#!/usr/bin/env bash
# Webhost Availability Monitor - Single File - Loop
# user only. keine root.

set -o errexit
set -o nounset
set -o pipefail

INTERVAL=60

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
LOG_DIR="$ROOT_DIR/logs"
HOSTS_FILE="$ROOT_DIR/hosts.txt"
SEP=';'

timestamp_iso() {
  date -Iseconds
}

ensure_dirs() {
  mkdir -p "$LOG_DIR"
}

current_logfile() {
  printf "%s/%s.csv" "$LOG_DIR" "$(date +%F)"
}

write_header_if_needed() {
  local file="$1"
  if [ ! -f "$file" ] || [ ! -s "$file" ]; then
    printf "timestamp${SEP}label${SEP}http_code\n" >>"$file"
  fi
}

stop_requested=0
_on_exit() {
  stop_requested=1
  printf "\nstop received. exit after current batch\n" >&2
}
trap _on_exit INT TERM

ensure_dirs

printf "loop start. 60s. logs dir: %s\n" "$LOG_DIR"

while [ "$stop_requested" -eq 0 ]; do
  logfile="$(current_logfile)"
  write_header_if_needed "$logfile"

  while IFS= read -r line; do
    [ -z "$line" ] && continue
    case "$line" in \#*) continue ;; esac

    IFS='|' read -r label url expected <<<"$line"

    ts="$(timestamp_iso)"
    set +o errexit
    code="$(curl -sS -o /dev/null -w "%{http_code}" --max-time 10 -L "$url" 2>/dev/null)" || code="000"
    set -o errexit

    printf "%s%s%s%s%s\n" "$ts" "$SEP" "$label" "$SEP" "$code" >>"$logfile"
  done <"$HOSTS_FILE"

  # interruptable sleep
  waited=0
  while [ "$waited" -lt "$INTERVAL" ] && [ "$stop_requested" -eq 0 ]; do
    sleep 1
    waited=$((waited+1))
  done
done

printf "exit\n"