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

cd "$(dirname "$0")"

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_TOOLDATA_MMAP_SYMBOLS_BUILD_DIR-build/wasm-tooldata-mmap-symbols}
if [[ -z "$build_dir" ]]; then
    echo "CNC_SIM_WASM_TOOLDATA_MMAP_SYMBOLS_BUILD_DIR must not be empty" >&2
    exit 1
fi
if [[ "$build_dir" =~ [[:space:]] ]]; then
    echo "CNC_SIM_WASM_TOOLDATA_MMAP_SYMBOLS_BUILD_DIR must not contain whitespace: $build_dir" >&2
    exit 1
fi
mkdir -p "$build_dir"
build_dir=$(cd "$build_dir" && pwd)
if [[ "$build_dir" == "/" ]]; then
    echo "CNC_SIM_WASM_TOOLDATA_MMAP_SYMBOLS_BUILD_DIR must not be the filesystem root" >&2
    exit 1
fi
exec 9>"$build_dir/tooldata-mmap-symbols.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)

tooldata_mmap_backend_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_mmap_backend.cc)
tooldata_mmap_source=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh src/emc/tooldata/tooldata_mmap.cc)

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

sources=(
    "$tooldata_mmap_backend_shim"
    "$tooldata_mmap_source"
)
objects=(
    "$build_dir/tooldata_mmap_backend.o"
    "$build_dir/linuxcnc_tooldata_mmap.o"
)

signature="$build_dir/tooldata-mmap-symbols.signature"
next_signature="$build_dir/tooldata-mmap-symbols.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' "${sources[@]}"
} > "$next_signature"
if [[ ! -f "$signature" ]] || ! cmp -s "$signature" "$next_signature"; then
    rm -f "$build_dir"/*.o "$build_dir"/*.d
fi
mv "$next_signature" "$signature"

makefile="$build_dir/tooldata-mmap-symbols.mk"
{
    printf 'CXX := %s\n' "$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: $(OBJECTS)\n\n'

    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
    printf '\n-include $(DEP_FILES)\n'
} > "$makefile"
make --output-sync=target -j"$build_jobs" -f "$makefile" >/dev/null

symbols_signature="$build_dir/tooldata-mmap-symbols.nm.signature"
symbols_next_signature="$build_dir/tooldata-mmap-symbols.nm.signature.next"
{
    printf 'SYMBOL_RULE_VERSION=1\n'
    stat -c 'OBJECT=%n:%s:%y' "${objects[@]}"
} > "$symbols_next_signature"
if [[ ! -f "$symbols_signature" || ! -f "$build_dir/backend.exports" || ! -f "$build_dir/linuxcnc.exports" ]] ||
    ! cmp -s "$symbols_signature" "$symbols_next_signature"; then
    nm --defined-only "$build_dir/tooldata_mmap_backend.o" \
        | awk '$2 ~ /^[A-Z]$/ {print $3}' \
        | LC_ALL=C sort -u \
        > "$build_dir/backend.exports"

    nm --defined-only "$build_dir/linuxcnc_tooldata_mmap.o" \
        | awk '$2 ~ /^[A-Z]$/ {print $3}' \
        | LC_ALL=C sort -u \
        > "$build_dir/linuxcnc.exports"
    mv "$symbols_next_signature" "$symbols_signature"
else
    rm -f "$symbols_next_signature"
fi

if ! comm -23 "$build_dir/linuxcnc.exports" "$build_dir/backend.exports" > "$build_dir/missing.exports"; then
    exit 1
fi

if [[ -s "$build_dir/missing.exports" ]]; then
    echo "missing wasm tooldata mmap backend exports from LinuxCNC tooldata_mmap.cc:" >&2
    cat "$build_dir/missing.exports" >&2
    exit 1
fi

comm -13 "$build_dir/linuxcnc.exports" "$build_dir/backend.exports" > "$build_dir/unexpected.exports"
if [[ -s "$build_dir/unexpected.exports" ]]; then
    echo "unexpected wasm tooldata mmap backend exports beyond LinuxCNC tooldata_mmap.cc:" >&2
    cat "$build_dir/unexpected.exports" >&2
    exit 1
fi

echo "linuxcnc wasm tooldata_mmap symbol probe passed"