#!/bin/bash
# =============================================================================
# plugin/sbin/podman-preflight.sh
#
# Startup validation, run by `rc.podman start` BEFORE anything is mounted or
# started. The goal is to fail fast with one clear message, instead of
# letting `podman system service` fail three steps later with a cryptic
# error. See docs/ARCHITECTURE.md section 16.1 (Startup-Robustheit).
#
# Every check below is independent and all of them run even if an earlier
# one fails, so a single invocation reports every problem at once rather
# than forcing the user through a fix-one-rerun-find-the-next loop.
#
# Exit code: 0 if every check passed, 1 if any failed (with all failures
# already logged/notified by that point).
# =============================================================================

set -u  # deliberately not -e: see the "run every check" note above

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

podman_load_cfg

FAILURES=0

fail() {
  podman_log_error "preflight: $1"
  FAILURES=$((FAILURES + 1))
}

ok() {
  podman_log "preflight: OK - $1"
}

# -----------------------------------------------------------------------------
# 1. Required binaries are actually installed.
# -----------------------------------------------------------------------------
for bin in podman conmon crun mount umount xfs_repair mkfs.xfs; do
  if command -v "$bin" > /dev/null 2>&1; then
    ok "$bin found"
  else
    fail "required binary '$bin' not found on PATH — is the plugin fully installed?"
  fi
done

for helper in /usr/libexec/podman/netavark /usr/libexec/podman/aardvark-dns; do
  if [ -x "$helper" ]; then
    ok "$helper found"
  else
    fail "required helper '$helper' not found — is the plugin fully installed?"
  fi
done

# -----------------------------------------------------------------------------
# 2. Storage path configured, safe, and mounted (cache pool / disk, not
#    /mnt/user — see docs/ARCHITECTURE.md section 4.3).
# -----------------------------------------------------------------------------
if podman_storage_path_is_safe "$STORAGE_PATH" 2> /tmp/podman-preflight-storage-safety.log; then
  ok "STORAGE_PATH ($STORAGE_PATH) is not under /mnt/user"
else
  fail "$(cat /tmp/podman-preflight-storage-safety.log)"
fi
rm -f /tmp/podman-preflight-storage-safety.log

if [ -d "$STORAGE_PATH" ] && mountpoint -q "$STORAGE_PATH" 2> /dev/null; then
  ok "STORAGE_PATH ($STORAGE_PATH) is a mounted filesystem"
elif [ -d "$STORAGE_PATH" ]; then
  # Not every valid target is a mountpoint itself (e.g. a subdirectory of a
  # cache pool root) — warn rather than fail, but only if the parent chain
  # is mounted somewhere.
  if findmnt -T "$STORAGE_PATH" > /dev/null 2>&1; then
    ok "STORAGE_PATH ($STORAGE_PATH) resolves onto a mounted filesystem"
  else
    fail "STORAGE_PATH ($STORAGE_PATH) does not appear to be on a mounted filesystem"
  fi
else
  fail "STORAGE_PATH ($STORAGE_PATH) does not exist — is the configured cache pool/disk present and started?"
fi

# -----------------------------------------------------------------------------
# 3. Free space check (only meaningful once STORAGE_PATH exists).
# -----------------------------------------------------------------------------
if [ -d "$STORAGE_PATH" ]; then
  available_kb=$(df --output=avail -k "$STORAGE_PATH" 2> /dev/null | tail -n1 | tr -d '[:space:]')
  if [ -n "${available_kb:-}" ]; then
    available_gb=$((available_kb / 1024 / 1024))
    if [ -f "$PODMAN_STORAGE_IMAGE" ]; then
      # Image already exists — just warn if the pool itself is nearly full,
      # since podman.img growth or new image pulls need headroom too.
      if [ "$available_gb" -lt 2 ]; then
        fail "less than 2G free on $STORAGE_PATH (${available_gb}G) — image pulls will likely fail"
      else
        ok "${available_gb}G free on $STORAGE_PATH"
      fi
    elif [ "$available_gb" -lt "$STORAGE_IMAGE_SIZE_GB" ]; then
      fail "not enough free space on $STORAGE_PATH to create a ${STORAGE_IMAGE_SIZE_GB}G podman.img (only ${available_gb}G free)"
    else
      ok "${available_gb}G free on $STORAGE_PATH (enough for a fresh ${STORAGE_IMAGE_SIZE_GB}G podman.img)"
    fi
  fi
fi

# -----------------------------------------------------------------------------
# 4. Kernel supports cgroup v2 (required by crun/netavark's expectations).
# -----------------------------------------------------------------------------
if [ -f /sys/fs/cgroup/cgroup.controllers ]; then
  ok "cgroup v2 unified hierarchy is active"
else
  fail "cgroup v2 unified hierarchy not detected (/sys/fs/cgroup/cgroup.controllers missing) — check Unraid's syslinux cgroup boot parameters"
fi

# -----------------------------------------------------------------------------
# 5. No orphaned socket/pidfile from a previous unclean shutdown.
# -----------------------------------------------------------------------------
if [ -S "$PODMAN_SOCKET" ]; then
  if [ -f "$PODMAN_SERVICE_PID_FILE" ] && kill -0 "$(cat "$PODMAN_SERVICE_PID_FILE")" 2> /dev/null; then
    fail "podman system service already appears to be running (pid $(cat "$PODMAN_SERVICE_PID_FILE")) — is rc.podman already started?"
  else
    podman_log "preflight: removing orphaned socket $PODMAN_SOCKET from a previous unclean shutdown"
    rm -f "$PODMAN_SOCKET"
    ok "cleared orphaned socket"
  fi
else
  ok "no orphaned podman.sock"
fi

# -----------------------------------------------------------------------------
# 6. Boot-config directory exists (i.e. 'seed' has run at least once).
# -----------------------------------------------------------------------------
if [ -f "$PODMAN_CFG_FILE" ]; then
  ok "$PODMAN_CFG_FILE present"
else
  fail "$PODMAN_CFG_FILE missing — run 'podman-config.sh seed' (should happen automatically on install)"
fi

# -----------------------------------------------------------------------------
# Summary
# -----------------------------------------------------------------------------
if [ "$FAILURES" -gt 0 ]; then
  podman_notify "Podman preflight checks failed" \
    "$FAILURES check(s) failed — podman was not started. See $PODMAN_PLUGIN_LOG for details." \
    "alert"
  podman_log_error "preflight: $FAILURES check(s) failed, aborting start"
  exit 1
fi

podman_log "preflight: all checks passed"
exit 0