# Client image (share and/or use mode).
#
# Unlike the relay this container needs real access to the host's USB stack,
# which only works on a Linux host: containers share the host kernel, and that
# kernel is the one managing the devices. On macOS and Windows, Docker runs
# inside a Linux VM that never sees the USB hardware, so this image cannot
# share devices there — see README.
FROM --platform=$BUILDPLATFORM golang:1.26-alpine AS builder

ARG TARGETARCH
ARG TARGETVARIANT

WORKDIR /app

COPY go.mod go.sum ./
RUN go mod download

COPY . .

RUN GOARM=$(echo "$TARGETVARIANT" | tr -d 'v') \
    CGO_ENABLED=0 GOOS=linux GOARCH=$TARGETARCH \
    go build -ldflags="-s -w" -o /usb-client ./cmd/usb-client/

FROM alpine:3.21

# usbutils gives lsusb for diagnosing what the container can actually see;
# kmod lets the entrypoint check whether vhci-hcd is loaded on the host.
RUN apk add --no-cache ca-certificates usbutils kmod

COPY --from=builder /usb-client /usr/local/bin/usb-client
COPY docker/client-entrypoint.sh /usr/local/bin/client-entrypoint.sh
RUN chmod +x /usr/local/bin/client-entrypoint.sh

# Runs as root deliberately: opening /dev/bus/usb, detaching kernel drivers
# and rebinding them afterwards all need privileges.
EXPOSE 8080

ENTRYPOINT ["/usr/local/bin/client-entrypoint.sh"]
CMD ["both"]