gol4ng/logger

package formatter

import (
    "github.com/gol4ng/logger"
    "github.com/valyala/bytebufferpool"
)

var falseCondition = func(entry logger.Entry) bool {
    return false
}

// DefaultFormatter is the default Entry formatter
type DefaultFormatter struct {
    colored        func(entry logger.Entry) bool
    displayContext func(entry logger.Entry) bool
}

// Format will return Entry as string
func (n *DefaultFormatter) Format(entry logger.Entry) string {
    byteBuffer := bytebufferpool.Get()
    defer bytebufferpool.Put(byteBuffer)

    colored := n.colored(entry)
    if colored {
        switch entry.Level {
        case logger.DebugLevel:
            byteBuffer.WriteString("\x1b[1;36m")
        case logger.InfoLevel:
            byteBuffer.WriteString("\x1b[1;32m")
        case logger.NoticeLevel:
            byteBuffer.WriteString("\x1b[1;34m")
        case logger.WarningLevel:
            byteBuffer.WriteString("\x1b[1;33m")
        case logger.ErrorLevel:
            byteBuffer.WriteString("\x1b[1;31m")
        case logger.CriticalLevel:
            byteBuffer.WriteString("\x1b[1;30;47m")
        case logger.AlertLevel:
            byteBuffer.WriteString("\x1b[1;30;43m")
        case logger.EmergencyLevel:
            byteBuffer.WriteString("\x1b[1;37;41m")
        }
    }

    byteBuffer.WriteString(`<`)
    byteBuffer.WriteString(entry.Level.String())
    byteBuffer.WriteString(`>`)
    if colored {
        byteBuffer.WriteString("\x1b[m")
    }
    if entry.Message != "" {
        byteBuffer.WriteString(` `)
        byteBuffer.WriteString(entry.Message)
    }
    if entry.Context != nil && n.displayContext(entry) {
        byteBuffer.WriteString(` `)
        ContextToJSON(entry.Context, byteBuffer)
    }
    return byteBuffer.String()
}

// NewDefaultFormatter will create a new DefaultFormatter
func NewDefaultFormatter(options ...Option) *DefaultFormatter {
    f := &DefaultFormatter{
        colored: falseCondition,
        displayContext: falseCondition,
    }
    for _, option := range options {
        option(f)
    }
    return f
}

// Option is the option pattern interface for the DefaultFormatter
type Option func(*DefaultFormatter)

// WithColor function will enable ANSI colored formatting
func WithColor(enable bool) Option {
    return WithConditionalColor(func(_ logger.Entry) bool {
        return enable
    })
}

// WithConditionalColor function will enable ANSI colored formatting
func WithConditionalColor(conditional func(_ logger.Entry) bool) Option {
    return func(formatter *DefaultFormatter) {
        formatter.colored = conditional
    }
}

// WithContext function will display context printing
func WithContext(enable bool) Option {
    return WithConditionalContext(func(_ logger.Entry) bool {
        return enable
    })
}

// WithConditionalContext function will display context printing
func WithConditionalContext(conditional func(_ logger.Entry) bool) Option {
    return func(formatter *DefaultFormatter) {
        formatter.displayContext = conditional
    }
}