#!/usr/bin/env bash
set -euo pipefail

# ==============================================
# Arch Secure Install - Stage 1 (Live ISO)
# ==============================================

# Load configuration
if [[ ! -f .env ]]; then
  echo "Missing .env. Copy .env.template and edit it before running."
  exit 1
fi
source .env

echo ">>> Arch Secure Install starting on ${DISK}"

# Basic sanity
[[ -b "${DISK}" ]] || { echo "Error: ${DISK} not found."; exit 1; }
[[ -n "${HOSTNAME:-}" ]] || { echo "Error: HOSTNAME not set."; exit 1; }

timedatectl set-ntp true

# ----------------------------------------------
# Partitioning
# ----------------------------------------------
echo ">>> Partitioning ${DISK}"
sgdisk --zap-all "${DISK}"
sgdisk -n1:0:+512M -t1:EF00 -c1:"EFI System Partition" "${DISK}"
sgdisk -n2:0:0     -t2:8309 -c2:"Linux LUKS" "${DISK}"
partprobe "${DISK}"

EFI="${DISK}p1"
ROOT="${DISK}p2"

# ----------------------------------------------
# Encryption setup
# ----------------------------------------------
echo ">>> Formatting EFI partition"
mkfs.fat -F32 "${EFI}"

echo ">>> Setting up LUKS2 on ${ROOT}"
echo -n "${LUKS_PASSPHRASE}" | cryptsetup luksFormat --type luks2 "${ROOT}" -
echo -n "${LUKS_PASSPHRASE}" | cryptsetup open "${ROOT}" "${LUKS_NAME}" -

# ----------------------------------------------
# Btrfs setup
# ----------------------------------------------
echo ">>> Creating Btrfs filesystem"
mkfs.btrfs /dev/mapper/"${LUKS_NAME}"

echo ">>> Creating Btrfs subvolumes"
mount /dev/mapper/"${LUKS_NAME}" /mnt

IFS=' ' read -r -a SUBVOLS <<< "${BTRFS_SUBVOLS}"

for subvol in "${SUBVOLS[@]}"; do
  echo "  -> creating ${subvol}"
  btrfs subvolume create "/mnt/${subvol}"
done

echo ">>> Subvolumes created:"
btrfs subvolume list /mnt || true
umount /mnt

# Mount structure
echo ">>> Mounting Btrfs subvolumes"
mount -o subvol=@,${BTRFS_OPTS} /dev/mapper/"${LUKS_NAME}" /mnt
mkdir -p /mnt/{boot,home,var/log,var/cache}

# Only mount if subvol exists
for subvol in @home @log @cache; do
  if btrfs inspect-internal subvolid-map /dev/mapper/"${LUKS_NAME}" | grep -q "${subvol}"; then
    case "${subvol}" in
      @home)  mount -o subvol=@home,${BTRFS_OPTS} /dev/mapper/"${LUKS_NAME}" /mnt/home ;;
      @log)   mount -o subvol=@log /dev/mapper/"${LUKS_NAME}" /mnt/var/log ;;
      @cache) mount -o subvol=@cache /dev/mapper/"${LUKS_NAME}" /mnt/var/cache ;;
    esac
  fi
done

mount "${EFI}" /mnt/boot

# ----------------------------------------------
# Base system installation
# ----------------------------------------------
echo ">>> Installing base system"
pacstrap -K /mnt base linux linux-firmware btrfs-progs systemd-ukify systemd-bootctl

# ----------------------------------------------
# fstab and chroot handoff
# ----------------------------------------------
echo ">>> Generating fstab"
genfstab -U /mnt >> /mnt/etc/fstab

echo ">>> Copying configuration into target"
mkdir -p /mnt/root/install
cp .env /mnt/root/install/.env
cp chroot_setup.sh /mnt/root/install/
cp firstboot.sh /mnt/root/install/
chmod +x /mnt/root/install/{chroot_setup.sh,firstboot.sh}

echo ">>> Entering chroot"
arch-chroot /mnt /root/install/chroot_setup.sh

echo ">>> Installation complete. You may now reboot."