ARG BASE_IMAGE

# Build dumb-init
FROM alpine AS dumb-init-builder

ARG DI_VER=1.2.5

WORKDIR /app

# Build dumb-init & download tshock
RUN apk add --update --no-cache build-base unzip curl && \
    curl -Lo - "https://github.com/Yelp/dumb-init/archive/refs/tags/v${DI_VER}.tar.gz" | tar -xzf - && \
    cd "dumb-init-${DI_VER}" && \
    make SHELL=/bin/sh && \
    mv dumb-init ..


# We use ${:-} instead of a default value because the argument is always passed
# to the build, it'll just be blank most likely
FROM ${BASE_IMAGE:-'openjdk:18-slim'}

# Build arguments
ARG MC_VERSION
ARG PAPERMC_VERSION

# Install mcstatus for healthchecks
RUN apt update && \
    apt install --no-install-recommends -y python3-minimal python3-setuptools python3-pip && \
    python3 -m pip install mcstatus && \
    apt --purge remove -y python3-pip python3-setuptools && \
    apt clean && \
    groupadd -g 1000 paper && \
    useradd -rMg paper -u 1000 paper

# Create worlds and config directory
WORKDIR /app
RUN mkdir -p worlds config/cache

# Download server file
ADD "https://papermc.io/api/v2/projects/paper/versions/$MC_VERSION/builds/$PAPERMC_VERSION/downloads/paper-$MC_VERSION-$PAPERMC_VERSION.jar" server.jar

# Make sure the server user can access all necessary folders
RUN chown -R paper:paper /app

# Store the cache in an anonymous volume, which means it won't get stored in the other volumes
VOLUME /app/config/cache

# Default value to keep users from eating up all ram accidentally
ENV XMX=4
ENV MC_VERSION="${MC_VERSION}"
ENV PAPERMC_VERSION="${PAPERMC_VERSION}"

# Document exposed ports
EXPOSE 25565

# Switch to non-root user
USER paper:paper

# Entrypoint runs in /app/config
COPY --from=dumb-init-builder /app/dumb-init /dumb-init
COPY entrypoint.sh /entrypoint.sh

WORKDIR /app/config
ENTRYPOINT ["/dumb-init", "--"]
CMD /entrypoint.sh

HEALTHCHECK --interval=30s --timeout=5s --start-period=1m --retries=5 \
    CMD mcstatus localhost:25565 ping