package viper

import (

	"fmt"

	jww "github.com/spf13/jwalterweatherman"

)

// Logger is a unified interface for various logging use cases and practices, including:

// 		- leveled logging

// 		- structured logging

type Logger interface {

	// Trace logs a Trace event.

	//

	// Even more fine-grained information than Debug events.

	// Loggers not supporting this level should fall back to Debug.

	Trace(msg string, keyvals ...interface{})

	// Debug logs a Debug event.

	//

	// A verbose series of information events.

	// They are useful when debugging the system.

	Debug(msg string, keyvals ...interface{})

	// Info logs an Info event.

	//

	// General information about what's happening inside the system.

	Info(msg string, keyvals ...interface{})

	// Warn logs a Warn(ing) event.

	//

	// Non-critical events that should be looked at.

	Warn(msg string, keyvals ...interface{})

	// Error logs an Error event.

	//

	// Critical events that require immediate attention.

	// Loggers commonly provide Fatal and Panic levels above Error level,

	// but exiting and panicing is out of scope for a logging library.

	Error(msg string, keyvals ...interface{})

}

type jwwLogger struct{}

func (jwwLogger) Trace(msg string, keyvals ...interface{}) {

	jww.TRACE.Printf(jwwLogMessage(msg, keyvals...))

}

func (jwwLogger) Debug(msg string, keyvals ...interface{}) {

	jww.DEBUG.Printf(jwwLogMessage(msg, keyvals...))

}

func (jwwLogger) Info(msg string, keyvals ...interface{}) {

	jww.INFO.Printf(jwwLogMessage(msg, keyvals...))

}

func (jwwLogger) Warn(msg string, keyvals ...interface{}) {

	jww.WARN.Printf(jwwLogMessage(msg, keyvals...))

}

func (jwwLogger) Error(msg string, keyvals ...interface{}) {

	jww.ERROR.Printf(jwwLogMessage(msg, keyvals...))

}

func jwwLogMessage(msg string, keyvals ...interface{}) string {

	out := msg

	if len(keyvals) > 0 && len(keyvals)%2 == 1 {

		keyvals = append(keyvals, nil)

	}

	for i := 0; i <= len(keyvals)-2; i += 2 {

		out = fmt.Sprintf("%s %v=%v", out, keyvals[i], keyvals[i+1])

	}

	return out

}