// this struct normally resides in <sys/un.h> (for C)
/// a sockaddr for local connections (AF_UNIX)
struct sockaddr_un {
	ushort sun_family = AF_UNIX; // addr family
	char sun_path[108]; // pathname
};

/// an Address for local addresses (AF_UNIX) - (derived from std.socket.Address) with public getters
class LocalAddress : Address { 
	// NOTE: this is currently not used and untested.
	sockaddr_un addr;
	
	/// constructs a LocalAddress of the unnamed type
	this() {
		addr.sun_family = AF_UNIX;
	}
	
	this(char[] path) {
		addr.sun_family = AF_UNIX;
		// see man 7 unix for further information about the path/address types
		if(path && path.length>0) {
			// unnamed type
			if(path[0] == '\0' && path[1] == '\0')
				return;
			// abstract type
			if(path[0] == '\0'){ 
				if(path.length > 108)
					throw new Exception("path to long - must be at most 108 chars");
				addr.sun_path[0..path.length] = path[];
			}
			// pathname type
			path ~= '\0'; // just to be sure
			int len = cast(int)strlen(cast(char*)addr.sun_path);
			if(len > 107) // nullterminated path doesn't fit into sun_path
				throw new Exception("path to long - must be at most 108 chars");
			addr.sun_path[0..len] = path[0..len];
		}
	}
	
	this(sockaddr_un *sadr){
		if(sadr.sun_family != AF_UNIX) {
			throw new Exception("this was not a AF_UNIX socketaddr!");
		}
		addr = *sadr;
	}
	
	protected sockaddr* name() { return cast(sockaddr*) &addr; }
	protected int nameLen() { 
		// if the address is the unnamed type
		if(addr.sun_path[0] == '\0' && addr.sun_path[1] == '\0')
			return cast(int)ushort.sizeof;
		
		// if the address is the abstract type
		if(addr.sun_path[0] == '\0')
			return cast(int)addr.sizeof; 
		
		// at this point it has to be the pathname type
		assert(addr.sun_path[107] == '\0');
		int len = cast(int)strlen(cast(char*)addr.sun_path) + 1; // + terminating \0
		return cast(int)(ushort.sizeof + len);
	}
	
	AddressFamily addressFamily() { return AddressFamily.UNIX; }
	
	string toString() { return "local:"~getPath(); }
	
	char[] getPath() { 
		// if the address is the unnamed type
		if(addr.sun_path[0] == '\0' && addr.sun_path[1] == '\0')
			return "\0\0";
		
		// if the address is the abstract type
		if(addr.sun_path[0] == '\0')
			return addr.sun_path; 
		
		// at this point it has to be the pathname type
		assert(addr.sun_path[107] == '\0');
		int len = cast(int)strlen(cast(char*)addr.sun_path)+1; // + terminating \0
		return addr.sun_path[0..len]; 
	}
}