#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2023 JELOS (https://github.com/JustEnoughLinuxOS)

. /etc/profile
. /etc/os-release

### Vars
UPDATE_ROOT="/storage/.update"
MOUNT_GAMES=$(get_setting system.automount)
GAMES_DEVICE=$(get_setting system.gamesdevice)
MS_PATH="/storage/roms"

function unmount() {
  log $0 "Unmount ${1}."
  umount -f "${1}" 2>/dev/null ||:
}

function add_readme() {
  cat <<EOF >/storage/roms/README
Use the \`Create Game Directories\` option in \`System Settings\` to create your game directories.
EOF
}

function start_ms() {
  ### Entrypoint will be either games card found (external), or not found (internal).
  MOUNT_PATH="/storage/games-${1}"

  MS_DEVICE=$(get_setting system.merged.device)
  ### If the merge target isn't defined and we have an external microsd, we should use the external card by default.
  if [ -z "${MS_DEVICE}" ] && \
     [ "${1}" = "external" ]
  then
    set_setting system.merged.device external
  fi

  ### Determine if internal or external is the primary target by configuration.
  case ${MS_DEVICE} in
    internal)
      LOWER="external"
      UPPER="internal"
    ;;
    *)
      LOWER="internal"
      UPPER="external"
    ;;
  esac

  for GAME_PATH in internal external
  do
    if [ ! -d "/storage/games-${GAME_PATH}/roms" ]
    then
      log $0 "Create /storage/games-${GAME_PATH}/roms."
      mkdir -p "/storage/games-${GAME_PATH}/roms"
    fi
  done

  MS_ENABLED=$(get_setting system.merged.storage)
  if [ -e "/storage/.ms_unsupported" ] || \
     [ ! "${MS_ENABLED}" = 1 ]
  then
    log $0 "Executing bind mount of ${MOUNT_PATH} to ${MS_PATH}"
    mount --bind ${MOUNT_PATH}/roms ${MS_PATH}
  else
    log $0 "Enabling merged storage of /storage/games-${LOWER} and /storage/games-${UPPER} to ${MS_PATH}."

    for DIR in /storage/games-${UPPER}/.tmp/games-workdir /storage/games-${LOWER}/roms /storage/games-${UPPER}/roms
    do
      if [ ! -d "${DIR}" ]
      then
        mkdir -p "${DIR}"
      fi
    done
    mount overlay -t overlay -o lowerdir=/storage/games-${LOWER}/roms,upperdir=/storage/games-${UPPER}/roms,workdir=/storage/games-${UPPER}/.tmp/games-workdir ${MS_PATH}
  fi
}

if [[ ! "${MOUNT_GAMES}" =~ [0-9] ]]
then
  set_setting system.automount 1
elif [[ "${MOUNT_GAMES}" == "0" ]]
then
  start_ms internal
  add_readme
  exit 0
fi

function load_modules() {
  for MODULE in exfat vfat
  do
    lsmod | grep ${MODULE} >/dev/null 2>&1
    if [ ! $? = 0 ]
    then
      log $0 "Loading ${MODULE}."
      modprobe ${MODULE} >/dev/null 2>&1
    fi
  done
}

function mount_games() {
      MOUNT_PATH="/storage/games-external"
      FSTYPE=$(blkid -o export ${1} | awk 'BEGIN {FS="="} /TYPE/ {print $2}')
      case ${FSTYPE} in
        ext4)
          log $0 "Found supported partition for overlayfs."
          if [ -e "/storage/.ms_unsupported" ]
          then
            rm -f /storage/.ms_unsupported
          fi
	  touch /storage/.ms_supported
        ;;
        *)
          log $0 "Partition does not support overlayfs, disabling."
          if [ -e "/storage/.ms_supported" ]
          then
            rm -f /storage/.ms_supported
          fi
          touch /storage/.ms_unsupported
        ;;
      esac

      if [ ! -d "${MOUNT_PATH}" ]
      then
        log $0 "Create directory ${MOUNT_PATH}"
        /usr/bin/busybox mkdir -p ${MOUNT_PATH} >/dev/null 2>&1
      fi

      NULL=$(cat /proc/mounts | grep -v -e "/var/media" 2>/dev/null | grep ${1})
      if [ ! "$?" = "0" ] && \
         [ -e "${1}" ] && \
         [ ! -e "/storage/.please_resize_me" ]
      then

        ### Udevil shouldn't mount it this early, but just in-case.
        umount /var/media/* 2>/dev/null

        log $0 "Checking filesystem ${1}."
        fsck -Mly ${1} >/dev/null 2>&1

        log $0 "Mounting ${1} on ${MOUNT_PATH}"
        /usr/bin/busybox mount ${1} ${MOUNT_PATH} >/dev/null 2>&1
      fi
      start_ms external
      add_readme
      exit 0
}

function find_games() {
  if /usr/bin/busybox mountpoint -q /storage
  then
    for DEV in $(for dev in mmcblk[0-9] sd[a-z] nvme[0-9]; do blkid | grep ${dev} | awk 'BEGIN {FS=":"}; /ext4/ || /fat/ {print $1}' | sort -r; done)
    do
      ROOTDEV=$(echo ${DEV} | sed -e "s#^/.*/##g" -e "s#p[0-9].*\$##g")
      log $0 "Inspecting ${DEV}."
      SIZE=$(awk '/'${ROOTDEV}'$/ {print $3}' /proc/partitions)
      if (( ${SIZE} <= 8388608 ))
      then
        log $0 "Device ${ROOTDEV} is too small, ignoring."
        # We don't want to mount partitions smaller than ~8GB.
        continue
      fi
      if [ -L "/sys/class/block/${ROOTDEV}boot0" ]
      then
        log $0 "Device ${ROOTDEV} might be Android, ignoring."
        # Assume this is an android boot device and ignore it.
        continue
      fi
      ISMOUNTED="$(grep "${DEV}" /proc/mounts) >/dev/null 2>&1"
      if [ ! "$?" = 0 ] && \
         [ -e "${DEV}" ] && \
         [ ! -e "/storage/.please_resize_me" ]
      then
        GAMES_DEVICE=${DEV}
        log $0 "Found ${DEV} available to mount."
        mount_games "${DEV}"
      else
        log $0 "${DEV} not available."
      fi
    done
    log $0 "Could not find external card to mount, assume internal."

    MS_DEVICE=$(get_setting system.merged.device)
    ### If the merge target isn't defined and we do not have an external microsd, we should use the internal card by default.
    if [ -z "${MS_DEVICE}" ]
    then
      set_setting system.merged.device internal
    fi
    start_ms internal
    add_readme
    exit 0
  fi
}

## Main..

load_modules

### Unmount any existing storage before beginning operations.
unmount /storage/games-external
unmount /storage/roms

if [ -e "${GAMES_DEVICE}" ]
then
  mount_games ${GAMES_DEVICE}
else
  find_games
fi