use crate::vertex_2d::{ColoredVertex2D, Vertex2D};
use vulkano::command_buffer::{AutoCommandBufferBuilder, DynamicState};
use std::collections::HashMap;
use vulkano::buffer::{BufferAccess, BufferUsage, ImmutableBuffer, CpuAccessibleBuffer};
use std::sync::Arc;
use vulkano::format::{ClearValue, Format};
use vulkano::framebuffer::{FramebufferAbstract, Framebuffer, RenderPass, RenderPassAbstract};
use vulkano::device::{Device, Queue};
use vulkano::instance::PhysicalDevice;
use vulkano::image::immutable::ImmutableImage;
use vulkano::image::{Dimensions, ImageAccess, ImageDimensions, SwapchainImage, ImageUsage, AttachmentImage};
use vulkano::sampler::{Sampler, SamplerAddressMode, MipmapMode, Filter};
use vulkano::descriptor::DescriptorSet;
use vulkano::descriptor::descriptor_set::PersistentDescriptorSet;
use std::path::PathBuf;
use image::GenericImageView;
use std::iter::FromIterator;
use vulkano::swapchain::Capabilities;
use winit::Window;
use vulkano::pipeline::viewport::Viewport;
use vulkano::descriptor::descriptor::DescriptorDescTy::TexelBuffer;
use crate::canvas_frame::CanvasFrame;
use std::hash::Hash;
use crate::canvas_shader::{CanvasShader, CanvasShaderHandle};
use crate::canvas_buffer::{CanvasImage, CanvasTexture};

/// Vertex trait for Drawable Vertices.
pub trait Vertex {
    fn position(&self) -> (f32, f32) {
        (0.0, 0.0)
    }
    fn color(&self) -> Option<(f32, f32, f32, f32)> {
        Some((0., 0., 0., 0.))
    }
}

impl Vertex for ColoredVertex2D {
    fn position(&self) -> (f32, f32) {
        (0.0, 0.0)
    }

    fn color(&self) -> Option<(f32, f32, f32, f32)> {
        Some((0., 0., 0., 0.))
    }
}

/// A drawable object can be passed into a CanvasFrame to be rendered
/// Allows Texture or Image drawing via their handles
pub trait Drawable {
    fn get_vertices(&self) -> Vec<(f32, f32)>;
    fn get_color(&self) -> (f32, f32, f32, f32);
    fn get_texture_handle(&self) -> Option<Arc<CanvasTextureHandle>>;
    fn get_image_handle(&self) -> Option<Arc<CanvasImageHandle>>;
}

/// Legacy ShaderType enum for single type shaders.
#[derive(PartialEq, Eq, Hash, Clone)]
pub enum ShaderType {
    SOLID = 0,
    TEXTURED = 1,
    IMAGE = 2,
}

/// Typed wrapper for a u32 texture handle (index id)
#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
pub struct CanvasTextureHandle {
    pub handle: u32
}

/// Typed wrapper for a u32 image handle (index id)
#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
pub struct CanvasImageHandle {
    pub handle: u32
}

/// Canvas state is used for storage of texture and image buffers in addition to vertex buffers
/// Canvas state also contains logic for writing the stored buffers to the command_buffer
#[derive(Clone)]
pub struct CanvasState {

    /// Generated during new()
    dynamic_state: DynamicState,
    /// Generated during new()
    sampler: Arc<Sampler>,

    // hold the image, texture, and shader buffers the same was as we do CompuState
    image_buffers: Vec<Arc<CanvasImage>>,
    texture_buffers: Vec<Arc<CanvasTexture>>,
    shader_buffers: Vec<Arc<CanvasShader>>,

    // Hold onto the vertices we get from the Compu and Canvas Frames
    // When the run comes around, push the vertices to the GPU
    colored_drawables: Vec<ColoredVertex2D>,
    colored_vertex_buffer: Vec<Arc<(dyn BufferAccess + std::marker::Send + std::marker::Sync)>>,

    textured_drawables: HashMap<Arc<CanvasTextureHandle>, Vec<Vec<Vertex2D>>>,
    textured_vertex_buffer: HashMap<Arc<CanvasTextureHandle>, Arc<(dyn BufferAccess + std::marker::Send + std::marker::Sync)>>,

    image_drawables: HashMap<Arc<CanvasImageHandle>, Vec<Vec<Vertex2D>>>,
    image_vertex_buffer: HashMap<Arc<CanvasImageHandle>, Arc<(dyn BufferAccess + std::marker::Send + std::marker::Sync)>>,

    // Looks like we gotta hold onto the queue for managing textures
    queue: Arc<Queue>,
    device: Arc<Device>,
    render_pass: Arc<dyn RenderPassAbstract + Send + Sync>,
}


impl CanvasState {

    /// This method is called once during initialization, then again whenever the window is resized
    pub fn window_size_dependent_setup(&mut self, images: &[Arc<SwapchainImage<Window>>])
                                       -> Vec<Arc<dyn FramebufferAbstract + Send + Sync>> {

        let dimensions = images[0].dimensions();

        self.dynamic_state.viewports =
            Some(vec![Viewport {
                origin: [0.0, 0.0],
                dimensions: [dimensions.width() as f32, dimensions.height() as f32],
                depth_range: 0.0..1.0,
            }]);

        images.iter().map(|image| {
            Arc::new(
                Framebuffer::start(self.render_pass.clone())
                    .add(image.clone()).unwrap()
                    .build().unwrap()
            ) as Arc<dyn FramebufferAbstract + Send + Sync>
        }).collect::<Vec<_>>()
    }

    /// Creates a Canvas State. Which at this point is pretty empty
    pub fn new(queue: Arc<Queue>,
               device: Arc<Device>,
               physical: PhysicalDevice,
               capabilities: Capabilities) -> CanvasState {


        let format = capabilities.supported_formats[0].0;

        let render_pass = Arc::new(vulkano::single_pass_renderpass!(
            device.clone(),

            // Attachments are outgoing like f_color
            attachments: {
                // `color` is a custom name we give to the first and only attachment.
                color: {
                    // `load: Clear` means that we ask the GPU to clear the content of this
                    // attachment at the start of the drawing.
                    load: Clear,
                    // `store: Store` means that we ask the GPU to store the output of the draw
                    // in the actual image. We could also ask it to discard the result.
                    store: Store,
                    // `format: <ty>` indicates the type of the format of the image. This has to
                    // be one of the types of the `vulkano::format` module (or alternatively one
                    // of your structs that implements the `FormatDesc` trait). Here we use the
                    // same format as the swapchain.
                    format: format,
                    // TODO:
                    samples: 1,
                }
            },
            pass: {
                // We use the attachment named `color` as the one and only color attachment.
                color: [color],
                //color: [],
                // No depth-stencil attachment is indicated with empty brackets.
                depth_stencil: {}
            }
        ).unwrap());


        CanvasState {
            dynamic_state: DynamicState { line_width: None, viewports: None, scissors: None },
            sampler: Sampler::new(device.clone(), Filter::Linear, Filter::Linear,
                                  MipmapMode::Nearest, SamplerAddressMode::Repeat, SamplerAddressMode::Repeat,
                                  SamplerAddressMode::Repeat, 0.0, 1.0, 0.0, 0.0).unwrap(),
            image_buffers: vec![],
            texture_buffers: vec![],
            shader_buffers: vec![],

            colored_drawables: vec![],
            colored_vertex_buffer: vec![],
            textured_drawables: HashMap::default(),
            textured_vertex_buffer: Default::default(),
            image_drawables: Default::default(),
            image_vertex_buffer: Default::default(),

            queue: queue.clone(),
            device: device.clone(),
            render_pass: render_pass.clone(),
        }
    }

    /// Using the dimensions and suggested usage, load a CanvasImage and return it's handle
    pub fn create_image(&mut self, dimensions: (u32, u32), usage: ImageUsage) -> Arc<CanvasImageHandle> {
        let handle = Arc::new(CanvasImageHandle { handle: self.image_buffers.len() as u32 });

        let image = CanvasImage {
            handle: handle.clone(),
            buffer: AttachmentImage::with_usage(
                self.device.clone(),
                [dimensions.0, dimensions.1],
                Format::R8G8B8A8Uint,
                usage).unwrap(),
            size: dimensions,
        };

        self.image_buffers.push(Arc::new(image));

        handle
    }

    /// Return the image buffer from an input image handle
    pub fn get_image(&self, image_handle: Arc<CanvasImageHandle>) -> Arc<AttachmentImage> {
        self.image_buffers.get((*image_handle).clone().handle as usize).unwrap()
            .clone().buffer.clone()
    }

    /// Load a texture buffer from an input filename
    fn get_texture_from_file(&self, image_filename: String) -> Arc<ImmutableImage<Format>> {
        let project_root =
            std::env::current_dir()
                .expect("failed to get root directory");

        let mut compute_path = project_root.clone();
        compute_path.push(PathBuf::from("resources/images/"));
        compute_path.push(PathBuf::from(image_filename));

        let img = image::open(compute_path).expect("Couldn't find image");

        let xy = img.dimensions();

        let data_length = xy.0 * xy.1 * 4;
        let pixel_count = img.raw_pixels().len();

        let mut image_buffer = Vec::new();

        if pixel_count != data_length as usize {
            println!("Creating apha channel...");
            for i in img.raw_pixels().iter() {
                if (image_buffer.len() + 1) % 4 == 0 {
                    image_buffer.push(255);
                }
                image_buffer.push(*i);
            }
            image_buffer.push(255);
        } else {
            image_buffer = img.raw_pixels();
        }

        let (texture, tex_future) = ImmutableImage::from_iter(
            image_buffer.iter().cloned(),
            Dimensions::Dim2d { width: xy.0, height: xy.1 },
            Format::R8G8B8A8Srgb,
            self.queue.clone(),
        ).unwrap();

        texture
    }

    /// Load a texture using it's filename from a file. Returns the handle of the loaded texture
    pub fn load_texture(&mut self, filename: String) -> Option<Arc<CanvasTextureHandle>> {
        let texture_buffer = self.get_texture_from_file(filename.clone());

        let handle = Arc::new(CanvasTextureHandle {
            handle: self.texture_buffers.len() as u32
        });

        let texture = Arc::new(CanvasTexture {
            handle: handle.clone(),
            buffer: self.get_texture_from_file(filename.clone()),
            name: filename.clone(),
            size: (0, 0),
        });

        self.texture_buffers.push(texture);

        Some(handle)
    }

    /// Load and Compile a shader with the filename at resources/shaders
    /// Takes physical and capabilities as we don't store that in Canvas
    pub fn load_shader(&mut self,
                       filename: String,
                       physical: PhysicalDevice,
                       capabilities: Capabilities) -> Option<Arc<CanvasShaderHandle>> {

        let handle = Arc::new(CanvasShaderHandle {
            handle: self.shader_buffers.len() as u32
        });

        let shader = Arc::new(CanvasShader::new_colored(
            filename.clone(),
            capabilities.clone(),
            self.queue.clone(),
            physical.clone(),
            self.device.clone(),
            handle.clone(),
            self.render_pass.clone())
        );

        self.shader_buffers.push(shader.clone());

        Some(handle)
    }

    /// Using the texture name, iterates through the stored textures and matches by the name
    pub fn get_texture_handle(&self, texture_name: String)
                              -> Option<Arc<CanvasTextureHandle>> {
        for i in self.texture_buffers.clone() {
            if i.name == texture_name {
                return Some(i.handle.clone());
            }
        }
        None
    }

    /// Using the shader name, iterates through the stored textures and matches by the name
    pub fn get_shader_handle(&self, shader_name: String)
                             -> Option<Arc<CanvasShaderHandle>> {
        for shader in self.shader_buffers.clone() {
            if shader.name == shader_name {
                return Some(shader.handle.clone());
            }
        }
        None
    }

    /// Using the texture handle, grab the stored texture and return the buffer
    pub fn get_texture(&self, texture_handle: Arc<CanvasTextureHandle>)
                       -> Arc<ImmutableImage<Format>> {
        let handle = texture_handle.handle as usize;

        if let Some(i) = self.texture_buffers.get(handle) {
            return i.clone().buffer.clone();
        } else {
            panic!("{} : Texture not loaded", handle);
        }
    }

    /// Scrape all the values from the CanvasFrame and then allocate the vertex buffers
    pub fn draw(&mut self, canvas_frame: CanvasFrame) {
        self.textured_drawables = canvas_frame.textured_drawables;
        self.colored_drawables = canvas_frame.colored_drawables;
        self.image_drawables = canvas_frame.image_drawables;

        self.allocate_vertex_buffers();
    }

    /// draw(canvas_fame) stored all the intermediate information, this function
    /// allocates the vertex buffers using that information
    fn allocate_vertex_buffers(&mut self) {
        self.colored_vertex_buffer.clear();
        {
            let g = hprof::enter("Colored Vertex Buffer");
            self.colored_vertex_buffer.push(
                ImmutableBuffer::from_iter(
                    self.colored_drawables.iter().cloned(),
                    BufferUsage::vertex_buffer(),
                    self.queue.clone(),
                ).unwrap().0
            );
        }

        self.textured_vertex_buffer.clear();
        {
            let g = hprof::enter("Textured Vertex Buffer");
            for (k, v) in self.textured_drawables.drain() {
                self.textured_vertex_buffer.insert(
                    k.clone(),
                    ImmutableBuffer::from_iter(
                        v.first().unwrap().iter().cloned(),
                        BufferUsage::vertex_buffer(),
                        self.queue.clone(),
                    ).unwrap().0,
                );
            }
        }

        self.image_vertex_buffer.clear();
        {
            let g = hprof::enter("Image Vertex Buffer");
            for (k, v) in self.image_drawables.drain() {
                self.image_vertex_buffer.insert(
                    k.clone(),
                    ImmutableBuffer::from_iter(
                        v.first().unwrap().iter().cloned(),
                        BufferUsage::vertex_buffer(),
                        self.queue.clone(),
                    ).unwrap().0,
                );
            }
        }
    }

    /// Builds the descriptor set for solid colors using the input kernel (needs to support solid colors)
    fn get_solid_color_descriptor_set(&self, kernel: Arc<CanvasShader>) -> Box<dyn DescriptorSet + Send + Sync> {
        let o: Box<dyn DescriptorSet + Send + Sync> = Box::new(
            PersistentDescriptorSet::start(
                kernel.clone().get_pipeline().clone(), 0,
            ).build().unwrap());
        o
    }

    /// Pushes the draw commands to the command buffer. Requires the framebuffers and
    /// image number to be passed in as they are taken care of by the vkprocessor
    pub fn draw_commands(&self,
                         mut command_buffer: AutoCommandBufferBuilder,
                         framebuffers: Vec<Arc<dyn FramebufferAbstract + Send + Sync>>,
                         image_num: usize) -> AutoCommandBufferBuilder {

        // Specify the color to clear the framebuffer with i.e. blue
        let clear_values = vec!(ClearValue::Float([0.0, 0.0, 1.0, 1.0]));

        let mut command_buffer = command_buffer.begin_render_pass(
            framebuffers[image_num].clone(), false, clear_values.clone(),
        ).unwrap();

        // Solid colors
        let mut shader = self.shader_buffers.get(
            self.get_shader_handle(String::from("color-passthrough"))
                .unwrap().clone().handle as usize
        ).unwrap();

        // This looks a little weird as colored_vertex_buffer is a vec of GPU allocated vecs.
        // But we can pass in multiple vertex buffers
        if !self.colored_vertex_buffer.is_empty() {
            command_buffer = command_buffer.draw(
                shader.get_pipeline().clone(),
                &self.dynamic_state.clone(),
                self.colored_vertex_buffer.clone(),
                (), (),
            ).unwrap();
        }

        // Textures
        let mut shader = self.shader_buffers.get(
            self.get_shader_handle(String::from("simple_texture"))
                .unwrap().clone().handle as usize
        ).unwrap();

        if !self.textured_vertex_buffer.is_empty() {
            for (texture_handle, vertex_buffer) in self.textured_vertex_buffer.clone() {
                let handle = texture_handle.clone().handle as usize;
                let descriptor_set = self.texture_buffers.get(handle).clone().unwrap().clone()
                    .get_descriptor_set(shader.clone(), self.sampler.clone());

                command_buffer = command_buffer.draw(
                    shader.get_pipeline().clone(),
                    &self.dynamic_state.clone(), vec![vertex_buffer],
                    vec![descriptor_set], (),
                ).unwrap();
            }
        }

        // Images
        let mut shader = self.shader_buffers.get(
            self.get_shader_handle(String::from("simple_image"))
                .unwrap().clone().handle as usize
        ).unwrap();

        if !self.image_vertex_buffer.is_empty() {
            for (image_handle, vertex_buffer) in self.image_vertex_buffer.clone() {
                let handle = image_handle.clone().handle as usize;
                let descriptor_set = self.image_buffers.get(handle).clone().unwrap().clone()
                    .get_descriptor_set(shader.clone());

                command_buffer = command_buffer.draw(
                    shader.get_pipeline().clone(),
                    &self.dynamic_state.clone(), vec![vertex_buffer],
                    vec![descriptor_set], (),
                ).unwrap();
            }
        }

        command_buffer
            .end_render_pass()
            .unwrap()
    }
}