/*
   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package log

import (
	"fmt"
	"time"
)

var defaultTimeFormat = time.RFC3339 // 2006-01-02T15:04:05Z07:00

// TextFormatter represents a kind of formatter that formats the logs as plain text
type TextFormatter struct {
	timeFormat string
}

// NewTextFormatter returns a customized TextFormatter
func NewTextFormatter(timeFormat string) *TextFormatter {
	if len(timeFormat) == 0 {
		timeFormat = defaultTimeFormat
	}

	return &TextFormatter{
		timeFormat: timeFormat,
	}
}

// Format formats the logs as "time [level] line message"
func (t *TextFormatter) Format(r *Record) (b []byte, err error) {
	s := fmt.Sprintf("%s [%s] ", r.Time.Format(t.timeFormat), r.Lvl.string())

	if len(r.Line) != 0 {
		s = s + r.Line + " "
	}

	if len(r.Msg) != 0 {
		s = s + r.Msg
	}

	b = []byte(s)

	if len(b) == 0 || b[len(b)-1] != '\n' {
		b = append(b, '\n')
	}

	return
}