#!/bin/sh

## Grimshot: a helper for screenshots within sway
## Requirements:
##  - `grim`: screenshot utility for wayland
##  - `slurp`: to select an area
##  - `swaymsg`: to read properties of current window
##  - `wl-copy`: clipboard utility
##  - `jq`: json utility to parse swaymsg output
##  - `notify-send`: to show notifications
## Those are needed to be installed, if unsure, run `grimshot check`
##
## See `man 1 grimshot` or `grimshot usage` for further details.

getTargetDirectory() {
  test -f "${XDG_CONFIG_HOME:-$HOME/.config}/user-dirs.dirs" && \
    . "${XDG_CONFIG_HOME:-$HOME/.config}/user-dirs.dirs"

  echo "${XDG_SCREENSHOTS_DIR:-${XDG_PICTURES_DIR:-$HOME}}"
}

NOTIFY=no
CURSOR=
WAIT=no

while [ $# -gt 0 ]; do
  key="$1"

  case $key in
    -n|--notify)
      NOTIFY=yes
      shift # past argument
      ;;
    -c|--cursor)
      CURSOR=yes
      shift # past argument
      ;;
    -w|--wait)
      shift
      WAIT="$1"
      if echo "$WAIT" | grep "[^0-9]" -q; then
        echo "invalid value for wait '$WAIT'" >&2
        exit 3
      fi
      shift
      ;;
    *)    # unknown option
      break # done with parsing --flags
      ;;
  esac
done

ACTION=${1:-usage}
SUBJECT=${2:-screen}
FILE=${3:-$(getTargetDirectory)/$(date -Ins).png}

if [ "$ACTION" != "save" ] && [ "$ACTION" != "copy" ] && [ "$ACTION" != "savecopy" ] && [ "$ACTION" != "check" ]; then
  echo "Usage:"
  echo "  grimshot [--notify] [--cursor] [--wait N] (copy|save) [active|screen|output|area|window|anything] [FILE|-]"
  echo "  grimshot check"
  echo "  grimshot usage"
  echo ""
  echo "Commands:"
  echo "  copy: Copy the screenshot data into the clipboard."
  echo "  save: Save the screenshot to a regular file or '-' to pipe to STDOUT."
  echo "  savecopy: Save the screenshot to a regular file and copy the data into the clipboard."
  echo "  check: Verify if required tools are installed and exit."
  echo "  usage: Show this message and exit."
  echo ""
  echo "Targets:"
  echo "  active: Currently active window."
  echo "  screen: All visible outputs."
  echo "  output: Currently active output."
  echo "  area: Manually select a region."
  echo "  window: Manually select a window."
  echo "  anything: Manually select an area, window, or output."
  exit
fi

notify() {
  notify-send -t 3000 -a grimshot "$@"
}
notifyOk() {
  [ "$NOTIFY" = "no" ] && return

  TITLE=${2:-"Screenshot"}
  MESSAGE=${1:-"OK"}
  notify "$TITLE" "$MESSAGE"
}
notifyError() {
  if [ $NOTIFY = "yes" ]; then
    TITLE=${2:-"Screenshot"}
    MESSAGE=${1:-"Error taking screenshot with grim"}
    notify -u critical "$TITLE" "$MESSAGE"
  else
    echo "$1"
  fi
}

die() {
  MSG=${1:-Bye}
  notifyError "Error: $MSG"
  exit 2
}

check() {
  COMMAND=$1
  if command -v "$COMMAND" > /dev/null 2>&1; then
    RESULT="OK"
  else
    RESULT="NOT FOUND"
  fi
  echo "   $COMMAND: $RESULT"
}

takeScreenshot() {
  FILE=$1
  GEOM=$2
  OUTPUT=$3
  if [ -n "$OUTPUT" ]; then
    grim ${CURSOR:+-c} -o "$OUTPUT" "$FILE" || die "Unable to invoke grim"
  elif [ -z "$GEOM" ]; then
    grim ${CURSOR:+-c} "$FILE" || die "Unable to invoke grim"
  else
    grim ${CURSOR:+-c} -g "$GEOM" "$FILE" || die "Unable to invoke grim"
  fi
}

if [ "$ACTION" = "check" ] ; then
  echo "Checking if required tools are installed. If something is missing, install it to your system and make it available in PATH..."
  check grim
  check slurp
  check swaymsg
  check wl-copy
  check jq
  check notify-send
  exit
elif [ "$SUBJECT" = "area" ] ; then
  GEOM=$(slurp -d)
  # Check if user exited slurp without selecting the area
  if [ -z "$GEOM" ]; then
    exit 1
  fi
  WHAT="Area"
elif [ "$SUBJECT" = "active" ] ; then
  FOCUSED=$(swaymsg -t get_tree | jq -r 'recurse(.nodes[]?, .floating_nodes[]?) | select(.focused)')
  GEOM=$(echo "$FOCUSED" | jq -r '.rect | "\(.x),\(.y) \(.width)x\(.height)"')
  APP_ID=$(echo "$FOCUSED" | jq -r '.app_id')
  WHAT="$APP_ID window"
elif [ "$SUBJECT" = "screen" ] ; then
  GEOM=""
  WHAT="Screen"
elif [ "$SUBJECT" = "output" ] ; then
  GEOM=""
  OUTPUT=$(swaymsg -t get_outputs | jq -r '.[] | select(.focused)' | jq -r '.name')
  WHAT="$OUTPUT"
elif [ "$SUBJECT" = "window" ] ; then
  GEOM=$(swaymsg -t get_tree | jq -r '.. | select(.pid? and .visible?) | .rect | "\(.x),\(.y) \(.width)x\(.height)"' | slurp -r)
  # Check if user exited slurp without selecting the area
  if [ -z "$GEOM" ]; then
   exit 1
  fi
  WHAT="Window"
elif [ "$SUBJECT" = "anything" ] ; then
  GEOM=$(swaymsg -t get_tree | jq -r '.. | select(.pid? and .visible?) | .rect | "\(.x),\(.y) \(.width)x\(.height)"' | slurp -o)
  # Check if user exited slurp without selecting the area
  if [ -z "$GEOM" ]; then
    exit
  fi
  WHAT="Selection"
else
  die "Unknown subject to take a screen shot from" "$SUBJECT"
fi

if [ "$WAIT" != "no" ]; then
  sleep "$WAIT"
fi

if [ "$ACTION" = "copy" ] ; then
  takeScreenshot - "$GEOM" "$OUTPUT" | wl-copy --type image/png || die "Clipboard error"
  notifyOk "$WHAT copied to buffer"
else
  if takeScreenshot "$FILE" "$GEOM" "$OUTPUT"; then
    TITLE="Screenshot of $SUBJECT"
    MESSAGE=$(basename "$FILE")
    notifyOk "$MESSAGE" "$TITLE"
    echo "$FILE"
    if [ "$ACTION" = "savecopy" ]; then
      wl-copy --type image/png < "$FILE" || die "Clipboard error"
      notifyOk "$WHAT copied to buffer"
    fi
  else
    notifyError "Error taking screenshot with grim"
  fi
fi