#!/usr/bin/env bash
# 16-grow-root-online.sh — kill swap (8.8G, 0B used, 47G RAM) and grow
# the ext4 root ONLINE to fill the 438G NVMe (~158G of trailing free
# space becomes contiguous with sda1 once sda2/sda5 are deleted).
# Charles authorized swap removal 2026-09-01; agent wrote the script
# (agent's tool layer blocks sudo). ONLINE-ONLY: no reboot, no unmount,
# no data movement (ext4 grow is forward metadata only).
#
# Protocol: gates -> table backup -> swapoff+fstab -> delete sda5+sda2
# -> rewrite table with sda1 filling the disk (start sector UNCHANGED)
# -> partx online update -> resize2fs -> verify.
set -euo pipefail
[ "$EUID" -eq 0 ] || exec sudo bash "$0"

OUT=/home/reachableceo/projects/ultix/16-grow-root-online.out
exec > >(tee "$OUT") 2>&1
echo "== grow / online $(date -Is) =="

DEV=/dev/sda
PART=${DEV}1

echo "-- gates"
[ "$(findmnt -n -o SOURCE /)" = "$PART" ] || { echo "FAIL: / is not on $PART"; exit 1; }
[ "$(findmnt -n -o FSTYPE /)" = "ext4" ]  || { echo "FAIL: / is not ext4"; exit 1; }
SWAP_USED=$(awk '$1=="/dev/sda5" {print $4}' /proc/swaps)
[ "${SWAP_USED:-0}" = "0" ] || { echo "FAIL: swap has ${SWAP_USED}kB in use; retry when empty"; exit 1; }
AVAIL_MB=$(free -m | awk '/^Mem:/ {print $7}')
[ "$AVAIL_MB" -gt 4096 ] || { echo "FAIL: only ${AVAIL_MB}MB free RAM"; exit 1; }

echo "-- backup partition table (rollback artifact)"
TS=$(date +%Y%m%d-%H%M%S)
sfdisk -d "$DEV" > "/root/sda-table.backup-$TS"
cp "/root/sda-table.backup-$TS" /home/reachableceo/projects/ultix/
cat "/root/sda-table.backup-$TS" | sed 's/^/  /'

DUMP=$(sfdisk -d "$DEV")
echo "$DUMP" | grep -q 'start= *2048,' || { echo "FAIL: sda1 does not start at sector 2048; abort"; exit 1; }

echo "-- swapoff + comment fstab swap line"
swapoff /dev/sda5
sed -i 's/^UUID=611d6da8-3fd6-40f0-9239-d8825a6d256c/#&/' /etc/fstab
grep -n swap /etc/fstab | sed 's/^/  /'

echo "-- delete sda5 (swap) and sda2 (extended container)"
sfdisk --delete "$DEV" 5
sfdisk --delete "$DEV" 2
partprobe "$DEV" || true
lsblk "$DEV" | sed 's/^/  /'

echo "-- rewrite table: sda1 fills the disk (start 2048 unchanged)"
DISKSECT=$(blockdev --getsz "$DEV")
NEWSEC=$((DISKSECT - 2048))
echo "  disk sectors: $DISKSECT, new sda1 size: $NEWSEC"
sfdisk -d "$DEV" | awk -v new="$NEWSEC" '
    /^last-lba:/ { next }
    /^\/dev\/sda1/ { sub(/size= *[0-9]+/, "size=" new); print; next }
    { print }
' > /tmp/sda-grown.table
cat /tmp/sda-grown.table | sed 's/^/  /'
sfdisk --force "$DEV" < /tmp/sda-grown.table
partx --update "$DEV" || partprobe "$DEV"

echo "-- online ext4 grow"
resize2fs "$PART"

echo "-- verify"
blockdev --getsz "$PART"
lsblk -o NAME,SIZE,FSTYPE,MOUNTPOINT "$DEV" | sed 's/^/  /'
df -h / | sed 's/^/  /'
cat /proc/swaps
echo "== done $(date -Is) — no reboot needed; swap is gone by design"
echo "    (rollback BEFORE resize2fs only: sfdisk $DEV < /root/sda-table.backup-$TS)"
chown reachableceo:reachableceo "$OUT" 2>/dev/null || true