//! # Enkou
#![no_std]
#![deny(missing_docs)]
#![allow(clippy::needless_range_loop)] // SPIR-V backend has issues with iteration over items

pub mod camera;
pub mod chaos_game;
mod rng;
pub mod transform;
pub mod variation;

use glam::Affine2;

/// Utility trait to convert between `flam3` notation and [`glam`].
#[allow(missing_docs)]
pub trait Coefficients2 {
    /// Convert affine transformation coefficients to the [`glam`] representation.
    /// Parameters use the following form:
    ///
    /// ```text
    /// (a * x + b * y + c, d * x + e * y + f)
    /// ```
    ///
    /// ```
    /// # use glam::{Affine2, vec2};
    /// # use crate::enkou_shaders::Coefficients2;
    /// let coefs = Affine2::from_coefficients(1.0, 2.0, 3.0, 4.0, 5.0, 6.0);
    /// let (x, y) = (7.0, 8.0);
    /// assert_eq!(
    ///     coefs.transform_point2(vec2(x, y)),
    ///     vec2(
    ///         coefs.a() * x + coefs.b() * y + coefs.c(),
    ///         coefs.d() * x + coefs.e() * y + coefs.f()
    ///     )
    /// );
    /// ```
    fn from_coefficients(a: f32, b: f32, c: f32, d: f32, e: f32, f: f32) -> Affine2;

    /// Convert affine transformation coefficients to the [`glam`] representation.
    /// Parameters use the following form:
    ///
    /// ```text
    /// (a * x + b * y + c, d * x + e * y + f)
    /// ```
    ///
    /// ```
    /// # use glam::{Affine2, vec2};
    /// # use crate::enkou_shaders::Coefficients2;
    /// let coefs = Affine2::from_coefficients_arr([1.0, 2.0, 3.0, 4.0, 5.0, 6.0]);
    /// let (x, y) = (7.0, 8.0);
    /// assert_eq!(
    ///     coefs.transform_point2(vec2(x, y)),
    ///     vec2(
    ///         coefs.a() * x + coefs.b() * y + coefs.c(),
    ///         coefs.d() * x + coefs.e() * y + coefs.f()
    ///     )
    /// );
    /// ```
    fn from_coefficients_arr(coefficients: [f32; 6]) -> Affine2;

    fn a(&self) -> f32;
    fn b(&self) -> f32;
    fn c(&self) -> f32;
    fn d(&self) -> f32;
    fn e(&self) -> f32;
    fn f(&self) -> f32;
}

impl Coefficients2 for Affine2 {
    #[inline]
    fn from_coefficients(a: f32, b: f32, c: f32, d: f32, e: f32, f: f32) -> Affine2 {
        Affine2::from_cols_array(&[a, d, b, e, c, f])
    }

    #[inline]
    fn from_coefficients_arr(coefficients: [f32; 6]) -> Affine2 {
        Affine2::from_coefficients(
            coefficients[0],
            coefficients[1],
            coefficients[2],
            coefficients[3],
            coefficients[4],
            coefficients[5],
        )
    }

    fn a(&self) -> f32 {
        self.matrix2.x_axis.x
    }

    fn b(&self) -> f32 {
        self.matrix2.y_axis.x
    }

    fn c(&self) -> f32 {
        self.translation.x
    }

    fn d(&self) -> f32 {
        self.matrix2.x_axis.y
    }

    fn e(&self) -> f32 {
        self.matrix2.y_axis.y
    }

    fn f(&self) -> f32 {
        self.translation.y
    }
}