#!/bin/sh

set -e

# Variables
FORGEJO_URL="https://forgejo.mixinet.net"
RUNNER_NAME="forgejo-docker-runner"

# Compute WORK_DIR
SCRIPT="$(readlink -f "$0")"
SCRIPT_DIR="$(dirname "$SCRIPT")"
WORK_DIR_RELPATH=".."
WORK_DIR="$(readlink -f "$SCRIPT_DIR/$WORK_DIR_RELPATH")"

DATA_DIR="$WORK_DIR/data"

setup_user() {
  if id -u forgejo-runner >/dev/null 2>&1; then
    echo "User 'forgejo-runner' already exists."
    return
  fi
  if id -g forgejo-runner >/dev/null 2>&1; then
    echo "Group 'forgejo-runner' already exists."
  else
    sudo addgroup --system forgejo-runner
  fi
  sudo adduser --system --home /srv/forgejo-runner --no-create-home --ingroup forgejo-runner forgejo-runner
}

setup_data_dir() {
  mkdir -p "$DATA_DIR"
  sudo chown "$(id -u forgejo-runner):$(id -g forgejo-runner)" "$DATA_DIR"
  sudo chmod 0775 "$DATA_DIR"

  test -d "$DATA_DIR/.cache" || mkdir "$DATA_DIR/.cache"
  sudo chown -R "$(id -u forgejo-runner):$(id -g forgejo-runner)" "$DATA_DIR/.cache"
  sudo chmod 2775 "$DATA_DIR/.cache"
}

setup_runner() {
  if [ -f "$DATA_DIR/.runner" ]; then
    sudo chown "$(id -u forgejo-runner):$(id -g forgejo-runner)" "$DATA_DIR/.runner"
    echo "Runner already configured, remove '$DATA_DIR/.runner' to configure again."
    return
  fi
  forgejo_secret="$(openssl rand -hex 20)"
  cd "$WORK_DIR" || exit 1
  # Run the runner on a container usign the existing docker-compose file
  RUNNER_UID="$(id -u forgejo-runner)" RUNNER_GID="$(id -g forgejo-runner)" docker compose run --rm runner \
    forgejo-runner create-runner-file --instance "$FORGEJO_URL" --name "$RUNNER_NAME" --secret "$forgejo_secret"
  # Stop the dind container (it is started because it is a dependency of the runner)
  RUNNER_UID="$(id -u forgejo-runner)" RUNNER_GID="$(id -g forgejo-runner)" docker compose down
  # Update the labels on the runner config
  TMP_FILE="$(mktemp)"
  jq '.labels |= ["docker:docker://node:22-bookworm"]' "$DATA_DIR/.runner" >"$TMP_FILE"
  sudo sh -c "cat '$TMP_FILE' >'$DATA_DIR/.runner'"
  rm "$TMP_FILE"
  # Print message to register the runner with the secret
  cat <<EOF
Runner configuration file created. Please register the runner with the following command:

  forgejo forgejo-cli actions register --name "$RUNNER_NAME" --secret "$forgejo_secret"
EOF
}

# ====
# MAIN
# ====

setup_user
setup_data_dir
setup_runner
cat <<EOF
Runner setup complete. You can now start the runner with:

  cd "$WORK_DIR"
  RUNNER_UID="$(id -u forgejo-runner)" RUNNER_GID="$(id -g forgejo-runner)" docker compose up -d
EOF