#!/bin/bash

set -eo pipefail

confirmation() {
	local message
	message="${1}"

	local choice

	while :; do
		printf "%s (Y/n) " "${message}"
		read -r choice
		case "${choice}" in
		y | Y)
			return 0
			;;
		n | N)
			return 1
			;;
		*) printf "\nInput must be either y, Y, n, or N" ;;
		esac
	done
}

print-break() {
	local green
	green="$(tput setaf 2)"
	local reset
	reset="$(tput sgr0)"
	printf "${green}%.s─${reset}" $(seq 1 "$(tput cols)")
}

print-title() {
	local title
	title="${*}"
	local bold
	bold="$(tput bold)"
	local underline
	underline="$(tput smul)"

	local cyan
	cyan="$(tput setaf 6)"
	local reset
	reset="$(tput sgr0)"

	printf "%s%s%s%s%s\n" "${bold}" "${underline}" "${cyan}" "${title}" "${reset}" >&2
}

echo-rgb() {
	# Echo a colored string to the terminal based on rgb values
	#
	# Positional Arguments:
	#
	#   message <type: string> <position: 1> <required: true>
	#     - The message to be printed to stdout
	#   red <type: int> <position: 2> <required: true>
	#     - The red value from 0 to 255
	#   green <type: int> <position: 3> <required: true>
	#     - The green value from 0 to 255
	#   blue <type: int> <position: 4> <required: true>
	#     - The blue value from 0 to 255
	#
	# Usage:
	#   echo-rgb "Yep" 10 8 30
	#
	# POSIX Compliant:
	#   N/A
	#

	local red
	local green
	local blue
	local input

	input="${1}"
	red="${2}"
	green="${3}"
	blue="${4}"

	printf "\e[0;38;2;%s;%s;%sm%s\e[m\n" "${red}" "${green}" "${blue}" "${input}"
}

important() {
	echo-rgb "${1}" 135 195 255
}

log() {
	# Print a message and send it to stdout or stderr depending upon log level, also configurable with debug etc.
	#
	# Arguments:
	#   level <type: string> <position: 1> <required: true>
	#     - The log level, defined within a case check in this function
	#   message <type: string> <position: 2> <required: true>
	#     - The info message
	#   line_number <type: int> <position: 3> <required: false>
	#     - The line number of the calling function (${LINNO})
	#
	# Usage:
	#   log "info" "Could not find that directory"
	#
	# POSIX Compliant:
	#   Yes
	#

	# Set debug status depending if a global debug variable has been set to either 1 or 0
	local debug
	if [ ${DEBUG} ]; then
		debug=${DEBUG}
	else
		debug=0
	fi

	local FORMAT
	FORMAT="[$(echo-rgb "$(date +%Y-%m-%dT%H:%M:%S)" 180 140 255)]"

	# Convert the level to uppercase
	local level
	level=$(echo "${1}" | tr '[:lower:]' '[:upper:]')

	local message
	message="${2}"

	case "${level}" in
	INFO)
		# Output all info log levels to stdout
		printf "${FORMAT}[$(echo-rgb "INFO" 0 140 255)] %s\n" "${message}" >&2
		return 0
		;;
	WARN | WARNING)
		# Output all warning log levels to stdout
		printf "${FORMAT}[$(echo-rgb "WARNING" 255 255 0)] %s\n" "${message}" >&2
		return 0
		;;
	DEBUG)
		# Output all debug log levels to stdout
		if [ "${DEBUG}" ]; then
			printf "${FORMAT}[$(echo-rgb "DEBUG" 0 160 110)] %s\n" "${message}" >&2
		fi
		return 0
		;;
	ERROR)
		# Output all error log levels to stderr
		printf "${FORMAT}[$(echo-rgb "ERROR" 255 0 0)] %s\n" "${message}" >&2
		return 0
		;;
	# Further log levels can be added by extending this switch statement with more comparisons

	*) # Default case, no matches
		# Returns non-zero code as an improper log option was passed, this helps with using `set -e`
		printf "${FORMAT}[ERROR] %s\n" "Invalid log level passed, received level \"${level}\" with message \"${message}\"" >&2
		return 1
		;;
	esac
}

get-available-disks() {
	local available_disks=()

	local disk_line
	local disk
	while read -r; do
		# tr is used to change multiple whitespaces into a single space for processing by cut
		disk_line="$(printf "%s" "${REPLY}" | tr -s " ")"
		disk=$(printf "%s" "${disk_line}" | cut -d " " -f2)
		if [[ "${disk}" = "disk" ]]; then
			available_disks+=("$(printf "/dev/%s" "${disk_line}" | cut -d " " -f1)")
		fi
	done <<<"$(lsblk --output NAME,TYPE)"

	printf "%s" "${available_disks[*]}"
}

get-disk-partitions() {
	local disk="${1}"

	if [[ -z "${disk}" ]]; then
		log "error" "No disk passed!"
		return 1
	fi

	if ! blkid | grep "${disk}" >/dev/null; then
		return 1
	fi
	local partitions
	IFS=$'\n' partitions=("$(blkid -o device | grep "${disk}")")
	printf "%s" "${partitions[@]}"
}

check-connectivity() {
	if ! host "google.com" >/dev/null; then
		log "error" "Unable to reach google, network is down. This script requires network connectivity with active DNS resolution"
		return 1
	fi
}

select-item() {
	local item_name="${1}"
	shift
	local items
	# shellcheck disable=2206
	items=($@)
	local item_selected
	while :; do
		local count=1
		for item in "${items[@]}"; do
			printf "%s %s\n" "${count}.)" "$(important "${item}")" >&2
			count=$((count + 1))
		done
		count=1

		read -rp "Select a ${item_name} number: " item_selected
		case "${item_selected}" in
		'' | *[!0-9]*)
			log "error" "A number was not passed"
			continue
			;;
		esac

		for item in "${items[@]}"; do
			# printf -- "--> %s | %s\n" "${item_selected}" "${count}"
			if [[ ${count} -eq ${item_selected} ]]; then
				printf "%s" "${item}"
				return 0
			fi
			count="$((count + 1))"
		done
		log "error" "Invalid selection made, received: \"${item_selected}\""
	done
}

partition-disk() {
	local disk="${1}"
	(
		echo n
		echo "${BOOT_PARTITION_NUMBER}"
		echo
		echo +512M
		echo ef00
		echo n
		echo "${ROOT_PARTITION_NUMBER}"
		echo
		echo
		echo 8300
		echo w
		echo Y
	) | gdisk "${disk}" >/dev/null
	mkfs.vfat -F32 -n EFI "${disk}"*"${BOOT_PARTITION_NUMBER}"
}

main() {
	local ARCH_TIMEZONE="CST"
	local LOCALE="en_US.UTF-8 UTF-8"
	local LANG="en_US.UTF-8"
	local DISK_PARTITION_LETTER=""
	local HOSTNAME="Arch-Linux"
	local MICROCODE="amd"

	clear
	if ! check-connectivity; then
		exit 1
	fi

	print-title "Install Needed PGP Keys"
	pacman -Syy --noconfirm
	pacman -S --noconfirm archlinux-keyring
	print-break

	local selected_disk
	local i_selected_disk
	while :; do
		print-title "Select the installation disk"
		selected_disk="$(select-item "disk" "$(get-available-disks)")"
		i_selected_disk="$(important "${selected_disk}")"
		if confirmation "Is ${i_selected_disk} the correct disk to install to?"; then
			break
		fi
	done
	printf "Disk set as %s\n" "${i_selected_disk}" >&2
	print-break

	print-title "Partition Creation"
	export BOOT_PARTITION_NUMBER=120
	export ROOT_PARTITION_NUMBER=121
	if ! confirmation "Begin installation of Arch Linux to ${i_selected_disk}?"; then
		printf "Install request denied, exiting..." >&2
		exit 0
	fi
	printf "Writing new partitions to %s\n" "${i_selected_disk}" >&2
	partition-disk "${selected_disk}"
	local boot_partion="${selected_disk}${DISK_PARTITION_LETTER}${BOOT_PARTITION_NUMBER}"
	local root_partition="${selected_disk}${DISK_PARTITION_LETTER}${ROOT_PARTITION_NUMBER}"
	mkfs.vfat -F32 -n EFI "${boot_partion}"
	printf "Successfully wrote partitions to %s\n" "${i_selected_disk}" >&2
	print-break

	print-title "Partition Encryption"
	printf "Encrypting %s\n" "$(important "${root_partition}")" >&2
	cryptsetup -y -v luksFormat "${root_partition}" || exit
	printf "Opening encrypted device %s\n" \
		"$(important "${root_partition}")" >&2
	cryptsetup open "${root_partition}" cryptroot || exit
	printf "Configuring LVM\n" >&2
	pvcreate /dev/mapper/cryptroot
	vgcreate vg0 /dev/mapper/cryptroot
	lvcreate --size 16G vg0 --name swap
	lvcreate -l +100%FREE vg0 --name root
	printf "Writing filesystems\n" >&2
	mkfs.ext4 -L root "/dev/mapper/vg0-root"
	mkswap /dev/mapper/vg0-swap
	print-break

	print-title "Install Arch Into Encrypted Volume"
	printf "Mounting Needed Directores\n" >&2
	mount /dev/mapper/vg0-root /mnt
	swapon /dev/mapper/vg0-swap
	mkdir /mnt/boot
	mount "${boot_partion}" /mnt/boot
	printf "Doing Pacstrap\n" >&2
	pacstrap /mnt linux linux-firmware base base-devel grub efibootmgr vim git "${MICROCODE}"-ucode networkmanager
	genfstab -U /mnt >>/mnt/etc/fstab
	print-break

	print-title "Configure System"
	printf "Entering Chroot\n" >&2
	arch-chroot /mnt <<-__END_CHROOT_CMDS__
		printf "Setting default password as toor\n"
		printf "toor\ntoor\n" | passwd

		printf "Linking timezone as %s\n" "$(important "${ARCH_TIMEZONE}")" >&2
		ln -sf "/usr/share/zoneinfo/${ARCH_TIMEZONE}" "/etc/localtime"

		printf "Setting Hardware Clock\n" >&2
		hwclock --systohc

		printf "Setting LOCALE to %s\n" "$(important "${LOCALE}")" >&2
		printf "%s\n" "${LOCALE}" >/etc/locale.gen

		printf "Generting Locale\n" >&2
		locale-gen

		printf "Setting LANG to %s\n" "$(important "${LANG}")" >&2
		printf "%s\n" "${LANG}" >>/etc/locale.conf

		printf "Setting HOSTNAME to %s\n" "$(important "${HOSTNAME}")"
		printf "%s\n" "${HOSTNAME}" >>/etc/hostname

		printf "Set mkinitcipio hooks\n" >&2
		sed -i 's/HOOKS=.*/HOOKS=(base udev autodetect keyboard modconf block encrypt filesystems fsck)/' /etc/mkinitcpio.conf
		mkinitcpio -P

		printf "Configure Grub\n" >&2
		yes | pacman -S grub efibootmgr intel-ucode amd-ucode
		sed -i "s/GRUB_CMDLINE_LINUX=.*/GRUB_CMDLINE_LINUX=\"cryptdevice=UUID=$(blkid -s UUID -o value "${root_partition}"):cryptroot root=\/dev\/mapper\/cryptroot"/" /etc/default/grub
		printf "GRUB_ENABLE_CRYPTO_DISK=y\n" >> /etc/default/grub
		grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=GRUB
		grub-mkconfig -o /boot/grub/grub.cfg

		printf "Setting up networkmanager\n" >&2
		yes | pacman -S networkmanager
		systemctl enable NetworkManager
	__END_CHROOT_CMDS__
	print-break
	printf "%s\n\tUsername: root\n\tPassword: toor\n" "$(important "Finished with installation, login is:")"

}

main