#!/usr/bin/env bash

usage()
{
cat << EOF
GAM installation script.

OPTIONS:
   -h      show help.
   -d      Directory where gam folder will be installed. Default is \$HOME/bin/
   -a      Architecture to install (i386, x86_64, arm). Default is to detect your arch with "uname -m".
   -o      OS we are running (linux, macos). Default is to detect your OS with "uname -s".
   -p      Profile update (true, false). Should script add gam command to environment. Default is true.
   -v      Version to install (latest, prerelease, draft, 3.8, etc). Default is latest.
EOF
}

target_dir="$HOME/bin"
gamarch=$(uname -m)
gamos=$(uname -s)
update_profile=true
gamversion="latest"
while getopts "hd:a:o:p:v:" OPTION
do
     case $OPTION in
         h) usage; exit;;
         d) target_dir=$OPTARG;;
         a) gamarch=$OPTARG;;
         o) gamos=$OPTARG;;
         p) update_profile=$OPTARG;;
         v) gamversion=$OPTARG;;
         ?) usage; exit;;
     esac
done

update_profile() {
	[ -f "$1" ] || return 1

	grep -F "$alias_line" "$1" > /dev/null 2>&1
	if [ $? -ne 0 ]; then
                echo_yellow "Adding gam alias to profile file $1."
		echo -e "\n$alias_line" >> "$1"
        else
          echo_yellow "gam alias already exists in profile file $1. Skipping add."
	fi
}

echo_red()
{
echo -e "\x1B[1;31m$1"
echo -e '\x1B[0m'
}

echo_green()
{
echo -e "\x1B[1;32m$1"
echo -e '\x1B[0m'
}

echo_yellow()
{
echo -e "\x1B[1;33m$1"
echo -e '\x1B[0m'
}

case $gamos in
  [lL]inux)
    gamos="linux"
    case $gamarch in
      x86_64) gamfile="linux-x86_64.tar.xz";;
      i?86) gamfile="linux-i686.tar.xz";;
      arm*) gamfile="linux-armv7l.tar.xz";;
      *)
        echo_red "ERROR: this installer currently only supports i386, x86_64 and arm Linux. Looks like you're running on $gamarch. Exiting."
        exit
    esac
    ;;
  [Mm]ac[Oo][sS]|[Dd]arwin)
    osver=$(sw_vers -productVersion | awk -F'.' '{print $2}')
    if (( $osver < 10 )); then
      echo_red "ERROR: GAM currently requires MacOS 10.10 or newer. You are running MacOS 10.$osver. Please upgrade." 
      exit
    else
      echo_green "Good, you're running MacOS 10.$osver..."
    fi
    gamos="macos"
    gamfile="macos.tar.xz"
    ;;
  *)
    echo_red "Sorry, this installer currently only supports Linux and MacOS. Looks like you're runnning on $gamos. Exiting."
    exit
    ;;
esac

if [ "$gamversion" == "latest" -o "$gamversion" == "prerelease" -o "$gamversion" == "draft" ]; then
  release_url="https://api.github.com/repos/jay0lee/GAM/releases"
else
  release_url="https://api.github.com/repos/jay0lee/GAM/releases/tags/v$gamversion"
fi

echo_yellow "Checking GitHub URL $release_url for $gamversion GAM release..."
release_json=$(curl -s $release_url 2>&1 /dev/null)

echo_yellow "Getting file and download URL..."
# Python is sadly the nearest to universal way to safely handle JSON with Bash
# At least this code should be compatible with just about any Python version ever
# unlike GAM itself. If some users don't have Python we can try grep / sed / etc
# but that gets really ugly
pycode="import json
import sys

attrib = sys.argv[1]
gamversion = sys.argv[2]

release = json.load(sys.stdin)
if type(release) is list:
  for a_release in release:
    if a_release['prerelease'] and gamversion != 'prerelease':
      continue
    elif a_release['draft'] and gamversion != 'draft':
      continue
    release = a_release
    break
for asset in release['assets']:
  if asset[sys.argv[1]].endswith('$gamfile'):
    print asset[sys.argv[1]]
    break"
browser_download_url=$(echo "$release_json" | python -c "$pycode" browser_download_url $gamversion)
name=$(echo "$release_json" | python -c "$pycode" name $gamversion)
# Temp dir for archive
temp_archive_dir=$(mktemp -d)

echo_yellow "Downloading file $name from $browser_download_url to $temp_archive_dir."
# Save archive to temp w/o losing our path
(cd $temp_archive_dir && curl -O -L $browser_download_url)

mkdir -p $target_dir

echo_yellow "Extracting archive to $target_dir"
tar xf $temp_archive_dir/$name -C $target_dir
rc=$?
if (( $rc != 0 )); then
  echo_red "ERROR: extracting the GAM archive with tar failed with error $rc. Exiting."
  exit
else
  echo_green "Finished extracting GAM archive."
fi

# Update profile to add gam command
if [ "$update_profile" = true ]; then
  alias_line="alias gam=$target_dir/gam/gam"
  if [ "$gamos" == "linux" ]; then
    update_profile "$HOME/.bashrc" || update_profile "$HOME/.bash_profile"
  elif [ "$gamos" == "macos" ]; then
    update_profile "$HOME/.profile" || update_profile "$HOME/.bash_profile"
  fi
else
  echo_yellow "skipping profile update."
fi

while true; do
  read -p "Can you run a full browser on this machine? (usually Y for MacOS, N for Linux if you SSH into this machine) " yn
  case $yn in
    [Yy]*) break;;
    [Nn]*) touch $target_dir/gam/nobrowser.txt; break;;
    * ) echo_red "Please answer yes or no.";;
  esac
done

echo -e "\n"

while true; do
  read -p "GAM is now installed. Are you ready to set up a Google API project for GAM? (yes or no) " yn
  case $yn in
    [Yy]*) $target_dir/gam/gam create project; break;;
    [Nn]*) echo -e "\nYou can create an API project later by running:\n\ngam create project\n"; break;;
    * ) echo_red "Please answer yes or no.";;
  esac
done

echo_green "Here's information about your new GAM installation:\n"
$target_dir/gam/gam version
rc=$?
if (( $rc != 0 )); then
  echo_red "ERROR: Failed running GAM for the first time with $rc. Please report this error to GAM mailing list. Exiting."
  exit
fi

# Clean up after ourselves even if we are killed with CTRL-C
trap "rm -rf $temp_archive_dir" EXIT