// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.

package logging

import (
	"io"
)

// Logger defines the interface that is used to keep a record of all events that
// happen to the program
type Logger interface {
	io.Writer // For logging pre-formated messages

	// Log that a fatal error has occurred. The program should likely exit soon
	// after this is called
	Fatal(format string, args ...interface{})
	// Log that an error has occurred. The program should be able to recover
	// from this error
	Error(format string, args ...interface{})
	// Log that an event has occurred that may indicate a future error or
	// vulnerability
	Warn(format string, args ...interface{})
	// Log an event that may be useful for a user to see to measure the progress
	// of the protocol
	Info(format string, args ...interface{})
	// Log an event that may be useful for a programmer to see when debuging the
	// execution of the protocol
	Debug(format string, args ...interface{})
	// Log extremely detailed events that can be useful for inspecting every
	// aspect of the program
	Verbo(format string, args ...interface{})

	// If assertions are enabled, will result in a panic if err is non-nil
	AssertNoError(err error)
	// If assertions are enabled, will result in a panic if b is false
	AssertTrue(b bool, format string, args ...interface{})
	// If assertions are enabled, the function will be called and will result in
	// a panic the returned value is non-nil
	AssertDeferredNoError(f func() error)
	// If assertions are enabled, the function will be called and will result in
	//  a panic the returned value is false
	AssertDeferredTrue(f func() bool, format string, args ...interface{})

	// Recovers a panic, logs the error, and rethrows the panic.
	StopOnPanic()
	// If a function panics, this will log that panic and then re-panic ensuring
	// that the program logs the error before exiting.
	RecoverAndPanic(f func())

	SetLogLevel(Level)
	SetDisplayLevel(Level)
	SetPrefix(string)
	SetLoggingEnabled(bool)
	SetDisplayingEnabled(bool)
	SetContextualDisplayingEnabled(bool)

	// Stop this logger and write back all meta-data.
	Stop()
}