#!/usr/bin/env bash
# Cross-compile win64_mp for Windows amd64.
set -euo pipefail
cd "$(dirname "$0")/.."

out="${1:-win64_mp.exe}"

version_file="VERSION"
if [[ ! -f "$version_file" ]]; then
  echo "1.0.0" > "$version_file"
fi
old="$(tr -d '[:space:]' < "$version_file")"
if [[ ! "$old" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "bad VERSION: $old" >&2
  exit 1
fi
IFS=. read -r major minor patch <<< "$old"
ver="${major}.${minor}.$((10#$patch + 1))"
printf '%s\n' "$ver" > "$version_file"

ldflags="-s -w -H windowsgui -X tea.chunkbyte.com/kato/go-worm/lib/config.Version=${ver}"
GOOS=windows GOARCH=amd64 go build -ldflags "$ldflags" -o "$out" .
# Belt-and-suspenders: PE subsystem WINDOWS (2) even if ldflags were dropped.
python3 - "$out" <<'PY'
import struct, sys
path = sys.argv[1]
with open(path, "r+b") as f:
    f.seek(0x3C)
    pe = struct.unpack("<I", f.read(4))[0]
    f.seek(pe)
    if f.read(4) != b"PE\x00\x00":
        raise SystemExit(f"not a PE file: {path}")
    opt = pe + 24
    f.seek(opt)
    magic, = struct.unpack("<H", f.read(2))
    if magic not in (0x10B, 0x20B):
        raise SystemExit(f"unknown PE magic {magic:#x}")
    f.seek(opt + 68)
    f.write(struct.pack("<H", 2))
print(f"pe subsystem=gui {path}")
PY
echo "built $out $ver"