#!/usr/bin/env bash

# Copyright 2021 The KCP Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

###############################################################################
#
# demo-magic.sh
#
# Copyright (c) 2015 Paxton Hare
#
# This script lets you script demos in bash. It runs through your demo script when you press
# ENTER. It simulates typing and runs commands.
#
###############################################################################

# the speed to "type" the text
TYPE_SPEED=${TYPE_SPEED:-20}

# no wait after "p" or "pe"
NO_WAIT=${NO_WAIT:-"false"}

# if > 0, will pause for this amount of seconds before automatically proceeding with any p or pe
PROMPT_TIMEOUT=${PROMPT_TIMEOUT:-0}

# don't show command number unless user specifies it
SHOW_CMD_NUMS=false

if [[ "${NO_COLORS}" != "true" ]]
then
  # handy color vars for pretty prompts
  BLACK="\033[0;30m"
  BLUE="\033[0;34m"
  GREEN="\033[0;32m"
  GREY="\033[0;90m"
  CYAN="\033[0;36m"
  RED="\033[0;31m"
  PURPLE="\033[0;35m"
  BROWN="\033[0;33m"
  WHITE="\033[1;37m"
  COLOR_RESET="\033[0m"
fi

C_NUM=0

# prompt and command color which can be overridden
DEMO_PROMPT="$ "
DEMO_CMD_COLOR=$WHITE
DEMO_COMMENT_COLOR=$GREY

##
# prints the script usage
##
function usage() {
  echo -e ""
  echo -e "Usage: $0 [options]"
  echo -e ""
  echo -e "\tWhere options is one or more of:"
  echo -e "\t-h\tPrints Help text"
  echo -e "\t-d\tDebug mode. Disables simulated typing"
  echo -e "\t-n\tNo wait"
  echo -e "\t-w\tWaits max the given amount of seconds before proceeding with demo (e.g. '-w5')"
  echo -e ""
}

##
# wait for user to press ENTER
# if $PROMPT_TIMEOUT > 0 this will be used as the max time for proceeding automatically
##
function wait() {
  if [[ "$PROMPT_TIMEOUT" == "0" ]]; then
    read -rs
  else
    read -rst "$PROMPT_TIMEOUT"
  fi
}

##
# render the prompt by itself
#
##
function pr() {
  # render the prompt
  x=$(PS1="$DEMO_PROMPT" "$BASH" --norc -i </dev/null 2>&1 | sed -n '${s/^\(.*\)exit$/\1/p;}')

  # show command number is selected
  if $SHOW_CMD_NUMS; then
   printf "[$((++C_NUM))] $x"
  else
   printf "$x"
  fi
}

##
# print command only. Useful for when you want to pretend to run a command
#
# takes 1 param - the string command to print
#
# usage: p "ls -l"
#
##
function p() {
  if [[ ${1:0:1} == "#" ]]; then
    cmd=$DEMO_COMMENT_COLOR$1$COLOR_RESET
  else
    cmd=$DEMO_CMD_COLOR$1$COLOR_RESET
  fi

  if [[ -z "$PROMPT_AFTER" ]]; then
    pr "$@"
  fi

  # wait for the user to press a key before typing the command
  if [ $NO_WAIT = false ]; then
    wait
  fi

  if [[ -z $TYPE_SPEED ]]; then
    echo -en "$cmd"
  else
    echo -en "$cmd" | pv -qL $[$TYPE_SPEED+(-2 + RANDOM%5)];
  fi

  # wait for the user to press a key before moving on
  if [ $NO_WAIT = false ]; then
    wait
  fi
  echo ""
}

##
# Prints and executes a command
#
# takes 1 parameter - the string command to run
#
# usage: pe "ls -l"
#
##
function pe() {
  # print the command
  p "$@"
  run_cmd "$@"
  if [[ -n "$PROMPT_AFTER" ]]; then
    pr
  fi
}

##
# print and executes a command immediately
#
# takes 1 parameter - the string command to run
#
# usage: pei "ls -l"
#
##
function pei {
  NO_WAIT=true pe "$@"
}

##
# Enters script into interactive mode
#
# and allows newly typed commands to be executed within the script
#
# usage : cmd
#
##
function cmd() {
  # render the prompt
  x=$(PS1="$DEMO_PROMPT" "$BASH" --norc -i </dev/null 2>&1 | sed -n '${s/^\(.*\)exit$/\1/p;}')
  printf "$x$COLOR_RESET"
  read command
  run_cmd "${command}"
}

function run_cmd() {
  function handle_cancel() {
    printf ""
  }

  trap handle_cancel SIGINT
  if [[ "$NO_COLORS" == "" ]]; then stty -echoctl ; fi
  eval "$@"
  if [[ "$NO_COLORS" == "" ]]; then stty echoctl ; fi
  trap - SIGINT
}


function check_pv() {
  command -v pv >/dev/null 2>&1 || {

    echo ""
    echo -e "${RED}##############################################################"
    echo "# HOLD IT!! I require pv but it's not installed.  Aborting." >&2;
    echo -e "${RED}##############################################################"
    echo ""
    echo -e "${COLOR_RESET}Installing pv:"
    echo ""
    echo -e "${BLUE}Mac:${COLOR_RESET} $ brew install pv"
    echo ""
    echo -e "${BLUE}Other:${COLOR_RESET} http://www.ivarch.com/programs/pv.shtml"
    echo -e "${COLOR_RESET}"
    exit 1;
  }
}

check_pv
#
# handle some default params
# -h for help
# -d for disabling simulated typing
#
while getopts ":dhncw:" opt; do
  case $opt in
    h)
      usage
      exit 1
      ;;
    d)
      unset TYPE_SPEED
      ;;
    n)
      NO_WAIT=true
      ;;
    c)
      SHOW_CMD_NUMS=true
      ;;
    w)
      PROMPT_TIMEOUT=$OPTARG
      ;;
  esac
done
