#!/usr/bin/env bash

set -euo pipefail

err() {
  printf "%s\n" "$*" >&2
}

NAME='sharpshot'
SELF="${0:-$NAME}"
VERSION='0.0.1'
OUTPUT_FILE=${SHARPSHOT_OUTPUT_FILE:-/tmp/sharpshot.png}
COMMAND=${SHARPSHOT_COMMAND:-spectacle -b -o ${OUTPUT_FILE}}
COPY_COMMAND=${SHARPSHOT_COPY_COMMAND:-wl-copy}
FULL_SWITCH=${SHARPSHOT_FULL_SWITCH:--f}
ACTIVE_SWITCH=${SHARPSHOT_ACTIVE_SWITCH:--a}
REGION_SWITCH=${SHARPSHOT_REGION_SWITCH:--r}
VERBOSE=false
DRY=false

verbose() {
  if $VERBOSE; then
    printf "%s\n" "$*"
  fi
}

full() {
  verbose 'Capturing full desktop'
  if $DRY; then
    echo "DRY-RUN, would execute: '$COMMAND $FULL_SWITCH'"
  else
    $COMMAND "$FULL_SWITCH" &
  fi
}

active() {
  verbose 'Capturing active window'
  if $DRY; then
    echo "DRY-RUN, would execute: '$COMMAND $ACTIVE_SWITCH'"
  else
    $COMMAND "$ACTIVE_SWITCH" &
  fi
}

region() {
  verbose 'Capturing region'
  if $DRY; then
    echo "DRY-RUN, would execute: '$COMMAND $REGION_SWITCH'"
  else
    $COMMAND "$REGION_SWITCH" &
  fi
}

printversion() {
  echo "$NAME v$VERSION"
}

usage() {
  echo 'Usage:'
  echo "  $SELF [options] [action]"
}

help() {
  cat <<EOF
$(printversion)

$(usage)

Screenshot helper

Options:
  -o <PATH>     Set the output path to write to
  -c <COMMAND>  Set the base command to use
  -f <SWITCH>   Set the switch to add to the base command for full screen capture
  -a <SWITCH>   Set the switch to add to the base command for active window capture
  -r <SWITCH>   Set the switch to add to the base command for region capture
  -v            Enable verbose logging
  -d            Enable dry-run

  -h            Display this help
  -V            Display version
EOF
}

while getopts ':hvdVo:c:f:a:r:' option; do
  case "$option" in
    v)
      VERBOSE=true
      ;;
    d)
      DRY=true
      ;;
    V)
      printversion
      exit
      ;;
    h)
      help
      exit
      ;;
    o)
      OUTPUT_FILE="$OPTARG"
      ;;
    c)
      COMMAND="$OPTARG"
      ;;
    f)
      FULL_SWITCH="$OPTARG"
      ;;
    a)
      ACTIVE_SWITCH="$OPTARG"
      ;;
    r)
      REGION_SWITCH="$OPTARG"
      ;;
    \?)
      err "Invalid option '$OPTARG'"
      exit 1
      ;;
    :)
      err "Missing value for option '$OPTARG'"
      exit 1
      ;;
    *)
      usage
      exit 1
      ;;
  esac
done

shift $((OPTIND - 1))

ACTION="${*:-full}"

$DRY && echo "$NAME running in dry-run mode"

verbose "Outputting to $OUTPUT_FILE"
verbose "Base command: $COMMAND"
verbose "Full switch: $FULL_SWITCH"
verbose "Active switch: $ACTIVE_SWITCH"
verbose "Region switch: $REGION_SWITCH"
verbose "Action: $ACTION"

case "$ACTION" in
  a*)
    active
    ;;
  r*)
    region
    ;;
  f*)
    full
    ;;
  *)
    err "Unknown capture mode '$ACTION'"
    exit 1
    ;;
esac