#!/bin/sh

# Travis doesn't provide FreeBSD machines, so we just take a Linux one and run
# FreeBSD in qemu virtual machine. qemu is being ran in curses mode inside a
# screen session, because screen allows to easily send input and read output.
# The input is sent using `screen -S session-name -X stuff ...` and the output
# is read from the screen's log file. Note that for some reason you can't send
# long input lines on Travis (it works just fine when I do it on my machine...),
# but that limitation is not an issue, as we don't really need to send long
# lines of input anyway. Also, note that since we run qemu in curses mode, the
# output contains control characters intended for a terminal emulator telling
# how to position and color the text, so it might be a little tricky to read it
# sometimes. The only time when this script has to send input to and read the
# output from the screen session is during the initial setup when we setup the
# network, install and configure the ssh server, and update the system. After
# this initial setup, ssh is used to communicate with the FreeBSD running in the
# VM, which is a lot friendlier way of communication. Please note that Travis
# doesn't seem to allow KVM passthrough, so qemu has to emulate all the
# hardware, which makes it quite slow compared to the host machine. We cache
# the qemu image since it takes a long time to run the initial system and
# package updates, and we do incremental system and package updates on every
# change to the list of git tags (i.e. on every toxcore release, presumably).

sudo apt-get install qemu -y

git tag -l --sort=version:refname > GIT_TAGS

OLD_PWD="$PWD"

mkdir -p /opt/freebsd/cache
cd /opt/freebsd/cache

IMAGE_NAME=FreeBSD-11.0-RELEASE-amd64.raw

# Sends keys to the VM as they are
send_keys()
{
  screen -S $SCREEN_SESSION -X stuff "$1"
}

# Runs until a specific text appears on VM's screen
wait_for()
{
  while ! grep "$1" screenlog.0 -q
  do
    sleep 1
  done
}

# Starts VM and waits until it's fully running (until a login prompt is shown)
start_vm()
{
  rm -f screenlog.0

  # Start emulator. 2000mb RAM should be enough, right? The build machine has over 7gb.
  screen -L -S $SCREEN_SESSION -d -m qemu-system-x86_64 -curses -m 2000 -smp $NPROC -net user,hostfwd=tcp::${SSH_PORT}-:22 -net nic $IMAGE_NAME

  # Wait for the boot screen options
  wait_for "Autoboot in"

  # Select the 1st option
  send_keys '
'

  # Wait for the system to boot and present the login prompt
  wait_for "FreeBSD/amd64 ("
}

# Shuts VM down and waits until its process finishes
stop_vm()
{
  # Turn it off
  RUN poweroff

  # Wait for qemu process to terminate
  while ps aux | grep qemu | grep -vq grep
  do
    sleep 1
  done
}

# Let's see what's in the cache directory
ls -lh

# === Get the VM running, configured to run ssh server and updated ===

# Create image if it's not cached
if [ ! -f ./$IMAGE_NAME.tgz ]; then

  rm -rf ./*

  # https://download.freebsd.org/ftp/releases/VM-IMAGES/11.0-RELEASE/amd64/Latest/
  DL_SHA512="1bfdef9a106e41134cf92c5ceb7f7da468293d6611d16c0bc51482a8fb3088064204bacfe6a8b1afda169d9ab63e4bbd1c9ba1de06fe3fd604864d3fb0c07326"
  # Selecting random mirror from https://www.freebsd.org/doc/handbook/mirrors-ftp.html
  # Note that not all mirrors listed on that page are working, so we have removed them
  # I'm so sorry, there are no arrays in sh and we are not using bash...
  DL_MIRROR_1=1
  DL_MIRROR_2=4
  DL_MIRROR_3=5
  DL_MIRROR_4=6
  DL_MIRROR_5=8
  DL_MIRROR_6=10
  DL_MIRROR_7=14
  DL_MIRROR_8=15
  # There are 8 mirrors
  DL_MIRROR_RANDOM=`expr $(date +%s) % 8 + 1`
  DL_URL=ftp://ftp$(eval echo \$DL_MIRROR_$DL_MIRROR_RANDOM).us.freebsd.org/pub/FreeBSD/releases/VM-IMAGES/11.0-RELEASE/amd64/Latest/${IMAGE_NAME}.xz

  wget $DL_URL

  if ! ( echo "$DL_SHA512  $IMAGE_NAME.xz" | sha512sum -c --status - ) ; then
      echo "Error: sha512 of $IMAGE_NAME.xz doesn't match the known one"
      exit 1
  fi

  unxz $IMAGE_NAME.xz

  # With this we don't have to guess how long a command will run for and sleeping
  # for that amount of time, risking either under sleeping or over sleeping, instead
  # we will sleep exactly until the command is finished by printing out a unique
  # string after the command is executed and then checking if it was printed.
  execute_shell_and_wait()
  {
    # $RANDOM is a bash built-in, so we try to avoid name collision here by using ugly RANDOM_STR name
    RANDOM_STR=$(< /dev/urandom tr -dc _A-Za-z0-9 | head -c16)
    send_keys "$1;echo $RANDOM_STR

"
    # \[1B is a control escape sequence for a new line in the terminal.
    # We want to wait for <new-line>$RANDOM_STR instead of just $RANDOM_STR because
    # $RANDOM_STR we have inputted with send_keys above would appear in the screenlog.0
    # file and we don't want to much our input.
    # The .\? optionally matches any character. Sometimes it happens that there is some
    # random character inserved between the new line control escape sequence and $RANDOM_STR.
    wait_for "\[1B.\?$RANDOM_STR"
  }

  start_vm

  # Login as root user
  send_keys 'root

'

  # Wait for the prompt
  wait_for "root@:~"

  # Configure network, ssh and start changing password
  execute_shell_and_wait 'echo "ifconfig_em0=DHCP"          >> /etc/rc.conf'
  execute_shell_and_wait 'echo "Port 22"                    >> /etc/ssh/sshd_config'
  execute_shell_and_wait 'echo "PermitRootLogin yes"        >> /etc/ssh/sshd_config'
  execute_shell_and_wait 'echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config'
  execute_shell_and_wait 'echo "PermitEmptyPasswords yes"   >> /etc/ssh/sshd_config'
  execute_shell_and_wait 'echo "sshd_enable=YES"            >> /etc/rc.conf'
  send_keys 'sh /etc/rc.d/netif restart && sh /etc/rc.d/sshd start && passwd
'

  # Wait for the password prompt
  wait_for "Changing local password for root"

  # Reset password to empty for the passwordless ssh to work
  send_keys '
'
  wait_for "New Password"
  send_keys '
'

  # Update system
  RUN freebsd-update --not-running-from-cron fetch
  # It fails if there is nothing to install, so we make it always succeed with true
  RUN freebsd-update --not-running-from-cron install || true

  # Update packages
  RUN env ASSUME_ALWAYS_YES=YES pkg upgrade

  # Install and set bash as the default shell for the root user
  RUN env ASSUME_ALWAYS_YES=YES pkg install bash
  RUN chsh -s /usr/local/bin/bash root

  # Install required toxcore dependencies
  RUN ASSUME_ALWAYS_YES=YES pkg install git opus libvpx libsodium gmake cmake pkgconf check opencv2 portaudio libsndfile texinfo autotools

  # === Cache the VM image ===

  stop_vm

  # Create cache
  tar -Sczvf $IMAGE_NAME.tgz $IMAGE_NAME
  rm screenlog.0

  cp "$OLD_PWD/GIT_TAGS" .

  ls -lh
fi

if [ ! -f ./$IMAGE_NAME ]; then
  # Extract the cached image
  tar -Sxzvf $IMAGE_NAME.tgz
fi

# === Update the image on new version (tag) of toxcore ===
if ! diff -u ./GIT_TAGS "$OLD_PWD/GIT_TAGS" ; then
  start_vm

  # Update system
  RUN freebsd-update --not-running-from-cron fetch
  RUN freebsd-update --not-running-from-cron install || true

  # Update packages
  RUN ASSUME_ALWAYS_YES=YES pkg upgrade

  # === Cache the updated VM image ===

  stop_vm

  # Create/Update cache
  rm $IMAGE_NAME.tgz
  tar -Sczvf $IMAGE_NAME.tgz $IMAGE_NAME
  rm screenlog.0

  cp "$OLD_PWD/GIT_TAGS" .

  ls -lh
fi

# Get the image we will be using out of the cached directory
mv $IMAGE_NAME ..
ls -lh

cd ..

ls -lh

# === Get VM ready to build the code ===

start_vm

# Display FreeBSD kernel info and last login
RUN uname -a
RUN last

cd "$OLD_PWD"

# Copy over toxcore code from Travis to qemu
scp -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -P $SSH_PORT -r ./* root@localhost:~

RUN ls -lh