package logging

import (
	`errors`
	`path`
	`strings`

	`r00t2.io/goutils/bitmask`
	`r00t2.io/sysutils/paths`
)

/*
	GetLogger returns an instance of Logger that best suits your system's capabilities.
	Note that this is a VERY generalized interface to the Windows Event Log to conform with multiplatform compat.
	You'd have a little more flexibility with [GetLoggerWindows] (this function wraps that one).
	If you need more custom behavior than that, I recommend using [golang.org/x/sys/windows/svc/eventlog] directly
	(or using another logging module).

	If `enableDebug` is true, debug messages (which according to your program may or may not contain sensitive data) are rendered and written (otherwise they are ignored).

	The `prefix` correlates to the `source` parameter in [GetLoggerWindows], and this function inherently uses [DefaultEventID],
	but otherwise it remains the same as [GetLoggerWindows] - refer to it for documentation on the other parameters.

	If you call [GetLogger], you will only get a single ("best") logger your system supports.
	If you want to log to multiple [Logger] destinations at once (or want to log to an explicit [Logger] type),
	use [GetMultiLogger].
*/
func GetLogger(enableDebug bool, prefix string, logConfigFlags int, logPaths ...string) (logger Logger, err error) {

	if logger, err = GetLoggerWindows(enableDebug, prefix, DefaultEventID, logConfigFlags, logPaths...); err != nil {
		return
	}

	return
}

/*
	GetLoggerWindows returns an instance of Logger that best suits your system's capabilities.
	This is a slightly less (but still quite) generalized interface to the Windows Event Log than [GetLogger].

	If you require more robust logging capabilities (e.g. custom event IDs per uniquely identifiable event),
	you will want to set up your own logger via [golang.org/x/sys/windows/svc/eventlog].

	If `enableDebug` is true, debug messages (which according to your program may or may not contain sensitive data)
	are rendered and written (otherwise they are ignored).

	A blank `source` will return an error as it's used as the source name.
	Throughout the rest of this documentation you will see this referred to as the `prefix` to remain platform-agnostic.

	A pointer to a [WinEventID] struct may be specified for `eventIDs` to map extended logging levels
	(as Windows only supports three levels natively).
	If it is nil, a default one (DefaultEventID) will be used.

	`logConfigFlags` is the corresponding flag(s) OR'd for [StdLogger.LogFlags] (and/or the [StdLogger.LogFlags] for [FileLogger])
	if either is selected. See [StdLogger.LogFlags] and [stdlib log's constants] for details.

	`logPaths` is an (optional) list of strings to use as paths to test for writing.
	If the file can be created/written to, it will be used (assuming you have no higher-level loggers available).

	Only the first `logPaths` entry that "works" will be used, later entries will be ignored.
	Currently this will almost always return a [WinLogger].

	If you call [GetLoggerWindows], you will only get a single ("best") logger your system supports.
	If you want to log to multiple [Logger] destinations at once (or want to log to an explicit [Logger] type),
	use [GetMultiLogger].

	[stdlib log's constants]: https://pkg.go.dev/log#pkg-constants
*/
func GetLoggerWindows(enableDebug bool, source string, eventIDs *WinEventID, logConfigFlags int, logPaths ...string) (logger Logger, err error) {

	var logPath string
	var logFlags bitmask.MaskBit
	var exists bool
	var success bool
	var ckLogPaths []string
	var prefix string

	if strings.TrimSpace(source) == "" {
		err = errors.New("invalid source for Windows logging")
		return
	}

	// Configure system-supported logger(s). The Windows Event Logger (should) ALWAYS be available.
	logFlags.AddFlag(LogWinLogger)
	if eventIDs == nil {
		eventIDs = DefaultEventID
	}

	if logPaths != nil {
		ckLogPaths = logPaths
		ckLogPaths = append(ckLogPaths, defLogPaths...)

		for _, p := range ckLogPaths {
			if exists, _ = paths.RealPathExists(&p); exists {
				if success, err = testOpen(p); err != nil {
					continue
				} else if !success {
					continue
				}
				logFlags.AddFlag(LogFile)
				logPath = p
				break
			} else {
				dirPath := path.Dir(p)
				if err = paths.MakeDirIfNotExist(dirPath); err != nil {
					continue
				}
				if success, err = testOpen(p); err != nil {
					continue
				} else if !success {
					continue
				}
				logFlags.AddFlag(LogFile)
				logPath = p
				break
			}
		}
	}

	if logFlags.HasFlag(LogWinLogger) {
		logger = &WinLogger{
			Prefix:      source,
			EnableDebug: enableDebug,
			EIDs:        eventIDs,
		}
	} else {
		if logFlags.HasFlag(LogFile) {
			logger = &FileLogger{
				StdLogger: StdLogger{
					Prefix:      source,
					EnableDebug: enableDebug,
					LogFlags:    logConfigFlags,
				},
				Path: logPath,
			}
		} else {
			logger = &StdLogger{
				Prefix:      source,
				EnableDebug: enableDebug,
				LogFlags:    logConfigFlags,
			}
		}
	}

	if err = logger.Setup(); err != nil {
		return
	}
	if source != "\x00" {
		if err = logger.SetPrefix(source); err != nil {
			return
		}
	}

	if prefix, err = logger.GetPrefix(); err != nil {
		return
	}

	logger.Debug("logger initialized of type %T with source %v", logger, prefix)

	return

}