#!/bin/sh
set -e

# Adapted from official docker-library/docker dind entrypoint
# https://github.com/docker-library/docker/blob/master/24/dind/dockerd-entrypoint.sh

if [ -z "$DOCKER_HOST" ]; then
  case "$1" in
    dockerd*)
      # If we're running dockerd, we need to make sure we have cgroups mounted
      if [ ! -d /sys/fs/cgroup ]; then
        mkdir -p /sys/fs/cgroup
      fi
      if ! mountpoint -q /sys/fs/cgroup; then
        mount -t tmpfs -o uid=0,gid=0,mode=0755 cgroup /sys/fs/cgroup
      fi

      # Mount cgroup v2 if available and not mounted
      if [ -e /sys/fs/cgroup/cgroup.controllers ] && ! mountpoint -q /sys/fs/cgroup; then
        mount -t cgroup2 -o nsdelegate cgroup2 /sys/fs/cgroup
      fi

      # If /sys/fs/cgroup is not a cgroup2 mount, we might need to mount cgroup v1 hierarchies
      if ! mountpoint -q /sys/fs/cgroup || [ "$(stat -f -c %T /sys/fs/cgroup)" != "cgroup2fs" ]; then
        if [ -d /sys/fs/cgroup/cgroup.controllers ]; then
          # It is cgroup2 but maybe not mounted as such?
          # Actually if it exists, it's likely v2.
          :
        else
          # cgroup v1
          for subsystem in $(awk '/^[^#]/ { print $1 }' /proc/cgroups); do
            mkdir -p "/sys/fs/cgroup/$subsystem"
            if ! mountpoint -q "/sys/fs/cgroup/$subsystem"; then
              mount -t cgroup -o "$subsystem" cgroup "/sys/fs/cgroup/$subsystem"
            fi
          done
        fi
      fi
      ;;
  esac
fi

# Configure Docker daemon with Kata runtime support
mkdir -p /etc/docker
cat > /etc/docker/daemon.json <<EOF
{
  "storage-driver": "overlay2",
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "runtimes": {
    "kata": {
      "path": "/usr/bin/containerd-shim-kata-v2",
      "runtimeArgs": [
        "--kata-config",
        "/etc/kata-containers/configuration-qemu.toml"
      ]
    },
    "kata-fc": {
      "path": "/usr/bin/containerd-shim-kata-v2",
      "runtimeArgs": [
        "--kata-config",
        "/etc/kata-containers/configuration-fc.toml"
      ]
    }
  }
}
EOF

# Configure Kata to use Firecracker if available
if [ -f /etc/kata-containers/configuration-fc.toml ] && [ -x /usr/local/bin/firecracker ]; then
    echo "[INFO] Firecracker configuration found"
    # Update path in configuration if needed
    if ! grep -q "path = \"/usr/local/bin/firecracker\"" /etc/kata-containers/configuration-fc.toml 2>/dev/null; then
        if [ -w /etc/kata-containers/configuration-fc.toml ]; then
            sed -i 's|path = ".*firecracker"|path = "/usr/local/bin/firecracker"|g' /etc/kata-containers/configuration-fc.toml || true
        fi
    fi

    # Update jailer path if available
    if [ -x /usr/local/bin/jailer ]; then
        if ! grep -q "jailer_path = \"/usr/local/bin/jailer\"" /etc/kata-containers/configuration-fc.toml 2>/dev/null; then
             if [ -w /etc/kata-containers/configuration-fc.toml ]; then
                sed -i 's|jailer_path = ".*jailer"|jailer_path = "/usr/local/bin/jailer"|g' /etc/kata-containers/configuration-fc.toml || true
             fi
        fi
    fi
fi

# Enable debug logging if requested
if [ "${KATA_LOGGING_LEVEL}" = "debug" ]; then
    echo "[INFO] Enabling debug logging for Kata"
    for config in /etc/kata-containers/configuration-*.toml; do
        if [ -f "$config" ]; then
            sed -i 's/enable_debug = false/enable_debug = true/g' "$config"
            sed -i 's/#log_path = .*/log_path = "\/var\/log\/kata\/kata.log"/g' "$config"
            sed -i 's/level = "info"/level = "debug"/g' "$config"
        fi
    done
    mkdir -p /var/log/kata
fi

if [ "$1" = 'dockerd' ] || [ "${1#-}" != "$1" ]; then
  # if the first argument is "dockerd" or a flag (starts with -)
  if [ "${1#-}" != "$1" ]; then
    set -- dockerd "$@"
  fi

    # Explicitly use iptables-legacy if available, as it is often more stable for DinD
    if command -v update-alternatives >/dev/null; then
        if update-alternatives --query iptables | grep -q "iptables-legacy"; then
            update-alternatives --set iptables /usr/sbin/iptables-legacy || true
            update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy || true
        fi
    fi
fi

exec "$@"