#!/usr/bin/env bash
# cluster-init.sh — one-time HA cluster initialisation script
#
# Run ONCE from ha-server-1 as root AFTER both VMs are booted and have SSH
# access.  It:
#   1. Generates and distributes the corosync authkey
#   2. Waits for corosync quorum and pacemaker
#   3. Initialises DRBD metadata, promotes node1 to primary
#   4. Creates XFS on /dev/drbd0 and mounts it
#   5. Creates the directory tree and iSCSI LUN backing file
#   6. Configures LIO iSCSI target (file-backed LUN)
#   7. Configures Pacemaker resources: DRBD → XFS → iSCSI → NFS → VIP
#
# Prerequisites:
#   - Both VMs booted with the ha-server config (nixos-rebuild done)
#   - SSH key access from node1 to root@NODE2_IP
#   - VMID_NODE1 / VMID_NODE2 filled in below (needed for STONITH setup;
#     cluster starts without STONITH, which you enable separately via
#     scripts/ha/cluster-enable-stonith.sh)
#   - Run as root on ha-server-1
set -euo pipefail

# ── Configuration ─────────────────────────────────────────────────────────
# These must match variables.nix haServer* values and the Proxmox VMID
# assignments.  Update before running.
NODE1="ha-server-1"
NODE2="ha-server-2"
NODE1_IP="192.168.2.200"   # vars.haServer1Ip
NODE2_IP="192.168.2.201"   # vars.haServer2Ip
VIP="192.168.2.202"        # vars.haServerVip
XFS_MOUNT="/srv/ha-data"   # vars.haStorageRoot
ISCSI_IQN="iqn.2026-01.home.sweet:ha-storage"  # vars.haIscsiIqn
ISCSI_LUN_FILE="${XFS_MOUNT}/iscsi-lun.img"
ISCSI_LUN_SIZE="10G"
DRBD_DEVICE="/dev/drbd0"
VMID_NODE1=""              # FILL IN: Proxmox VMID for ha-server-1
VMID_NODE2=""              # FILL IN: Proxmox VMID for ha-server-2
PVE_HOST="pve1.sweet.home"
PVE_USER="wayne"

# NFS dataset subdirectories to create under XFS_MOUNT.
# Must mirror vars.nfsShares subpath values in variables.nix.
NFS_SUBDIRS=(
  "docker/config"
  "docker/volumes"
  "docker/databases"
  "docker/nextcloud-data"
  "raspi/volumes"
  "proxmox/iso"
  "proxmox/lxc"
  "pxe-boot/images"
)
# ──────────────────────────────────────────────────────────────────────────

log()  { echo "[cluster-init] $*"; }
die()  { echo "[cluster-init] ERROR: $*" >&2; exit 1; }
warn() { echo "[cluster-init] WARNING: $*" >&2; }

[[ $(id -u) -eq 0 ]] || die "must run as root"
[[ "$(hostname)" == "$NODE1" ]] || die "must run on $NODE1"

# ── 0. Corosync authkey ───────────────────────────────────────────────────
AUTHKEY="/etc/corosync/authkey"
mkdir -p /etc/corosync
if [[ ! -f "$AUTHKEY" ]]; then
  log "Generating corosync authkey..."
  corosync-keygen -k "$AUTHKEY"
  chmod 0400 "$AUTHKEY"
fi
log "Distributing authkey to $NODE2..."
ssh "root@${NODE2_IP}" "mkdir -p /etc/corosync"
scp -q "$AUTHKEY" "root@${NODE2_IP}:${AUTHKEY}"
ssh "root@${NODE2_IP}" "chmod 0400 '${AUTHKEY}'"

log "Restarting corosync on both nodes..."
systemctl restart corosync
ssh "root@${NODE2_IP}" "systemctl restart corosync"
sleep 3

# ── 1. Corosync quorum ────────────────────────────────────────────────────
log "Waiting for corosync quorum..."
for i in $(seq 1 30); do
  if corosync-quorumtool -s 2>/dev/null | grep -q 'Quorate:.*Yes'; then
    log "Quorum established"
    break
  fi
  [[ $i -eq 30 ]] && die "corosync quorum not established after 60 s"
  sleep 2
done

log "Waiting for pacemaker..."
for i in $(seq 1 30); do
  if crm_mon -1 &>/dev/null; then
    log "Pacemaker running"
    break
  fi
  [[ $i -eq 30 ]] && die "pacemaker not running after 60 s"
  sleep 2
done

# ── 2. DRBD initialisation ────────────────────────────────────────────────
log "Initialising DRBD metadata on $NODE1..."
if ! drbdadm dstate ha-data 2>/dev/null | grep -q "UpToDate\|Inconsistent\|Diskless"; then
  drbdadm create-md ha-data --force
fi

log "Initialising DRBD metadata on $NODE2..."
ssh "root@${NODE2_IP}" "
  if ! drbdadm dstate ha-data 2>/dev/null | grep -q 'UpToDate\|Inconsistent\|Diskless'; then
    drbdadm create-md ha-data --force
  fi
"

log "Bringing up DRBD on both nodes..."
drbdadm up ha-data 2>/dev/null || true
ssh "root@${NODE2_IP}" "drbdadm up ha-data 2>/dev/null" || true

log "Forcing $NODE1 to DRBD Primary for initial sync..."
drbdadm primary ha-data --force

log "Waiting for DRBD to finish initial sync (this may take several minutes)..."
for i in $(seq 1 300); do
  state=$(drbdadm dstate ha-data 2>/dev/null || echo "unknown")
  if echo "$state" | grep -q "UpToDate/UpToDate"; then
    log "DRBD sync complete: $state"
    break
  fi
  [[ $i -eq 300 ]] && warn "DRBD not UpToDate after 300 s — continuing anyway (check drbdadm status)"
  sleep 1
done

# ── 3. XFS filesystem ─────────────────────────────────────────────────────
log "Creating XFS on ${DRBD_DEVICE}..."
if ! xfs_info "${DRBD_DEVICE}" &>/dev/null; then
  mkfs.xfs -f "${DRBD_DEVICE}"
fi

log "Mounting ${DRBD_DEVICE} at ${XFS_MOUNT}..."
mkdir -p "${XFS_MOUNT}"
mount "${DRBD_DEVICE}" "${XFS_MOUNT}"

# ── 4. NFS dataset directories ────────────────────────────────────────────
log "Creating NFS dataset directories..."
for subdir in "${NFS_SUBDIRS[@]}"; do
  mkdir -p "${XFS_MOUNT}/${subdir}"
done

# ── 5. iSCSI LUN backing file ─────────────────────────────────────────────
log "Creating iSCSI LUN backing file ${ISCSI_LUN_FILE} (${ISCSI_LUN_SIZE})..."
if [[ ! -f "${ISCSI_LUN_FILE}" ]]; then
  fallocate -l "${ISCSI_LUN_SIZE}" "${ISCSI_LUN_FILE}"
fi

# ── 6. LIO iSCSI target ───────────────────────────────────────────────────
log "Configuring LIO iSCSI target via targetcli..."
targetcli <<EOF
/backstores/fileio create name=ha-lun0 file_or_dev=${ISCSI_LUN_FILE} size=0 write_back=false
/iscsi create ${ISCSI_IQN}
/iscsi/${ISCSI_IQN}/tpg1/luns create /backstores/fileio/ha-lun0
/iscsi/${ISCSI_IQN}/tpg1/portals create ${VIP}
/iscsi/${ISCSI_IQN}/tpg1 set attribute authentication=0
/iscsi/${ISCSI_IQN}/tpg1 set attribute demo_mode_write_protect=0
saveconfig /etc/target/saveconfig.json
EOF

log "Distributing iSCSI saveconfig to $NODE2..."
scp -q /etc/target/saveconfig.json "root@${NODE2_IP}:/etc/target/saveconfig.json"

log "Unmounting ${XFS_MOUNT} — Pacemaker manages it..."
umount "${XFS_MOUNT}"

log "Demoting DRBD to Secondary — Pacemaker manages primary role..."
drbdadm secondary ha-data

# ── 7. Pacemaker resources ────────────────────────────────────────────────
log "Configuring Pacemaker cluster properties..."
crm_attribute -t crm_config -n stonith-enabled -v false
crm_attribute -t crm_config -n no-quorum-policy -v ignore

log "Creating DRBD promotable clone resource..."
cibadmin --replace --scope resources --xml-text "
<resources>
  <clone id=\"ms-drbd0\" globally-unique=\"false\">
    <meta_attributes id=\"ms-drbd0-meta\">
      <nvpair id=\"ms-drbd0-promotable\" name=\"promotable\" value=\"true\"/>
      <nvpair id=\"ms-drbd0-master-max\" name=\"master-max\" value=\"1\"/>
      <nvpair id=\"ms-drbd0-master-node-max\" name=\"master-node-max\" value=\"1\"/>
      <nvpair id=\"ms-drbd0-clone-max\" name=\"clone-max\" value=\"2\"/>
      <nvpair id=\"ms-drbd0-clone-node-max\" name=\"clone-node-max\" value=\"1\"/>
      <nvpair id=\"ms-drbd0-notify\" name=\"notify\" value=\"true\"/>
      <nvpair id=\"ms-drbd0-interleave\" name=\"interleave\" value=\"true\"/>
    </meta_attributes>
    <primitive id=\"drbd0\" class=\"ocf\" type=\"drbd\" provider=\"linbit\">
      <instance_attributes id=\"drbd0-attrs\">
        <nvpair id=\"drbd0-resource\" name=\"drbd_resource\" value=\"ha-data\"/>
      </instance_attributes>
      <operations>
        <op id=\"drbd0-start\" name=\"start\" interval=\"0\" timeout=\"240s\"/>
        <op id=\"drbd0-stop\" name=\"stop\" interval=\"0\" timeout=\"120s\"/>
        <op id=\"drbd0-promote\" name=\"promote\" interval=\"0\" timeout=\"90s\"/>
        <op id=\"drbd0-demote\" name=\"demote\" interval=\"0\" timeout=\"90s\"/>
        <op id=\"drbd0-monitor-master\" name=\"monitor\" interval=\"20s\" timeout=\"20s\" role=\"Promoted\"/>
        <op id=\"drbd0-monitor-slave\" name=\"monitor\" interval=\"30s\" timeout=\"20s\" role=\"Unpromoted\"/>
      </operations>
    </primitive>
  </clone>
  <group id=\"ha-group\">
    <primitive id=\"xfs-data\" class=\"ocf\" type=\"Filesystem\" provider=\"heartbeat\">
      <instance_attributes id=\"xfs-data-attrs\">
        <nvpair id=\"xfs-data-device\" name=\"device\" value=\"${DRBD_DEVICE}\"/>
        <nvpair id=\"xfs-data-directory\" name=\"directory\" value=\"${XFS_MOUNT}\"/>
        <nvpair id=\"xfs-data-fstype\" name=\"fstype\" value=\"xfs\"/>
        <nvpair id=\"xfs-data-options\" name=\"options\" value=\"defaults\"/>
        <nvpair id=\"xfs-data-force_unmount\" name=\"force_unmount\" value=\"false\"/>
      </instance_attributes>
      <operations>
        <op id=\"xfs-data-start\" name=\"start\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"xfs-data-stop\" name=\"stop\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"xfs-data-monitor\" name=\"monitor\" interval=\"20s\" timeout=\"40s\"/>
      </operations>
    </primitive>
    <primitive id=\"iscsi-target\" class=\"systemd\" type=\"targetctl\">
      <operations>
        <op id=\"iscsi-start\" name=\"start\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"iscsi-stop\" name=\"stop\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"iscsi-monitor\" name=\"monitor\" interval=\"20s\" timeout=\"40s\"/>
      </operations>
    </primitive>
    <primitive id=\"nfs-server\" class=\"systemd\" type=\"nfs-server\">
      <operations>
        <op id=\"nfs-start\" name=\"start\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"nfs-stop\" name=\"stop\" interval=\"0\" timeout=\"60s\"/>
        <op id=\"nfs-monitor\" name=\"monitor\" interval=\"30s\" timeout=\"40s\"/>
      </operations>
    </primitive>
    <primitive id=\"vip\" class=\"ocf\" type=\"IPaddr2\" provider=\"heartbeat\">
      <instance_attributes id=\"vip-attrs\">
        <nvpair id=\"vip-ip\" name=\"ip\" value=\"${VIP}\"/>
        <nvpair id=\"vip-cidr\" name=\"cidr_netmask\" value=\"24\"/>
      </instance_attributes>
      <operations>
        <op id=\"vip-start\" name=\"start\" interval=\"0\" timeout=\"20s\"/>
        <op id=\"vip-stop\" name=\"stop\" interval=\"0\" timeout=\"20s\"/>
        <op id=\"vip-monitor\" name=\"monitor\" interval=\"10s\" timeout=\"20s\"/>
      </operations>
    </primitive>
  </group>
</resources>
"

log "Adding ordering and colocation constraints..."
cibadmin --create --scope constraints --xml-text "
<constraints>
  <rsc_order id=\"order-drbd-group\" first=\"ms-drbd0\" first-action=\"promote\" then=\"ha-group\" then-action=\"start\"/>
  <rsc_colocation id=\"coloc-group-with-drbd\" rsc=\"ha-group\" with-rsc=\"ms-drbd0\" with-rsc-role=\"Master\" score=\"INFINITY\"/>
</constraints>
"

log "Waiting for resources to start..."
for i in $(seq 1 60); do
  if crm_resource -r vip --locate 2>/dev/null | grep -q "running on"; then
    log "VIP is up: $(crm_resource -r vip --locate)"
    break
  fi
  [[ $i -eq 60 ]] && { warn "VIP not up after 120 s — check: crm_mon -1"; break; }
  sleep 2
done

log ""
log "═══════════════════════════════════════════════════════════════"
log " HA cluster initialised."
log ""
log "  crm_mon -1                         — cluster status"
log "  iscsiadm -m discovery -t st -p ${VIP}  — verify iSCSI target"
log "  showmount -e ${VIP}                    — verify NFS exports"
log ""
log "  To enable STONITH (after deploying fence SSH key):"
log "    1. Fill in VMID_NODE1 / VMID_NODE2 in cluster-enable-stonith.sh"
log "    2. Copy scripts/ha/fence-pve-ssh.py to /etc/pacemaker/fence_pve_ssh"
log "       on both nodes (chmod +x)"
log "    3. Generate and distribute the fence SSH key"
log "       (see docs or cluster-enable-stonith.sh header)"
log "    4. bash scripts/ha/cluster-enable-stonith.sh"
log "═══════════════════════════════════════════════════════════════"