#!/bin/bash
# Sync calcurse with Google Calendar via calcurse-caldav; notify once when the weekly OAuth login expires.
# --now: called from the UI's pre-load hook (skip the UI check, shorter timeout, no daemon restart).
set -uo pipefail

data=${XDG_DATA_HOME:-$HOME/.local/share}/calcurse
state=${XDG_STATE_HOME:-$HOME/.local/state}/calcurse-sync
expired_flag=$state/login-expired
now=false
[[ ${1:-} == --now ]] && now=true

# The UI keeps the data in memory, so syncing under it would lose changes; its post-save hook syncs after it exits.
ui_running() {
    # shellcheck disable=SC2009 # pgrep can't match "has any terminal"
    ps -C calcurse -o tty= | grep -qv '?'
}

if ! $now && ui_running; then
    echo "calcurse UI is running, skipping"
    exit 0
fi

mkdir -p "$state"
# BROWSER=true: an expired login must not open browser tabs on its own.
out=$(BROWSER=true timeout "$($now && echo 15 || echo 60)" calcurse-caldav 2>&1)
rc=$?
printf '%s\n' "$out"

if ((rc != 0)); then
    if grep -q 'Access token is missing or refresh token is expired' <<<"$out"; then
        if [[ ! -e $expired_flag ]]; then
            notify-send -a calcurse -u critical -i x-office-calendar "Google Calendar login expired" \
                "Run calcurse-caldav in a terminal, allow access in the browser, then calcurse-caldav --authcode '<code>'."
            touch "$expired_flag"
        fi
    elif grep -q 'Another synchronization instance' <<<"$out"; then
        exit 0
    fi
    exit "$rc"
fi
rm -f "$expired_flag"

# A running daemon never re-reads the data files: restart it so imported appointments get alerts.
if ! $now && ! grep -q '^0 items imported, 0 items removed locally' <<<"$out"; then
    pidfile=$data/.daemon.pid
    if [[ -s $pidfile ]] && pid=$(<"$pidfile") && kill "$pid" 2>/dev/null; then
        timeout 5 tail --pid="$pid" -f /dev/null
        # Own scope, so the daemon outlives this oneshot service.
        systemd-run --user --scope -q calcurse --daemon
        echo "restarted calcurse daemon"
    fi
fi