use super::matrix::{F16x1, F16x16};
use aarch64_cpu::asm::barrier;
use core::panic;
use core::{arch::asm, cell::RefCell};
use half::f16;
use nalgebra::{Const, Dyn, RawStorage, RawStorageMut, SMatrix, Storage};

// const NUMBER_OF_BANKS: usize = 32;
const EVEN_BANK_INDEX: usize = 0;
const ODD_BANK_INDEX: usize = 8;

#[derive(Clone, Debug)]
#[repr(C, align(1024))]
pub struct PimMatrixArena<const R: usize, const C: usize>(pub [[F16x16; R]; C]);

#[derive(Debug)]
pub struct PimStorage<'a, const R: usize, const C: usize> {
    pub arena: &'a RefCell<PimMatrixArena<R, C>>,
    pub index: usize,
}

unsafe impl<'a, const R: usize, const C: usize> RawStorage<F16x1, Const<R>, Const<C>>
    for PimStorage<'a, R, C>
{
    type RStride = Dyn;
    type CStride = Dyn;

    fn ptr(&self) -> *const F16x1 {
        unsafe {
            (&self.arena.borrow().0[0][0] as *const F16x16 as *const F16x1).offset(self.index as _)
        }
    }

    fn shape(&self) -> (Const<R>, Const<C>) {
        (Const::<R>, Const::<C>)
    }

    fn strides(&self) -> (Self::RStride, Self::CStride) {
        (Dyn(16), Dyn(16 * R))
    }

    fn is_contiguous(&self) -> bool {
        false
    }

    unsafe fn as_slice_unchecked(&self) -> &[F16x1] {
        panic!("PimStorage is not contiguous!");
    }
}

unsafe impl<'a, const R: usize, const C: usize> RawStorageMut<F16x1, Const<R>, Const<C>>
    for PimStorage<'a, R, C>
{
    fn ptr_mut(&mut self) -> *mut F16x1 {
        unsafe {
            (&mut self.arena.borrow_mut().0[0][0] as *mut F16x16 as *mut F16x1)
                .offset(self.index as _)
        }
    }

    unsafe fn as_mut_slice_unchecked(&mut self) -> &mut [F16x1] {
        panic!("PimStorage is not contiguous!");
    }
}

// #[repr(C, align(1024))]
// #[derive(Clone, Debug, Default)]
// pub struct PimMatrix(pub SMatrix<f166, 8, 8>);

// impl PimRegion for PimMatrix {
//     const NUMBER_OF_BANKS: usize = 64;

//     fn bank_ptr(&self, bank_index: usize) -> *const f16 {
//         return &self.0[bank_index].0 as _;
//     }

//     fn bank_ptr_mut(&mut self, bank_index: usize) -> *mut f16 {
//         return &mut self.0[bank_index].0 as _;
//     }
// }

pub trait PimRegion {
    const NUMBER_OF_BANKS: usize;

    fn bank_ptr(&self, bank_index: usize) -> *const f16;
    fn bank_ptr_mut(&mut self, bank_index: usize) -> *mut f16;

    fn execute_instruction_read_single_bank(&self) {
        if !cfg!(feature = "cacheless") {
            self.invalidate_bank(EVEN_BANK_INDEX);

            barrier::dsb(barrier::SY);
        }

        // Read from first bank
        self.read_data_bank(EVEN_BANK_INDEX);

        barrier::dsb(barrier::SY);
    }

    fn execute_instruction_read_dual_bank(&self) {
        if !cfg!(feature = "cacheless") {
            self.invalidate_bank(EVEN_BANK_INDEX);
            self.invalidate_bank(ODD_BANK_INDEX);

            barrier::dsb(barrier::SY);
        }

        // Read from first and second bank
        self.read_data_bank(EVEN_BANK_INDEX);
        self.read_data_bank(ODD_BANK_INDEX);

        barrier::dsb(barrier::SY);
    }

    fn read_data_bank(&self, bank_index: usize) {
        let bank = self.bank_ptr(bank_index);
        unsafe {
            core::ptr::read_volatile(bank);
        }
    }

    fn execute_instruction_write_single_bank(&mut self) {
        if !cfg!(feature = "cacheless") {
            self.preload_zero();
            barrier::dsb(barrier::SY);
        }

        // Write to first bank
        self.write_data_bank(EVEN_BANK_INDEX);

        if !cfg!(feature = "cacheless") {
            self.invalidate_flush_bank(EVEN_BANK_INDEX);
        }

        barrier::dsb(barrier::SY);
    }

    fn execute_instruction_write_dual_bank(&mut self) {
        if !cfg!(feature = "cacheless") {
            self.preload_zero();
            barrier::dsb(barrier::SY);
        }

        // Write to first and second bank
        self.write_data_bank(EVEN_BANK_INDEX);
        self.write_data_bank(ODD_BANK_INDEX);

        if !cfg!(feature = "cacheless") {
            self.invalidate_flush_bank(EVEN_BANK_INDEX);
            self.invalidate_flush_bank(ODD_BANK_INDEX);
        }

        barrier::dsb(barrier::SY);
    }

    fn write_data_bank(&mut self, bank_index: usize) {
        let bank = self.bank_ptr_mut(bank_index);
        unsafe {
            core::ptr::write_volatile(bank, Default::default());
        }
    }

    fn invalidate(&self) {
        (0..Self::NUMBER_OF_BANKS).for_each(|idx| self.invalidate_bank(idx));
    }

    fn invalidate_bank(&self, bank_index: usize) {
        let bank = self.bank_ptr(bank_index);
        unsafe {
            asm!("dc ivac, {val}", val = in(reg) bank);
        }
    }

    fn invalidate_flush(&self) {
        (0..Self::NUMBER_OF_BANKS).for_each(|idx| self.invalidate_flush_bank(idx));
    }

    fn invalidate_flush_bank(&self, bank_index: usize) {
        let bank = self.bank_ptr(bank_index);
        unsafe {
            asm!("dc civac, {val}", val = in(reg) bank);
        }
    }

    fn preload_zero(&self) {
        (0..Self::NUMBER_OF_BANKS).for_each(|idx| self.preload_zero_bank(idx));
    }

    fn preload_zero_bank(&self, bank_index: usize) {
        let bank = self.bank_ptr(bank_index);
        unsafe {
            // Preload first bank
            asm!("dc zva, {val}", val = in(reg) bank);
        }
    }
}

#[derive(Clone, Debug)]
#[repr(C, align(65536))]
pub struct ComputeArray<T: PimRegion, const N: usize>(pub [T; N]);

impl<T: PimRegion, const N: usize> ComputeArray<T, N> {
    pub fn invalidate_flush(&self) {
        self.0
            .iter()
            .for_each(|bank_array| bank_array.invalidate_flush());
    }

    pub fn invalidate(&self) {
        self.0.iter().for_each(|bank_array| bank_array.invalidate());
    }
}

impl<T: PimRegion + Default, const N: usize> Default for ComputeArray<T, N> {
    fn default() -> Self {
        Self(core::array::from_fn(|_| Default::default()))
    }
}