#!/bin/bash

# Program name
PROGRAM_NAME="Frameless"
PROGRAM_V="2.0"

# Make sure the required packages are installed
command -v mplayer >/dev/null 2>&1 || {
  echo >&2 "[error] We require mplayer for $PROGRAM_NAME v${PROGRAM_V} to work, but it's not installed.  Aborting."
  exit 1
}
command -v zenity >/dev/null 2>&1 || {
  echo >&2 "[error] We require zenity for $PROGRAM_NAME v${PROGRAM_V} to work, but it's not installed.  Aborting."
  exit 1
}
dpkg -l | grep v4l-utils >/dev/null 2>&1 || {
  echo >&2 "[error] We require v4l-utils for $PROGRAM_NAME v${PROGRAM_V} to work, but it's not installed.  Aborting."
  exit 1
}

# to install the needed packages :)
# sudo apt-get install mplayer zenity v4l-utils

# the device name
DEVICE=''

# the screen number
SCREEN_NUMBER=''

# main function
function main() {
  # select the video to use
  selectVideoDevice

  # select the screen to use
  selectScreen

  # open the menu
  mainMenu

  exit 0;
}

# select the screen
function selectScreen() {
  local screen_count
  local screen_index
  # get the screens
  local screens=''
  screens=$(getScreens)

  # check the number of screens
  screen_count=$(echo "$screens" | wc -l)

  if [ "$screen_count" -eq 1 ]; then
    # only one screen is available, so set the screen number to 0
    SCREEN_NUMBER=0
  else
    # get the selection
    local selected=""

    while [ -z "$selected" ]; do
      # Display the list of screens using Zenity
      selected=$(zenity --list --title "Select a Screen" --column "Index" --column "Screen Name" $screens)
      # Check the exit status of Zenity
      if [ $? -eq 1 ]; then
        # The user clicked the "Cancel" button, exit the loop
        exit 0
      elif [ -z "$selected" ]; then
        # No screen was selected, display an error message
        zenity --error --text "No screen was selected. Please select a screen."
      fi
    done

    # Extract the screen index from the selection
    screen_index=$(echo "$selected" | awk '{print $1}')

    SCREEN_NUMBER="${screen_index}"
  fi
}

# function get screens
function getScreens() {
  # Get a list of available screens and their index
  local screens
  screens=$(xrandr | grep " connected" | awk '{print NR-1 " " $1}')
  echo "$screens"
}

# select the video camera
function selectVideoDevice() {

  # get the cameras
  local cameras=''
  cameras=$(getDevices)

  # stop all videos
  stopVideo

  # get the selection
  local selected=""

  while [ -z "$selected" ]; do
    # Display the list of cameras using Zenity
    # shellcheck disable=SC2086
    selected=$(zenity --list --title "Select a Video Camera" --column "Camera" $cameras)
    # Check the exit status of Zenity
    if [ $? -eq 1 ]; then
      # The user clicked the "Cancel" button, exit the loop
      exit 0
    elif [ -z "$selected" ]; then
      # No camera was selected, display an error message
      zenity --error --text "No camera was selected. Please select a camera."
    fi
  done

  # Camera was selected, display a preview
  previewDevice "${selected}"

  DEVICE="${selected}"

  zenity --question --text "Is this the camera you would like to use?"

  # Check the exit status of Zenity
  if [ $? -eq 1 ]; then
    selectVideoDevice
  fi

  # stop all videos
  stopVideo
}

# function get devices
function getDevices() {
  # Our local values
  local devices=''
  local list=''
  # Get a list of video cameras
  # shellcheck disable=SC2010
  devices=$(ls /dev | grep '^video')
  # Check which devices can be displayed by MPlayer
  for device in $devices; do
    # Use v4l2-ctl to check if the device supports previewing
    if v4l2-ctl --device="/dev/$device" --list-formats | grep -q "YUYV" ; then
      # The device supports previewing, add it to the list
      list="$list $device"
    fi
  done

  echo "$list"
}

# Function to display a preview of the given video device
function previewDevice() {
  device=$1
  mplayer tv:// -tv driver=v4l2:device="/dev/$device" -geometry "300x300" -quiet -nolirc -ontop -noborder -nosound -vo xv &
  disown
}

# MAIN MENU
function mainMenu() {
  local CHOICE=''
  # select your position
  CHOICE=$(zenity --list \
    --title="Tutorial Video Player" --radiolist --width=400 --height=300 \
    --text "Select where you want the video to display on (screen-${SCREEN_NUMBER})" \
    --radiolist --column "Select" --column "Value" --column="Position Options" \
    TRUE large "Large Center" \
    FASLE bottomleft "Left Corner" \
    FASLE bottomright "Right Corner" \
    FASLE topleft "Top Left Corner" \
    FASLE topright "Top Right Corner" \
    FASLE camera "Select Camera" \
    --hide-column=2 --cancel-label "Close")

  # always first stop videos playing
  stopVideo

  # trigger the choose action
  case $CHOICE in
    "large")
      showLarge
      ;;
    "bottomleft")
      showVideo "bottomleft"
      ;;
    "bottomright")
      showVideo "bottomright"
      ;;
    "topleft")
      showVideo "topleft"
      ;;
    "topright")
      showVideo "topright"
      ;;
    "camera")
      selectVideoDevice
      ;;
    *) exit 0;;
  esac

  # menu loop
  mainMenu
}

# show large center video
function showLarge() {
  mplayer -zoom -ontop -noborder -nosound -vo gl:nomanyfmts \
    -vf mirror -xy 2 tv:// -tv driver=v4l2:device="/dev/${DEVICE}" -screen "${SCREEN_NUMBER}" &
  disown
}

# function to get screen dimensions
function getScreenDimensions() {
  local screen_name
  local dimensions
  local adjusted_screen_number=$(( $1 + 1 ))
  screen_name=$(xrandr | grep " connected" | awk -v screen_number="$adjusted_screen_number" 'NR==screen_number {print $1}')
  dimensions=$(xrandr | grep "$screen_name" | grep -oP '\d+x\d+\+\d+\+\d+' | cut -d'+' -f1)
  echo "$dimensions"
}

# show video at a specified position
function showVideo() {
  local position=$1
  local dimensions
  local width
  local height
  local x
  local y

  dimensions=$(getScreenDimensions "${SCREEN_NUMBER}")
  width=$(echo "$dimensions" | cut -d'x' -f1)
  height=$(echo "$dimensions" | cut -d'x' -f2)

  case $position in
    "topleft")
      x=30
      y=30
      ;;
    "topright")
      x=$(expr $width - 320 - 30)
      y=30
      ;;
    "bottomleft")
      x=30
      y=$(expr $height - 240 - 30)
      ;;
    "bottomright")
      x=$(expr $width - 320 - 30)
      y=$(expr $height - 240 - 30)
      ;;
    *)
      echo "Invalid position specified"
      return 1
      ;;
  esac

  mplayer -zoom -ontop -noborder -nosound -vo gl:nomanyfmts \
    -geometry 320x240+"${x}"+"${y}" -vf mirror tv:// -tv driver=v4l2:device="/dev/${DEVICE}" -screen "${SCREEN_NUMBER}" &
  disown
}

# stop videos playing
function stopVideo() {
  pkill mplayer
  sleep 1
}

# start program
main