#!/usr/bin/env bash
# resize-data-disk.sh — online resize of the HA cluster data disk
#
# Three-phase process (all online-safe, no downtime required):
#   1. Proxmox: grow scsi1 on both HA VMs   (qm resize)
#   2. Guest:   rescan block device on both nodes so the kernel sees the new size
#   3. DRBD + XFS: drbdadm resize, then xfs_growfs — active node only
#
# Usage:
#   scripts/ha/resize-data-disk.sh --size +20G [--force] [--dry-run]
#
#   --size +NNg    amount to grow scsi1 by, e.g. +20G, +50G (required)
#                  XFS and DRBD cannot shrink; only positive deltas accepted
#   --force        skip the interactive confirmation prompt
#   --dry-run      show what would be done without changing anything
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=../env.sh
source "${SCRIPT_DIR}/../env.sh"

# ── Configuration ─────────────────────────────────────────────────────────
NODE1="${NODE1:-ha-server-1}"
NODE2="${NODE2:-ha-server-2}"
NODE1_IP="${NODE1_IP:-192.168.2.228}"
NODE2_IP="${NODE2_IP:-192.168.2.227}"
XFS_MOUNT="${XFS_MOUNT:-/srv/ha-data}"
DRBD_RESOURCE="${DRBD_RESOURCE:-ha-data}"
DATA_DISK_SLOT="${DATA_DISK_SLOT:-scsi1}"   # Proxmox disk name (scsi1 = data disk)
HA_USER="${HA_USER:-nixos}"
PVE_HOST="${PVE_HOST:-${PVE1_HOST}}"
PVE_SSH_USER="${PVE_SSH_USER:-${PROXMOX_SSH_USER}}"
PVE_SUDO=""
[[ "$PVE_SSH_USER" != "root" ]] && PVE_SUDO="sudo"
# By-id symlink for the data disk; basename resolves to the raw block device.
# matches variables.nix's haServerDrbdDisk.
DATA_DISK_BYID="${DATA_DISK_BYID:-scsi-0QEMU_QEMU_HARDDISK_drive-${DATA_DISK_SLOT}}"
# ──────────────────────────────────────────────────────────────────────────

pve() { ssh -i ~/.ssh/id_ed25519 -o StrictHostKeyChecking=no -o ConnectTimeout=10 \
          "${PVE_SSH_USER}@${PVE_HOST}" "$@"; }
n1()  { ssh -i ~/.ssh/id_ed25519 -o StrictHostKeyChecking=no -o ConnectTimeout=5 \
          "${HA_USER}@${NODE1_IP}" sudo "$@" 2>/dev/null; }
n2()  { ssh -i ~/.ssh/id_ed25519 -o StrictHostKeyChecking=no -o ConnectTimeout=5 \
          "${HA_USER}@${NODE2_IP}" sudo "$@" 2>/dev/null; }

# ── Argument parsing ───────────────────────────────────────────────────────
SIZE=""
FORCE=false
DRY_RUN=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    --size)    shift; SIZE="${1:?--size requires a value (e.g. +20G)}" ;;
    --force)   FORCE=true ;;
    --dry-run) DRY_RUN=true ;;
    *) echo "Unknown argument: $1"
       echo "Usage: $0 --size +NNg [--force] [--dry-run]"
       exit 1 ;;
  esac
  shift
done

if [[ -z "$SIZE" ]]; then
  echo "ERROR: --size is required (e.g. --size +20G)"
  echo "Usage: $0 --size +NNg [--force] [--dry-run]"
  exit 1
fi

# Only positive deltas — qm resize, DRBD, and XFS all refuse to shrink.
if [[ ! "$SIZE" =~ ^\+[0-9]+(G|M|T)$ ]]; then
  echo "ERROR: --size must be a positive delta like +20G, +50G, +500M, +2T"
  echo "       (qm resize, drbdadm resize, and xfs_growfs can only grow, not shrink)"
  exit 1
fi

DRY_PREFIX=""
$DRY_RUN && DRY_PREFIX="[dry-run] "

echo "════════════════════════════════════════════════════"
echo " HA Data Disk Resize — $(date '+%Y-%m-%d %H:%M:%S')"
echo " Size delta: $SIZE  •  Proxmox: $PVE_HOST"
$DRY_RUN && echo " MODE: dry-run — no changes will be made"
echo "════════════════════════════════════════════════════"

# ── Detect active node ─────────────────────────────────────────────────────
echo ""
echo "Detecting active node..."

CRM_OUT=""
if ssh -i ~/.ssh/id_ed25519 -o StrictHostKeyChecking=no -o ConnectTimeout=5 \
     "${HA_USER}@${NODE1_IP}" true 2>/dev/null; then
  CRM_OUT=$(n1 "crm_mon -1" 2>/dev/null || true)
fi
if [[ -z "$CRM_OUT" ]]; then
  if ssh -i ~/.ssh/id_ed25519 -o StrictHostKeyChecking=no -o ConnectTimeout=5 \
       "${HA_USER}@${NODE2_IP}" true 2>/dev/null; then
    CRM_OUT=$(n2 "crm_mon -1" 2>/dev/null || true)
  fi
fi

# crm_mon 2.x formats Promoted lines as "    * Promoted: [ node ]" (bullet *),
# so ^\s*(Promoted|Masters): never matches; filter Unpromoted first instead.
ACTIVE_NODE=$(echo "$CRM_OUT" | grep -v 'Unpromoted\|Unmanaged' | \
  grep -E '(Promoted|Masters):' | \
  grep -oE '\b(ha-server-[0-9]+)\b' | head -1 || true)

if [[ -z "$ACTIVE_NODE" ]]; then
  echo "ERROR: could not determine active node from crm_mon."
  echo "  Is Pacemaker still settling?  Try running scripts/ha/health.sh first."
  exit 1
fi

if [[ "$ACTIVE_NODE" == "$NODE1" ]]; then
  ACTIVE_IP="$NODE1_IP"
  na() { n1 "$@"; }
else
  ACTIVE_IP="$NODE2_IP"
  na() { n2 "$@"; }
fi

echo "  Active node: $ACTIVE_NODE ($ACTIVE_IP)"

# ── Pre-check DRBD state ───────────────────────────────────────────────────
echo ""
echo "Pre-checks..."

DRBD_DSTATE=$(na "drbdadm dstate ${DRBD_RESOURCE} 2>/dev/null" 2>/dev/null || echo "unknown")
if ! echo "$DRBD_DSTATE" | grep -q "UpToDate/UpToDate"; then
  echo "  WARNING: DRBD dstate is '$DRBD_DSTATE' (expected UpToDate/UpToDate)."
  echo "  Resizing with a partially-synced disk may cause issues."
  if ! $FORCE; then
    echo "  Use --force to proceed anyway."
    exit 1
  fi
  echo "  --force specified — proceeding despite non-ideal DRBD state."
else
  echo "  DRBD dstate: $DRBD_DSTATE — OK"
fi

# ── Find VMIDs on Proxmox ─────────────────────────────────────────────────
echo ""
echo "Looking up VM IDs on ${PVE_HOST}..."

QM_LIST=$(pve "$PVE_SUDO qm list 2>/dev/null" || true)
VMID1=$(echo "$QM_LIST" | awk -v name="$NODE1" '$0 ~ name {print $1}' | head -1)
VMID2=$(echo "$QM_LIST" | awk -v name="$NODE2" '$0 ~ name {print $1}' | head -1)

if [[ -z "$VMID1" ]]; then
  echo "  ERROR: could not find VMID for $NODE1 on $PVE_HOST"
  echo "  qm list output:"
  echo "$QM_LIST" | sed 's/^/    /'
  exit 1
fi
if [[ -z "$VMID2" ]]; then
  echo "  ERROR: could not find VMID for $NODE2 on $PVE_HOST"
  echo "  qm list output:"
  echo "$QM_LIST" | sed 's/^/    /'
  exit 1
fi

echo "  $NODE1: VMID $VMID1"
echo "  $NODE2: VMID $VMID2"

# ── Confirm ────────────────────────────────────────────────────────────────
if ! $FORCE && ! $DRY_RUN; then
  echo ""
  echo "  Plan:"
  echo "    Phase 1 — qm resize $VMID1 ${DATA_DISK_SLOT} ${SIZE}  (on $PVE_HOST)"
  echo "              qm resize $VMID2 ${DATA_DISK_SLOT} ${SIZE}  (on $PVE_HOST)"
  echo "    Phase 2 — block device rescan on $NODE1 and $NODE2"
  echo "    Phase 3 — drbdadm resize + xfs_growfs on $ACTIVE_NODE"
  echo "  No downtime required (all operations are online-safe)."
  printf "  Proceed? [y/N] "
  read -r ANSWER
  [[ "${ANSWER,,}" == "y" || "${ANSWER,,}" == "yes" ]] || { echo "Aborted."; exit 0; }
fi

# ═══════════════════════════════════════════════════════════════
# Phase 1 — Resize both VM data disks in Proxmox
# ═══════════════════════════════════════════════════════════════
echo ""
echo "── Phase 1 — Proxmox disk resize (${DATA_DISK_SLOT} ${SIZE} on both VMs) ──"

echo "  ${DRY_PREFIX}qm resize $VMID1 ${DATA_DISK_SLOT} ${SIZE}  ($NODE1 on ${PVE_HOST})"
if ! $DRY_RUN; then
  pve "$PVE_SUDO qm resize $VMID1 ${DATA_DISK_SLOT} ${SIZE}"
fi

echo "  ${DRY_PREFIX}qm resize $VMID2 ${DATA_DISK_SLOT} ${SIZE}  ($NODE2 on ${PVE_HOST})"
if ! $DRY_RUN; then
  pve "$PVE_SUDO qm resize $VMID2 ${DATA_DISK_SLOT} ${SIZE}"
fi

echo "  Phase 1 done."

# ═══════════════════════════════════════════════════════════════
# Phase 2 — Rescan block device on both guest nodes
# ═══════════════════════════════════════════════════════════════
echo ""
echo "── Phase 2 — Block device rescan (both nodes) ──"

rescan_node() {
  local node_name=$1 run_fn=$2

  # Resolve block device name from the stable by-id symlink on the guest.
  # Read-only lookup — safe to run even in dry-run so we show the real device.
  local blk_dev=""
  blk_dev=$($run_fn "bash -c 'basename \$(readlink -f /dev/disk/by-id/${DATA_DISK_BYID})'" 2>/dev/null || true)
  if [[ -z "$blk_dev" ]]; then
    echo "  ERROR: /dev/disk/by-id/${DATA_DISK_BYID} not found on $node_name" >&2
    echo "         Check DATA_DISK_BYID or DATA_DISK_SLOT configuration." >&2
    exit 1
  fi

  echo "  ${DRY_PREFIX}Rescanning /dev/${blk_dev} on ${node_name}..."
  if ! $DRY_RUN; then
    $run_fn "bash -c 'echo 1 > /sys/block/${blk_dev}/device/rescan'" 2>/dev/null
    local new_size
    new_size=$($run_fn "lsblk -nd -o SIZE /dev/${blk_dev} 2>/dev/null" 2>/dev/null || echo "unknown")
    echo "    /dev/${blk_dev} on $node_name now reports: $new_size"
  fi
}

rescan_node "$NODE1" n1
rescan_node "$NODE2" n2

echo "  Phase 2 done."

# ═══════════════════════════════════════════════════════════════
# Phase 3 — Grow DRBD metadata, then XFS (active node only)
# ═══════════════════════════════════════════════════════════════
echo ""
echo "── Phase 3 — DRBD resize + XFS grow (on active node: $ACTIVE_NODE) ──"

echo "  ${DRY_PREFIX}drbdadm resize ${DRBD_RESOURCE}"
if ! $DRY_RUN; then
  na "drbdadm resize ${DRBD_RESOURCE}"
fi

echo "  ${DRY_PREFIX}xfs_growfs ${XFS_MOUNT}"
if ! $DRY_RUN; then
  na "xfs_growfs ${XFS_MOUNT}"
fi

echo "  Phase 3 done."

# ── Verify ────────────────────────────────────────────────────────────────
echo ""
echo "── Verify ──"

if ! $DRY_RUN; then
  DF_OUT=$(na "df -h '${XFS_MOUNT}' 2>/dev/null" 2>/dev/null || echo "")
  if [[ -n "$DF_OUT" ]]; then
    echo "  ${XFS_MOUNT}:"
    echo "$DF_OUT" | sed 's/^/    /'
  fi

  DRBD_DSTATE_AFTER=$(na "drbdadm dstate ${DRBD_RESOURCE} 2>/dev/null" 2>/dev/null || echo "unknown")
  echo "  DRBD dstate: $DRBD_DSTATE_AFTER"
  if ! echo "$DRBD_DSTATE_AFTER" | grep -q "UpToDate/UpToDate"; then
    echo "  NOTE: DRBD is resyncing — normal immediately after resize."
    echo "        Monitor: ssh nixos@${ACTIVE_IP} 'sudo watch -n3 cat /proc/drbd'"
  fi
else
  echo "  [dry-run] would verify df -h ${XFS_MOUNT} and drbdadm dstate on $ACTIVE_NODE"
fi

echo ""
echo "════════════════════════════════════════════════════"
echo " Resize complete."
echo " Active node: $ACTIVE_NODE"
echo "════════════════════════════════════════════════════"
echo ""