#!/usr/bin/env zsh
#

svc="psi-monitor.service"
cpu="/proc/pressure/cpu"
mem="/proc/pressure/memory"
io="/proc/pressure/io"
email_to="trey@blancher.net"
sms_dst="2517511550@msg.fi.google.com"
sms_domain="msg.fi.google.com"
port="5999"
ssh_host="localhost"
clear_threshold="5.0"
notification_cmd="dunstify"
notification_opts="--timeout=0 --printid --urgency=critical --icon=/usr/share/icons/breeze-dark/emblems/16/emblem-warning.svg"
id_idx=15

print_psi () {
    local psi_file="${1}"
    cat "${(P)psi_file}"
}

print_pidstat () {
    local psi_type="${1}"
    local opts="-l --human"

    case "${psi_type}" in
        MEM)
            opts="-r ${opts}"
            ;;
        IO)
            opts="-d ${opts}"
            ;;
        CPU)
            opts="-u ${opts}"
            ;;
        *)
            print "Invalid psi_type:  ${psi_type}" >&2
            ;;
    esac

    pidstat "${opts}"
}

send_notice () {
    local psi_type="${1}"
    shift
    
    local current_alarms=""
    if [[ -n "${1}" ]]; then
        current_alarms="${1}"
    fi

    local psi
    case "${psi_type}" in
        CPU|MEM|IO)
            psi="$(print_psi $(tr '[[:upper:]]' '[[:lower:]]' <<< "${psi_type}"))"
            ;;
        *)
            psi="Multiple alarms, current alarms are ${current_alarms}!"
            ;;
    esac

    integer dunst_id
    if ! dunst_id=$(ssh -q "${ssh_host}" -p ${port} \
        "${notification_cmd} ${notification_opts} 'deltachunk:  PSI ${psi_type} triggered!' '${psi}'"); then
            print "Connection to dunst failed!" >&2
            false
    else
        echo ${dunst_id}
        true
    fi
}

send () {
    if [[ "${#@}" -lt 2 ]] && [[ "${#@}" -gt 3 ]]; then
        echo "Wrong number of arguments to send()!" >&2
        return false
    fi

    local psi_type="${1}"
    shift

    local current_alarms="${1}"
    shift

    local dst
    if [[ "${current_alarms}" =~ "@" ]]; then
        dst="${current_alarms}"
        unset current_alarms
    else
        dst="${1}"
    fi

    local psi="$(print_psi $(tr '[[:upper:]]' '[[:lower:]]' <<< ${psi_type}))"

    local subj="PSI on deltachunk ${psi_type} triggered!"


    local body="Pressure Stall Information triggered on ${psi_type} at $(date +'%FT%T %Z')"
    if [[ -n "${current_alarms}" ]]; then
        body="${body}\nMultiple alarms triggered:  ${current_alarms}"
        # if this is not an SMS, include pidstat info
        if [[ ! "${dst}" =~ "${sms_domain}" ]]; then
            for p in $(tr '|' ' ' <<< "${current_alarms}"); do
                body="${body}\n\n$(print_pidstat ${p})"
            done
        fi
    fi


    local email=$(mktemp /tmp/psi.eml.XXXX)

    cat <<-EOF > ${email}
        ${body}

EOF


    /usr/bin/mail --resource-files=/ \
                  --subject="${subj}" \
                  --end-options \
                  ${dst} < ${email}
}

is_clear () {
    local psi_type="${1}"
    local psi_file="$(tr '[[:upper:]]' '[[:lower:]]' <<< "${psi_type}")"

    local avg10=$(grep some "${(P)psi_file}" | awk '{print $2}' | awk -F= '{print $2}')
    local prev=$(grep some "${(P)psi_file}" | awk '{print $5}' | awk -F= '{print $2}')

    
    if [[ ${avg10} -lt ${clear_threshold} ]]; then
        return 0
    else
        return 1
    fi
}

exec_notices () {
    local psi_type="${1}"
    shift
    local current_alarms="${1}"

    local dunst_id=-1
    if [[ -n "${psi_type}" ]]; then
        case "${psi_type}" in
            CPU|MEM|IO)
                dunst_id=$(send_notice "${psi_type}" "${current_alarms}");
                send "${psi_type}" "${current_alarms}" "${sms_dst}"
                send "${psi_type}" "${current_alarms}" "${email_to}"
                ;;
            *)
                echo "Something went wrong!" >&2
                false
                ;;
        esac
    fi
    if [[ "${dunst_id}" -ge 0 ]]; then
        print "${dunst_id}"
        true
    else
        false
    fi
}

check_dunst_id_is_visible () {
    local dunst_id="${1}"

    typeset -a ids
    if ids=$(ssh -q "${ssh_host}" -p ${port} \
        "dunstctl history | jq '.data[0][][${id_idx}].data'"); then
            echo "Connection to dunst failed!" >&2
            return 2
    fi

    if grep -qP "\b${dunst_id}\b" <<< "${ids}"; then
        true
    else
        false
    fi
}
#set -x
local current_alarm=""
local last_alarm=""
typeset -A notice_sent
typeset -A secs
integer last_dunst_id=-1

journalctl -b 0 -fu "${svc}"  | \
while read line; do
    local psi_type="$(grep -Eo "(CPU|MEM|IO) PSI event" <<< "${line}" | grep -Eo "CPU|MEM|IO")"
    if [[ -n "${psi_type}" ]]; then
        secs+=(${psi_type} $(date +%s))
        if [[ "${psi_type}" != "${last_alarm}" ]]; then
            if [[ ! ${notice_sent[${psi_type}]} ]]; then
                last_dunst_id=$(exec_notices "${psi_type}" "${current_alarms}")
                notice_sent+=(${psi_type} true)
            elif (( last_dunst_id >= 0 )) && ! check_dunst_id_is_visible "${last_dunst_id}"; then
                continue
            fi
        fi
        last_alarm="${psi_type}"
        if [[ -z "${current_alarms}" ]]; then
            current_alarms="${psi_type}"
        else
            if ! grep -q "${psi_type}" <<< "${current_alarms}"; then
                current_alarms="${current_alarms}|${psi_type}"
            fi
        fi
    else
        typeset -a alarms=( $(tr '|' ' ' <<< "$current_alarms") )
        for alarm in ${alarms}; do
            integer elapsed=$(( $(date +%s) - ${secs[${alarm}]} ))
            if is_clear "${alarm}" && (( elapsed > 300 )); then
                current_alarms=$(sed -E "s/${alarm}\|?//" <<< "${current_alarms}")
                last_alarm=$(awk -F'|' '{print $NF}' <<< "${current_alarms}")
            fi
        done
    fi
done
#set +x