mesh-drop/build/docker/Dockerfile.cross

# Cross-compile Wails v3 apps to any platform
#
# Darwin: Zig + macOS SDK
# Linux: Native GCC when host matches target, Zig for cross-arch
# Windows: Zig + bundled mingw
#
# Usage:
#   docker build -t wails-cross -f Dockerfile.cross .
#   docker run --rm -v $(pwd):/app wails-cross darwin arm64
#   docker run --rm -v $(pwd):/app wails-cross darwin amd64
#   docker run --rm -v $(pwd):/app wails-cross linux amd64
#   docker run --rm -v $(pwd):/app wails-cross linux arm64
#   docker run --rm -v $(pwd):/app wails-cross windows amd64
#   docker run --rm -v $(pwd):/app wails-cross windows arm64

FROM golang:1.25-bookworm

ARG TARGETARCH

# Install base tools, GCC, and GTK/WebKit dev packages
RUN apt-get update && apt-get install -y --no-install-recommends \
    curl xz-utils nodejs npm pkg-config gcc libc6-dev \
    libgtk-3-dev libwebkit2gtk-4.1-dev \
    libgtk-4-dev libwebkitgtk-6.0-dev \
    && rm -rf /var/lib/apt/lists/*

# Install Zig - automatically selects correct binary for host architecture
ARG ZIG_VERSION=0.14.0
RUN ZIG_ARCH=$(case "${TARGETARCH}" in arm64) echo "aarch64" ;; *) echo "x86_64" ;; esac) && \
    curl -L "https://ziglang.org/download/${ZIG_VERSION}/zig-linux-${ZIG_ARCH}-${ZIG_VERSION}.tar.xz" \
    | tar -xJ -C /opt \
    && ln -s /opt/zig-linux-${ZIG_ARCH}-${ZIG_VERSION}/zig /usr/local/bin/zig

# Download macOS SDK (required for darwin targets)
ARG MACOS_SDK_VERSION=14.5
RUN curl -L "https://github.com/joseluisq/macosx-sdks/releases/download/${MACOS_SDK_VERSION}/MacOSX${MACOS_SDK_VERSION}.sdk.tar.xz" \
    | tar -xJ -C /opt \
    && mv /opt/MacOSX${MACOS_SDK_VERSION}.sdk /opt/macos-sdk

ENV MACOS_SDK_PATH=/opt/macos-sdk

# Create Zig CC wrappers for cross-compilation targets
# Darwin and Windows use Zig; Linux uses native GCC (run with --platform for cross-arch)

# Darwin arm64
COPY <<'ZIGWRAP' /usr/local/bin/zcc-darwin-arm64
#!/bin/sh
ARGS=""
SKIP_NEXT=0
for arg in "$@"; do
    if [ $SKIP_NEXT -eq 1 ]; then
        SKIP_NEXT=0
        continue
    fi
    case "$arg" in
        -target) SKIP_NEXT=1 ;;
        -mmacosx-version-min=*) ;;
        *) ARGS="$ARGS $arg" ;;
    esac
done
exec zig cc -fno-sanitize=all -target aarch64-macos-none -isysroot /opt/macos-sdk -I/opt/macos-sdk/usr/include -L/opt/macos-sdk/usr/lib -F/opt/macos-sdk/System/Library/Frameworks -w $ARGS
ZIGWRAP
RUN chmod +x /usr/local/bin/zcc-darwin-arm64

# Darwin amd64
COPY <<'ZIGWRAP' /usr/local/bin/zcc-darwin-amd64
#!/bin/sh
ARGS=""
SKIP_NEXT=0
for arg in "$@"; do
    if [ $SKIP_NEXT -eq 1 ]; then
        SKIP_NEXT=0
        continue
    fi
    case "$arg" in
        -target) SKIP_NEXT=1 ;;
        -mmacosx-version-min=*) ;;
        *) ARGS="$ARGS $arg" ;;
    esac
done
exec zig cc -fno-sanitize=all -target x86_64-macos-none -isysroot /opt/macos-sdk -I/opt/macos-sdk/usr/include -L/opt/macos-sdk/usr/lib -F/opt/macos-sdk/System/Library/Frameworks -w $ARGS
ZIGWRAP
RUN chmod +x /usr/local/bin/zcc-darwin-amd64

# Windows amd64 - uses Zig's bundled mingw
COPY <<'ZIGWRAP' /usr/local/bin/zcc-windows-amd64
#!/bin/sh
ARGS=""
SKIP_NEXT=0
for arg in "$@"; do
    if [ $SKIP_NEXT -eq 1 ]; then
        SKIP_NEXT=0
        continue
    fi
    case "$arg" in
        -target) SKIP_NEXT=1 ;;
        -Wl,*) ;;
        *) ARGS="$ARGS $arg" ;;
    esac
done
exec zig cc -target x86_64-windows-gnu $ARGS
ZIGWRAP
RUN chmod +x /usr/local/bin/zcc-windows-amd64

# Windows arm64 - uses Zig's bundled mingw
COPY <<'ZIGWRAP' /usr/local/bin/zcc-windows-arm64
#!/bin/sh
ARGS=""
SKIP_NEXT=0
for arg in "$@"; do
    if [ $SKIP_NEXT -eq 1 ]; then
        SKIP_NEXT=0
        continue
    fi
    case "$arg" in
        -target) SKIP_NEXT=1 ;;
        -Wl,*) ;;
        *) ARGS="$ARGS $arg" ;;
    esac
done
exec zig cc -target aarch64-windows-gnu $ARGS
ZIGWRAP
RUN chmod +x /usr/local/bin/zcc-windows-arm64

# Build script
COPY <<'SCRIPT' /usr/local/bin/build.sh
#!/bin/sh
set -e

OS=${1:-darwin}
ARCH=${2:-arm64}

case "${OS}-${ARCH}" in
    darwin-arm64|darwin-aarch64)
        export CC=zcc-darwin-arm64
        export GOARCH=arm64
        export GOOS=darwin
        ;;
    darwin-amd64|darwin-x86_64)
        export CC=zcc-darwin-amd64
        export GOARCH=amd64
        export GOOS=darwin
        ;;
    linux-arm64|linux-aarch64)
        export CC=gcc
        export GOARCH=arm64
        export GOOS=linux
        ;;
    linux-amd64|linux-x86_64)
        export CC=gcc
        export GOARCH=amd64
        export GOOS=linux
        ;;
    windows-arm64|windows-aarch64)
        export CC=zcc-windows-arm64
        export GOARCH=arm64
        export GOOS=windows
        ;;
    windows-amd64|windows-x86_64)
        export CC=zcc-windows-amd64
        export GOARCH=amd64
        export GOOS=windows
        ;;
    *)
        echo "Usage: <os> <arch>"
        echo "  os: darwin, linux, windows"
        echo "  arch: amd64, arm64"
        exit 1
        ;;
esac

export CGO_ENABLED=1
export CGO_CFLAGS="-w"

# Build frontend if exists and not already built (host may have built it)
if [ -d "frontend" ] && [ -f "frontend/package.json" ] && [ ! -d "frontend/dist" ]; then
    (cd frontend && npm install --silent && npm run build --silent)
fi

# Build
APP=${APP_NAME:-$(basename $(pwd))}
mkdir -p bin

EXT=""
LDFLAGS="-s -w"
if [ "$GOOS" = "windows" ]; then
    EXT=".exe"
    LDFLAGS="-s -w -H windowsgui"
fi

go build -ldflags="$LDFLAGS" -o bin/${APP}-${GOOS}-${GOARCH}${EXT} .
echo "Built: bin/${APP}-${GOOS}-${GOARCH}${EXT}"
SCRIPT
RUN chmod +x /usr/local/bin/build.sh

WORKDIR /app
ENTRYPOINT ["/usr/local/bin/build.sh"]
CMD ["darwin", "arm64"]