#!/usr/bin/env bash

# Tell somebody when a program crashes.
#
# On GNOME, ABRT says so. Under a hand-assembled Hyprland desktop nothing does,
# and applications die silently -- which is most of how "Linux is flaky" gets
# earned. Fedora ships systemd-coredump by default, so the information is
# already there; nobody is reading it.
#
# Follows the journal for systemd-coredump's own message id and reports each
# program once per session.
#
# ONCE PER SESSION IS THE WHOLE DESIGN. This machine's portal backend crashes
# between eleven and sixty times a day -- see the portal-stability check in
# panama-doctor -- and a notification per crash would be a notification every
# few minutes for something the user can do nothing about. The first one is
# news; the fortieth is why people turn notifications off. The health page
# carries the running count for anyone who wants it.

set -uo pipefail

PANAMA_PATH="${PANAMA_PATH:-$HOME/.local/share/Panama}"

# systemd-coredump's MESSAGE_ID. Matching on this rather than on text keeps
# working when the wording changes and never matches a program that merely
# mentions the word "crash" in its own logs.
readonly COREDUMP_MESSAGE_ID='fc2e22bc6ee647b6b90729ab34a250b1'

command -v journalctl >/dev/null 2>&1 || exit 0
command -v notify-send >/dev/null 2>&1 || exit 0

# The shell owns org.freedesktop.Notifications, and the crash most worth
# reporting is the one that took the shell with it. Waiting means that report
# arrives rather than vanishing into a bus nobody is serving.
for _ in $(seq 1 60); do
    busctl --user status org.freedesktop.Notifications >/dev/null 2>&1 && break
    sleep 1
done

declare -A reported=()

# -f from now, not from the boot: a session that starts after a crash should
# not open with a notification about something the user has already lived
# through and cannot act on.
journalctl --user -f -n 0 --output=json MESSAGE_ID="$COREDUMP_MESSAGE_ID" 2>/dev/null \
    | while IFS= read -r line; do
        [[ -n "$line" ]] || continue

        uid="$(jq -r '.COREDUMP_UID // empty' <<<"$line" 2>/dev/null)"
        exe="$(jq -r '.COREDUMP_EXE // empty' <<<"$line" 2>/dev/null)"
        comm="$(jq -r '.COREDUMP_COMM // empty' <<<"$line" 2>/dev/null)"

        # Another user's crash is not this session's business, and reporting it
        # would leak what they are running.
        [[ "$uid" == "$(id -u)" ]] || continue
        [[ -n "$exe" || -n "$comm" ]] || continue

        # The executable name first: COREDUMP_COMM is the kernel's comm field
        # and is truncated to fifteen characters, so it reports
        # "panama-test-cra" for a program called panama-test-crasher.
        if [[ -n "$exe" ]]; then
            program="$(basename "$exe")"
        else
            program="$comm"
        fi
        [[ -z "${reported[$program]:-}" ]] || continue
        reported[$program]=1

        notify-send --icon=dialog-error-symbolic --app-name=Panama \
            "$program stopped unexpectedly" \
            "It crashed and was not able to recover. System Health has the details." \
            2>/dev/null || true
    done