#!/bin/bash

## Send a notification with NTFY and check if the config file is complete

if [[ "$UID" == "0" ]]; then
    NTFY_CONFIG_DIR="${NTFY_CONFIG_DIR:-/etc/ntfy}"
else
    NTFY_CONFIG_DIR="${NTFY_CONFIG_DIR:-~/.config/ntfy}"
fi
NTFY_CONFIG_FILE="$NTFY_CONFIG_DIR/ntfy.conf"

SERVER="https://ntfy.0k.io"

[ -f "$NTFY_CONFIG_DIR/topics.yml" ] || {
    echo "Error: no 'topics.yml' file found in $NTFY_CONFIG_DIR" >&2
    echo "  Please setup the topics for the notification channels in this file." >&2
    exit 1
}

if ! [ -e "$NTFY_CONFIG_FILE" ]; then
    mkdir -p "${NTFY_CONFIG_FILE%/*}"
    ## default option to change if needed
    echo "SERVER=$SERVER" > "$NTFY_CONFIG_FILE"
elif ! grep -q "^SERVER=" "$NTFY_CONFIG_FILE"; then
    echo "SERVER=$SERVER" >> "$NTFY_CONFIG_FILE"
fi

source "$NTFY_CONFIG_FILE" || {
    echo "Error: could not source '$NTFY_CONFIG_FILE'" >&2
    exit 1
}

SERVER="${SERVER%/}"

for var in SERVER LOGIN PASSWORD; do
    if ! [ -v "$var" ]; then
        echo "Error: missing $var in $NTFY_CONFIG_FILE"
        exit 1
    fi
done


exname=${0##*/}
channels=()


usage="Usage: $exname [-c CHANNEL...] [-t TITLE ] MESSAGE 
----------------------------------------------
--- Send MESSAGE with TITLE to the differents topics defined by a CHANNEL. ---
--- If no CHANNEL is provided, the message will be sent to the default channel. ---
----------------------------------------------
-c CHANNEL: One or multiple channels. If no CHANNEL is provided,
    the message will be sent to the main channel.
    You can provide multiple channels with -c channel1 -c channel2 ...  
    topics are configured in $NTFY_CONFIG_DIR/topics.yml
-t TITLE: If no TITLE is provided, the message will be sent with the hostname as title.
- MESSAGE: The message to send.
"

while [ "$#" -gt 0 ]; do
    arg="$1"
    shift
    case "$arg" in
        -h|--help)
            echo "$usage"
            exit 0
            ;;
        -c|--channel)
            [ -n "$1" ] || {
                echo "Error: no argument for channel option." >&2
                echo "$usage" >&2
                exit 1
            }
            IFS=", " channels+=($1)
            shift
            ;;
        -t|--title)
            [ -n "$1" ] || {
                echo "Error: no argument for title option." >&2
                echo "$usage" >&2
                exit 1
            }
            title="$1"
            shift 
            ;;
        *)  
            [ -z "$message" ] && { message="$arg"; continue; }
            echo "Error : Unexpected positional argument '$arg'." >&2
            echo "$usage" >&2
            exit 1
            ;;
    esac
done

[ -n "$message" ] || {
    echo "Error: missing message." >&2
    echo "$usage" >&2
    exit 1
}

read-0() {
    local eof='' IFS=''
    while [ "$1" ]; do
        read -r -d '' -- "$1" || eof=1
        shift
    done
    [ -z "$eof" ]
}

curl_opts=(
    -s 
    -u "$LOGIN:$PASSWORD"
    -d "$message"
)

title="[$(hostname)] $title"
title="${title%%+([[:space:]])}"
curl_opts+=(-H "Title: $title")

declare -A sent_topic=()

if [ "${#channels[@]}" -eq 0 ]; then
    channels=("main")
fi

for channel in "${channels[@]}"; do
    channel_quoted=$(printf "%q" "$channel")
    content=$(cat "$NTFY_CONFIG_DIR/topics.yml")
    while read-0 channel_regex topics; do
        [[ "$channel" =~ ^$channel_regex$ ]] || continue
        rematch=("${BASH_REMATCH[@]}")
        while read-0 topic; do
            ttopic=$(printf "%s" "$topic" | yq "type")
            if [ "$ttopic" != '!!str' ]; then
                echo "Error: Unexpected '$ttopic' type for value of channel $channel." >&2
                exit 1
            fi
            topic=$(printf "%s" "$topic" | yq -r " \"\" + .")
            if ! [[ "$topic" =~ ^[a-zA-Z0-9\$\{\}*\ \,_.-]+$ ]]; then
                echo "Error: Invalid topic value '$topic' expression in $channel channel." >&2
                exit 1
            fi
            new_topics=($(set -- "${rematch[@]}"; eval echo "${topic//\*/\\*}"))
            for new_topic in "${new_topics[@]}"; do
                [ -n "${sent_topic["$new_topic"]}" ] && continue
                sent_topic["$new_topic"]=1
                if ! out=$(curl "${curl_opts[@]}" "$SERVER/${new_topic}"); then
                    echo "Error: could not send message to $new_topic." >&2
                    echo "curl command:" >&2
                    echo "  curl ${curl_opts[@]} $SERVER/${new_topic}" >&2
                    echo "$out" | sed 's/^/  | /' >&2
                    exit 1
                fi
            done
        done < <(printf "%s" "$topics" | yq e -0 '.[]')
    done < <(printf "%s" "$content" | yq e -0 'to_entries | .[] | [.key, .value] |.[]')
done