#!/bin/sh

PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin

# Load Telegram bot info
source .httpcheck_telegram  #Provides KEY, CHATID, CHKLIST

TIME="10"
URL="https://api.telegram.org/bot$KEY/sendMessage"

#Telegram message function
send_message() {
    curl -s --max-time $TIME -d "chat_id=${CHATID}&disable_web_page_preview=1&text=$1" $URL >/dev/null
}

get_http_code() {
    if host $(awk '{gsub("https?://|/.*","")}1' <<< $1) &>/dev/null; then
        curl -sILk --max-time $TIME $1 | grep HTTP | tail -n 1 | grep -Eo '[0-9]{3}' || printf '%s\n' 999
    else
        printf '%s\n' 000
    fi
}

# Prepare message header
MSG='HTTP/S Problems Found:'
FAILURE=false

# Check HTTP codes
for site in $(< $CHKLIST); do
    respcode=$(get_http_code $site)
    case $respcode in
        000)
            printf '%s\n' "[$(date '+%Y%m%d %H:%M:%S')]: PROBLEM -- $site: DNS record not found" >&2
            MSG="${MSG}%0A%0A %2B ${site}%0A    DNS record not found"
            FAILURE=true
            ;;
        200)
            printf '%s\n' "[$(date '+%Y%m%d %H:%M:%S')]: OK -- $site returns $respcode"
            ;;
        999)
            printf '%s\n' "[$(date '+%Y%m%d %H:%M:%S')]: PROBLEM -- $site caused general cURL failure" >&2
            ;;
        *)
            printf '%s\n' "[$(date '+%Y%m%d %H:%M:%S')]: PROBLEM -- $site returns $respcode" >&2
            MSG="${MSG}%0A%0A %2B ${site}%0A    responding ${respcode}"
            FAILURE=true
            ;;
    esac
done || exit 2

# Send compiled message if any problems were found
send_message "$MSG" && printf '%s\n' "Problems found. Message sent via Telegram bot" >&2 || printf '%s\n' "Problems found. Message sending has failed"

exit 0