colors.go

// Copyright 2022 Namespace Labs 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.

package colors

import (
	"context"

	"github.com/morikuni/aec"
)

type contextKey string

var (
	_styleKey = contextKey("fn.colors")
)

type Style struct {
	Header           Applicable // Timestamps, etc.
	Comment          Applicable // Faded out, at the end of a line.
	CommentHighlight Applicable
	Progress         Applicable // Inline content that is updated w/ progress.
	ErrorHeader      Applicable // Error prefixes.
	LessRelevant     Applicable // A passing detail, like the fact that a list is empty.
	Highlight        Applicable // Something we should highlight, usually in bold.
	ErrorWhat        Applicable // When formatting errors, the kind of error.
	LogError         Applicable // An error displayed in a log line.
	LogCategory      Applicable // Log line category.
	LogCachedName    Applicable // Names, when cached.
	LogArgument      Applicable // An argument to an invocation.
	LogResult        Applicable // The result of an invocation.
	LogErrorReason   Applicable // An expected error reason.
	LogScope         Applicable // Highlight of a package for which an invocation is being made.
	TestSuccess      Applicable // It says it on the tin.
	TestFailure      Applicable // Here too.
}

func WithStyle(ctx context.Context, s Style) context.Context {
	return context.WithValue(ctx, _styleKey, &s)
}

func Ctx(ctx context.Context) Style {
	if style := ctx.Value(_styleKey); style != nil {
		return *style.(*Style)
	}
	return NoColors
}

type Applicable interface {
	Apply(string) string
}

var WithColors = Style{
	Header:           aec.LightBlackF,
	Comment:          aec.LightBlackF,
	CommentHighlight: aec.LightBlackF.With(aec.Bold),
	LogCategory:      aec.LightBlueF,
	LogCachedName:    aec.LightBlackF,
	Progress:         aec.LightBlackF,
	LogArgument:      aec.CyanF,
	LogResult:        aec.BlueF,
	LogErrorReason:   aec.BlueF,
	LogError:         aec.RedF,
	LogScope:         aec.Italic,
	ErrorHeader:      aec.RedF.With(aec.Bold),
	LessRelevant:     aec.Italic,
	Highlight:        aec.Bold,
	ErrorWhat:        aec.MagentaF,
	TestSuccess:      aec.GreenF,
	TestFailure:      aec.RedF,
}

var NoColors = Style{
	Header:           noOpANSI,
	Comment:          noOpANSI,
	CommentHighlight: noOpANSI,
	LogCategory:      noOpANSI,
	LogCachedName:    noOpANSI,
	Progress:         noOpANSI,
	LogArgument:      noOpANSI,
	LogResult:        noOpANSI,
	LogErrorReason:   noOpANSI,
	LogError:         noOpANSI,
	LogScope:         noOpANSI,
	ErrorHeader:      noOpANSI,
	LessRelevant:     noOpANSI,
	Highlight:        noOpANSI,
	ErrorWhat:        noOpANSI,
	TestSuccess:      noOpANSI,
	TestFailure:      noOpANSI,
}

// An implementation of aec.ANSI that does completely nothing.
// It is more appropriate to use it in for non-TTY output since
// [aec.EmptyBuilder.ANSI] inserts reset codes "ESC[0m" regardless.
type noOpANSIImpl struct{}

func (noOpANSIImpl) Apply(s string) string {
	return s
}

var noOpANSI = noOpANSIImpl{}