#!/usr/bin/env bash

set -euo pipefail

# Kafka 集群只需在一台装有 Kafka CLI、能够访问集群的服务器上执行一次。
# 示例：
#   export KAFKA_BIN=<现场Kafka客户端bin目录>
#   export BOOTSTRAP=<现场broker1地址>:<端口>,<现场broker2地址>:<端口>
#   export RAW_TOPIC=<现场原始Topic名称>
#   export COMMAND_CONFIG=<现场client.properties路径>  # 无认证时不设置
#   ./kafka-cluster-upgrade.sh
# BOOTSTRAP 必须使用客户 Kafka 运维提供的地址；集群建议填写两个以上 broker。

: "${KAFKA_BIN:?请根据现场环境设置 KAFKA_BIN}"
: "${BOOTSTRAP:?请填写客户 Kafka 运维提供的 broker 地址和端口}"
: "${RAW_TOPIC:?请填写现场实际使用的原始 Topic 名称}"

TOPICS_CMD="${KAFKA_BIN}/kafka-topics.sh"
CONFIGS_CMD="${KAFKA_BIN}/kafka-configs.sh"

if [[ ! -x "${TOPICS_CMD}" ]] || [[ ! -x "${CONFIGS_CMD}" ]]; then
  echo "ERROR: ${KAFKA_BIN} 下缺少 kafka-topics.sh 或 kafka-configs.sh" >&2
  exit 1
fi

COMMON_ARGS=(--bootstrap-server "${BOOTSTRAP}")
if [[ -n "${COMMAND_CONFIG:-}" ]]; then
  if [[ ! -r "${COMMAND_CONFIG}" ]]; then
    echo "ERROR: 无法读取认证配置 ${COMMAND_CONFIG}" >&2
    exit 1
  fi
  COMMON_ARGS+=(--command-config "${COMMAND_CONFIG}")
fi

echo "[1/4] 测试 Kafka 集群连接：${BOOTSTRAP}"
"${TOPICS_CMD}" "${COMMON_ARGS[@]}" --list >/dev/null

echo "[2/4] 读取原始 Topic：${RAW_TOPIC}"
RAW_INFO=$("${TOPICS_CMD}" "${COMMON_ARGS[@]}" --describe --topic "${RAW_TOPIC}")
printf '%s\n' "${RAW_INFO}"

PARTITIONS=$(printf '%s\n' "${RAW_INFO}" | awk '
  /PartitionCount:/ {
    for (i = 1; i <= NF; i++) if ($i == "PartitionCount:") { print $(i + 1); exit }
  }
')
REPLICAS=$(printf '%s\n' "${RAW_INFO}" | awk '
  /ReplicationFactor:/ {
    for (i = 1; i <= NF; i++) if ($i == "ReplicationFactor:") { print $(i + 1); exit }
  }
')

if [[ ! "${PARTITIONS}" =~ ^[1-9][0-9]*$ ]] || [[ ! "${REPLICAS}" =~ ^[1-9][0-9]*$ ]]; then
  echo "ERROR: 无法读取原始 Topic 的分区数或副本数" >&2
  exit 1
fi

echo "新 Topic 使用分区数=${PARTITIONS}，副本数=${REPLICAS}"

SUFFIXES=("RETRY.1M" "RETRY.10M" "RETRY.1H" "DLT" "REPLAY")
RETENTIONS=(259200000 604800000 604800000 7776000000 604800000)

echo "[3/4] 创建或更新升级 Topic"
for i in 0 1 2 3 4; do
  TOPIC="${RAW_TOPIC}.${SUFFIXES[$i]}"
  RETENTION_MS="${RETENTIONS[$i]}"

  echo "处理 ${TOPIC}"
  "${TOPICS_CMD}" "${COMMON_ARGS[@]}" \
    --create --if-not-exists \
    --topic "${TOPIC}" \
    --partitions "${PARTITIONS}" \
    --replication-factor "${REPLICAS}" \
    --config cleanup.policy=delete \
    --config "retention.ms=${RETENTION_MS}"

  "${CONFIGS_CMD}" "${COMMON_ARGS[@]}" \
    --alter --entity-type topics --entity-name "${TOPIC}" \
    --add-config "cleanup.policy=delete,retention.ms=${RETENTION_MS}"
done

echo "[4/4] 显示升级结果"
for SUFFIX in "${SUFFIXES[@]}"; do
  "${TOPICS_CMD}" "${COMMON_ARGS[@]}" \
    --describe --topic "${RAW_TOPIC}.${SUFFIX}"
done

echo "PASS: Kafka 集群 Topic 已创建或更新；未删除 Topic，未修改消费组 offset。"