#!/usr/bin/env bash
# SelfHeal Kafka Setup Script (Dev / Lab Only)
# -------------------------------------------
# Single-node Kafka broker with ZooKeeper for lab / Quickstart usage.
#
# This script:
#   * Downloads Kafka (default 3.7.0, Scala 2.13)
#   * Starts ZooKeeper and a single Kafka broker on localhost:9092
#   * Creates the SelfHeal topics:
#       - selfheal.alerts.raw.generic
#       - selfheal.alerts.normalized
#       - actions-review
#       - alerts-dlq
#
# Usage:
#   ./selfheal-setup-kafka.sh
# or:
#   KAFKA_VERSION=3.7.2 ./selfheal-setup-kafka.sh
#
# NOTE: This is for dev / lab only. For production, use a proper Kafka
#       cluster (KRaft or managed Kafka) and just point SelfHeal at it.

set -euo pipefail

KAFKA_VERSION="${KAFKA_VERSION:-3.7.0}"
SCALA_SUFFIX="2.13"
KAFKA_TGZ="kafka_${SCALA_SUFFIX}-${KAFKA_VERSION}.tgz"
KAFKA_DIR="$HOME/kafka_${SCALA_SUFFIX}-${KAFKA_VERSION}"
KAFKA_URL="https://downloads.apache.org/kafka/${KAFKA_VERSION}/${KAFKA_TGZ}"

ZOOKEEPER_CONFIG="$KAFKA_DIR/config/zookeeper.properties"
SERVER_CONFIG="$KAFKA_DIR/config/server.properties"
ZOOKEEPER_DATA_DIR="$KAFKA_DIR/zookeeper-data"
KAFKA_LOG_DIR="$KAFKA_DIR/kafka-logs"

echo "==> SelfHeal Kafka setup (dev / lab only)"
echo "    KAFKA_VERSION = ${KAFKA_VERSION}"
echo "    KAFKA_DIR     = ${KAFKA_DIR}"
echo ""

# 1) Ensure basic tools
echo "==> Installing prerequisites (curl, tar, Java)..."
sudo apt-get update -y
sudo apt-get install -y curl tar openjdk-17-jre-headless

# 2) Download Kafka if needed
if [ ! -d "$KAFKA_DIR" ]; then
  echo "==> Kafka directory not found. Downloading ${KAFKA_TGZ} ..."
  cd "$HOME"
  if [ ! -f "$KAFKA_TGZ" ]; then
    echo "    Downloading from: ${KAFKA_URL}"
    curl -fSL "$KAFKA_URL" -o "$KAFKA_TGZ"
  else
    echo "    Found existing tarball: $KAFKA_TGZ"
  fi

  echo "==> Extracting Kafka to $KAFKA_DIR ..."
  tar xzf "$KAFKA_TGZ"
else
  echo "==> Using existing Kafka directory: $KAFKA_DIR"
fi

cd "$KAFKA_DIR"

# 3) Configure ZooKeeper and Kafka paths
echo "==> Configuring ZooKeeper and Kafka log directories ..."

mkdir -p "$ZOOKEEPER_DATA_DIR"
mkdir -p "$KAFKA_LOG_DIR"

# zookeeper.properties: dataDir
sed -i "s|^dataDir=.*|dataDir=$ZOOKEEPER_DATA_DIR|" "$ZOOKEEPER_CONFIG"

# server.properties: log.dirs and listeners
if grep -q "^log.dirs=" "$SERVER_CONFIG"; then
  sed -i "s|^log.dirs=.*|log.dirs=$KAFKA_LOG_DIR|" "$SERVER_CONFIG"
else
  echo "log.dirs=$KAFKA_LOG_DIR" >> "$SERVER_CONFIG"
fi

if grep -q "^listeners=" "$SERVER_CONFIG"; then
  sed -i "s|^listeners=.*|listeners=PLAINTEXT://:9092|" "$SERVER_CONFIG"
else
  echo "listeners=PLAINTEXT://:9092" >> "$SERVER_CONFIG"
fi

echo "==> Starting ZooKeeper (background)..."
if pgrep -f "org.apache.zookeeper.server.quorum.QuorumPeerMain" >/dev/null 2>&1; then
  echo "    ZooKeeper already running; skipping start."
else
  nohup bin/zookeeper-server-start.sh "$ZOOKEEPER_CONFIG" > "$KAFKA_DIR/zookeeper.log" 2>&1 &
  sleep 10
fi

echo "==> Starting Kafka broker (background)..."
if pgrep -f "kafka.Kafka" >/dev/null 2>&1; then
  echo "    Kafka broker already running; skipping start."
else
  nohup bin/kafka-server-start.sh "$SERVER_CONFIG" > "$KAFKA_DIR/kafka.log" 2>&1 &
  sleep 15
fi

# 5) Create SelfHeal topics
echo "==> Creating SelfHeal topics (if not present)..."
TOPICS=(
  "selfheal.alerts.raw.generic"
  "selfheal.alerts.normalized"
  "actions-review"
  "alerts-dlq"
)

for t in "${TOPICS[@]}"; do
  echo "  -> Ensuring topic '$t' exists..."
  bin/kafka-topics.sh --create \
    --if-not-exists \
    --bootstrap-server localhost:9092 \
    --topic "$t" \
    --partitions 3 \
    --replication-factor 1
done

echo "==> Current topics:"
bin/kafka-topics.sh --list --bootstrap-server localhost:9092 || true

echo ""
echo "==> Kafka lab setup complete."
echo "    Broker is listening on localhost:9092 via ZooKeeper."
echo ""
echo "    To stop processes manually (lab only):"
echo "      pkill -f kafka.Kafka || true"
echo "      pkill -f org.apache.zookeeper.server.quorum.QuorumPeerMain || true"
echo ""
echo "    In /etc/selfheal/selfheal.env, set:"
echo "      KAFKA_BOOTSTRAP=localhost:9092"
echo "      KAFKA_BOOTSTRAP_SERVERS=localhost:9092"
echo "      KAFKA_INCOMING_TOPIC=selfheal.alerts.raw.generic"
echo "      ALERTS_TOPIC=selfheal.alerts.normalized"
echo "      ACTION_REVIEW_TOPIC=actions-review"
echo "      ALERTS_DLQ_TOPIC=alerts-dlq"
echo ""
echo "    For production, point SelfHeal at your organisation's real Kafka"
echo "    cluster or a managed Kafka service instead of this single-node lab setup."