#!/bin/sh
# Usage: start.sh valkey|sentinel. valkey boots read-only as a replica of
# 127.0.0.1:1 ("undecided") so peers can compare offsets; decide() then follows
# the sentinels' master, a live peer master, or the highest-offset node.
set -eu
name="$(hostname)"
sts="${name%-*}"
self="${name}${DOMAIN_SUFFIX}"

info() {
  timeout 3 valkey-cli -h "$1" info replication 2>/dev/null | tr -d '\r' || true
}

field() {
  printf '%s\n' "$1" | sed -n "s/^$2://p"
}

undecided() {
  [ "$(field "$1" master_host)" = 127.0.0.1 ]
}

choose_master() {
  deadline=$(($(date +%s) + 60))
  while :; do
    best=""
    best_off=-1
    answered=0
    for i in 0 1 2; do
      peer="${sts}-${i}${DOMAIN_SUFFIX}"
      if [ "$peer" = "$self" ]; then
        r="$(info 127.0.0.1)"
      else
        m="$(timeout 3 valkey-cli -h "$peer" -p 26379 --raw sentinel get-master-addr-by-name rspamd 2>/dev/null | head -n1 || true)"
        [ -n "$m" ] && { echo "$m"; return; }
        r="$(info "$peer")"
        [ -n "$r" ] || continue
        answered=$((answered + 1))
        [ "$(field "$r" role)" = master ] && { echo "$peer"; return; }
      fi
      undecided "$r" || continue
      off="$(field "$r" master_repl_offset)"
      [ "${off:-0}" -gt "$best_off" ] && best="$peer" best_off="${off:-0}"
    done
    if [ "$best" = "$self" ] && { [ "$answered" -eq 2 ] || [ "$(date +%s)" -ge "$deadline" ]; }; then
      echo "$self"
      return
    fi
    sleep 3
  done
}

decide() {
  until valkey-cli ping >/dev/null 2>&1; do sleep 1; done
  master="$(choose_master)"
  target="$master 6379"
  [ "$master" = "$self" ] && target="no one"
  until valkey-cli replicaof $target; do sleep 1; done
}

if [ "$1" = sentinel ]; then
  until r="$(info 127.0.0.1)" && [ -n "$(field "$r" role)" ] && ! undecided "$r"; do sleep 2; done
  master="$self"
  [ "$(field "$r" role)" = master ] || master="$(field "$r" master_host)"
  cat > /sentinel/sentinel.conf <<CONF
port 26379
protected-mode no
sentinel resolve-hostnames yes
sentinel announce-hostnames yes
sentinel announce-ip $self
sentinel monitor rspamd $master 6379 2
sentinel down-after-milliseconds rspamd 5000
sentinel failover-timeout rspamd 60000
sentinel parallel-syncs rspamd 1
CONF
  exec valkey-sentinel /sentinel/sentinel.conf
fi

decide &
# RDB only: an AOF reload resets the replication offset that choose_master compares.
exec valkey-server --dir /data --appendonly no --save "60 1" \
  --maxmemory 384mb --maxmemory-policy volatile-ttl \
  --protected-mode no --replica-announce-ip "$self" --replicaof 127.0.0.1 1