#!/bin/bash

# exit on error; treat unset variables as errors; exit on errors in piped commands
set -euo pipefail

# Ensure we operate from consistent pwd for the rest of the script
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )" # Figure out the ABSOLUTE PATH of this script without relying on the realpath command, which may not always be available
cd "$DIR"

if [ "$OSTYPE" == "linux-gnu" ]; then
  MOUNTED_BOOT_VOLUME="/media/$(whoami)/boot" # i.e. under which name is the SD card mounted under /media in Linux (Ubuntu)
  SD_DD_BS="1M"
  SD_DD_PROGRESS="status=progress"
elif [ "$OSTYPE" == "darwin" ]; then
  MOUNTED_BOOT_VOLUME="/Volumes/boot" # i.e. under which name is the SD card mounted under /Volumes on macOS
  SD_DD_BS="1m"
  SD_DD_PROGRESS=""
else
  echo "Error: Unsupported platform $OSTYPE, sorry"
  exit 1
fi

BOOT_CMDLINE_TXT="$MOUNTED_BOOT_VOLUME/cmdline.txt"
BOOT_CONFIG_TXT="$MOUNTED_BOOT_VOLUME/config.txt"
SD_SIZE_REAL=2500 # this is in MB
SD_SIZE_SAFE=2800 # this is in MB
SD_SIZE_ZERO=3200 # this is in MB
SSH_PUBKEY="$(cat ~/.ssh/id_rsa.pub)"
SSH_CONNECT_TIMEOUT=30
LOCALE="en_US.UTF-8 UTF-8" # or e.g. "fi_FI.UTF-8 UTF-8" for Finland
LANGUAGE="en_US.UTF-8" # should match above
KEYBOARD="us" # or e.g. "fi" for Finnish
TIMEZONE="Etc/UTC" # or e.g. "Europe/Helsinki"; see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

function echo-bold {
  echo -e "$(tput -Txterm-256color bold)$1$(tput -Txterm-256color sgr 0)" # https://unix.stackexchange.com/a/269085; the -T arg accounts for $ENV not being set
}
function working {
  echo-bold "\n[WORKING] $1"
}
function question {
  echo-bold "\n[QUESTION] $1"
}
function ssh {
  /usr/bin/ssh -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o ConnectTimeout="$SSH_CONNECT_TIMEOUT" "pi@$IP" "$1"
}
function scp {
  /usr/bin/scp -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null "$@" "pi@$IP:/home/pi"
}
function figureOutSdCard {
  if [ "$OSTYPE" == "linux-gnu" ]; then
    lsblk --fs
    DISK="/dev/$(lsblk -l | grep "$MOUNTED_BOOT_VOLUME" | sed 's/[0-9].*//')"
    DISK_SAMPLE="/dev/sda"
  elif [ "$OSTYPE" == "darwin" ]; then
    diskutil list
    DISK="$(diskutil list | grep /dev/ | grep external | grep physical | cut -d ' ' -f 1 | head -n 1)"
    DISK_SAMPLE="/dev/disk2"
  else
    echo "Error: Unsupported platform $OSTYPE, sorry"
    exit 1
  fi
}
function unmountSdCard {
  if [ "$OSTYPE" == "linux-gnu" ]; then
    for part in $(lsblk --list "$DISK" | grep part | sed 's/ .*//'); do
      udisksctl unmount -b "/dev/$part"
    done
  elif [ "$OSTYPE" == "darwin" ]; then
    diskutil unmountDisk "$DISK"
  else
    echo "Error: Unsupported platform $OSTYPE, sorry"
    exit 1
  fi
}

question "Enter version (e.g. \"1.2.3\") being built"
echo "Omit the \"v\" prefix, it'll be added where needed"
echo "For alpha/beta builds, use a \"-betaN\" suffic"
echo "For RC builds, DO NOT use any suffix, as then the same image can't be promoted to stable without rebuilding"
echo "Enter version:"
read TAG

working "Updating version file"
echo -e "$TAG\n\nhttps://github.com/futurice/chilipie-kiosk" > ../home/.chilipie-kiosk-version

working "Generating first-boot.html"
if [ ! -d "node_modules" ]; then
  npm install markdown-styles@3.1.10 html-inline@1.2.0
fi
rm -rf md-input md-output
mkdir md-input md-output
cp ../docs/first-boot.md md-input
./node_modules/.bin/generate-md --layout github --input md-input/ --output md-output/
./node_modules/.bin/html-inline -i md-output/first-boot.html > ../home/first-boot.html
rm -rf md-input md-output

question "Mount the SD card (press enter when ready)"
read

working "Figuring out SD card device"
figureOutSdCard

question "Based on the above, SD card determined to be \"$DISK\" (should be e.g. \"$DISK_SAMPLE\"), press enter to continue"
read

working "Safely unmounting the card"
unmountSdCard

working "Writing the card full of zeros (for security and compressibility reasons)"
echo "This may take a long time"
echo "You may be prompted for your password by sudo"
sudo dd bs="$SD_DD_BS" count="$SD_SIZE_ZERO" if=/dev/zero of="$DISK" "$SD_DD_PROGRESS"

question "Prepare baseline Raspbian:"
echo "* Flash Raspbian Lite with Etcher"
echo "* Eject the SD card"
echo "* Mount the card back"
echo "* Wait for your OS to mount it"
echo "(press enter when ready)"
read

working "Backing up original boot files"
cp -v "$BOOT_CMDLINE_TXT" "$BOOT_CMDLINE_TXT.backup"
cp -v "$BOOT_CONFIG_TXT" "$BOOT_CONFIG_TXT.backup"

working "Disabling automatic root filesystem expansion"
echo "Updating: $BOOT_CMDLINE_TXT"
cat "$BOOT_CMDLINE_TXT" | sed "s#init=/usr/lib/raspi-config/init_resize.sh##" > temp
mv temp "$BOOT_CMDLINE_TXT"

working "Enabling SSH for first boot"
# https://www.raspberrypi.org/documentation/remote-access/ssh/
touch "$MOUNTED_BOOT_VOLUME/ssh"

working "Safely unmounting the card"
unmountSdCard

question "Do initial Pi setup:"
echo "* Eject the card"
echo "* Connect your Pi to Ethernet"
echo "* Boot the Pi from your card"
echo "* Make note of the \"My IP address is\" message at the end of boot"
echo "Enter the IP address:"
read IP

working "Installing temporary SSH pubkey"
echo -e "Password hint: \"raspberry\""
ssh "mkdir .ssh && echo '$SSH_PUBKEY' > .ssh/authorized_keys"

working "Figuring out partition start"
ssh "echo -e 'p\nq\n' | sudo fdisk /dev/mmcblk0 | grep /dev/mmcblk0p2 | tr -s ' ' | cut -d ' ' -f 2" > temp
START="$(cat temp)"
rm temp

question "Partition start determined to be \"$START\" (should be e.g. \"98304\"), press enter to continue"
read

working "Resizing the root partition on the Pi"
ssh "echo -e 'd\n2\nn\np\n2\n$START\n+${SD_SIZE_REAL}M\ny\nw\n' | sudo fdisk /dev/mmcblk0"

working "Setting locale"
# We want to do this as early as possible, so perl et al won't complain about misconfigured locales for the rest of the image prep
ssh "echo $LOCALE | sudo tee /etc/locale.gen"
ssh "sudo locale-gen"
ssh "echo -e \"LANGUAGE=$LANGUAGE\nLC_ALL=$LANGUAGE\" | sudo tee /etc/environment"

working "Setting hostname"
# We want to do this right before reboot, so we don't get a lot of unnecessary complaints about "sudo: unable to resolve host chilipie-kiosk" (https://askubuntu.com/a/59517)
ssh "sudo hostnamectl set-hostname chilipie-kiosk"
ssh "sudo perl -i -p0e 's/raspberrypi/chilipie-kiosk/g' /etc/hosts" # "perl" is more cross-platform than "sed -i"

# From now on, some ssh commands will exit non-0, which should be fine
set +e

working "Rebooting the Pi"
ssh "sudo reboot"

echo "Waiting for host to come back up..."
until SSH_CONNECT_TIMEOUT=5 ssh "echo OK"
do
  sleep 1
done

working "Finishing the root partition resize"
ssh "df -h . && sudo resize2fs /dev/mmcblk0p2 && df -h ."

# From raspi-config: https://github.com/RPi-Distro/raspi-config/blob/c0ddae8a2e99ecf15759c7cb8f0681cb0e7ce63a/raspi-config#L1141
# See also: https://github.com/futurice/chilipie-kiosk/issues/61#issuecomment-524622522
working "Enabling auto-login to CLI"
ssh "sudo systemctl set-default multi-user.target"
ssh "sudo ln -fs /lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/getty@tty1.service"
ssh "sudo ln -fs /lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/getty@tty2.service"
ssh "sudo ln -fs /lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/getty@tty3.service"
ssh "sudo mkdir -p /etc/systemd/system/getty@tty1.service.d"
ssh "sudo mkdir -p /etc/systemd/system/getty@tty2.service.d"
ssh "sudo mkdir -p /etc/systemd/system/getty@tty3.service.d"
ssh "echo -e '[Service]\nExecStart=\nExecStart=-/sbin/agetty --autologin pi --noclear %I \$TERM\n' | sudo tee /etc/systemd/system/getty@tty1.service.d/autologin.conf"
ssh "echo -e '[Service]\nExecStart=\nExecStart=-/sbin/agetty --autologin pi --noclear %I \$TERM\n' | sudo tee /etc/systemd/system/getty@tty2.service.d/autologin.conf"
ssh "echo -e '[Service]\nExecStart=\nExecStart=-/sbin/agetty --autologin pi --noclear %I \$TERM\n' | sudo tee /etc/systemd/system/getty@tty3.service.d/autologin.conf"

working "Setting timezone"
ssh "(echo '$TIMEZONE' | sudo tee /etc/timezone) && sudo dpkg-reconfigure --frontend noninteractive tzdata"

working "Setting keyboard layout"
ssh "(echo -e 'XKBMODEL="pc105"\nXKBLAYOUT="$KEYBOARD"\nXKBVARIANT=""\nXKBOPTIONS=""\nBACKSPACE="guess"\n' | sudo tee /etc/default/keyboard) && sudo dpkg-reconfigure --frontend noninteractive keyboard-configuration"

working "Silencing console logins" # this is to avoid a brief flash of the console login before X comes up
ssh "sudo rm /etc/profile.d/sshpwd.sh /etc/profile.d/wifi-check.sh" # remove warnings about default password and WiFi country (https://raspberrypi.stackexchange.com/a/105234)
ssh "touch .hushlogin" # https://scribles.net/silent-boot-on-raspbian-stretch-in-console-mode/

working "Installing packages"
ssh "sudo apt-get update && DEBIAN_FRONTEND=noninteractive sudo apt-get install -y vim matchbox-window-manager unclutter mailutils nitrogen jq chromium-browser xserver-xorg xinit rpd-plym-splash xdotool rng-tools"
# We install mailutils just so that you can check "mail" for cronjob output

working "Setting home directory default content"
ssh "rm -rfv /home/pi/*"
scp $(find ../home -type f)

working "Setting splash screen background"
ssh "sudo rm /usr/share/plymouth/themes/pix/splash.png && sudo ln -s /home/pi/background.png /usr/share/plymouth/themes/pix/splash.png"

working "Installing default crontab"
ssh "crontab /home/pi/crontab.example"

working "Rebooting the Pi"
ssh "sudo reboot"

question "Once the Pi has rebooted into Chromium:"
echo "* Tell Chromium we don't want to sign in"
echo "* Configure Chromium to start \"where you left off\""
echo "  * F11 to exit full screen"
echo "  * Alt + F, then S to go to Settings"
echo "  * Type \"continue\" to filter the options"
echo "  * Tab to select \"Continue where you left off\""
echo "* Navigate to \"file:///home/pi/first-boot.html\""
echo "(press enter when ready)"
read

working "Figuring out software versions"
ssh "hostnamectl | grep 'Operating System:' | tr -s ' ' | cut -d ' ' -f 4-" > temp
VERSION_LINUX="$(cat temp)"
ssh "hostnamectl | grep 'Kernel:' | tr -s ' ' | cut -d ' ' -f 3-4" > temp
VERSION_KERNEL="$(cat temp)"
ssh "chromium-browser --version | cut -d ' ' -f 1-2" > temp
VERSION_CHROMIUM="$(cat temp)"
rm temp

working "Removing SSH host keys & enable regeneration"
ssh "sudo rm -f -v /etc/ssh/ssh_host_*_key* && sudo systemctl enable regenerate_ssh_host_keys"

working "Removing temporary SSH pubkey, disabling SSH & shutting down"
ssh "(echo > .ssh/authorized_keys) && sudo systemctl disable ssh && sudo shutdown -h now"

question "Eject the SD card from the Pi, and mount it back to this computer (press enter when ready)"
read

# We do this again now just to be safe
working "Figuring out SD card device"
figureOutSdCard

question "Based on the above, SD card determined to be \"$DISK\" (should be e.g. \"$DISK_SAMPLE\"), press enter to continue"
read

working "Making boot quieter (part 1)" # https://scribles.net/customizing-boot-up-screen-on-raspberry-pi/
echo "Updating: $BOOT_CONFIG_TXT"
perl -i -p0e "s/#disable_overscan=1/disable_overscan=1/g" "$BOOT_CONFIG_TXT"
echo -e "\ndisable_splash=1" >> "$BOOT_CONFIG_TXT"

working "Making boot quieter (part 2)" # https://scribles.net/customizing-boot-up-screen-on-raspberry-pi/
echo "You may want to revert these changes if you ever need to debug the startup process"
echo "Updating: $BOOT_CMDLINE_TXT"
cat "$BOOT_CMDLINE_TXT" \
  | sed 's/console=tty1/console=tty3/' \
  | sed 's/$/ splash plymouth.ignore-serial-consoles logo.nologo vt.global_cursor_default=0/' \
  > temp
mv temp "$BOOT_CMDLINE_TXT"

working "Safely unmounting the card"
unmountSdCard

working "Dumping the image from the card"
cd ..
echo "This may take a long time"
echo "You may be prompted for your password by sudo"
sudo dd bs="$SD_DD_BS" count="$SD_SIZE_SAFE" if="$DISK" of="chilipie-kiosk-$TAG.img" "$SD_DD_PROGRESS"

working "Compressing image"
COPYFILE_DISABLE=1 tar -zcvf chilipie-kiosk-$TAG.img.tar.gz chilipie-kiosk-$TAG.img

working "Listing image sizes"
du -hs chilipie-kiosk-$TAG.img*

working "Calculating image hashes"
openssl sha1 chilipie-kiosk-$TAG.img*

working "Software versions are:"
echo "* Linux: \`$VERSION_LINUX\`"
echo "* Kernel: \`$VERSION_KERNEL\`"
echo "* Chromium: \`$VERSION_CHROMIUM\`"