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

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

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

MS_ENABLED=$(get_setting system.merged.storage)
MS_DEVICE=$(get_setting system.merged.device)
MS_PATH="/storage/roms"
if [ -z "${MS_DEVICE}" ]
then
  MS_DEVICE="external"
fi
MOUNT_PATH="/storage/games-${MS_DEVICE}"

function start_ms() {
  if [ -e "/storage/.ms_unsupported" ] || \
     [ "${MS_ENABLED}" = "false" ]
  then
    # If we're not using merged storage, bind mount the external storage path
    # so we don't need to change any configs.
    grep ${MOUNT_PATH} /proc/mounts >/dev/null 2>&1
    if [ ! $? = 0 ]
    then
      MOUNT_PATH="/storage/games-internal"
    fi
    log $0 "Executing bind mount of ${MOUNT_PATH} to ${MS_PATH}"
    mount --bind ${MOUNT_PATH}/roms ${MS_PATH}
    exit 0
  else
    log $0 "Enabling merged storage."

    case ${MS_DEVICE} in
      internal)
        LOWER="internal"
        UPPER="external"
      ;;
      *)
        LOWER="external"
        UPPER="internal"
      ;;
    esac
    for DIR in /storage/games-${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 /storage/roms
  fi
}

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

function unmount_roms() {
  NULL=$(cat /proc/mounts | grep -v -e "${MS_PATH}" 2>/dev/null | grep ${1})
  if [ ! "$?" = "0" ]
  then
    umount -f "${MS_PATH}"
  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() {
      unmount_roms
      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
          set_setting system.merged.storage 1
        ;;
        *)
          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
      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 ${DEV} | sed -e "s#^/.*/##g" -e "s#p[0-9].*\$##g")
      SIZE=$(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 ${ROOTDEV} might be Android, ignoring."
        # Assume this is an android boot device and ignore it.
        continue
      fi
      # Udevil might mount it, and we shouldn't care if it does.
      NULL=$(cat /proc/mounts | grep -v -e "/var/media" 2>/dev/null | grep ${DEV})
      if [ ! "$?" = "0" ] && \
         [ -e "${DEV}" ] && \
         [ ! -e "/storage/.please_resize_me" ]
      then
        GAMES_DEVICE=${DEV}
        log $0 "Found ${DEV} available to mount."
        mount_games "${DEV}"
        break
      fi
    done
    # If we're here there is no external storage to use, but we want to start merged storage or the bind mount anyway.
    start_ms
  fi
}

load_modules

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