#!/bin/bash -eu
ARCHIVE_HOST_NAME="$1"

LOG_FILE=/tmp/archiveloop.log

export CAM_MOUNT=/mnt/cam
export MUSIC_MOUNT=/mnt/music

function log () {
  echo "$( date )" >> "$LOG_FILE"
  echo "$1" >> "$LOG_FILE"
}

function fix_errors_in_mount_point () {
  local mount_point="$1"
  log "Running fsck on $mount_point..."
  /sbin/fsck "$mount_point" -- -a >> "$LOG_FILE" 2>&1 || echo ""
  log "Finished fsck on $mount_point."
}

function fix_errors_in_mounted_files () {
  fix_errors_in_mount_point "$CAM_MOUNT"
  fix_errors_in_mount_point "$MUSIC_MOUNT"
}

function archive_is_reachable () {
  local reachable=true
  ping -q -w 1 -c 1 "$ARCHIVE_HOST_NAME" > /dev/null 2>&1 || reachable=false
  if [ "$reachable" = false ]
  then
    false
    return
  fi
  true
}

function connect_usb_drives_to_host() {
  log "Connecting usb to host..."
  modprobe g_mass_storage
  log "Connected usb to host."
}

function wait_for_archive_to_be_reachable () {
  log "Waiting for archive to be reachable..."
  while [ true ]
  do
    if archive_is_reachable
    then
      log "Archive is reachable."
      break
    fi
    if [ -e /tmp/archive_is_reachable ]
    then
      log "Simulating archive is reachable"
      rm /tmp/archive_is_reachable
      break
    fi
    sleep 1
  done
}

function retry () {
  local attempts=0
  while [ true ]
  do
    if eval "$@"
    then
      true
      return
    fi
    if [ "$attempts" -ge 10 ]
    then
      log "Attempts exhausted."
      false
      return
    fi
    log "Sleeping before retry..."
    /bin/sleep 1
    attempts=$((attempts + 1))
    log "Retrying..."
  done
  false
  return
}

function mount_mountpoint () {
  local mount_point="$1"
  log "Mounting $mount_point..."

  local mounted=true
  mount "$mount_point" >> "$LOG_FILE" 2>&1 || mounted=false
  if [ "$mounted" = true ]
  then
    log "Mounted $mount_point."
    true
    return
  else
    log "Failed to mount $mount_point."
    false
    return
  fi
}

function ensure_mountpoint_is_mounted () {
  local mount_point="$1"
  local mount_exists=true

  findmnt --mountpoint "$mount_point" > /dev/null || mount_exists=false

  if [ "$mount_exists" = true ]
  then
    log "$mount_point is already mounted."
  else
    mount_mountpoint "$mount_point"
  fi
}

function ensure_mountpoint_is_mounted_with_retry () {
  retry ensure_mountpoint_is_mounted "$1"
}

function fix_errors_in_cam_file () {
  fix_errors_in_mount_point "$CAM_MOUNT"
}

function ensure_cam_file_is_mounted () {
  log "Ensuring cam file is mounted..."
  ensure_mountpoint_is_mounted_with_retry "$CAM_MOUNT"
  log "Ensured cam file is mounted."
}

function ensure_music_file_is_mounted () {
  log "Ensuring music backing file is mounted..."
  ensure_mountpoint_is_mounted_with_retry "$MUSIC_MOUNT"
  log "Ensured cam drive is mounted."
}

function unmount_mount_point () {
  local mount_point="$1"
  log "Unmounting $mount_point..."
  umount "$mount_point" >> "$LOG_FILE" 2>&1
  log "Unmounted $mount_point."
}

function unmount_cam_file () {
  unmount_mount_point "$CAM_MOUNT"
}

function unmount_music_file () {
  unmount_mount_point "$MUSIC_MOUNT"
}

function fix_errors_in_music_file () {
  fix_errors_in_mount_point "$MUSIC_MOUNT"
}

function archive_clips () {
  log "Archiving..."
  /root/bin/archive-teslacam-clips
  log "Finished archiving."
}

function wait_for_archive_to_be_unreachable () {
  log "Waiting for archive to be unreachable..."
  while [ true ]
    do
      if ! archive_is_reachable
      then
        log "Archive is unreachable."
        break
      fi
      if [ -e /tmp/archive_is_unreachable ]
      then
        log "Simulating archive being unreachable."
        rm /tmp/archive_is_unreachable
        break
      fi
      sleep 1
  done
}

function mount_and_fix_errors_in_cam_file () {
  ensure_cam_file_is_mounted
  fix_errors_in_cam_file
  unmount_cam_file
}

function mount_and_fix_errors_in_music_file () {
  if [ -e "$MUSIC_MOUNT" ]
  then
    ensure_music_file_is_mounted
    fix_errors_in_music_file
    unmount_music_file
  fi
}

function mount_and_fix_errors_in_files () {
  mount_and_fix_errors_in_cam_file
  mount_and_fix_errors_in_music_file
}

export -f fix_errors_in_mount_point
export -f fix_errors_in_cam_file
export -f retry
export -f mount_mountpoint
export -f ensure_mountpoint_is_mounted
export -f ensure_mountpoint_is_mounted_with_retry
export -f ensure_cam_file_is_mounted
export -f fix_errors_in_cam_file
export -f unmount_mount_point
export -f unmount_cam_file
export -f connect_usb_drives_to_host

log "Starting..."

if archive_is_reachable
then
  # archive_clips will fix errors in the cam file
  mount_and_fix_errors_in_music_file

  archive_clips

  wait_for_archive_to_be_unreachable
else
  mount_and_fix_errors_in_files

  connect_usb_drives_to_host
fi

while [ true ]
do
  wait_for_archive_to_be_reachable

  archive_clips

  wait_for_archive_to_be_unreachable
done