# This NixOS script efficiently manages the startup of a Hugo server within the Kitty terminal.
{ pkgs ? import  {} }: # Accepts an optional argument `pkgs`,...
# defaulting to importing the Nixpkgs repository.

# Uses writeShellScriptBin. This Nix function creates a packaged script that can be executed as a standalone executable script.
# The script is named myStartup.
pkgs.writeShellScriptBin "myStartup" ''
  #!${pkgs.zsh}/bin/zsh # The Shebang specifies the interpreter for this script.
  # More specifically, it specifies the script should be executed ...
  # using the Zsh shell provided by the Nix package set.

  # Variables:
  PATH_BLOG=~/justtothepoint  # Sets the path to the blog directory (where your Hugo project resides).
  SITE_URL="http://localhost:1313" # Defines the URL where the local site (local Hugo server) will be accessible.

  # Function to kill any existing Hugo processes to prevent...
  # multiple instances from running simultaneously
  function kill_blogserv() {
    echo "Starting blog" # Inform the user that the blog service is being started.
    cd $PATH_BLOG || return 1  # Change to the blog directory; exit if it fails.
    ${pkgs.procps}/bin/pkill hugo # Kill any running Hugo processes.
  }

  # Main function to manage the startup process.
  function main() {
    kill_blogserv # Call the function to stop existing Hugo processes.

    # Check if the Kitty terminal is running.
    if ${pkgs.procps}/bin/pgrep -x "kitty" > /dev/null
    then
      echo "Kitty is already running" # Inform the user if Kitty is already running.
    else
      echo "Kitty is not running. Launching..."
      ${pkgs.kitty}/bin/kitty & # Start Kitty in the background.
      sleep 1  # Wait for a moment to ensure Kitty starts up.
    fi

    # Start the Hugo server within the Kitty terminal...
    # ensuring that the terminal remains open (--hold) after the Hugo server stops
    ${pkgs.kitty}/bin/kitty --hold sh -c "${pkgs.hugo}/bin/hugo server --disableFastRender --gc --cleanDestinationDir"
  }

  main # Call the main function to execute the script.
''

#!/bin/sh

# Instantiate the derivation defined in myStartup.nix...
# and create a permanent root reference (--add-root), preventing it from being garbage collected.
DRV_PATH=$(nix-instantiate --add-root /nix/var/nix/gcroots/auto/myStartup.drv ~/dotfiles/scripts/myStartup.nix)
echo "Derivation path: $DRV_PATH"

# Build the derivation,...
# resulting in a path within the Nix store where the executable script resides.
RESULT_PATH=$(nix-build $DRV_PATH)
echo "Result path: $RESULT_PATH"

✦ ❯ sudo sh ./build_and_run_myStartup.sh
# Example Output:
Derivation path: /nix/var/nix/gcroots/auto/myStartup.drv
Result path: /nix/store/v6waz0jv3vavhyraf88h5h1x7b0lpv3g-myStartup

nmaximo7 on nixos ~/dotfiles/scripts
✦ ❯ /nix/store/v6waz0jv3vavhyraf88h5h1x7b0lpv3g-myStartup/bin/myStartup
Starting blog
# The script ensures that any existing Hugo process is terminated before starting a new one.
Kitty is already running
# It verifies if the Kitty terminal emulator is running. If not, it launches Kitty.
Hugo Static Site Generator v...
[...]
Web Server is available at http://localhost:1313/
Press Ctrl+C to stop
# It verifies if the Kitty terminal emulator is running. If not, it launches Kitty.
# The Hugo server starts within Kitty, serving your local Hugo site at http://localhost:1313/.

{ config, pkgs, ... }:

let
  username = config.home.username;
  dotDir = "/home/${username}/dotfiles";
in

{
  programs.zsh = {
    enable = true;

    [...]

    shellAliases = { # Defines custom aliases for your shell
      webserver = "/nix/store/v6waz0jv3vavhyraf88h5h1x7b0lpv3g-myStartup/bin/myStartup";
      [... add other aliases ...]
      # webserver is an alias that runs the myStartup script
      # After rebuilding your NixOS configuration and restarting your shell,...
      # you can start the Hugo server by simply typing: webserver
    };
  };
}

# cd myPython, nix-shell
{ pkgs ? import  {} }:
# This line defines a function that takes pkgs as an argument,...
# which represents the Nix packages available from the Nix Packages collection (nixpkgs).
# If pkgs is not provided, it defaults (with the ? operator) to importing the  package set from your Nix installation.

let
  # Declare a set of environment variables
  # This is a set of key-value pairs specifying environment variables for your Python application, e.g., NEWS_API_KEY.
  envVariables = {
    NEWS_API_KEY = "YOUR_NEWS_API";
    TIME_PROGRESS = "100";
    CITY = "Bangkok";
    TIMEZONE = "Asia/Bangkok";
    WEBSITE = "https://justtothepoint.com";
    WEBSITE_INSECURE = "http://justtothepoint.com";
    LOCALWEB = "http://localhost:1313/";
    TIME_MONITORING = "20";
    KEYBINDING = "~/dotfiles/docs/assets/keybindings.txt";
    HUGO_CONTENT_DIR = "~/justtothepoint/content/";
  };

  # Create a string representation of the .env file content
  envFileContent = pkgs.lib.concatStrings (
    pkgs.lib.mapAttrsToList (name: value: "${name}=${value}\n") envVariables
	# pkgs.lib.mapAttrsToList iterates over each key-value pair in envVariables and formats them as "key=value\n".
	# pkgs.lib.concatStrings concatenates the list of strings into a single string (envFileContent).
  );

# After defining variables with let, we specify the shell environment using pkgs.mkShell.
in pkgs.mkShell {
  # Define build input (packages and dependencies) for the shell environment
  buildInputs = [
    pkgs.neofetch
    pkgs.tk  # Add the Tk library
    pkgs.xorg.libX11
    # X11 libraries, both libraries ensure a typical Python environment that have GUI elements (Tkinter)
    pkgs.python311Packages.tkinter
    (pkgs.python3.withPackages (python-pkgs: [
    # pkgs.python3.withPackages: Produces a Python 3 distribution that includes...
    # the specified packages (pip, python-dotenv, and requests) in our shell environment
      python-pkgs.pip
      python-pkgs.python-dotenv
      python-pkgs.requests
    ]))
  ];

  # The shellHook is a script that runs automatically when you enter the nix-shell. It sets up the development environment by performing several tasks.
  shellHook = ''
    # This command writes the content of envFileContent to a file named .env, which will be used to load environment variables.
    echo "${envFileContent}" > .env

    # Create and activate a Python virtual environment
    python -m venv .venv # Creates a new virtual environment in the .venv directory.
    source .venv/bin/activate # Activates the virtual environment so that installed packages are isolated from the global Python environment.

	  # Upgrade pip to ensure that the latest version of pip is used within the virtual environment.
    pip install --upgrade pip

    # Install the Python packages listed in requirements.
    pip install -r requirements.txt

    # Optionally run a script automatically, e.g., greeting.py
    python greeting.py
  '';

import os # Provides functions for interacting with the operating system.
from dotenv import load_dotenv # Loads environment variables from a .env file.
from newsapi import NewsApiClient # A client library for the News API that fetches top headlines.
from rich.console import Console # Provides advanced console output capabilities, including colors and formatting.

def fetch_headlines():
    """
    Fetches the latest headlines from the News API and prints them.
    """
    # Initialize Rich Console for colorful output
    console = Console()

    # Load environment variables from .env file
    load_dotenv()
    # Reads the NEWS_API key from .env
    # If your environment variables contain sensitive data,...
    # avoid committing .env or shell.nix with real credentials to public repositories.
    api_key = os.getenv("NEWS_API_KEY")

    # Check if API key is available
    if not api_key:
        console.print("[red]Error:[/red] NEWS_API_KEY is not set.")
        return

    # Initialize NewsApiClient with the API key
    newsapi = NewsApiClient(api_key=api_key)

    # Retrieves the top headlines for the specified country, e.g., 'us' for the United States.
    top_headlines = newsapi.get_top_headlines(country='us')

    # Check if the request was successful
    if top_headlines['status'] == 'ok':
        articles = top_headlines['articles']
        # Extract and print the title of the first 10 headlines...
        # using Rich's console printing capabilities to add color formatting.
        print("Latest 10 Headlines:")
        for i, article in enumerate(articles, start=1):
            console.print(str(i) + ". [yellow]" + article['title'] + "[/yellow]. ")
    else: # Handle error
        print("Failed to fetch headlines:", top_headlines['message'])

# Main Execution Block
if __name__ == "__main__":
    # Ensures that fetch_headlines is called only when the script is run directly.
    fetch_headlines()

# Import the Nixpkgs package set, which contains a wide range of packages.
# This allows us to use the packages defined in Nixpkgs in our shell.
{ pkgs ? import  {} }:
with (import  {});

# Create a shell environment with specified packages and configuration.
mkShell {
  # List of packages to be included in the development environment.
  buildInputs = [
    cowsay    # Generates ASCII art with messages
    ripgrep   # A fast command-line search tool, faster than grep
    bat       # An enhanced version of 'cat', which includes syntax highlighting
    eza       # A modern alternative to 'ls' with more features
    htop      # An interactive process viewer and manager
    neofetch  # A tool to display system information in a visually appealing way
    figlet    # Converts text to ASCII art using various fonts
    lolcat    # A program to colorize text output with rainbow colors
    fortune   # Displays a random quote or saying
    feh       # A lightweight image viewer for X11
    gedit     # A simple and user-friendly text editor
    cmatrix   # A fun screensaver that displays a scrolling "Matrix" effect
    curl      # A command-line tool for transferring data with URLs
  ];

  # Shell hook that runs commands automatically when entering the shell.
  shellHook = ''
    # Use `figlet` to create a large ASCII art greeting and color it with `lolcat`.
    echo "Welcome master" | figlet | lolcat
    # Display system information using `neofetch`.
    neofetch
    # Show a random quote or saying using `fortune` piped into cowsay so an ASCCI cow says it.
    fortune | cowsay

	  # Fetch the current weather for Malaga using curl and handle potential errors.
    # The -s flag makes curl operate in silent mode (no progress output).
    weather=$(${curl}/bin/curl -s 'wttr.in/Malaga?format=3')
    if [ $? -eq 0 ]; then
      echo "Weather in Malaga: $weather"
    else
      echo "Failed to fetch weather information"
    fi

    # Get the current date and time in the specified format.
    dt=$(date '+%d/%m/%Y %H:%M:%S');
    # Print the current date and time.
    echo "$dt"

	  # Display the current month's calendar.
    cal
  '';
}