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

cd "$(dirname "$0")"

usage() {
    echo "usage: $0 --mode rs274ngc-pre|runtime [manifest]" >&2
}

mode=
manifest=linuxcnc-rs274-wasm-source-files.txt
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 link probe option: $1" >&2
            exit 1
            ;;
        *)
            manifest=$1
            shift
            ;;
    esac
done
case "$mode" in
    rs274ngc-pre|runtime)
        ;;
    "")
        usage
        echo "missing --mode" >&2
        exit 1
        ;;
    *)
        usage
        echo "unknown wasm link 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_LINK_PROBE_CACHE_DIR-build/wasm-link-probe-cache}
if [[ -z "$cache_dir" ]]; then
    echo "CNC_SIM_WASM_LINK_PROBE_CACHE_DIR must not be empty" >&2
    exit 1
fi
if [[ "$cache_dir" =~ [[:space:]] ]]; then
    echo "CNC_SIM_WASM_LINK_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_LINK_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"}
object_mode=$mode
main_source=core/wasm_shims/rs274ngc_pre_probe_main.cc
target_name=rs274ngc_pre_probe
common_flag_output=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-wasm-common-cxxflags.sh --profile core20-sections)
mapfile -t common_flags <<<"$common_flag_output"
case "$mode" in
    runtime)
        object_mode=runtime
        main_source=core/wasm_shims/cnc_sim_wasm_runtime_probe_main.cc
        target_name=cnc_sim_wasm_runtime_probe
        common_flags+=(-DCNC_SIM_ENABLE_LINUXCNC_RS274_BACKEND)
        ;;
esac

object_output=$(CNC_SIM_PREFLIGHT_CACHE_DIR="$preflight_cache_dir" LINUXCNC_ROOT="$linuxcnc_root" ./build-linuxcnc-wasm-probe-objects.sh --mode "$object_mode" "$manifest")
mapfile -t objects <<<"$object_output"
manifest=$(cd "$(dirname "$manifest")" && pwd)/$(basename "$manifest")
linuxcnc_root=$(cd "$linuxcnc_root" && pwd)

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

main_object="$mode_dir/main.o"
target="$mode_dir/$target_name"
signature="$mode_dir/link.signature"
next_signature="$mode_dir/link.signature.next"
{
    printf 'CXX=%s\n' "$cxx"
    printf 'PWD=%s\n' "$PWD"
    printf 'LINUXCNC_ROOT=%s\n' "$linuxcnc_root"
    printf 'MANIFEST=%s\n' "$manifest"
    printf 'MODE=%s\n' "$mode"
    printf 'BUILD_RULE_VERSION=1\n'
    printf 'COMMON_FLAGS='
    printf ' %s' "${common_flags[@]}"
    printf '\n'
    printf 'MAIN_SOURCE=%s\n' "$main_source"
    printf 'OBJECTS:\n'
    printf '%s\n' "${objects[@]}"
} > "$next_signature"
if [[ ! -f "$signature" ]] || ! cmp -s "$signature" "$next_signature"; then
    rm -f "$main_object" "$main_object.d" "$target" "$mode_dir/runtime.symbols"
fi
mv "$next_signature" "$signature"

makefile="$mode_dir/link.mk"
{
    printf 'CXX := %s\n' "$cxx"
    printf 'COMMON_FLAGS :='
    printf ' %s' "${common_flags[@]}"
    printf '\n\n'
    printf 'OBJECTS :='
    printf ' %s' "${objects[@]}"
    printf '\n\n'
    printf '.PHONY: all\n'
    printf 'all: %s\n\n' "$target"
    printf '%s: %s\n' "$main_object" "$main_source"
    printf '\t@$(CXX) $(COMMON_FLAGS) -MMD -MP -MF %s.d -c %s -o %s\n\n' "$main_object" "$main_source" "$main_object"
    printf '%s: $(OBJECTS) %s\n' "$target" "$main_object"
    printf '\t@$(CXX) $(OBJECTS) %s -Wl,--gc-sections -lfmt -o %s\n\n' "$main_object" "$target"
    printf '\n-include %s.d\n' "$main_object"
} > "$makefile"
make --output-sync=target -j"$build_jobs" -f "$makefile" >/dev/null

printf '%s\n' "$target"