// Copyright 2023 Martin Riedl
//
// 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 golog

import (
	"fmt"
	"strings"
	"time"
)

type FormatterKeyValue struct {
	TimeFormat       string
	builder          strings.Builder
	isFirstKVWritten bool
}

func NewFormatterKeyValue() *FormatterKeyValue {
	return &FormatterKeyValue{
		TimeFormat: time.RFC3339,
	}
}

func (formatter *FormatterKeyValue) Begin(entry *Entry) {
	// reset builder
	formatter.builder.Reset()

	// add timestamp
	formatter.addKV("time", entry.Time.Format(formatter.TimeFormat))

	// add loglevel
	formatter.addKV("level", entry.Level.String())
}

func (formatter *FormatterKeyValue) Process(entry *Entry) {
	// add message
	formatter.addKV("message", entry.Message)

	// add additional fields
	for _, content := range entry.Content {
		formatter.addKV(content.Key, content.Value)
	}
}

func (formatter *FormatterKeyValue) addKV(key string, value any) {
	// convert any to string
	val := fmt.Sprintf("%v", value)

	// check, if value should be escaped
	if strings.ContainsAny(val, " \t\n\r=") {
		val = fmt.Sprintf("%q", val)
	}

	// add space, if required
	if formatter.isFirstKVWritten {
		formatter.builder.WriteString(" ")
	}
	formatter.isFirstKVWritten = true

	// add field
	formatter.builder.WriteString(key)
	formatter.builder.WriteString("=")
	formatter.builder.WriteString(val)
}

func (formatter *FormatterKeyValue) End(entry *Entry) []byte {
	// send data
	return []byte(formatter.builder.String())
}