use glam::{DAffine2, DVec2};
use graphene::layers::{style::ViewMode, BlendMode, Layer, LayerData as DocumentLayerData, LayerDataType};
use graphene::LayerId;
use serde::{ser::SerializeStruct, Deserialize, Serialize};
use std::collections::HashMap;
use std::fmt;

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Copy)]
pub struct LayerData {
	pub selected: bool,
	pub expanded: bool,
	pub translation: DVec2,
	pub rotation: f64,
	pub scale: f64,
}

impl LayerData {
	pub fn new(expanded: bool) -> LayerData {
		LayerData {
			selected: false,
			expanded,
			translation: DVec2::ZERO,
			rotation: 0.,
			scale: 1.,
		}
	}

	pub fn calculate_offset_transform(&self, offset: DVec2, snapped_angle: f64) -> DAffine2 {
		// TODO: replace with DAffine2::from_scale_angle_translation and fix the errors
		let offset_transform = DAffine2::from_translation(offset);
		let scale_transform = DAffine2::from_scale(DVec2::new(self.scale, self.scale));
		let angle_transform = DAffine2::from_angle(snapped_angle);
		let translation_transform = DAffine2::from_translation(self.translation);
		scale_transform * offset_transform * angle_transform * translation_transform
	}
}

pub fn layer_data<'a>(layer_data: &'a mut HashMap<Vec<LayerId>, LayerData>, path: &[LayerId]) -> &'a mut LayerData {
	layer_data.get_mut(path).expect(&format!("Layer data cannot be found because the path {:?} does not exist", path))
}

pub fn layer_panel_entry(layer_data: &LayerData, transform: DAffine2, layer: &Layer, path: Vec<LayerId>) -> LayerPanelEntry {
	let layer_type: LayerType = (&layer.data).into();
	let name = layer.name.clone().unwrap_or_else(|| format!("Unnamed {}", layer_type));
	let arr = layer.data.bounding_box(transform).unwrap_or([DVec2::ZERO, DVec2::ZERO]);
	let arr = arr.iter().map(|x| (*x).into()).collect::<Vec<(f64, f64)>>();

	let mut thumbnail = String::new();
	layer.data.clone().render(&mut thumbnail, &mut vec![transform], ViewMode::Normal);
	let transform = transform.to_cols_array().iter().map(ToString::to_string).collect::<Vec<_>>().join(",");
	let thumbnail = if let [(x_min, y_min), (x_max, y_max)] = arr.as_slice() {
		format!(
			r#"<svg xmlns="http://www.w3.org/2000/svg" viewBox="{} {} {} {}"><g transform="matrix({})">{}</g></svg>"#,
			x_min,
			y_min,
			x_max - x_min,
			y_max - y_min,
			transform,
			thumbnail,
		)
	} else {
		String::new()
	};

	LayerPanelEntry {
		name,
		visible: layer.visible,
		blend_mode: layer.blend_mode,
		opacity: layer.opacity,
		layer_type: (&layer.data).into(),
		layer_data: *layer_data,
		path,
		thumbnail,
	}
}

#[derive(Debug, Clone, Deserialize, PartialEq)]
pub struct RawBuffer(Vec<u8>);

impl From<Vec<u64>> for RawBuffer {
	fn from(iter: Vec<u64>) -> Self {
		// https://github.com/rust-lang/rust-clippy/issues/4484
		let v_from_raw: Vec<u8> = unsafe {
			// prepare for an auto-forget of the initial vec:
			let v_orig: &mut Vec<_> = &mut *std::mem::ManuallyDrop::new(iter);
			Vec::from_raw_parts(v_orig.as_mut_ptr() as *mut u8, v_orig.len() * 8, v_orig.capacity() * 8)
			// v_orig is never used again, so no aliasing issue
		};
		Self(v_from_raw)
	}
}
impl Serialize for RawBuffer {
	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
	where
		S: serde::Serializer,
	{
		let mut buffer = serializer.serialize_struct("Buffer", 2)?;
		buffer.serialize_field("pointer", &(self.0.as_ptr() as usize))?;
		buffer.serialize_field("length", &(self.0.len()))?;
		buffer.end()
	}
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct LayerPanelEntry {
	pub name: String,
	pub visible: bool,
	pub blend_mode: BlendMode,
	pub opacity: f64,
	pub layer_type: LayerType,
	pub layer_data: LayerData,
	pub path: Vec<LayerId>,
	pub thumbnail: String,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]
pub enum LayerType {
	Folder,
	Shape,
}

impl fmt::Display for LayerType {
	fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
		let name = match self {
			LayerType::Folder => "Folder",
			LayerType::Shape => "Shape",
		};

		formatter.write_str(name)
	}
}

impl From<&LayerDataType> for LayerType {
	fn from(data: &LayerDataType) -> Self {
		use LayerDataType::*;
		match data {
			Folder(_) => LayerType::Folder,
			Shape(_) => LayerType::Shape,
		}
	}
}