#!/bin/bash
# Author: Alexander Epstein https://github.com/alexanderepstein

setglobal currentVersion = '"1.11.1'"
setglobal configuredClient = ''""
setglobal configuredPython = ''""

## This function determines which http get tool the system has installed and returns an error if there isnt one
proc getConfiguredClient
{
  if  command -v curl &>/dev/null  {
    setglobal configuredClient = '"curl'"
  } elif command -v wget &>/dev/null  {
    setglobal configuredClient = '"wget'"
  } elif command -v fetch &>/dev/null  {
    setglobal configuredClient = '"fetch'"
  } else {
    echo "Error: This tool reqires either curl, wget, or fetch to be installed."
    return 1
  }

}


proc getConfiguredPython
{
  if  command -v python2 &>/dev/null  {
    setglobal configuredPython = '"python2'"
  } elif command -v python &>/dev/null  {
    setglobal configuredPython = '"python'"
  } else {
    echo "Error: This tool requires python 2 to be installed."
    return 1
  }
}


proc python
{
  match $configuredPython {
    with python2 python2 @Argv
    with python python @Argv
  }
}

## Allows to call the users configured client without if statements everywhere
proc httpGet
{
  match $configuredClient {
    with curl curl -A curl -s @Argv
    with wget wget -qO- @Argv
    with fetch fetch -o "..."
  }
}

proc checkInternet
{
  echo -e "GET http://google.com HTTP/1.0\n\n" | nc google.com 80 > /dev/null !2 > !1 # query google with a get request
  if test $Status -eq 0 { #check if the output is 0, if so no errors have occured and we have connected to google successfully
    return 0
  } else {
    echo "Error: no active internet connection" > !2 #sent to stderr
    return 1
  }
}

proc update
{
  # Author: Alexander Epstein https://github.com/alexanderepstein
  # Update utility version 1.2.0
  # To test the tool enter in the defualt values that are in the examples for each variable
  setglobal repositoryName = '"Bash-Snippets'" #Name of repostiory to be updated ex. Sandman-Lite
  setglobal githubUserName = '"alexanderepstein'" #username that hosts the repostiory ex. alexanderepstein
  setglobal nameOfInstallFile = '"install.sh'" # change this if the installer file has a different name be sure to include file extension if there is one
  setglobal latestVersion = $[httpGet https://api.github.com/repos/$githubUserName/$repositoryName/tags | grep -Eo '"name":.*?[^\\]",'| head -1 | grep -Eo "[0-9.]+] #always grabs the tag without the v option

  if [[ $currentVersion == "" || $repositoryName == "" || $githubUserName == "" || $nameOfInstallFile == "" ]]{
    echo "Error: update utility has not been configured correctly." > !2
    exit 1
  } elif [[ $latestVersion == "" ]]{
    echo "Error: no active internet connection" > !2
    exit 1
  } else {
    if [[ "$latestVersion" != "$currentVersion" ]] {
      echo "Version $latestVersion available"
      echo -n "Do you wish to update $repositoryName [Y/n]: "
      read -r answer
      if [[ "$answer" == "Y" || "$answer" == "y" ]] {
        cd  ~ || do { echo 'Update Failed' ; exit 1 ; }
        if [[ -d  ~/$repositoryName ]] { rm -r -f $repositoryName  ||  do { echo "Permissions Error: try running the update as sudo"; exit 1; } ; }
        git clone "https://github.com/$githubUserName/$repositoryName" || do { echo "Couldn't download latest version" ; exit 1; }
        cd $repositoryName ||  do { echo 'Update Failed' ; exit 1 ;}
        git checkout "v$latestVersion" !2 > /dev/null || git checkout $latestVersion !2 > /dev/null || echo "Couldn't git checkout to stable release, updating to latest commit."
        chmod a+x install.sh #this might be necessary in your case but wasnt in mine.
        ./$nameOfInstallFile "update" || exit 1
        cd ..
        rm -r -f $repositoryName ||  do { echo "Permissions Error: update succesfull but cannot delete temp files located at ~/$repositoryName delete this directory with sudo"; exit 1; }
      } else {
        exit 1
      }
    } else {
      echo "$repositoryName is already the latest version"
    }
  }
}

proc usage
{
  echo "Short"
  echo "Description: Unmasks shortended urls."
  echo "Usage: short [shortURL] or short [flag]"
  echo "  -u Update Bash-Snippet Tools"
  echo "  -h Show the help"
  echo "  -v Get the tool version"
  echo "Example:"
  echo "   Input: short tinyurl.com/jhkj"
  echo "   Output: http://possiblemaliciouswebsiteornot.com"
}

proc expandURL
{
  setglobal testURL = $[ echo $1 | cut -c1-8]
  if [[ $testURL != "https://" ]]{
    setglobal testURL = $[ echo $1 | cut -c1-7]
    if [[ $testURL != "http://" ]]{
      setglobal url = ""http://$1""
    } else {
      setglobal url = $1
    }
  } else {
    setglobal url = $1
  }
  setglobal response = $[httpGet http://x.datasig.io/short?url=$url]
  setglobal errorCheck = $[echo $response | python -c "import sys, json; print json.load(sys.stdin)['/short']['message']" !2 >  /dev/null]
  if [[ $errorCheck == "Error in /short" ]]{
  echo "Error: 404 could not find the website"
  return 1
}
  setglobal expandedURL = $[echo $response | python -c "import sys, json; print json.load(sys.stdin)['/short']['destination']" !2 >  /dev/null]

}

proc printResults
{
  echo "====================================================================="
  echo "Short URL: $url"
  echo "Expanded URL: $expandedURL"
  echo "====================================================================="
}

getConfiguredPython || exit 1
getConfiguredClient || exit 1
checkInternet || exit 1

while getopts "uvh" opt {
  match $opt {
    with \?
      echo "Invalid option: -$OPTARG" > !2
      exit 1
    
    with h
      usage
      exit 0
    
    with v
      echo "Version $currentVersion"
      exit 0
    
    with u
      update
      exit 0
    
    with :
      echo "Option -$OPTARG requires an argument." > !2
      exit 1
    
  }
}


if [[ $# == 0 ]] {
  usage
  exit 0
} elif [[ $# == "1" ]] {
  if [[ $1 == "update" ]]{
    update
  } elif [[ $1 == "help" ]] {
    usage
  } else {
    expandURL $1 || exit 1
    printResults
  }
} else {
  echo "Error: short only accepts one argument"
  exit 1
}