#!/bin/bash
#
# 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.
#
# Notifies when mail arrives: one notification per account per batch, naming
# the newest senders and subjects.
#
# Watches the notmuch Xapian directory and, on each commit, asks notmuch what
# changed since the revision it last saw. A commit is NOT the same as new
# mail, since reading and tagging also commit, which is why the revision
# counter does the work rather than a count delta.
#
# This is its own process rather than part of waybar-mail.sh, which already
# has the same arrival edge: waybar owns that process, so a bar restart would
# stop notifications with nothing reporting it.
#
# Usage:
#   mail-notify.sh          watch forever (what autostart runs)
#   mail-notify.sh --once   process one tick and exit (what the test drives)

set -u

STATE="${MAIL_NOTIFY_STATE:-$HOME/.local/state/mail-notify.lastmod}"
CONFIG="${MAIL_NOTIFY_CONFIG:-$HOME/.config/qtmaildir/qtmaildir.conf}"
SCOPE='tag:unread and tag:inbox'

# How many threads a notification body lists before eliding into "+N more".
# Three matches the drawer's own --limit=3.
ROWS=3

# Accounts in file order, one "key<TAB>label" line each, read from stdin.
#
# Two things here are load-bearing, and both have already broken this
# component once:
#
# The key runs to the closing bracket, NOT to the first dot. Real keys
# contain dots, so splitting on the first one yields a notmuch tag matching
# nothing and an account that silently never notifies.
#
# And this walks lines rather than matching a section body as "everything up
# to the next [". Accounts have folders named like [Gmail]/Bozze, which ends
# the body before its label and makes the account display its raw key.
parse_accounts() {
    local line key label
    key=""
    label=""

    while IFS= read -r line || [[ -n "$line" ]]; do
        if [[ "$line" =~ ^\[account\.([^]]+)\] ]]; then
            [[ -n "$key" ]] && printf '%s\t%s\n' "$key" "${label:-$key}"
            key="${BASH_REMATCH[1]}"
            label=""
            continue
        fi
        # Any other section ends the current account.
        if [[ "$line" =~ ^\[ ]]; then
            [[ -n "$key" ]] && printf '%s\t%s\n' "$key" "${label:-$key}"
            key=""
            label=""
            continue
        fi
        [[ -n "$key" ]] || continue
        if [[ "$line" =~ ^[[:space:]]*label[[:space:]]*=[[:space:]]*(.*)$ ]]; then
            label="${BASH_REMATCH[1]}"
            # Trailing whitespace only; a label may contain spaces.
            label="${label%"${label##*[![:space:]]}"}"
        fi
    done

    [[ -n "$key" ]] && printf '%s\t%s\n' "$key" "${label:-$key}"
    return 0
}

# Renders notmuch search JSON into notification body text.
#   $1  the JSON array from `notmuch search --format=json`
#   $2  the true total for this batch, which may exceed the rows present
#
# dunst has body-markup in its capabilities, so a subject containing < or &
# would be parsed as markup and could vanish from the notification. Subjects
# are attacker-controlled text arriving from the internet, so the three XML
# characters are escaped here. This is the one place in this script where
# untrusted text reaches a renderer.
#
# Malformed JSON prints nothing and succeeds. A notification with no body is
# still worth sending: the summary already carries the account and the count.
build_body() {
    local json="$1" total="$2" shown

    local body
    body="$(printf '%s' "$json" | jq -r '
        .[] | ((.authors // "(unknown)") + " — " + (.subject // "(no subject)"))
        | gsub("&"; "&amp;") | gsub("<"; "&lt;") | gsub(">"; "&gt;")
    ' 2>/dev/null)" || return 0
    [[ -n "$body" ]] || return 0

    shown="$(printf '%s\n' "$body" | wc -l)"
    printf '%s' "$body"
    if [[ "$total" -gt "$shown" ]]; then
        printf '\n+%d more' "$((total - shown))"
    fi
    printf '\n'
}

main() {
    echo "not implemented"
}

# Sourced by the test with MAIL_NOTIFY_LIB set, which must not start a watch
# loop. The bash equivalent of Python's __name__ == "__main__".
[[ -n "${MAIL_NOTIFY_LIB:-}" ]] || main "$@"