COMMON_FLAGS='
    printf ' %s' "${common_flags[@]}"
    printf '\n'
    printf 'SOURCES:\n'
    printf '%s\n' "${object_sources[@]}"
    printf 'PROBE_SOURCES:\n'
    printf '%s\n' "${probe_sources[@]}"
} > "$next_signature"
if [[ ! -f "$signature" ]] || ! cmp -s "$signature" "$next_signature"; then
    rm -f "$build_dir"/*.o "$build_dir"/*.d "$build_dir/python_c_api_probe"
fi
mv "$next_signature" "$signature"

makefile="$build_dir/python-c-api.mk"
{
    printf 'CXX := %s\n' "$cxx"
    printf 'COMMON_FLAGS :='
    printf ' %s' "${common_flags[@]}"
    printf '\n\n'
    printf 'OBJECTS :='
    printf ' %s' "${objects[@]}"
    printf '\n\n'
    printf 'DEP_FILES :=\n'
    for object in "${objects[@]}"; do
        printf 'DEP_FILES += %s.d\n' "$object"
    done
    for object in "${probe_objects[@]}"; do
        printf 'DEP_FILES += %s.d\n' "$object"
    done
    printf '\n.PHONY: all\n'
    printf 'all: $(OBJECTS) %s\n\n' "$build_dir/python_c_api_probe"

    object_index=0
    for source in "${object_sources[@]}"; do
        printf '%s: %s\n' "${objects[$object_index]}" "$source"
        printf '\t@$(CXX) $(COMMON_FLAGS) -MMD -MP -MF %s.d -c %s -o %s\n\n' "${objects[$object_index]}" "$source" "${objects[$object_index]}"
        object_index=$((object_index + 1))
    done
    probe_index=0
    for source in "${probe_sources[@]}"; do
        printf '%s: %s\n' "${probe_objects[$probe_index]}" "$source"
        printf '\t@$(CXX) $(COMMON_FLAGS) -MMD -MP -MF %s.d -c %s -o %s\n\n' "${probe_objects[$probe_index]}" "$source" "${probe_objects[$probe_index]}"
        probe_index=$((probe_index + 1))
    done
    printf '%s: %s %s\n' "$build_dir/python_c_api_probe" "$build_dir/python_c_api_shim.o" "${probe_objects[*]}"
    printf '\t@$(CXX) %s %s -o %s\n\n' "$build_dir/python_c_api_shim.o" "${probe_objects[*]}" "$build_dir/python_c_api_probe"
    printf '\n-include $(DEP_FILES)\n'
} > "$makefile"
make --output-sync=target -j"$build_jobs" -f "$makefile" >/dev/null

source_symbols_signature="$build_dir/python-c-api.source-symbols.signature"
source_symbols_next_signature="$build_dir/python-c-api.source-symbols.signature.next"
{
    printf 'SOURCE_SYMBOL_RULE_VERSION=1\n'
    printf 'LINUXCNC_TOKEN_SOURCES:\n'
    printf '%s\n' "${python_token_sources[@]}"
    printf 'SOURCE_STATS:\n'
    stat -c 'SOURCE=%n:%s:%y' "${python_token_sources[@]}"
} > "$source_symbols_next_signature"
if [[ ! -f "$source_symbols_signature" || ! -f "$build_dir/linuxcnc.py-tokens" ]] ||
    ! cmp -s "$source_symbols_signature" "$source_symbols_next_signature"; then
    rg -o 'Py[A-Za-z0-9_]+' "${python_token_sources[@]}" \
        | sed 's/^.*://' \
        | LC_ALL=C sort -u \
        > "$build_dir/linuxcnc.py-tokens"
    mv "$source_symbols_next_signature" "$source_symbols_signature"
else
    rm -f "$source_symbols_next_signature"
fi

object_symbols_signature="$build_dir/python-c-api.object-symbols.signature"
object_symbols_next_signature="$build_dir/python-c-api.object-symbols.signature.next"
{
    printf 'OBJECT_SYMBOL_RULE_VERSION=1\n'
    stat -c 'OBJECT=%n:%s:%y' "${objects[@]}"
} > "$object_symbols_next_signature"
if [[ ! -f "$object_symbols_signature" ||
        ! -f "$build_dir/shim.exports" ||
        ! -f "$build_dir/object.undefined" ||
        ! -f "$build_dir/object.defined" ]] ||
    ! cmp -s "$object_symbols_signature" "$object_symbols_next_signature"; then
    nm --defined-only "$build_dir/python_c_api_shim.o" \
        | awk '$2 ~ /^[A-Z]$/ {print $3}' \
        | LC_ALL=C sort -u \
        > "$build_dir/shim.exports"

    nm -u "$build_dir"/*.o \
        | awk '{print $2}' \
        | sed '/^$/d' \
        | LC_ALL=C sort -u \
        > "$build_dir/object.undefined"
    nm --defined-only "$build_dir"/*.o \
        | awk '{print $3}' \
        | sed '/^$/d' \
        | LC_ALL=C sort -u \
        > "$build_dir/object.defined"
    mv "$object_symbols_next_signature" "$object_symbols_signature"
else
    rm -f "$object_symbols_next_signature"
fi

awk '
    $0 == "PyObject" { next }
    $0 == "PyTypeObject" { next }
    $0 == "Py_None" { next }
    $0 == "Py_TYPE" { next }
    $0 == "Py_XDECREF" { next }
    $0 == "Py_DECREF" { next }
    $0 == "PyList_SET_ITEM" { next }
    $0 == "PyTuple_SET_ITEM" { next }
    $0 == "PyObject_HEAD" { next }
    $0 == "PyVarObject_HEAD_INIT" { next }
    $0 == "PyModuleDef_HEAD_INIT" { next }
    $0 == "Py_TPFLAGS_DEFAULT" { next }
    $0 == "PyCFunction" { next }
    $0 == "PyConfig" { next }
    $0 == "PyGetSetDef" { next }
    $0 == "PyMemberDef" { next }
    $0 == "PyMethodDef" { next }
    $0 == "PyModuleDef" { next }
    $0 == "PyMODINIT_FUNC" { next }
    $0 == "PyObject_New" { next }
    $0 == "PyStatus" { next }
    $0 == "PyInit_emccanon" { next }
    $0 == "PyInit_gcode" { next }
    $0 == "PyInit_interpreter" { next }
    $0 == "PyErr_Ocurred" { next }
    $0 == "PyFloat_CheckAndError" { next }
    $0 == "PyLong_CheckAndError" { next }
    $0 == "Python" { next }
    $0 == "PythonPlugin" { next }
    { print }
' "$build_dir/linuxcnc.py-tokens" > "$build_dir/required.exports"

comm -23 "$build_dir/required.exports" "$build_dir/shim.exports" > "$build_dir/missing.exports"
if [[ -s "$build_dir/missing.exports" ]]; then
    echo "missing wasm Python C API shim exports used by LinuxCNC rs274 sources:" >&2
    cat "$build_dir/missing.exports" >&2
    exit 1
fi

for macro in Py_None Py_TYPE Py_XDECREF Py_DECREF PyTuple_SET_ITEM PyList_SET_ITEM PyObject_New; do
    if ! grep -F "#define $macro" core/wasm_shims/boost/python/object.hpp >/dev/null; then
        echo "missing wasm Python C API shim macro used by LinuxCNC rs274 sources: $macro" >&2
        exit 1
    fi
done

grep -F "Py_DecRef" core/wasm_shims/boost/python/object.hpp >/dev/null
grep -F "_Py_NoneStructPtr" core/wasm_shims/boost/python/object.hpp >/dev/null
grep -F 'extern "C" PyObject *PyInit_gcode(void)' core/wasm_shims/linuxcnc_runtime_shim.cc >/dev/null

comm -23 "$build_dir/object.undefined" "$build_dir/object.defined" \
    | awk '/^_?Py/ { print }' \
    > "$build_dir/object.missing-python"
if [[ -s "$build_dir/object.missing-python" ]]; then
    echo "missing wasm Python C API object definitions used by LinuxCNC rs274 bindings:" >&2
    cat "$build_dir/object.missing-python" >&2
    exit 1
fi

"$build_dir/python_c_api_probe"

echo "linuxcnc wasm Python C API symbol probe passed"