#!/bin/bash
# ~/bin/mailsync.sh
#
# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

# Defensive: don't rely on cron/systemd/whatever invokes this to have
# set these correctly. Explicit beats inferred, especially after the
# HOME-not-set failure we hit once already. Fall back to the invoking
# user's home from passwd rather than a hardcoded path.
export HOME="${HOME:-$(getent passwd "$(id -u)" | cut -d: -f6)}"
export GNUPGHOME="${GNUPGHOME:-$HOME/.gnupg}"

LOCKFILE="/tmp/mbsync.lock"
LOGFILE="$HOME/.local/state/mailsync.log"
MAX_LOG_BYTES=$((10 * 1024 * 1024))  # rotate past 10MB, see note below

exec 200>"$LOCKFILE"
if ! flock -n 200; then
    echo "$(date -Iseconds) === SKIPPED: previous run still in progress ===" >> "$LOGFILE"
    exit 1
fi

# Simple rotation: if the log's gotten big, keep the last run's worth
# and move the rest aside rather than letting it grow forever.
if [ -f "$LOGFILE" ] && [ "$(stat -c%s "$LOGFILE" 2>/dev/null || echo 0)" -gt "$MAX_LOG_BYTES" ]; then
    mv "$LOGFILE" "${LOGFILE}.1"
fi

START_TS="$(date -Iseconds)"
{
    echo "===== RUN START: $START_TS ====="

    # Timestamp every line of mbsync/notmuch output as it streams,
    # rather than only marking run boundaries, this is what actually
    # lets you tell which errors are from which run at a glance.
    mbsync -a 2>&1 | while IFS= read -r line; do
        echo "$(date '+%H:%M:%S') $line"
    done
    MBSYNC_STATUS=${PIPESTATUS[0]}

    notmuch new 2>&1 | while IFS= read -r line; do
        echo "$(date '+%H:%M:%S') $line"
    done
    NOTMUCH_STATUS=${PIPESTATUS[0]}

    END_TS="$(date -Iseconds)"
    if [ "$MBSYNC_STATUS" -eq 0 ] && [ "$NOTMUCH_STATUS" -eq 0 ]; then
        echo "===== RUN END: $END_TS  status=OK ====="
    else
        echo "===== RUN END: $END_TS  status=FAILED  mbsync=$MBSYNC_STATUS notmuch=$NOTMUCH_STATUS ====="
    fi
} >> "$LOGFILE"

exit 0