use std::any::Any;

use tracing::Level;

use crate::{DType, Primitive, Tensor};

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Negative;

impl Primitive for Negative {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        -tangent_x
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, _primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let cotangent_x = -cotangent;
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Sin;
impl Primitive for Sin {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        x.cos() * tangent_x
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * x.cos();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Cos;
impl Primitive for Cos {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        -x.sin() * tangent_x
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * -x.sin();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Square;
impl Primitive for Square {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        x * 2.0 * tangent_x
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * x * 2.0;
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Sqrt;

impl Primitive for Sqrt {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x * 0.5 / x.sqrt()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * 0.5 / x.sqrt();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Rsqrt;

impl Primitive for Rsqrt {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        -0.5 * tangent_x * (x.rsqrt() / x)
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = -0.5 * cotangent * (x.rsqrt() / x);
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Sign;

impl Primitive for Sign {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], _tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        x.zeros_like()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], _cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = x.zeros_like();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Abs;

impl Primitive for Abs {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x * x.sign()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * x.sign();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Exp;

impl Primitive for Exp {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x * x.exp()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent * x.exp();
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Log;

impl Primitive for Log {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x / x
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent / x;
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Log2;

impl Primitive for Log2 {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x / (x * f32::ln(2.0))
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent / (x * f32::ln(2.0));
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Log10;

impl Primitive for Log10 {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let x = &primals[0];
        let tangent_x = &tangents[0];
        tangent_x / (x * f32::ln(10.0))
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent / (x * f32::ln(10.0));
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct AsType {
    pub dtype: DType,
}
impl AsType {
    pub fn new(dtype: DType) -> Self {
        Self { dtype }
    }
}

impl Primitive for AsType {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn dot_label(&self) -> String {
        format!("AsType({:?})", &self.dtype)
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, _output: &Tensor, primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        tangent_x.as_type(self.dtype)
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, _output: &Tensor, primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let x = &primals[0];
        let cotangent_x = cotangent.as_type(x.dtype());
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Softmax {
    pub dim: usize,
}

impl Softmax {
    pub fn new(dim: usize) -> Self {
        Self { dim }
    }
}

impl Primitive for Softmax {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn dot_label(&self) -> String {
        format!("Softmax({:?})", &self.dim)
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        let sv = &(output * tangent_x);
        sv - output * sv.sum((self.dim, true))
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, output: &Tensor, _primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let sv = &(output * cotangent);
        let cotangent_x = sv - output * sv.sum((self.dim, true));
        vec![cotangent_x]
    }
}

#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct LogSoftmax {
    pub dim: usize,
}

impl LogSoftmax {
    pub fn new(dim: usize) -> Self {
        Self { dim }
    }
}

impl Primitive for LogSoftmax {
    fn clone_boxed(&self) -> Box<dyn Primitive> {
        Box::new(self.clone())
    }

    fn dot_label(&self) -> String {
        format!("LogSoftmax({:?})", &self.dim)
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn jvp(&self, output: &Tensor, _primals: &[Tensor], tangents: &[Tensor]) -> Tensor {
        let tangent_x = &tangents[0];
        tangent_x - tangent_x.sum((self.dim, true)) * output.exp()
    }

    #[tracing::instrument(ret(level = Level::TRACE))]
    fn vjp(&self, output: &Tensor, _primals: &[Tensor], cotangent: &Tensor) -> Vec<Tensor> {
        let cotangent_x = cotangent - cotangent.sum((self.dim, true)) * output.exp();
        vec![cotangent_x]
    }
}