//file format "sniff"

pub enum Error{
	InvalidMagic,
	InvalidVersion,
	UnexpectedEOF,
}

/* spec

//begin global header

//global metadata (32 bytes)
b"SNFB"
u32 format_version
u64 priming_bytes
	//how many bytes of the file must be read to guarantee all of the expected
	//format-specific metadata is available to facilitate streaming the remaining contents
	//used by the database to guarantee that it serves at least the bare minimum
u128 resource_uuid
	//identifies the file from anywhere for any other file

//global block layout (variable size)
u64 num_blocks
for block_id in 0..num_blocks{
	u64 first_byte
}

//end global header

//begin blocks

//each block is compressed with zstd or gz or something

*/
#[derive(Clone,Copy)]
pub(crate) enum FourCC{
	Map,
	Bot,
	Demo,
}

struct Header{
	/// Type of file
	fourcc:FourCC,
	/// Type version
	version:u32,
	/// Minimum data required to know the location of all streamable resources for this specific file
	priming:u64,
	/// uuid for this file
	resource:u128,
}

pub(crate) struct BlockLayout{
	count:u64,
	location:Vec<u64>,
}

pub(crate) struct File{
	header:Header,
	block_layout:BlockLayout,
	//reference to the data
}

impl File{
	pub(crate) fn new<R:std::io::Read+std::io::Seek>(input:R)->Result<Self,Error>{
		Self{
			header:input.read_le()?,
			block_layout:input.read_le()?,
		}
	}
	pub(crate) fn read_block(&mut self,block_id:u64)->Result<Vec<u8>,Error>{
		Err(Error::UnexpectedEOF)
	}
	pub(crate) fn fourcc(&self)->FourCC{
		self.header.fourcc
	}
}