#!/bin/sh
# micro-Max 4.8 Web (Core) - WebAssembly build
# Browser integration by 64Logic; micro-Max 4.8 by H.G. Muller
# SPDX-License-Identifier: MIT
#
# Builds ../../engine/micro-max-4.8-web-core.wasm from:
#   umax4_8.c                    micro-Max 4.8, byte for byte unchanged
#   micro-max-4.8-web-core.c     browser integration by 64Logic
#
# Requirements: clang and wasm-ld with the wasm32 target (LLVM 15 or later).
#   Linux:  apt install clang lld
#   macOS:  Apple's clang has no WebAssembly linker, so use Homebrew LLVM:
#           brew install llvm lld
#           CC=$(brew --prefix llvm)/bin/clang LD=$(brew --prefix lld)/bin/wasm-ld ./build-wasm.sh
#
# No Emscripten and no C library: the module is freestanding and needs no imports.

set -eu
cd "$(dirname "$0")"

CC=${CC:-clang}
LD=${LD:-wasm-ld}
OUT=${OUT:-../../engine/micro-max-4.8-web-core.wasm}
CANONICAL_SHA256=447cd24da6275221a1e9564d9282cb69f019b6c521dde1f063b9eb7de3fd34eb

# 1. Verify the preserved micro-Max source before building.
if command -v sha256sum >/dev/null 2>&1; then
    actual=$(sha256sum umax4_8.c | cut -d' ' -f1)
else
    actual=$(shasum -a 256 umax4_8.c | cut -d' ' -f1)
fi
if [ "$actual" != "$CANONICAL_SHA256" ]; then
    echo "umax4_8.c does not match the canonical micro-Max 4.8 source" >&2
    echo "  expected $CANONICAL_SHA256" >&2
    echo "  actual   $actual" >&2
    exit 1
fi
echo "umax4_8.c verified: $actual"

# 2. Compile. Core's engine-correctness flags are kept unchanged:
#    -std=gnu89 -fwrapv -fno-strict-aliasing -fsigned-char
TARGET="--target=wasm32 -mbulk-memory -nostdlib"
REQUIRED="-std=gnu89 -fwrapv -fno-strict-aliasing -fsigned-char"
BUILD=$(mktemp -d)
trap 'rm -rf "$BUILD"' EXIT

$CC $TARGET -O2 $REQUIRED -w -Dmain=umax_main \
    -c umax4_8.c -o "$BUILD/umax4_8.o"

$CC $TARGET -O2 $REQUIRED -Wall -Wextra -Wpedantic -Werror \
    -c micro-max-4.8-web-core.c -o "$BUILD/web-core.o"

# 3. Link. umax_main (the original play loop) is unreferenced and is removed,
#    along with its printf/getchar calls, so the module has no imports.
$LD --no-entry --gc-sections --allow-undefined \
    -z stack-size=1048576 \
    "$BUILD/web-core.o" "$BUILD/umax4_8.o" -o "$OUT"

echo "built $OUT"
if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$OUT"
else
    shasum -a 256 "$OUT"
fi