#!/usr/bin/env bash

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Determine the operating system
export OS=$(uname)

# Primary network interface
if [[ "$OS" != "Darwin" ]]; then
  export PRIMARY_IFACE=$(ip -o -4 route show to default | awk '{print $5}')
  echo -e "${GREEN}Found primary network interface $PRIMARY_IFACE${NC}"
fi

# Custom print function
_print() {
  if [[ "$OS" == "Darwin" ]]; then
    echo -e "$1"
  else
    echo "$1"
  fi
}

# Custom prompt function
_prompt() {
  local message="$1"
  local variable="$2"

  _print "$message"
  read -r $variable
}

# Fetch username from the system
export USERNAME=$(whoami)

# If the username is 'nixos' or 'root', ask the user for their username
if [[ "$USERNAME" == "nixos" ]] || [[ "$USERNAME" == "root" ]]; then
  _prompt "${YELLOW}You're running as $USERNAME. Please enter your desired username: ${NC}" USERNAME
fi

# Check if git is available
if command -v git >/dev/null 2>&1; then
  # Fetch email and name from git config
  export GIT_EMAIL=$(git config --get user.email)
  export GIT_NAME=$(git config --get user.name)
else
  _print "${RED}Git is not available on this system.${NC}"
fi

# If git email is not found or git is not available, ask the user
if [[ -z "$GIT_EMAIL" ]]; then
  _prompt "${YELLOW}Please enter your email: ${NC}" GIT_EMAIL
fi

# If git name is not found or git is not available, ask the user
if [[ -z "$GIT_NAME" ]]; then
  _prompt "${YELLOW}Please enter your name: ${NC}" GIT_NAME
fi

select_boot_disk() {
  local disks
  local _boot_disk

  _print "${YELLOW}Available disks:${NC}"
  disks=$(lsblk -nd --output NAME,SIZE | grep -v loop)
  echo "$disks"

  # Warning message for data deletion
  _print "${RED}WARNING: All data on the chosen disk will be erased during the installation!${NC}"
  _prompt "${YELLOW}Please choose your boot disk (e.g., nvme0n1, sda): ${NC}" _boot_disk

  # Confirmation for disk selection to prevent accidental data loss
  _print "${YELLOW}You have selected $_boot_disk as the boot disk. This will delete everything on this disk. Are you sure? (Y/N): ${NC}"
  read -r confirmation
  if [[ "$confirmation" =~ ^[Yy]$ ]]; then
    export BOOT_DISK=$_boot_disk
  else
    _print "${RED}Disk selection cancelled by the user. Please run the script again to select the correct disk.${NC}"
    exit 1
  fi
}

# Set hostname and find primary disk if this is NixOS
if [[ "$OS" != "Darwin" ]]; then
  _prompt "${YELLOW}Please enter a hostname for the system: ${NC}" HOST_NAME
  export HOST_NAME
  select_boot_disk
fi

# Confirmation step
confirm_details() {
  _print "${GREEN}Username: $USERNAME"
  _print "Email: $GIT_EMAIL"
  _print "Name: $GIT_NAME${NC}"

  if([[ "$OS" != "Darwin" ]]); then
    _print "${GREEN}Primary interface: $PRIMARY_IFACE"
    _print "Boot disk: $BOOT_DISK"
    _print "Hostname: $HOST_NAME${NC}"
  fi

  _prompt "${YELLOW}Is this correct? (Y/N): ${NC}" choice

  case "$choice" in
  [Nn] ) _print "${RED}Exiting script.${NC}" && exit 1;;
  [Yy] ) _print "${GREEN}Continuing...${NC}";;
  * ) _print "${RED}Invalid option. Exiting script.${NC}" && exit 1;;
  esac
}

# Call the confirmation function
confirm_details

# Function to replace tokens in each file
replace_tokens() {
  local file="$1"
  if [[ $(basename $1) != "apply" ]]; then
    if [[ "$OS" == "Darwin" ]]; then
      # macOS
      LC_ALL=C LANG=C sed -i '' -e "s/%USER%/$USERNAME/g" "$file"
      LC_ALL=C LANG=C sed -i '' -e "s/%EMAIL%/$GIT_EMAIL/g" "$file"
      LC_ALL=C LANG=C sed -i '' -e "s/%NAME%/$GIT_NAME/g" "$file"
    else
      # Linux or other
      sed -i -e "s/%USER%/$USERNAME/g" "$file"
      sed -i -e "s/%EMAIL%/$GIT_EMAIL/g" "$file"
      sed -i -e "s/%NAME%/$GIT_NAME/g" "$file"
      sed -i -e "s/%INTERFACE%/$PRIMARY_IFACE/g" "$file"
      sed -i -e "s/%DISK%/$BOOT_DISK/g" "$file"
      sed -i -e "s/%HOST%/$HOST_NAME/g" "$file"
    fi
  fi
}

# Traverse directories and call replace_tokens on each Nix file
export -f replace_tokens
find . -type f -exec bash -c 'replace_tokens "$0"' {} \;

echo "$USERNAME" > /tmp/username.txt
_print "${GREEN}User $USERNAME information applied.${NC}"