use oden_js::{module, ContextRef, Error, Result, Value};
use std::sync::atomic::{AtomicU32, Ordering};
use std::sync::mpsc::Sender;
use std::sync::Arc;

#[derive(Debug)]
pub struct PrintCommand {
    pub text: String,
}

#[derive(Debug)]
pub struct ClearCommand {
    pub color: [f64; 4],
}

#[derive(Debug)]
pub struct SpriteCommand {
    pub x: f32,
    pub y: f32,
    pub w: f32,
    pub h: f32,
    pub u: f32,
    pub v: f32,
    pub sw: f32,
    pub sh: f32,
}

#[derive(Debug)]
pub struct CreateTextureCommand {
    pub id: u32,
    pub image: image::DynamicImage,
    pub label: Option<String>,
}

#[derive(Debug)]
pub enum GraphicsCommand {
    Clear(ClearCommand),
    Print(PrintCommand),
    Sprite(SpriteCommand),
    CreateTexture(CreateTextureCommand),
    UseTexture(u32),
    EndFrame,
}

struct GraphicsImpl {
    next_texture_id: AtomicU32,
    sender: Sender<GraphicsCommand>,
}

impl GraphicsImpl {
    pub fn new(sender: Sender<GraphicsCommand>) -> Self {
        GraphicsImpl {
            sender,
            next_texture_id: AtomicU32::new(0),
        }
    }

    fn print(&self, text: String) -> () {
        let _ = self
            .sender
            .send(GraphicsCommand::Print(PrintCommand { text }));
    }

    fn cls(&self, r: f64, g: f64, b: f64) -> () {
        let _ = self.sender.send(GraphicsCommand::Clear(ClearCommand {
            color: [r, g, b, 1.0],
        }));
    }

    fn spr(&self, x: f32, y: f32, w: f32, h: f32, u: f32, v: f32, sw: f32, sh: f32) {
        let _ = self.sender.send(GraphicsCommand::Sprite(SpriteCommand {
            x,
            y,
            w,
            h,
            u,
            v,
            sw,
            sh,
        }));
    }

    fn create_texture(
        &self,
        context: &ContextRef,
        buffer: Value,
        label: Option<String>,
    ) -> Result<u32> {
        let bytes = buffer.get_array_buffer(context)?;
        let image = match image::load_from_memory(&bytes) {
            Ok(i) => i,
            Err(e) => return Err(Error::RustFunctionError(format!("{e}"))),
        };

        let id = self.next_texture_id.fetch_add(1, Ordering::SeqCst);
        let _ = self
            .sender
            .send(GraphicsCommand::CreateTexture(CreateTextureCommand {
                id,
                image,
                label,
            }));

        Ok(id)
    }

    fn use_texture(&self, id: u32) {
        let _ = self.sender.send(GraphicsCommand::UseTexture(id));
    }
}

pub struct GraphicsAPI {
    gfx: Arc<GraphicsImpl>,
}

impl GraphicsAPI {
    pub fn define(ctx: &ContextRef, sender: Sender<GraphicsCommand>) -> oden_js::Result<Self> {
        let gfx = Arc::new(GraphicsImpl::new(sender));
        let mut builder = module::native::NativeModuleBuilder::new(ctx);
        {
            let gfx = gfx.clone();
            builder.export(
                "print",
                ctx.new_fn(move |_: &ContextRef, t: String| gfx.print(t))?,
            )?;
        }
        {
            let gfx = gfx.clone();
            builder.export(
                "cls",
                ctx.new_fn(move |_: &ContextRef, r: f64, g: f64, b: f64| gfx.cls(r, g, b))?,
            )?;
        }
        {
            let gfx = gfx.clone();
            builder.export(
                "spr",
                ctx.new_fn(
                    move |_: &ContextRef,
                          x: f32,
                          y: f32,
                          w: f32,
                          h: f32,
                          u: f32,
                          v: f32,
                          sw: f32,
                          sh: f32| gfx.spr(x, y, w, h, u, v, sw, sh),
                )?,
            )?;
        }
        {
            let gfx = gfx.clone();
            builder.export(
                "use_texture",
                ctx.new_fn(move |_: &ContextRef, id: u32| gfx.use_texture(id))?,
            )?;
        }
        {
            let gfx = gfx.clone();
            builder.export(
                "create_texture",
                ctx.new_fn(
                    move |c: &ContextRef, buffer: Value, label: Option<String>| {
                        gfx.create_texture(c, buffer, label)
                    },
                )?,
            )?;
        }
        builder.build("graphics-core")?;
        Ok(GraphicsAPI { gfx })
    }

    pub fn end_frame(&self) {
        let _ = self.gfx.sender.send(GraphicsCommand::EndFrame);
    }
}