#!/usr/bin/env bash
set -uo pipefail

B="${PGBIN:-$HOME/.pgrx/18.4/pgrx-install/bin}"
R="${ROOT:-/tmp/hyperion-repl}"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
P1=54340 P2=54341 P3=54342

q() { "$B/psql" -h 127.0.0.1 -p "$1" -U postgres -tAc "$2" 2>&1; }
try_write() { "$B/psql" -h 127.0.0.1 -p "$1" -U postgres -tAc "INSERT INTO demo VALUES (\$tag\$$2\$tag\$)" 2>&1; }

echo "=== bring up fresh cluster ==="
bash "$SCRIPT_DIR/cluster-repl.sh" up >/dev/null 2>&1
for i in $(seq 1 60); do q "$P1" "SELECT replica.status()" | grep -q "decided_primary=1" && break; sleep 0.5; done
echo "  node1: $(q $P1 'SELECT replica.status()')"

echo
echo "=== sanity: primary (node 1) accepts writes while it has quorum ==="
W=$(try_write $P1 "with-quorum")
echo "  write result: $W"

echo
echo "=== induce loss of quorum: kill BOTH followers (node 2 + node 3) ==="
echo "  node 1 is now a minority of 1 — it MUST stop accepting writes on its own"
"$B/pg_ctl" -D "$R/n2" stop -m immediate >/dev/null 2>&1
"$B/pg_ctl" -D "$R/n3" stop -m immediate >/dev/null 2>&1

echo "  waiting for check_quorum self-demotion..."
for i in $(seq 1 40); do
  s=$(q "$P1" "SELECT replica.status()" 2>/dev/null)
  echo "$s" | grep -q "read_only=true" && break
  sleep 0.5
done
echo "  node1: $(q $P1 'SELECT replica.status()')"

echo
echo "=== attempt write on the isolated minority primary (must be REJECTED) ==="
W=$(try_write $P1 "split-brain-attempt")
echo "  write result: $W"
if echo "$W" | grep -qi "read-only"; then
  echo "  PASS: minority primary refused the write (no split-brain)"
  FENCED=1
else
  echo "  FAIL: minority primary ACCEPTED a write — split-brain!"
  FENCED=0
fi

echo
echo "=== restore quorum: bring node 2 + node 3 back ==="
for i in 2 3; do
  "$B/pg_ctl" -D "$R/n$i" -l "$R/n$i.log" start >/dev/null 2>&1
done
echo "  waiting for node 1 to regain quorum + read-write..."
for i in $(seq 1 60); do
  s=$(q "$P1" "SELECT replica.status()" 2>/dev/null)
  echo "$s" | grep -q "quorum=true read_only=false" && break
  sleep 0.5
done
echo "  node1: $(q $P1 'SELECT replica.status()')"
W=$(try_write $P1 "quorum-restored")
echo "  write result after restore: $W"
if echo "$W" | grep -qi "INSERT"; then RESTORED=1; else RESTORED=0; fi

echo
echo "=== M4 result ==="
if [ "${FENCED:-0}" = 1 ] && [ "$RESTORED" = 1 ]; then
  echo "  PASS: lost-quorum self-demotion (read-only) + automatic recovery on quorum return"
else
  echo "  CHECK: fenced=$FENCED restored=$RESTORED (inspect above)"
fi