#/bin/bash -eu

# This script will modify the cmdline.txt file on a freshly flashed Raspbian Stretch/Lite
# It readies it for SSH, USB OTG, USB networking, and Wifi
#
# Pass it the path to the location at which the "boot" filesystem is mounted.
# E.g. on a Mac:
#   ./setup-piForHeadlessConfig.sh /Volumes/boot
# or on Ubuntu:
#   ./setup-piForHeadlessConfig.sh /media/$USER/boot
# cd /Volumes/boot (or wherever the boot folder is mounted)
# chmod +x setup-piForHeadlessConfig.sh
# ./setup-piForHeadlessConfig.sh
#
# Put the card in your Pi, and reboot!

# Creates the ssh file if needed, since Raspbian now disables 
# ssh by default if the file isn't present

BOOT_DIR="$1"
RED='\033[0;31m' # Red for warning
NC='\033[0m' # No Color
GREEN='\033[0;32m'

function stop_message () {
  echo -e "${RED}${1} ${NC}"
}

function good_message () {
  echo -e "${GREEN}${1} ${NC}"
}

function show_setup_var_instructions () {

    stop_message 'STOP: You need to specify your setup variables first. Create the file "teslausb_setup_variables.conf" with: '
    echo ""
    echo '       export archiveserver=Nautilus'
    echo '       export sharename=SailfishCam'
    echo '       export shareuser=sailfish'
    echo '       export sharepassword=pa$$w0rd'
    echo '       export campercent=100'
    echo ""
    echo "Be sure to replace the values with your relevant choices."
    exit 1

}

function verify_file_exists () {
  local file_name="$1"
  local expected_path="$2"

  if [ ! -e "$expected_path/$file_name" ]
    then
      stop_message "STOP: Didn't find $file_name at $expected_path."
      exit 1
  fi
}

function verify_wifi_variables () {
  if [ ! -n "${SSID+x}" ] || [ ! -n "${WIFIPASS+x}"  ]
  then
    stop_message 'STOP: You need to specify your wifi name and password first. Run: '
    echo ""
    echo '      export SSID=your_ssid'
    echo '      export WIFIPASS=your_wifi_password'
    echo ""
    echo "Be sure to replace the values with your SSID (network name) and password."
    exit 1
  fi
}

function verify_setup_variables_file_exists () {
  local file_name="$1"
  local expected_path="$2"

  if [ ! -e "$expected_path/$file_name" ]
    then
      show_setup_var_instructions
      exit 1
  fi
}

function verify_setup_variables () {
  if [ ! -n "${archiveserver+x}" ]
  then
    show_setup_var_instructions
  fi
}

function verify_pushover_variables () {
  if [ ! -z "${pushover_enabled+x}" ]
  then
    if [ ! -n "${pushover_user_key+x}" ] || [ ! -n "${pushover_app_key+x}"  ]
    then
      stop_message "STOP: You're trying to setup Pushover but didn't provide your User and/or App key."
      echo 'Define the variables in "teslausb_setup_variables.conf" like this:'
      echo ""
      echo "       export pushover_user_key=put_your_userkey_here"
      echo "       export pushover_app_key=put_your_appkey_here"
      exit 1
    elif [ "${pushover_user_key}" = "put_your_userkey_here" ] || [  "${pushover_app_key}" = "put_your_appkey_here" ]
    then
      stop_message "STOP: You're trying to setup Pushover, but didn't replace the default User and App key values."
      echo 'Replace the default values in "teslausb_setup_variables.conf".'
      exit 1
    else
      user_enabled_pushover=true
      echo "export pushover_enabled=true" > $BOOT_DIR/.teslaCamPushoverCredentials
      echo "export pushover_user_key=$pushover_user_key" >> $BOOT_DIR/.teslaCamPushoverCredentials
      echo "export pushover_app_key=$pushover_app_key" >> $BOOT_DIR/.teslaCamPushoverCredentials
    fi
  fi
}


verify_file_exists "cmdline.txt" "$BOOT_DIR"
verify_file_exists "config.txt" "$BOOT_DIR"
verify_setup_variables_file_exists "teslausb_setup_variables.conf" "$BOOT_DIR"

source "$BOOT_DIR"/teslausb_setup_variables.conf

verify_wifi_variables
verify_setup_variables
verify_pushover_variables

CMDLINE_TXT_PATH="$BOOT_DIR/cmdline.txt"
CONFIG_TXT_PATH="$BOOT_DIR/config.txt"

if ! grep -q "dtoverlay=dwc2" $CONFIG_TXT_PATH
then
   echo "Updating $CONFIG_TXT_PATH ..."
   echo "" >> "$CONFIG_TXT_PATH"
   echo "dtoverlay=dwc2" >> "$CONFIG_TXT_PATH"
else
   good_message "config.txt already contains the required dwc2 module"
fi

if ! grep -q "dwc2,g_ether" $CMDLINE_TXT_PATH
then
  echo "Updating $CMDLINE_TXT_PATH ..."
  sed -i'.bak' -e "s/rootwait/rootwait modules-load=dwc2,g_ether/" -e "s@ init=/usr/lib/raspi-config/init_resize.sh@@" "$CMDLINE_TXT_PATH"
else
  good_message "cmdline.txt already updated with modules and removed initial resize script."
fi

if [ ! -e "$BOOT_DIR/ssh" ]
then 
  good_message "Ensuring SSH is setup..."
  touch "$BOOT_DIR/ssh"
fi

# Sets up wifi credentials so wifi will be 
# auto configured on first boot

WPA_SUPPLICANT_CONF_PATH="$BOOT_DIR/wpa_supplicant.conf"

good_message "Adding Wifi setup file (wpa_supplicant.conf)."
if [ -r "$WPA_SUPPLICANT_CONF_PATH" ]
then
  rm "$WPA_SUPPLICANT_CONF_PATH"
fi

cat << EOF >> "$WPA_SUPPLICANT_CONF_PATH"
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
  ssid="$SSID"
  psk="$WIFIPASS"
  key_mgmt=WPA-PSK
}
EOF

echo ""
good_message '-- Files updated and ready for headless setup --'
echo ''
good_message '-- You can now insert your SD card into the Pi for headless setup'
echo ''
echo "When done (this may take a vew minutes), the Pi should be available over SSH as pi@teslausb.local"
echo ""