//! Run this example with --feature convert_sigils

extern crate weave;
extern crate alchemy;
extern crate sigils;



use weave::Error;

use alchemy::F64_BYTES;
use alchemy::{Endianess, Transmutable};

use sigils::quaternion::Quaternion;



/// The size of 4 f64 Real numbers.
/// This would be different if the contained type
/// was something different, like an f32.
const SIZE_OF_QUATERNION: usize = F64_BYTES * 4; 



/// This just help pretty up the printing of an array of bytes.
fn stringify_array(buffer: &[u8]) -> String
{
   let mut result: String;
   let mut count: usize;

   // Create a new string that starts with just
   // the array opening bracket.
   result = String::new();
   result.push_str("[");

   // Loop through the buffer keeping track
   // of our place in it.
   count = 0usize;
   for byte in buffer
   {
      // Handle priting the last value differently.
      if count >= buffer.len() - 1
      {
         result.push_str(byte.to_string().as_str());
      }
      else
      {
         result.push_str(byte.to_string().as_str());
         result.push_str(", ");
      }

      // Mark that we are going to look at
      // the next byte in the array.
      count += 1;
   }

   // Add the array closing bracket and
   // return the new String.
   result.push_str("]");
   result
}


pub fn main()
{
   let quat: Quaternion<f64>;
   let endianess: Endianess;
   let mut buffer: Vec<u8>;

   // Initialize the variables.
   quat = Quaternion::<f64>::from_values(6.29f64, 1.9f64, 8.5f64, 7.11f64);
   buffer = Vec::with_capacity(SIZE_OF_QUATERNION);
   endianess = Endianess::Platform;

   println!("Transmuting a Quaternion:");

   println!("Converting the value {} into and out of an array of bytes.",
            quat);
   println!("Buffer starts as: {}", stringify_array(buffer.as_slice()));

   // Convert the Vector2 into an array of bytes.
   buffer = quat.as_endian_bytes(endianess);

   println!("Buffer contains: {}", stringify_array(buffer.as_slice()));

   // Convert the array of bytes into a Vector2.
   match Quaternion::<f64>::from_endian_bytes(buffer.as_slice(), endianess)
   {
      Ok(final_quat) =>
      {
         println!("The buffer converts back to: {}", final_quat);
      }

      Err(error) =>
      {
         println!("{}\n{}", error, error.get_description());
      }
   }
}