use librashader_common::{FilterMode, Size, WrapMode};
use windows::Win32::Graphics::Direct3D11::{ID3D11Device, ID3D11SamplerState, ID3D11ShaderResourceView, ID3D11Texture2D, D3D11_BIND_RENDER_TARGET, D3D11_BIND_SHADER_RESOURCE, D3D11_CPU_ACCESS_FLAG, D3D11_CPU_ACCESS_WRITE, D3D11_FORMAT_SUPPORT_RENDER_TARGET, D3D11_FORMAT_SUPPORT_SHADER_SAMPLE, D3D11_FORMAT_SUPPORT_TEXTURE2D, D3D11_RESOURCE_MISC_GENERATE_MIPS, D3D11_TEXTURE2D_DESC, D3D11_USAGE_DYNAMIC, D3D11_SHADER_RESOURCE_VIEW_DESC, D3D11_SHADER_RESOURCE_VIEW_DESC_0, D3D11_TEX2D_SRV, D3D11_BIND_FLAG, D3D11_RESOURCE_MISC_FLAG, D3D11_USAGE_STAGING, ID3D11DeviceContext, D3D11_SUBRESOURCE_DATA, D3D11_MAP_WRITE, D3D11_BOX};
use windows::Win32::Graphics::Direct3D::D3D_SRV_DIMENSION_TEXTURE2D;
use windows::Win32::Graphics::Dxgi::Common::DXGI_SAMPLE_DESC;
use librashader_common::image::Image;
use crate::util::d3d11_get_closest_format;
use crate::util::Result;

#[derive(Debug, Clone)]
pub struct DxImageView {
    pub handle: ID3D11ShaderResourceView,
    pub size: Size<u32>, // pub image: GlImage,
}
#[derive(Debug, Clone)]
pub struct Texture {
    pub view: DxImageView,
    pub filter: FilterMode,
    pub wrap_mode: WrapMode,
    // pub mip_filter: FilterMode,
    // pub wrap_mode: WrapMode,
}

#[derive(Debug, Clone)]
pub struct OwnedTexture {
    pub handle: ID3D11Texture2D,
    // pub staging: ID3D11Texture2D,
    pub desc: D3D11_TEXTURE2D_DESC,
    pub image: Texture,
}

impl OwnedTexture {
    pub fn new(device: &ID3D11Device, source: &Image, desc: D3D11_TEXTURE2D_DESC, filter: FilterMode, wrap_mode: WrapMode) -> Result<OwnedTexture> {
        let mut desc = D3D11_TEXTURE2D_DESC {
            Width: source.size.width,
            Height: source.size.height,
            // todo: set this to 0
            MipLevels: if (desc.MiscFlags & D3D11_RESOURCE_MISC_GENERATE_MIPS).0 != 0 {
                0
            } else {
                1
            },
            ArraySize: 1,
            SampleDesc: DXGI_SAMPLE_DESC {
                Count: 1,
                Quality: 0,
            },
            CPUAccessFlags: if desc.Usage == D3D11_USAGE_DYNAMIC {
                D3D11_CPU_ACCESS_WRITE
            } else {
                D3D11_CPU_ACCESS_FLAG(0)
            },
            ..desc
        };
        desc.BindFlags |= D3D11_BIND_SHADER_RESOURCE;

        // determine number of mipmaps required
        if (desc.MiscFlags & D3D11_RESOURCE_MISC_GENERATE_MIPS).0 != 0 {
            let mut width = desc.Width >> 5;
            let mut height = desc.Height >> 5;
            desc.BindFlags |= D3D11_BIND_RENDER_TARGET;

            while width != 0 && height != 0 {
                width >>= 1;
                height >>= 1;
                desc.MipLevels += 1;
            }
        }

        // determine if format is supported.
        // bruh why does  D3D11_FORMAT_SUPPORT not implement bitor???
        let mut format_support =
            D3D11_FORMAT_SUPPORT_TEXTURE2D.0 | D3D11_FORMAT_SUPPORT_SHADER_SAMPLE.0;
        if (desc.BindFlags & D3D11_BIND_RENDER_TARGET).0 != 0 {
            format_support |= D3D11_FORMAT_SUPPORT_RENDER_TARGET.0;
        }

        // eprintln!("s {:?}, p {:?}, l {:?}", source.size, source.pitch, source.bytes.len());
        // eprintln!("{:#?}", desc);

        unsafe {
            let handle = device.CreateTexture2D(&desc, None).unwrap();

            let srv = device.CreateShaderResourceView(&handle, Some(&D3D11_SHADER_RESOURCE_VIEW_DESC {
                Format: desc.Format,
                ViewDimension: D3D_SRV_DIMENSION_TEXTURE2D,
                Anonymous: D3D11_SHADER_RESOURCE_VIEW_DESC_0 {
                    Texture2D: D3D11_TEX2D_SRV {
                        MostDetailedMip: 0,
                        MipLevels: u32::MAX
                    }
                },
            }))?;


            let mut context = None;
            device.GetImmediateContext(&mut context);

            // todo: make this fallible
            let context = context.unwrap();

            // need a staging texture to defer mipmap generation
            let staging = device.CreateTexture2D(&D3D11_TEXTURE2D_DESC {
                MipLevels: 1,
                BindFlags: D3D11_BIND_FLAG(0),
                MiscFlags: D3D11_RESOURCE_MISC_FLAG(0),
                Usage: D3D11_USAGE_STAGING,
                CPUAccessFlags: D3D11_CPU_ACCESS_WRITE,
                ..desc
            }, Some(&D3D11_SUBRESOURCE_DATA {
                pSysMem: source.bytes.as_ptr().cast(),
                SysMemPitch: source.pitch as u32,
                SysMemSlicePitch: 0
            }))?;

            // todo: do format conversion (leverage image crate..?
            // is this necessary with CopySubresourceRegion)...

            context.CopySubresourceRegion(&handle, 0, 0, 0, 0,
            &staging, 0, Some(&D3D11_BOX {
                    left: 0,
                    top: 0,
                    front: 0,
                    right: source.size.width,
                    bottom: source.size.height,
                    back: 1,
                }));

            if (desc.MiscFlags & D3D11_RESOURCE_MISC_GENERATE_MIPS).0 != 0 {
               context.GenerateMips(&srv)
            }

            // let mut subresource = context.Map(staging, 0, D3D11_MAP_WRITE, 0)?;
            // staging.Upd



            Ok(OwnedTexture {
                handle,
                // staging,
                desc,
                image: Texture {
                    view: DxImageView {
                        handle: srv,
                        size: source.size,
                    },
                    filter,
                    wrap_mode
                }
            })
        }
    }
}