#!/bin/sh

set -e

# Validate environment
if ! command -v msgbus > /dev/null; then
  printf "missing msgbus command. Use:  go install git.mills.io/prologic/msgbus/cmd/msgbus@master"
  exit 1
fi

if ! command -v salty > /dev/null; then
  printf "missing salty command. Use:  go install go.mills.io/salty/cmd/salty@master"
  exit 1
fi

if ! command -v salty-keygen > /dev/null; then
  printf "missing salty-keygen command. Use:  go install go.mills.io/salty/cmd/salty-keygen@master"
  exit 1
fi

if [ -z "$SALTY_IDENTITY" ]; then
  export SALTY_IDENTITY="$HOME/.config/salty/$USER.key"
fi

get_user () {
  user=$(grep user: "$SALTY_IDENTITY" | awk '{print $3}')
  if [ -z "$user" ]; then
    user="$USER"
  fi
  echo "$user"
}

stream () {
  if [ -z "$SALTY_IDENTITY" ]; then
    echo "SALTY_IDENTITY not set"
    return 2
  fi

  echo '\007'
  jq -r '.payload' | base64 -d | salty -i "$SALTY_IDENTITY" -d
}

lookup () {
  if [ $# -lt 1 ]; then
    printf "lookup takes 1 arugment %d given\n" "$#"
    printf "Try %s lookup nick@domain\n" "$(basename "$0")"
    return 1
  fi

  user="$1"
  nick="$(echo "$user" | awk -F@ '{ print $1 }')"
  domain="$(echo "$user" | awk -F@ '{ print $2 }')"

  if ! curl -qfsSL "https://$domain/.well-known/salty/${nick}.json"; then
    echo "error: lookup failed"
    return 1
  fi
}

readmsgs () {
  topic="$1"

  if [ -z "$topic" ]; then
    topic=$(get_user)
  fi

  export SALTY_IDENTITY="$HOME/.config/salty/$topic.key"
  if [ ! -f "$SALTY_IDENTITY" ]; then
    echo "identity file missing for user $topic" >&2
    return 1
  fi

  msgbus sub "$topic" "$0"
}

sendmsg () {
  if [ $# -lt 2 ]; then
    printf "sendmsg requires 2 arguments %d provided" "$#"
    printf "Try %s send nick@domain message\n" "$(basename "$0")"
    return 1
  fi

  if [ -z "$SALTY_IDENTITY" ]; then
    echo "SALTY_IDENTITY not set"
    return 2
  fi

  user="$1"
  message="$2"

  if [ -z "$message" ]; then
    echo "error: empty message"
    exit 2
  fi

  salty_json="$(mktemp /tmp/salty.XXXXXX)"

  lookup "$user" > "$salty_json"

  endpoint="$(jq -r '.endpoint' < "$salty_json")"
  topic="$(jq -r '.topic' < "$salty_json")"
  key="$(jq -r '.key' < "$salty_json")"

  rm "$salty_json"

  message="[$(date +%FT%TZ)] <$(get_user)> $message"

  echo "$message" \
    | salty -i "$SALTY_IDENTITY" -r "$key" \
    | msgbus -u "$endpoint" pub "$topic"
}

chatwith() {
  if [ $# -lt 1 ]; then
    printf "chatwith requires 1 arguments %d provided" "$#"
    printf "Try %s chat nick@domain\n" "$(basename "$0")"
    return 1
  fi

  if [ -z "$SALTY_IDENTITY" ]; then
    echo "SALTY_IDENTITY not set"
    return 2
  fi

  user="$1"

  salty_json="$(mktemp /tmp/salty.XXXXXX)"

  lookup "$user" > "$salty_json"

  endpoint="$(jq -r '.endpoint' < "$salty_json")"
  topic="$(jq -r '.topic' < "$salty_json")"
  key="$(jq -r '.key' < "$salty_json")"

  rm "$salty_json"

  while true; do
    printf "> "
    read -r message
    if [ -z "$message" ]; then
      continue
    fi

    message="[$(date +%FT%TZ)] <$(get_user)> $message"

    echo "$message" \
      | salty -i "$SALTY_IDENTITY" -r "$key" \
      | msgbus -u "$endpoint" pub "$topic"
  done
}

make_user () {
  mkdir -p "$HOME/.config/salty"

  if [ $# -lt 1 ]; then
    user=$USER
  else
    user=$1
  fi

  identity_file="$HOME/.config/salty/$user.key"

  if [ -f "$identity_file" ]; then
    printf "user key already exists!"
    return 1
  fi

  # Check for msgbus env.. probably can make it fallback to looking for a config file?
  if [ -z "$MSGBUS_URI" ]; then
    printf "missing MSGBUS_URI in environment"
    return 1
  fi

  salty-keygen -o "$identity_file"
  echo "# user: $user" >> "$identity_file"

  pubkey=$(grep key: "$identity_file" | awk '{print $4}')

  cat <<- EOF
Create this file in your webserver well-known folder. https://hostname.tld/.well-known/salty/$user.json

{
  "endpoint": "$MSGBUS_URI",
  "topic": "$user",
  "key": "$pubkey"
}

EOF
}

show_help() {
  printf "Usage: %s [options] <command> [arguments]\n" "$(basename "$0")"
  printf "\n"
  printf "Options:\n"
  printf "  -h/--help  Show this help"
  printf "\n"
  printf "\n"
  printf "Commands:\n"
  printf "  chat       -- Chat with a user by nick@domain\n"
  printf "  lookup     -- Lookup a user by nick@domain\n"
  printf "  make-user  -- Generate a new user key pair\n"
  printf "  read       -- Reads your messages\n"
  printf "  send       -- Sends a message to nick@domain\n"
}

# check if streaming
if [ ! -t 1 ]; then
  stream
  exit 0
fi

# Show Help
if [ $# -lt 1 ]; then
  show_help
  exit 1
fi


CMD=$1
shift

case $CMD in
  -h|--help)
    show_help
    ;;
  chat)
    chatwith "$@"
    ;;
  send)
    sendmsg "$@"
  ;;
  read)
    readmsgs "$@"
  ;;
  lookup)
    lookup "$@"
  ;;
  make-user)
    make_user "$@"
  ;;
esac