//! Provides a simple aspect ratio struct to help with calculations.

use crate::Vec2;
use thiserror::Error;

#[cfg(feature = "bevy_reflect")]
use bevy_reflect::Reflect;

/// An `AspectRatio` is the ratio of width to height.
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
#[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug, PartialEq))]
pub struct AspectRatio(f32);

impl AspectRatio {
    /// Standard 16:9 aspect ratio
    pub const SIXTEEN_NINE: Self = Self(16.0 / 9.0);
    /// Standard 4:3 aspect ratio
    pub const FOUR_THREE: Self = Self(4.0 / 3.0);
    /// Standard 21:9 ultrawide aspect ratio
    pub const ULTRAWIDE: Self = Self(21.0 / 9.0);

    /// Attempts to create a new [`AspectRatio`] from a given width and height.
    ///
    /// # Errors
    ///
    /// Returns an `Err` with `AspectRatioError` if:
    /// - Either width or height is zero (`AspectRatioError::Zero`)
    /// - Either width or height is infinite (`AspectRatioError::Infinite`)
    /// - Either width or height is NaN (`AspectRatioError::NaN`)
    #[inline]
    pub fn try_new(width: f32, height: f32) -> Result<Self, AspectRatioError> {
        match (width, height) {
            (w, h) if w == 0.0 || h == 0.0 => Err(AspectRatioError::Zero),
            (w, h) if w.is_infinite() || h.is_infinite() => Err(AspectRatioError::Infinite),
            (w, h) if w.is_nan() || h.is_nan() => Err(AspectRatioError::NaN),
            _ => Ok(Self(width / height)),
        }
    }

    /// Attempts to create a new [`AspectRatio`] from a given amount of x pixels and y pixels.
    #[inline]
    pub fn try_from_pixels(x: u32, y: u32) -> Result<Self, AspectRatioError> {
        Self::try_new(x as f32, y as f32)
    }

    /// Returns the aspect ratio as a f32 value.
    #[inline]
    pub fn ratio(&self) -> f32 {
        self.0
    }

    /// Returns the inverse of this aspect ratio (height/width).
    #[inline]
    pub fn inverse(&self) -> Self {
        Self(1.0 / self.0)
    }

    /// Returns true if the aspect ratio represents a landscape orientation.
    #[inline]
    pub fn is_landscape(&self) -> bool {
        self.0 > 1.0
    }

    /// Returns true if the aspect ratio represents a portrait orientation.
    #[inline]
    pub fn is_portrait(&self) -> bool {
        self.0 < 1.0
    }

    /// Returns true if the aspect ratio is exactly square.
    #[inline]
    pub fn is_square(&self) -> bool {
        self.0 == 1.0
    }
}

impl TryFrom<Vec2> for AspectRatio {
    type Error = AspectRatioError;

    #[inline]
    fn try_from(value: Vec2) -> Result<Self, Self::Error> {
        Self::try_new(value.x, value.y)
    }
}

impl From<AspectRatio> for f32 {
    #[inline]
    fn from(aspect_ratio: AspectRatio) -> Self {
        aspect_ratio.0
    }
}

/// An Error type for when [`super::AspectRatio`] is provided invalid width or height values
#[derive(Error, Debug, PartialEq, Eq, Clone, Copy)]
pub enum AspectRatioError {
    /// Error due to width or height having zero as a value.
    #[error("AspectRatio error: width or height is zero")]
    Zero,
    /// Error due towidth or height being infinite.
    #[error("AspectRatio error: width or height is infinite")]
    Infinite,
    /// Error due to width or height being Not a Number (NaN).
    #[error("AspectRatio error: width or height is NaN")]
    NaN,
}