package logr

import (
	"fmt"
)

// Sugar provides a less structured API for logging.
type Sugar struct {
	logger Logger
}

func (s Sugar) sugarLog(lvl Level, msg string, args ...interface{}) {
	if s.logger.IsLevelEnabled(lvl) {
		fields := make([]Field, 0, len(args))
		for _, arg := range args {
			fields = append(fields, Any("", arg))
		}
		s.logger.Log(lvl, msg, fields...)
	}
}

// Trace is a convenience method equivalent to `Log(TraceLevel, msg, args...)`.
func (s Sugar) Trace(msg string, args ...interface{}) {
	s.sugarLog(Trace, msg, args...)
}

// Debug is a convenience method equivalent to `Log(DebugLevel, msg, args...)`.
func (s Sugar) Debug(msg string, args ...interface{}) {
	s.sugarLog(Debug, msg, args...)
}

// Print ensures compatibility with std lib logger.
func (s Sugar) Print(msg string, args ...interface{}) {
	s.Info(msg, args...)
}

// Info is a convenience method equivalent to `Log(InfoLevel, msg, args...)`.
func (s Sugar) Info(msg string, args ...interface{}) {
	s.sugarLog(Info, msg, args...)
}

// Warn is a convenience method equivalent to `Log(WarnLevel, msg, args...)`.
func (s Sugar) Warn(msg string, args ...interface{}) {
	s.sugarLog(Warn, msg, args...)
}

// Error is a convenience method equivalent to `Log(ErrorLevel, msg, args...)`.
func (s Sugar) Error(msg string, args ...interface{}) {
	s.sugarLog(Error, msg, args...)
}

// Fatal is a convenience method equivalent to `Log(FatalLevel, msg, args...)`
func (s Sugar) Fatal(msg string, args ...interface{}) {
	s.sugarLog(Fatal, msg, args...)
}

// Panic is a convenience method equivalent to `Log(PanicLevel, msg, args...)`
func (s Sugar) Panic(msg string, args ...interface{}) {
	s.sugarLog(Panic, msg, args...)
}

//
// Printf style
//

// Logf checks that the level matches one or more targets, and
// if so, generates a log record that is added to the main
// queue (channel). Arguments are handled in the manner of fmt.Printf.
func (s Sugar) Logf(lvl Level, format string, args ...interface{}) {
	if s.logger.IsLevelEnabled(lvl) {
		var msg string
		if format == "" {
			msg = fmt.Sprint(args...)
		} else {
			msg = fmt.Sprintf(format, args...)
		}
		s.logger.Log(lvl, msg)
	}
}

// Tracef is a convenience method equivalent to `Logf(TraceLevel, args...)`.
func (s Sugar) Tracef(format string, args ...interface{}) {
	s.Logf(Trace, format, args...)
}

// Debugf is a convenience method equivalent to `Logf(DebugLevel, args...)`.
func (s Sugar) Debugf(format string, args ...interface{}) {
	s.Logf(Debug, format, args...)
}

// Infof is a convenience method equivalent to `Logf(InfoLevel, args...)`.
func (s Sugar) Infof(format string, args ...interface{}) {
	s.Logf(Info, format, args...)
}

// Printf ensures compatibility with std lib logger.
func (s Sugar) Printf(format string, args ...interface{}) {
	s.Infof(format, args...)
}

// Warnf is a convenience method equivalent to `Logf(WarnLevel, args...)`.
func (s Sugar) Warnf(format string, args ...interface{}) {
	s.Logf(Warn, format, args...)
}

// Errorf is a convenience method equivalent to `Logf(ErrorLevel, args...)`.
func (s Sugar) Errorf(format string, args ...interface{}) {
	s.Logf(Error, format, args...)
}

// Fatalf is a convenience method equivalent to `Logf(FatalLevel, args...)`
func (s Sugar) Fatalf(format string, args ...interface{}) {
	s.Logf(Fatal, format, args...)
}

// Panicf is a convenience method equivalent to `Logf(PanicLevel, args...)`
func (s Sugar) Panicf(format string, args ...interface{}) {
	s.Logf(Panic, format, args...)
}

//
// K/V style
//

// With returns a new Sugar logger with the specified key/value pairs added to the
// fields list.
func (s Sugar) With(keyValuePairs ...interface{}) Sugar {
	return s.logger.With(s.argsToFields(keyValuePairs)...).Sugar()
}

// Tracew outputs at trace level with the specified key/value pairs converted to fields.
func (s Sugar) Tracew(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Trace, msg, s.argsToFields(keyValuePairs)...)
}

// Debugw outputs at debug level with the specified key/value pairs converted to fields.
func (s Sugar) Debugw(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Debug, msg, s.argsToFields(keyValuePairs)...)
}

// Infow outputs at info level with the specified key/value pairs converted to fields.
func (s Sugar) Infow(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Info, msg, s.argsToFields(keyValuePairs)...)
}

// Warnw outputs at warn level with the specified key/value pairs converted to fields.
func (s Sugar) Warnw(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Warn, msg, s.argsToFields(keyValuePairs)...)
}

// Errorw outputs at error level with the specified key/value pairs converted to fields.
func (s Sugar) Errorw(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Error, msg, s.argsToFields(keyValuePairs)...)
}

// Fatalw outputs at fatal level with the specified key/value pairs converted to fields.
func (s Sugar) Fatalw(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Fatal, msg, s.argsToFields(keyValuePairs)...)
}

// Panicw outputs at panic level with the specified key/value pairs converted to fields.
func (s Sugar) Panicw(msg string, keyValuePairs ...interface{}) {
	s.logger.Log(Panic, msg, s.argsToFields(keyValuePairs)...)
}

// argsToFields converts an array of args, possibly containing name/value pairs
// into a []Field.
func (s Sugar) argsToFields(keyValuePairs []interface{}) []Field {
	if len(keyValuePairs) == 0 {
		return nil
	}

	fields := make([]Field, 0, len(keyValuePairs))
	count := len(keyValuePairs)

	for i := 0; i < count; {
		if fld, ok := keyValuePairs[i].(Field); ok {
			fields = append(fields, fld)
			i++
			continue
		}

		if i == count-1 {
			s.logger.Error("invalid key/value pair", Any("arg", keyValuePairs[i]))
			break
		}

		// we should have a key/value pair now. The key must be a string.
		if key, ok := keyValuePairs[i].(string); !ok {
			s.logger.Error("invalid key for key/value pair", Int("pos", i))
		} else {
			fields = append(fields, Any(key, keyValuePairs[i+1]))
		}
		i += 2
	}
	return fields
}