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

# Colour helpers
b=$(tput bold); r=$(tput sgr0); g=$(tput setaf 2); y=$(tput setaf 3); c=$(tput setaf 6); e=$(tput setaf 1)
info(){ echo "${c}==>${r} $*"; }
warn(){ echo "${y}!${r} $*"; }
die(){ echo "${e}x${r} $*" >&2; exit 1; }

NO_PROMPT=0
[[ "${1:-}" =~ (--no-prompt|--auto) ]] && NO_PROMPT=1

# --- Load or create .env ---
[[ ! -f .env ]] && { warn ".env missing, creating from template"; cp .env.template .env 2>/dev/null || touch .env; }
source .env || true

prompt_var(){ local n=$1 t=$2 d="${!n:-}"; [[ $NO_PROMPT == 1 ]] && { info "Using $n=$d"; return; }
read -e -p "$t [$d]: " i; [[ -n $i ]] && eval "$n=\"\$i\""; }
prompt_secret(){ local n=$1 t=$2 d="${!n:-}"; if [[ -z $d ]]; then read -s -p "$t: " i; echo; eval "$n=\"\$i\""; else info "Using $n from .env"; fi; }
save_env(){ local n=$1 v="${!n}"; sed -i "/^$n=/d" .env; echo "$n=\"$v\"" >> .env; }

# --- Gather configuration ---
prompt_var HOSTNAME "Hostname"; prompt_var USERNAME "Username"; prompt_var KEYMAP "Keymap"
prompt_var TIMEZONE "Timezone"; prompt_var LOCALE "Locale"
save_env HOSTNAME; save_env USERNAME; save_env KEYMAP; save_env TIMEZONE; save_env LOCALE

# --- Networking ---
timedatectl set-ntp true
if [[ -z "$(ip link | grep -E 'state UP')" ]]; then
  warn "No active network found"
  prompt_var WIFI_SSID "Wi-Fi SSID"; prompt_secret WIFI_PASS "Wi-Fi password"
  iwctl station wlan0 scan || true
  iwctl station wlan0 connect "$WIFI_SSID" --passphrase "$WIFI_PASS" || die "Wi-Fi connect failed"
else info "Network detected"; fi

# --- Disk selection ---
if [[ -z "${DISK:-}" ]]; then
  info "Available disks:"; lsblk -dno NAME,SIZE,MODEL | grep -v loop | nl -w2 -s'. '
  [[ $NO_PROMPT == 1 ]] && die "No DISK specified in .env"
  read -p "Select disk number: " n; DISK="/dev/$(lsblk -dno NAME | grep -v loop | sed -n "${n}p")"
fi; save_env DISK
EFI="${DISK}p1"; ROOT="${DISK}p2"
read -p "${e}${b}⚠️  Erase $DISK? ENTER to confirm${r}"

# --- Partition + encrypt ---
sgdisk --zap-all "$DISK"
sgdisk -n1:0:+1G -t1:ef00 -c1:"EFI System" "$DISK"
sgdisk -n2:0:0 -t2:8300 -c2:"Linux LUKS" "$DISK"; partprobe "$DISK"
prompt_secret LUKS_PASSWORD "LUKS password"; save_env LUKS_PASSWORD
echo -n "$LUKS_PASSWORD" | cryptsetup luksFormat --batch-mode --type luks2 --cipher aes-xts-plain64 --key-size 512 --hash sha512 "$ROOT" -
echo -n "$LUKS_PASSWORD" | cryptsetup open "$ROOT" cryptroot -
mkfs.fat -F32 "$EFI"; mkfs.ext4 /dev/mapper/cryptroot
mount /dev/mapper/cryptroot /mnt; mkdir /mnt/boot; mount "$EFI" /mnt/boot

# --- Mirrors + base ---
pacman -Sy --noconfirm reflector
reflector --country "United Kingdom" --latest 20 --sort rate --save /etc/pacman.d/mirrorlist
pacstrap -K /mnt base linux linux-firmware vim networkmanager sudo base-devel git

genfstab -U /mnt >> /mnt/etc/fstab

# --- Chroot configuration ---
arch-chroot /mnt /bin/bash <<CHROOT
set -euo pipefail
ln -sf /usr/share/zoneinfo/$TIMEZONE /etc/localtime
hwclock --systohc
sed -i "s/^#${LOCALE}/${LOCALE}/" /etc/locale.gen
locale-gen
echo "LANG=$LOCALE" > /etc/locale.conf
echo "$HOSTNAME" > /etc/hostname
cat <<EOF >/etc/hosts
127.0.0.1 localhost
::1 localhost
127.0.1.1 $HOSTNAME.localdomain $HOSTNAME
EOF
echo "KEYMAP=$KEYMAP" > /etc/vconsole.conf

sed -i 's/\(filesystems\)/encrypt \1/' /etc/mkinitcpio.conf
mkinitcpio -P

bootctl install
UUID=\$(blkid -s UUID -o value ${ROOT})
cat <<EOF >/boot/loader/loader.conf
default arch.conf
timeout 3
console-mode max
editor no
EOF
cat <<EOF >/boot/loader/entries/arch.conf
title Arch Linux
linux /vmlinuz-linux
initrd /initramfs-linux.img
options cryptdevice=UUID=\${UUID}:cryptroot root=/dev/mapper/cryptroot rw
EOF

echo "Set root password:"; passwd
useradd -m -G wheel -s /bin/bash $USERNAME
echo "Set password for $USERNAME:"; passwd $USERNAME
sed -i 's/^# %wheel ALL=(ALL:ALL) ALL/%wheel ALL=(ALL:ALL) ALL/' /etc/sudoers
systemctl enable NetworkManager

# --- Optional yay ---
if [[ "${INSTALL_YAY,,}" == "yes" ]]; then
  pacman -Sy --noconfirm base-devel git
  su - $USERNAME -c "cd /tmp && git clone https://aur.archlinux.org/yay.git && cd yay && makepkg -si --noconfirm && rm -rf /tmp/yay"
fi

# --- Optional hardening ---
if [[ "${ENABLE_HARDENING,,}" == "yes" ]]; then
  pacman -Sy --noconfirm ufw apparmor fail2ban archlinux-keyring
  systemctl enable ufw; systemctl start ufw
  ufw default deny incoming; ufw default allow outgoing; ufw enable
  systemctl enable apparmor; systemctl enable fail2ban
  cat <<EOF >/etc/sysctl.d/99-hardening.conf
net.ipv4.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv6.conf.all.accept_source_route = 0
net.ipv4.tcp_syncookies = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
kernel.randomize_va_space = 2
EOF
  sysctl --system
  echo 'Defaults timestamp_timeout=5' > /etc/sudoers.d/hardening
fi
CHROOT

# --- Optional WireGuard setup ---
if [[ "${ENABLE_WIREGUARD,,}" == "yes" && -f "${WIREGUARD_CONF_PATH}" ]]; then
  info "Installing WireGuard..."
  install -Dm600 "$WIREGUARD_CONF_PATH" "/mnt/etc/wireguard/wg0.conf"
  arch-chroot /mnt pacman -Sy --noconfirm wireguard-tools
  arch-chroot /mnt systemctl enable wg-quick@wg0.service
else
  warn "WireGuard skipped (no config or disabled)."
fi

umount -R /mnt; cryptsetup close cryptroot
info "Installation complete"

cat <<EOF

${g}${b}✅ Arch Linux installation complete!${r}

Remove media and reboot:
  ${b}reboot${r}

Then log in as '${USERNAME}' and pull your next setup, e.g.:
  ${c}wget https://your.gitea.instance/raw/setup_dev_env.sh && bash setup_dev_env.sh${r}
EOF