# Asserts that o is not null and then returns it.
# Use this if you're sure o can't be null, but the
# static type checker doesn't realise.
T notnull(T)(T? o)

# Call o.toString(). If o is null, return "(null)".
string str(Object? o)

# General exception to throw if your function is called
# with invalid arguments.
class IllegalArgumentException extends Exception:
	this(string msg)

# Used to configure the logging system (e.g. levels, formats)
dlt.log.LogManager logManager

# Standard streams
dlt.io.InputStream stdin
dlt.io.Printer stdout
dlt.io.Printer stderr

# Access to the filesystem
dlt.io.FileSystem fs

# The current time and time-zone
dlt.time.Clock systemClock

# Access to the network
dlt.net.Network network

public import std.stream: OutputStream, InputStream

public alias Layout!(char).convert format

# Wraps an output stream with text formatting
class Printer:
	in OutputStream sink

	# Write a formatted string
	void format(string fmt, ...)

	# Write a formatted string and add a newline
	void formatln(string fmt, ...)

	# Non-varargs version
	void vformat(TypeInfo[] arguments, ArgList args, string fmt)

	# Write all characters in buffer to sink
	# Returns the length of the buffer
	uint write(const(char)[] buffer)

	# Flushes sink
	void flush()

interface FileSystem:
	FilePath path(string pathname)

	FilePath cwd()
	void cwd(FilePath)

# Mostly based on GIO
interface FilePath:
	string loadContents()
	OutputStream create(CreateFlags flags = CreateFlags.None)
	InputStream read()
	void move(FilePath destination, CopyFlags flags)
	void copy(FilePath destination, CopyFlags flags)
	void makeDirectory()
	void remove()
	FilePathEnumerator children(string attributes,
				    QueryInfoFlags flags)

enum Level: Trace, Info, Warn, Error

interface Appender:
	void log(int level, string src, string msg, TypeInfo[] arguments, va_list args)

class StreamAppender implements Appender:
	in Printer printer
	in Clock clock

class LogManager:
	Level level = Level.Warn
	Appender[] appenders

public import std.math: *

public import std.socket:
	AddressFamily, SocketType, ProtocolType
	SocketShutdown, SocketFlags, SocketOption, SocketOptionLevel

class Address:
	in string address
	AddressFamily addressFamily

	this()
	this(AddressFamily af)

class InternetHost:
	string name
	string[] aliases
	Address[] addrList

interface Socket:
	Address localAddress()
	int getOption(SocketOptionLevel level, SocketOption option, void[] result)
	void setOption(SocketOptionLevel level, SocketOption option, void[] value)

	bool isAlive()
	void shutdown(SocketShutdown how)
	void close()

interface ClientSocket extends Socket:
	Address remoteAddress()
	int send(const(void)[] buf, SocketFlags flags = SocketFlags.NONE)
	int receive(void[] buf, SocketFlags flags = SocketFlags.NONE)

interface ServerSocket extends Socket:
	ClientSocket accept()

interface ServerSocketFactory:
	ServerSocket create(const Address address,
			     int backlog = 32,
			     bool reuse = false)

interface ClientSocketFactory:
	ClientSocket create(const Address address,
			     SocketType type,
			     ProtocolType protocol)

interface NameResolver:
	const(InternetHost) getHostByName(string name)
	const(InternetHost) getHostByAddr(string addr)

interface Network:
	ServerSocketFactory server()
	ClientSocketFactory client()
	NameResolver resolver()
	string hostname()

interface Clock:
	Date now()
	TimeSpan zone()
	DateTime toLocalTime(Time utc)