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

#: "${GOTIFY_URL:?Set GOTIFY_URL (e.g. https://gotify.lan.ddnsgeek.com)}"
#: "${GOTIFY_TOKEN:?Set GOTIFY_TOKEN (AAM..CtNmUGoNIV)}"

GOTIFY_URL="${GOTIFY_URL}"
GOTIFY_TOKEN="${GOTIFY_TOKEN}"

STATE_DIR="./docker-health-alert"
STATE_FILE="${STATE_DIR}/last_unhealthy.txt"
mkdir -p "$STATE_DIR"

# Collect unhealthy running containers (ignore those with no healthcheck)
unhealthy="$(
  docker ps -q | while read -r id; do
    status="$(docker inspect --format '{{if .State.Health}}{{.State.Health.Status}}{{else}}no-healthcheck{{end}}' "$id")"
    name="$(docker inspect --format '{{.Name}}' "$id" | sed 's|^/||')"
    if [[ "$status" == "unhealthy" ]]; then
      echo "$name"
    fi
  done | sort
)"

# Only alert on change
last="$(cat "$STATE_FILE" 2>/dev/null || true)"
if [[ "$unhealthy" != "$last" ]]; then
  if [[ -n "$unhealthy" ]]; then
    msg="Unhealthy containers: $(echo "$unhealthy" | paste -sd ', ' -)"
    title="Docker: UNHEALTHY"
    priority=8
  else
    msg="All containers healthy again."
    title="Docker: RECOVERED"
    priority=4
  fi

  curl -fsS -X POST "${GOTIFY_URL%/}/message" \
    -H "X-Gotify-Key: ${GOTIFY_TOKEN}" \
    -F "title=${title}" \
    -F "message=${msg}" \
    -F "priority=${priority}" >/dev/null

  printf "%s" "$unhealthy" > "$STATE_FILE"
fi