#!/usr/bin/env bash

function osxiso() {
  PS3="
Select OS or Quit: "
  temp="$PWD/temp"
  dist="$PWD/dist"
  base_mount="/Volumes/OS X Base System"
  build_mount="/Volumes/install_build"
  app_mount="/Volumes/install_app"
  apps_v1="|macOS Sierra|OS X El Capitan|OS X Yosemite|OS X Mavericks|"
  apps_v2="|macOS High Sierra|"
  apps=(
    "macOS High Sierra"
    "macOS Sierra"
    "OS X El Capitan"
    "OS X Yosemite"
    "OS X Mavericks"
  )
  apps_available=()

  function log_warning() {
    echo "$(tput setab 3)$(tput setaf 0)>> $* $(tput sgr0)"
  }

  function log_error() {
    >&2 echo "$(tput setab 1)$(tput setaf 7)>> $* $(tput sgr0)"
  }

  function log_success() {
    echo "$(tput setab 2)$(tput setaf 7)$*$(tput sgr0)"
  }

  function detach_mounts() {
    # Unmount OS
    [[ ! -d "/Volumes/Install $1" ]] || hdiutil detach "/Volumes/Install $1"
    # Unmount the installer image
    [[ ! -d  "$app_mount" ]] || hdiutil detach "$app_mount"
    # Unmount the sparse bundle
    [[ ! -d  "$base_mount" ]] || hdiutil detach "$base_mount"
    # Unmount temporary build path
    [[ ! -d "$build_mount" ]] || hdiutil detach "$build_mount"
  }

  function cleanup() {
    detach_mounts "$1"
    # Remove temp directory
    rm -rf "$temp"
  }

  function abort() {
    echo
    log_error "Command returned with error, aborting ..."
    echo
    exit 2
  }

  function prep_build() {
    # Attempt cleanup of any failed previous attempts
    cleanup "$1"

    # Prepare to do work
    mkdir -p "$temp"
    mkdir -p "$dist"
  }

  function build_v1() {
    trap cleanup EXIT
    trap abort ERR

    local app_file="/Applications/Install $1.app"

    prep_build

    # Mount the installer image
    hdiutil attach "$app_file/Contents/SharedSupport/InstallESD.dmg" -noverify -nobrowse -mountpoint "$app_mount"

    # Create a blank ISO of 7316MB with a Single Partition
    hdiutil create -o "$temp/$1.cdr" -size 7316m -layout SPUD -fs HFS+J

    # Mount the blank ISO
    hdiutil attach "$temp/$1.cdr.dmg" -noverify -nobrowse -mountpoint "$build_mount"

    # Restore the Base System into the blank ISO
    asr restore -source "$app_mount/BaseSystem.dmg" -target "$build_mount" -noprompt -noverify -erase

    # Remove Package link and replace with actual files
    rm "$base_mount/System/Installation/Packages"
    cp -rp "$app_mount/Packages" "$base_mount/System/Installation/"

    # Copy "$1" installer dependencies
    cp -rp "$app_mount/BaseSystem.chunklist" "$base_mount/BaseSystem.chunklist"
    cp -rp "$app_mount/BaseSystem.dmg" "$base_mount/BaseSystem.dmg"

    detach_mounts "$1"

    # Convert the sparse bundle to ISO/CD master
    hdiutil convert "$temp/$1.cdr.dmg" -format UDTO -o "$temp/$1.iso"

    # Rename the ISO and move it to the distribution dir
    mv "$temp/$1.iso.cdr" "$dist/$1.iso"

    cleanup

    echo
    log_success "========== FINISHED =========="
    echo
    printf "ISO is located at: '%s'\n\n" "$dist/$1.iso"
  }

  function build_v2() {
    trap cleanup EXIT
    trap abort ERR

    local app_file="/Applications/Install $1.app"

    prep_build "$1"

    # Create a blank ISO of 7316MB with a Single Partition
    hdiutil create -o "$temp/$1.cdr" -size 7316m -layout SPUD -fs HFS+J

    # Mount the blank ISO
    hdiutil attach "$temp/$1.cdr.dmg" -noverify -nobrowse -mountpoint "$build_mount"

    # Let createinstallmedia populate the blank ISO
    printf "$(tput setab 3)$(tput setaf 0)%s$(tput sgr0) " "<sudo>"
    sudo "$app_file"/Contents/Resources/createinstallmedia --volume "$build_mount" --nointeraction

    detach_mounts "$1"

    # Convert the sparse bundle to ISO/CD master
    hdiutil convert "$temp/$1.cdr.dmg" -format UDTO -o "$temp/$1.iso"

    # Rename the ISO and move it to the distribution dir
    mv "$temp/$1.iso.cdr" "$dist/$1.iso"

    cleanup

    echo
    log_success "========== FINISHED =========="
    echo
    printf "ISO is located at: '%s'\n\n" "$dist/$1.iso"
  }

  function choose() {
    echo

    select app in "${apps_available[@]}"; do
      case "$app" in
        "Quit")
          break
          ;;
        *)
          if [[ "$apps_v2" == *"|$app|"* ]]; then
            log_success "** Building ISO for $app **"
            build_v2 "$app"
          elif [[ "$apps_v1" == *"|$app|"* ]]; then
            log_success "** Building ISO for $app **"
            build_v1 "$app"
          else
            log_error "You must select a valid option *number* from the list."
            choose
          fi
          break
          ;;
      esac
    done
  }

  function main() {
    for app in "${apps[@]}"; do
      if [[ -d "/Applications/Install $app.app" ]]; then
        apps_available+=("$app")
      else
        log_warning "Missing /Applications/Install $app.app"
      fi
    done

    [[ ${#apps_available[@]} -eq 0 ]] && log_error "You do not have any installer apps available. You can download them from the App Store and try again!" && exit 1

    apps_available+=("Quit")

    choose
  }

  main
}

## Export or run
if [[ "${BASH_SOURCE[0]}" != "$0" ]]; then
  export -f osxiso
else
  osxiso
fi