FROM "${JRE_IMAGE:-localhost/minecraft-jre}":"${JRE_TAG:-latest}"

# Server version to download
ARG VERSION=latest

# PaperMC base URL
ARG BASE_URL="https://api.papermc.io/v2/projects/velocity/versions"

# Consider turning bStats (https://bStats.org) on but I'm turning it off by
# default because it collects information
ARG BSTATS_ENABLED=false

# For the entrypoint.sh script
ENV VELOCITY=true

# Download files
USER root
WORKDIR /app

# Install expect
RUN apt-get update && \
    apt-get install -y expect && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

# Download and verify sha256sum for Velocity
RUN set -eux && \
  # Grab latest version if not specified
  if [ "$VERSION" = "latest" ]; then \
    VERSION="$( \
      curl -s https://api.papermc.io/v2/projects/velocity | \
        jq -r '.versions[-1]' \
    )"; \
  fi && \
  # Get latest build for the specified version
  BUILD="$( \
    curl -s "${BASE_URL}/${VERSION}" \
      | jq -r '.builds[-1]' \
  )" && \
  URL="${BASE_URL}/${VERSION}/builds/${BUILD}/downloads/velocity-${VERSION}-${BUILD}.jar" && \
  curl -s -o /tmp/server.jar "$URL" && \
  # Get SHA256 hash of server.jar and compare
  SHA256="$(sha256sum /tmp/server.jar | awk '{print $1}')" && \
  EXPECTED="$( \
    curl -s "$BASE_URL/$VERSION/builds/$BUILD" \
      | jq -r '.downloads.application.sha256' \
  )" && \
  if [ ! "$SHA256" = "$EXPECTED" ]; then \
    echo "[ERROR] SHA256=\"$SHA256\" expected \"$EXPECTED\""; \
    exit 1; \
  fi && \
  mv /tmp/server.jar /app/velocity.jar

# Generate files as minecraft user
USER minecraft
WORKDIR /app

# Start server to generate initial files
RUN set -ux; \
  expect -c "\
    set timeout -1; \
    spawn /usr/bin/java -Xms1G -Xmx1G -XX:+UseG1GC -XX:G1HeapRegionSize=4M \
      -XX:+UnlockExperimentalVMOptions -XX:+ParallelRefProcEnabled \
      -XX:+AlwaysPreTouch -XX:MaxInlineLevel=15 -jar velocity.jar; \
    expect -re {\[[0-9]{2}:[0-9]{2}:[0-9]{2} INFO\]: Done .*!} { \
      send \"stop\r\"; \
      expect eof \
    } \
  " && \
  # Disable bStats by default and clear server-uuid
  cd /app/plugins/bStats/ || exit 1; \
  sed -i.bak "s/^enabled=.*\$/enabled=${BSTATS_ENABLED}/" config.txt && \
  diff --unified=1 config.txt.bak config.txt || true && rm config.txt.bak && \
  sed -i.bak "s/^server-uuid=.*\$/server-uuid=/" config.txt && \
  diff --unified=1 config.txt.bak config.txt || true && rm config.txt.bak && \
  # Truncate forwarding secret
  truncate -s 0 /app/forwarding.secret

# Back to root to copy the entrypoint in
USER root
COPY ../entrypoint.sh /usr/local/bin/entrypoint.sh
RUN chmod +x /usr/local/bin/entrypoint.sh

# Run app as minecraft user
USER minecraft
WORKDIR /app

# Expose port and run entrypoint script
EXPOSE 25565
ENTRYPOINT ["entrypoint.sh"]