use crate::utils::ordered_float::F32;

#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum Eotf {
    Linear,
    St2084Pq,
    Bt1886(F32),
    Gamma22,
    Gamma24,
    Gamma28,
    St240,
    Log100,
    Log316,
    St428,
    Pow(EotfPow),
    CompoundPower24,
}

const MUL: u32 = 10_000;
const MUL_F32: f32 = MUL as f32;

#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub struct EotfPow(pub u32);

impl EotfPow {
    pub const MIN: Self = Self(10_000);
    pub const LINEAR: Self = Self(10_000);
    pub const GAMMA22: Self = Self(22_000);
    pub const GAMMA24: Self = Self(24_000);
    pub const GAMMA28: Self = Self(28_000);
    pub const MAX: Self = Self(100_000);

    pub fn eotf_f32(self) -> f32 {
        self.0 as f32 / MUL_F32
    }

    pub fn inv_eotf_f32(self) -> f32 {
        MUL_F32 / self.0 as f32
    }
}

pub fn bt1886_eotf_args(c: F32) -> [f32; 4] {
    let c = c.0;
    let gamma = 1.0 / 2.4;
    let a1 = 1.0 / (1.0 - c);
    let a2 = 1.0 - c.powf(gamma);
    let a3 = c.powf(gamma);
    let a4 = c;
    [a1, a2, a3, a4]
}

pub fn bt1886_inv_eotf_args(c: F32) -> [f32; 4] {
    let c = c.0;
    let gamma = 1.0 / 2.4;
    let a1 = 1.0 / (1.0 - c.powf(gamma));
    let a2 = 1.0 - c;
    let a3 = c;
    let a4 = c.powf(gamma);
    [a1, a2, a3, a4]
}