use std::io::Read;

#[derive(Debug)]
pub enum ReadError{
	Roblox(strafesnet_rbx_loader::ReadError),
	Source(strafesnet_bsp_loader::ReadError),
	Io(std::io::Error),
	UnknownFileFormat,
}
impl std::fmt::Display for ReadError{
	fn fmt(&self,f:&mut std::fmt::Formatter<'_>)->std::fmt::Result{
		write!(f,"{self:?}")
	}
}
impl std::error::Error for ReadError{}

pub enum DataStructure{
	Roblox(strafesnet_rbx_loader::Dom),
	Source(strafesnet_bsp_loader::Bsp)
}

pub fn read<R:Read>(input:R)->Result<DataStructure,ReadError>{
	let mut buf=std::io::BufReader::new(input);
	let peek=std::io::BufRead::fill_buf(&mut buf).map_err(ReadError::Io)?;
	match &peek[0..4]{
		b"<rob"=>Ok(DataStructure::Roblox(strafesnet_rbx_loader::read(buf).map_err(ReadError::Roblox)?)),
		b"VBSP"=>Ok(DataStructure::Source(strafesnet_bsp_loader::read(buf).map_err(ReadError::Source)?)),
		_=>Err(ReadError::UnknownFileFormat),
	}
}

#[derive(Debug)]
pub enum LoadError{
	ReadError(ReadError),
	File(std::io::Error),
	Io(std::io::Error),
}
impl std::fmt::Display for LoadError{
	fn fmt(&self,f:&mut std::fmt::Formatter<'_>)->std::fmt::Result{
		write!(f,"{self:?}")
	}
}
impl std::error::Error for LoadError{}

pub fn load(path:&std::path::Path)->Result<(strafesnet_common::map::CompleteMap,strafesnet_deferred_loader::texture::Textures),LoadError>{
	//blocking because it's simpler...
	let file=std::fs::File::open(path).map_err(LoadError::File)?;
	match read(file).map_err(LoadError::ReadError)?{
		DataStructure::Roblox(something)=>{
			let mut legacy_loader=strafesnet_deferred_loader::legacy();

			let map=strafesnet_rbx_loader::convert(&something,|name|{
				match legacy_loader.acquire_texture_id(name){
					Ok(texture_id)=>Some(texture_id),
					Err(e)=>{
						println!("legacy_loader error: {e}");
						None
					},
				}
			});

			let textures=legacy_loader.load_textures().map_err(LoadError::Io)?;

			Ok((map,textures))
		},
		DataStructure::Source(something)=>{
			let mut source_loader=strafesnet_deferred_loader::source();

			let (texture_loader,mesh_loader)=source_loader.get_inner_mut();

			let map=strafesnet_bsp_loader::convert(
				&something,
				//acquire_texture_id
				|name|texture_loader.acquire_texture_id(name),
				//acquire_mesh_id
				|name|mesh_loader.acquire_mesh_id(name),
			);

			let textures=source_loader.load_textures().map_err(LoadError::Io)?;

			Ok((map,textures))
		},
	}
}