use crate::{heap_drop, heap_move, heap_move_nonnull, ByteSlice};
use servicepoint::{Cp437Grid, DataRef, Grid};
use std::ptr::NonNull;

/// Creates a new [Cp437Grid] with the specified dimensions.
///
/// returns: [Cp437Grid] initialized to 0.
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_new(
    width: usize,
    height: usize,
) -> NonNull<Cp437Grid> {
    heap_move_nonnull(Cp437Grid::new(width, height))
}

/// Loads a [Cp437Grid] with the specified dimensions from the provided data.
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_load(
    width: usize,
    height: usize,
    data: ByteSlice,
) -> *mut Cp437Grid {
    let data = unsafe { data.as_slice() };
    let grid = Cp437Grid::load(width, height, data);
    if let Some(grid) = grid {
        heap_move(grid)
    } else {
        std::ptr::null_mut()
    }
}

/// Clones a [Cp437Grid].
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_clone(
    cp437_grid: NonNull<Cp437Grid>,
) -> NonNull<Cp437Grid> {
    heap_move_nonnull(unsafe { cp437_grid.as_ref().clone() })
}

/// Deallocates a [Cp437Grid].
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_free(cp437_grid: NonNull<Cp437Grid>) {
    unsafe { heap_drop(cp437_grid) }
}

/// Gets the current value at the specified position.
///
/// # Arguments
///
/// - `cp437_grid`: instance to read from
/// - `x` and `y`: position of the cell to read
///
/// # Panics
///
/// - when accessing `x` or `y` out of bounds
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_get(
    cp437_grid: NonNull<Cp437Grid>,
    x: usize,
    y: usize,
) -> u8 {
    unsafe { cp437_grid.as_ref().get(x, y) }
}

/// Sets the value of the specified position in the [Cp437Grid].
///
/// # Arguments
///
/// - `cp437_grid`: instance to write to
/// - `x` and `y`: position of the cell
/// - `value`: the value to write to the cell
///
/// returns: old value of the cell
///
/// # Panics
///
/// - when accessing `x` or `y` out of bounds
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_set(
    cp437_grid: NonNull<Cp437Grid>,
    x: usize,
    y: usize,
    value: u8,
) {
    unsafe { (*cp437_grid.as_ptr()).set(x, y, value) };
}

/// Sets the value of all cells in the [Cp437Grid].
///
/// # Arguments
///
/// - `cp437_grid`: instance to write to
/// - `value`: the value to set all cells to
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_fill(
    cp437_grid: NonNull<Cp437Grid>,
    value: u8,
) {
    unsafe { (*cp437_grid.as_ptr()).fill(value) };
}

/// Gets the width of the [Cp437Grid] instance.
///
/// # Arguments
///
/// - `cp437_grid`: instance to read from
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_width(
    cp437_grid: NonNull<Cp437Grid>,
) -> usize {
    unsafe { cp437_grid.as_ref().width() }
}

/// Gets the height of the [Cp437Grid] instance.
///
/// # Arguments
///
/// - `cp437_grid`: instance to read from
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_height(
    cp437_grid: NonNull<Cp437Grid>,
) -> usize {
    unsafe { cp437_grid.as_ref().height() }
}

/// Gets an unsafe reference to the data of the [Cp437Grid] instance.
///
/// The returned memory is valid for the lifetime of the grid.
#[no_mangle]
pub unsafe extern "C" fn sp_cp437_grid_unsafe_data_ref(
    cp437_grid: NonNull<Cp437Grid>,
) -> ByteSlice {
    unsafe { ByteSlice::from_slice((*cp437_grid.as_ptr()).data_ref_mut()) }
}