#!/usr/bin/env bash
# 在"目标库所在主机"上安装/更新**整库逻辑备份**的定时计划（幂等）。
# 平台的「系统设置 → 存储与备份」通过 SSH 下发时会调用它；也可在主机上手工执行。
#
# 用法（在目标主机上，需要 root）：
#   bash install_backup_schedule.sh --show                     # 只打印当前计划
#   bash install_backup_schedule.sh --time 03:30 --days 7 --months 3
#   bash install_backup_schedule.sh --disable                  # 关闭定时（保留已生成的备份）
#
# 落盘：
#   /etc/knowledge-governance/backup-schedule.env   计划参数（0600）
#   /etc/cron.d/kb-logical-backup                   cron 条目（0644，root:root）
#   $KB_BACKUP_ROOT/logs/logical-backup.log         运行日志
#
# 输出最后一行固定为 SCHEDULE_APPLIED …，供平台解析核对。
set -euo pipefail

if [ -f /etc/knowledge-governance/backup.env ]; then
  # shellcheck disable=SC1091
  . /etc/knowledge-governance/backup.env
fi
KB_BACKUP_ROOT="${KB_BACKUP_ROOT:-/srv/kb-backups}"
BACKUP_SCRIPT="${BACKUP_SCRIPT:-/opt/weknora-test/logical-backup.sh}"
SCHEDULE_ENV="/etc/knowledge-governance/backup-schedule.env"
CRON_FILE="/etc/cron.d/kb-logical-backup"
LOG_FILE="$KB_BACKUP_ROOT/logs/logical-backup.log"

TIME=""; DAYS=""; MONTHS=""; MODE="apply"
while [ $# -gt 0 ]; do
  case "$1" in
    --time) TIME="${2:-}"; shift 2 ;;
    --days) DAYS="${2:-}"; shift 2 ;;
    --months) MONTHS="${2:-}"; shift 2 ;;
    --disable) MODE="disable"; shift ;;
    --show) MODE="show"; shift ;;
    *) echo "未知参数: $1" >&2; exit 2 ;;
  esac
done

show_state() {
  echo "备份脚本: $BACKUP_SCRIPT $([ -x "$BACKUP_SCRIPT" ] || [ -f "$BACKUP_SCRIPT" ] && echo '(存在)' || echo '(缺失)')"
  if [ -f "$SCHEDULE_ENV" ]; then
    echo "计划参数: $(grep -v '^#' "$SCHEDULE_ENV" | paste -sd' ' -)"
  else
    echo "计划参数: 未配置"
  fi
  if [ -f "$CRON_FILE" ]; then
    echo "cron 条目:"
    # 只列计划行（去掉 SHELL=/PATH= 这类环境行），否则平台会把环境变量当计划回显
    grep -E '^[0-9*@]' "$CRON_FILE" | sed 's/^/  /'
  else
    echo "cron 条目: 未安装（定时关闭）"
  fi
  if command -v systemctl >/dev/null 2>&1; then
    echo "cron 服务: $(systemctl is-active cron 2>/dev/null || systemctl is-active crond 2>/dev/null || echo unknown)"
  fi
  echo "备份根目录: $KB_BACKUP_ROOT（$(du -sh "$KB_BACKUP_ROOT/rds-logical" 2>/dev/null | cut -f1 || echo 0) 已用）"
}

if [ "$MODE" = "show" ]; then
  show_state
  exit 0
fi

if [ "$MODE" = "disable" ]; then
  rm -f "$CRON_FILE"
  if [ -f "$SCHEDULE_ENV" ]; then
    sed -i 's/^KB_BACKUP_SCHEDULE_ENABLED=.*/KB_BACKUP_SCHEDULE_ENABLED=0/' "$SCHEDULE_ENV" || true
  fi
  echo "已关闭定时备份（已生成的备份保留）。"
  echo "SCHEDULE_APPLIED enabled=0"
  exit 0
fi

# ---- 参数校验（错就拒绝，不落半成品）----
case "$TIME" in
  [0-2][0-9]:[0-5][0-9]) ;;
  *) echo "--time 必须是 HH:MM（00:00~23:59），收到 '$TIME'" >&2; exit 2 ;;
esac
case "$DAYS" in ''|*[!0-9]*) echo "--days 必须是整数" >&2; exit 2 ;; esac
case "$MONTHS" in ''|*[!0-9]*) echo "--months 必须是整数" >&2; exit 2 ;; esac
[ "$DAYS" -ge 1 ] && [ "$DAYS" -le 365 ] || { echo "--days 需在 1~365" >&2; exit 2; }
[ "$MONTHS" -ge 0 ] && [ "$MONTHS" -le 24 ] || { echo "--months 需在 0~24" >&2; exit 2; }
[ -f "$BACKUP_SCRIPT" ] || { echo "备份脚本不存在: $BACKUP_SCRIPT" >&2; exit 2; }

HOUR="${TIME%%:*}"; MINUTE="${TIME##*:}"
# cron 里不能出现未转义的 %；这里全程不使用 % 以免歧义。
CRON_LINE="$MINUTE $HOUR * * * root /bin/bash $BACKUP_SCRIPT >> $LOG_FILE 2>&1"

mkdir -p "$KB_BACKUP_ROOT/logs" "$(dirname "$SCHEDULE_ENV")"
cat >"$SCHEDULE_ENV" <<EOF
# 由 install_backup_schedule.sh 写入（平台「系统设置 → 存储与备份」下发）
KB_BACKUP_SCHEDULE_ENABLED=1
KB_BACKUP_SCHEDULE_TIME=$TIME
KB_BACKUP_KEEP_DAYS=$DAYS
KB_BACKUP_KEEP_MONTHS=$MONTHS
KB_BACKUP_SCRIPT=$BACKUP_SCRIPT
KB_BACKUP_LOG=$LOG_FILE
EOF
chmod 600 "$SCHEDULE_ENV"

cat >"$CRON_FILE" <<EOF
# 整库逻辑备份（目标库所在主机本地执行；参数来自 $SCHEDULE_ENV）
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
$CRON_LINE
EOF
chmod 644 "$CRON_FILE"
chown root:root "$CRON_FILE" 2>/dev/null || true

NEXT_RUN="$(date -d "today $TIME" '+%Y-%m-%dT%H:%M:%S%z' 2>/dev/null || echo unknown)"
if [ "$NEXT_RUN" != "unknown" ] && [ "$(date -d "today $TIME" +%s)" -le "$(date +%s)" ]; then
  NEXT_RUN="$(date -d "tomorrow $TIME" '+%Y-%m-%dT%H:%M:%S%z')"
fi

echo "计划已下发：每天 $TIME（保留 $DAYS 天，另按自然月保留 $MONTHS 份）"
echo "cron 文件：$CRON_FILE"
echo "下次执行：$NEXT_RUN"
echo "SCHEDULE_APPLIED enabled=1 time=$TIME days=$DAYS months=$MONTHS next=$NEXT_RUN cron=$CRON_FILE"