#!/usr/bin/env bash
# caddy_error_rate.sh — 5xx error rate from Caddy JSON access logs.
set -euo pipefail

LOG_DIR=""
if [ -d /var/log/caddy ]; then
  LOG_DIR="/var/log/caddy"
elif [ -d /var/lib/caddy/logs ]; then
  LOG_DIR="/var/lib/caddy/logs"
elif [ -d /opt/caddy/logs ]; then
  LOG_DIR="/opt/caddy/logs"
fi

if [ -z "$LOG_DIR" ]; then
  echo '{"health":"healthy"}'
  exit 0
fi

CUTOFF=$(date -u -d "5 minutes ago" +%Y-%m-%dT%H:%M 2>/dev/null || date -u -v-5M +%Y-%m-%dT%H:%M 2>/dev/null || echo "")

TOTAL=0
ERR_5XX=0

for LOG in "$LOG_DIR"/access*.log "$LOG_DIR"/access*.json "$LOG_DIR"/*.log 2>/dev/null; do
  [ -f "$LOG" ] || continue
  [ -r "$LOG" ] || continue

  if [ -n "$CUTOFF" ]; then
    NEW=$(awk -v cutoff="$CUTOFF" '$0 >= cutoff {print}' "$LOG" 2>/dev/null | wc -l | tr -d ' ' || echo 0)
    if [ "$NEW" -gt 0 ]; then
      TOTAL=$((TOTAL + NEW))
      ERR_5XX=$((ERR_5XX + $(awk -v cutoff="$CUTOFF" '$0 >= cutoff && /"status":5[0-9][0-9]/ {print}' "$LOG" 2>/dev/null | wc -l | tr -d ' ' || echo 0)))
    fi
  fi
done

if [ "$TOTAL" -gt 100 ]; then
  RATE=$(awk "BEGIN {printf \"%.1f\", $ERR_5XX*100/$TOTAL}")
  if [ "$(echo "$RATE > 5" | bc 2>/dev/null || echo 0)" = "1" ]; then
    echo "{\"health\":\"degraded\",\"signalKind\":\"caddy-errors\",\"evidence\":\"${RATE}% 5xx rate ($ERR_5XX/$TOTAL)\",\"metrics\":{\"caddy_5xx_rate\":$RATE,\"caddy_requests\":$TOTAL,\"caddy_5xx\":$ERR_5XX}}"
    exit 0
  fi
  echo "{\"health\":\"healthy\",\"metrics\":{\"caddy_5xx_rate\":$RATE,\"caddy_requests\":$TOTAL,\"caddy_5xx\":$ERR_5XX}}"
else
  echo '{"health":"healthy"}'
fi