#!/usr/bin/bash
# Deliver announcements as notifications.
#
# Related files:
#   - /usr/share/ublue-os/announcements/*.msg.json : Announcement files.
#   - /etc/xdg/bazzite-announcement.desktop : Shortcut that launches the announcement script when the user logins.
#   - /usr/libexec/bazzite-announcement : Script that delivers the announcements as notifications.

set -o pipefail

declare -r ANNOUNCEMENTS_DIR=/usr/share/ublue-os/announcements
declare -r ANNOUNCEMENTS_SEEN_DIR="$HOME/.local/share/bazzite/announcements_seen"

# Get the sha256 hash of a message file, disregarding whitespaces.
#
# Args:
#   1: Path of message file.
get_msg_sha() {
    local sha
    sha=$(tr -d '[:space:]' <"$1" | sha256sum | cut -d ' ' -f 1) || return
    echo "$sha"
}

if [[ $UID -eq 0 ]]; then
    echo "This script should not be run as root." >&2
    exit 1
fi

for msg_file in "$ANNOUNCEMENTS_DIR"/*.msg.json; do
    # We omit not existing files and example files.
    if [[ ! -f "$msg_file" || $msg_file == */example.msg.json ]]; then
        continue
    fi

    # Check if we have already seen this message.
    # A file is considered seen when a file with named after the matching hash exists at ANNOUNCEMENTS_SEEN_DIR.
    msg_sha=$(get_msg_sha "$msg_file")
    if [[ -f "${ANNOUNCEMENTS_SEEN_DIR}/${msg_sha}" ]]; then
        continue
    fi

    sleep 1 # Small delay between notifications to avoid notify-send being overwhelmed.
    (
        # Parse the message file. We expect the following fields:
        #   - title: The title of the message. Must be short
        #   - body: The body of the message. Supports html tags.
        #   - seeMoreUrl: The url to open when the button "See more" is pressed.
        #   - if: shell line to execute to check whenever the message should display.
        #         It wont override the pressence of the seen message file.
        unset -v _msg_file_contents title body see_more_url if

        _msg_file_contents="$(<"$msg_file")"
        title=$(jq -r '.title // ""' <<<"$_msg_file_contents")
        body=$(jq -r '.body // ""' <<<"$_msg_file_contents")
        see_more_url=$(jq -r '.seeMoreUrl // ""' <<<"$_msg_file_contents")
        if=$(jq -r '.if // ""' <<<"$_msg_file_contents")
        unset -v _msg_file_contents

        (eval "$if") || exit

        notify_cmd="/usr/bin/notify-send --app-name=\"Announcements\" --expire-time=0"
        notify_cmd+=" \"${title:+$title}\" \"${body:+$body}\""
        if [[ -n "$see_more_url" ]]; then
            notify_cmd+=" --action=\"see_more=See more\""
        fi
        notify_cmd+=' --action="dont_show_again=Dont show me this again"'

        action=$(eval "$notify_cmd") || exit
        case "$action" in
        see_more)
            xdg-open "$see_more_url"
            ;;
        dont_show_again)
            # Create a file with the hash of the message as name to mark it as seen.
            mkdir -p "${ANNOUNCEMENTS_SEEN_DIR}"
            touch "${ANNOUNCEMENTS_SEEN_DIR}/${msg_sha}"
            ;;
        *)
            # Do nothing
            :
            ;;
        esac
    ) &
done