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

cd "$(dirname "$0")"

# LinuxCNC source basis: standalone probe modes either compile LinuxCNC
# rs274/tooldata sources directly or link wasm-safe shims whose source basis is
# checked against LinuxCNC source comments before building.
usage() {
    echo "usage: $0 --mode tooldata-link|tooldata-common-link|interp-base-link|python-plugin-link|python-plugin-inittab-link|rs274ngc-pre-object" >&2
}

mode=
while [[ "$#" -gt 0 ]]; do
    case "$1" in
        --mode)
            if [[ "$#" -lt 2 ]]; then
                echo "missing --mode value" >&2
                exit 1
            fi
            mode=$2
            shift 2
            ;;
        --help|-h)
            usage
            exit 0
            ;;
        *)
            usage
            echo "unknown wasm standalone probe option: $1" >&2
            exit 1
            ;;
    esac
done
case "$mode" in
    tooldata-link|tooldata-common-link|interp-base-link|python-plugin-link|python-plugin-inittab-link|rs274ngc-pre-object)
        ;;
    "")
        usage
        echo "missing --mode" >&2
        exit 1
        ;;
    *)
        usage
        echo "unknown wasm standalone probe mode: $mode" >&2
        exit 1
        ;;
esac

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: $build_jobs" >&2
    exit 1
fi
cache_dir=${CNC_SIM_WASM_STANDALONE_PROBE_CACHE_DIR-build/wasm-standalone-probe-cache}
if [[ -z "$cache_dir" ]]; then
    echo "CNC_SIM_WASM_STANDALONE_PROBE_CACHE_DIR must not be empty" >&2
    exit 1
fi
if [[ "$cache_dir" =~ [[:space:]] ]]; then
    echo "CNC_SIM_WASM_STANDALONE_PROBE_CACHE_DIR must not contain whitespace: $cache_dir" >&2
    exit 1
fi
mkdir -p "$cache_dir"
cache_dir=$(cd "$cache_dir" && pwd)
if [[ "$cache_dir" == "/" ]]; then
    echo "CNC_SIM_WASM_STANDALONE_PROBE_CACHE_DIR must not be the filesystem root" >&2
    exit 1
fi

preflight_cache_dir=${CNC_SIM_PREFLIGHT_CACHE_DIR:-"$cache_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)

common_flag_args=()
sources=()
target_name=
case "$mode" in
    tooldata-link|tooldata-common-link)
        if [[ "$mode" == "tooldata-common-link" ]]; then
            common_flag_args+=(--tooldata-include)
        fi
        tooldata_mmap_backend_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_mmap_backend.cc)
        tooldata_runtime_stubs_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_runtime_stubs.cc)
        tooldata_common_source=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh src/emc/tooldata/tooldata_common.cc)
        grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_common.cc provides' core/wasm_shims/tooldata/tooldata_common_probe_main.cc >/dev/null
        grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_mmap.cc, tooldata_nml.cc,' core/wasm_shims/tooldata/tooldata_probe_main.cc >/dev/null
        sources+=(
            "$tooldata_common_source"
            "$tooldata_mmap_backend_shim"
            "$tooldata_runtime_stubs_shim"
        )
        if [[ "$mode" == "tooldata-link" ]]; then
            sources+=(core/wasm_shims/tooldata/tooldata_probe_main.cc)
            target_name=tooldata_probe
        else
            sources+=(core/wasm_shims/tooldata/tooldata_common_probe_main.cc)
            target_name=tooldata_common_probe
        fi
        ;;
    interp-base-link)
        dlfcn_shim=$(./list-linuxcnc-wasm-safe-shims.sh dlfcn.cc)
        interp_base_source=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh src/emc/rs274ngc/interp_base.cc)
        grep -F 'LinuxCNC source basis: src/emc/rs274ngc/interp_base.cc provides' core/wasm_shims/interp_base_probe_main.cc >/dev/null
        sources+=(
            "$dlfcn_shim"
            "$interp_base_source"
            core/wasm_shims/interp_base_probe_main.cc
        )
        target_name=interp_base_probe
        ;;
    python-plugin-link|python-plugin-inittab-link)
        python_plugin_shim=$(./list-linuxcnc-wasm-safe-shims.sh python_plugin.cc)
        if [[ "$mode" == "python-plugin-link" ]]; then
            probe_source=core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
            target_name=python_plugin_probe
            grep -F 'LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc and' "$probe_source" >/dev/null
        else
            probe_source=core/wasm_shims/pythonplugin/python_plugin_inittab_probe_main.cc
            target_name=python_plugin_inittab_probe
            grep -F 'LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc' "$probe_source" >/dev/null
        fi
        sources+=(
            "$python_plugin_shim"
            "$probe_source"
        )
        ;;
    rs274ngc-pre-object)
        rs274ngc_pre_source=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh src/emc/rs274ngc/rs274ngc_pre.cc)
        grep -F 'core:src/emc/rs274ngc/rs274ngc_pre.cc:Interp implementation covered by rs274ngc_pre link probe' linuxcnc-rs274-wasm-source-files.txt >/dev/null
        sources+=("$rs274ngc_pre_source")
        target_name=rs274ngc_pre.o
        ;;
esac

common_flag_output=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-wasm-common-cxxflags.sh "${common_flag_args[@]}")
mapfile -t common_flags <<<"$common_flag_output"

mode_dir="$cache_dir/$mode"
mkdir -p "$mode_dir"
exec 8>"$mode_dir/probe.lock"
flock 8

objects=()
object_index=0
for source in "${sources[@]}"; do
    objects+=("$mode_dir/source_${object_index}.o")
    object_index=$((object_index + 1))
done
target="$mode_dir/$target_name"
if [[ "$mode" == "rs274ngc-pre-object" ]]; then
    target=${objects[0]}
fi

signature="$mode_dir/probe.signature"
next_signature="$mode_dir/probe.signature.next"
{
    printf 'CXX=%s\n' "$cxx"
    printf 'PWD=%s\n' "$PWD"
    printf 'LINUXCNC_ROOT=%s\n' "$linuxcnc_root"
    printf 'MODE=%s\n' "$mode"
    printf 'BUILD_RULE_VERSION=1\n'
    printf 'COMMON_FLAGS='
    printf ' %s' "${common_flags[@]}"
    printf '\n'
    printf 'SOURCES:\n'
    printf '%s\n' "${sources[@]}"
} > "$next_signature"
if [[ ! -f "$signature" ]] || ! cmp -s "$signature" "$next_signature"; then
    rm -f "$mode_dir"/source_*.o "$mode_dir"/source_*.d "$target"
fi
mv "$next_signature" "$signature"

makefile="$mode_dir/probe.mk"
{
    printf 'CXX := %s\n' "$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
    printf '\n.PHONY: all\n'
    printf 'all: %s\n\n' "$target"

    object_index=0
    for source in "${sources[@]}"; do
        printf '%s: %s\n' "${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

    if [[ "$mode" != "rs274ngc-pre-object" ]]; then
        printf '%s: $(OBJECTS)\n' "$target"
        printf '\t@$(CXX) $(OBJECTS) -o %s\n\n' "$target"
    fi
    printf '\n-include $(DEP_FILES)\n'
} > "$makefile"
make --output-sync=target -j"$build_jobs" -f "$makefile" >/dev/null

printf '%s\n' "$target"