#!/usr/bin/env bash
# ---------------------------------------------------------------------------
# tilde - manage user-submitted scripts and apps

# Copyright 2018, Ben Harris <ben@tilde.team>

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# 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 at <http://www.gnu.org/licenses/> for
# more details.

# Usage: tilde [-h|--help]

# ---------------------------------------------------------------------------

PROGNAME=${0##*/}
VERSION="0.0.1"


clean_up() { # Perform pre-exit housekeeping
  return
}


error_exit() {
  echo -e "${1:-"unknown Error"}" >&2
  clean_up
  exit 1
}


graceful_exit() {
  clean_up
  exit
}


signal_exit() { # Handle trapped signals
  case $1 in
    INT)
      error_exit "program interrupted by user" ;;
    TERM)
      echo -e "\n$PROGNAME: program terminated" >&2
      graceful_exit ;;
    *)
      error_exit "$PROGNAME: terminating on unknown signal" ;;
  esac
}


prompt_confirm() {
  while true; do
    read -r -n 1 -p "${1:-continue?} [y/n]: " REPLY
    case $REPLY in
      [yY]) echo ; return 0 ;;
      [nN]) echo ; return 1 ;;
      *) printf " \033[31m %s \n\033[0m" "invalid input"
    esac
  done
}


usage() {
  echo -e "\nusage: $PROGNAME [help|list|submit|about|script_name]\n"
  echo "  $PROGNAME list                 - show a list of approved userscripts"
  echo "  $PROGNAME submit               - start the submission flow for your own script"
  [[ $(id -u) == 0 ]] && {
    echo "  $PROGNAME approve              - enter the approval queue"
    echo "  $PROGNAME revoke <script_name> - send a script back to the author and remove from /tilde/bin"
  }
  echo "  $PROGNAME about <script_name>  - get the description for script_name"
  echo "  $PROGNAME <script_name>        - run script_name with all remaining args are passed to the script"

  if [[ :$PATH: != *:"/tilde/bin":* ]] ; then
    echo -e "\nadd /tilde/bin to your PATH to use approved scripts without this wrapper"
    echo "if you're using bash, run the following to add it quickly"
    echo "  echo 'export PATH=\$PATH:/tilde/bin' >> ~/.bashrc && source ~/.bashrc"
  fi
}


help_message() {
  cat <<- _EOF_
$PROGNAME ver. $VERSION
wrapper for user-submitted scripts
supports user submission and admin approval
$(usage)
_EOF_
  return
}


verify_script_name() {
  [[ $1 == "" ]] && error_exit "please start over and enter the script name"
  [[ $(type -P "$1") ]] &&
    [[ -x $HOME/bin/$1 ]] ||
    error_exit "$1 already exists. rename your script and try again."
  [[ -x /tilde/bin/$1 ]] && error_exit "$1 is already taken. rename your script and try again."
  case $1 in
    about|description|list|ls|submit|about|help|apropos|submit|approve)
      error_exit "$1 is a subcommand of tilde. rename your script and try again." ;;
    *)
      return ;;
  esac
}


submission_checklist() {
  cat <<- _EOF_
requirements for submitting a user script or program:

  - placed in your ~/bin
  - executable
  - responds to help or --help
  - no name collisions with existing scripts or $PROGNAME subcommands

_EOF_
}


mail_body() {
  cat <<- _EOF_
Subject: tilde script submission from $USER
From: $USER@tilde.team
To: ben@tilde.team

tilde script submission from $USER

script name: $1

description:
-----------------------------------------------------------------------

$2

-----------------------------------------------------------------------
you'll find the script and description in: /tilde/pending-submissions/$USER/$1

run this to see the approval queue:
sudo tilde approve
_EOF_
}


# Trap signals
trap "signal_exit TERM" TERM HUP
trap "signal_exit INT"  INT

# Check for root UID


# Parse command-line
case $1 in
  -h | --help | help)
    help_message; graceful_exit ;;

  -v | --version)
    echo $VERSION ;;

  -* | --*)
    usage
    error_exit "Unknown option $1" ;;

  list | ls)
    echo -e "available scripts:\n"
    for scr in /tilde/bin/*; do
      script_name=$(basename $scr)
      target=$(readlink -f "$scr")
      echo "$script_name by "$(stat -c '%U' $target)
      cat /tilde/descriptions/$script_name
      echo ""
    done ;;

  about | apropos | description)
    if [[ -f /tilde/descriptions/$2 ]]; then
      cat /tilde/descriptions/$2
    else
      echo "$2 not found. try $PROGNAME list to see available user scripts."
    fi
  ;;

  submit)
    echo "hello, $USER! so it's time to submit your script?"
    submission_checklist
    prompt_confirm "are you ready to continue?" || graceful_exit
    echo -n "enter the name of your script: "
    read script_name

    verify_script_name $script_name

    if [[ -x $HOME/bin/$script_name ]]; then
      echo "cool, found your script"
      [[ -x /tilde/pending-submissions/$USER/$script_name/$script_name ]] && error_exit "you've already submitted $script_name"
    else
      error_exit "$script_name not found in ~/bin"
    fi

    echo "enter a description of your script: "
    read description
    echo -e "\nyour script, along with your description will be sent to the admins for approval"
    prompt_confirm "ready to submit?" || graceful_exit

    # submit now
    mkdir -p /tilde/pending-submissions/$USER/$script_name
    ln -s $HOME/bin/$script_name /tilde/pending-submissions/$USER/$script_name/$script_name
    echo $description > /tilde/pending-submissions/$USER/$script_name/description.txt
    mail_body $script_name "$description" | sendmail ben
    echo "script submitted. thanks! :)" ;;

  approve)
    [[ $(id -u) != 0 ]] && error_exit "re-run this as sudo to access the approval queue"

    echo -e "welcome to the approval queue\n\n"

    for user in /tilde/pending-submissions/*; do
      for scr in $user/*; do
        user=$(basename $user)
        script_name=$(basename $scr)
        [[ -f $scr/approved ]] && continue
        script=$scr/$script_name
        echo "$script_name by $user"
        cat $scr/description.txt
        prompt_confirm "approve?" || continue

        sudo ln -s $(readlink -f $script) /tilde/bin/$script_name
        sudo cp $scr/description.txt /tilde/descriptions/$script_name
        sudo touch $scr/approved
        sudo chmod 664 /tilde/descriptions/*
        echo "your submission of $script_name has been approved and is now available at /tilde/bin/$script_name" | sendmail $user
      done
    done
    echo "~~done for now~~" ;;

  revoke)
    [[ $(id -u) != 0 ]] && error_exit "re-run this as sudo to access the revoke menu"
    [[ -f /tilde/bin/$2 ]] || error_exit "$2 isn't an approved script"

    prompt_confirm "revoke $2?"
    echo -n "please provide a reason: "
    read reason

    original_script=$(readlink -f /tilde/bin/$2)
    author=$(stat -c '%U' $original_script)
    sudo rm /tilde/{bin,descriptions}/$2
    sudo rm -rf /tilde/pending-submissions/$author/$2

    echo -e "your script $2 has been returned because: $reason\nfeel free to resubmit" | sendmail $author
    echo "$2 revoked and returned to author" ;;

  *)
    if [[ -f /tilde/bin/$1 ]]; then
      prog=/tilde/bin/$1
      shift
      $prog "$@"
      graceful_exit
    else
      [[ $1 == "" ]] || echo -e "$1 not found. try $PROGNAME list to see what's available\n"
      help_message; graceful_exit;
    fi ;;

esac

# Main logic

graceful_exit