package smtp2shoutrrr

import (
	"slices"
	"strings"
)

// BodyFormat names the representation a recipient's targets want the message
// body in. Only an HTML body is ever rewritten: a message that already arrived
// as plain text is forwarded untouched whatever the recipient asked for.
type BodyFormat string

const (
	// FormatRaw forwards the body exactly as the message carried it.
	FormatRaw BodyFormat = "raw"
	// FormatMarkdown renders an HTML body as Markdown. There is deliberately
	// no plain-text format beside it: Markdown reads as plain text wherever
	// nothing renders it, so a second conversion would only be a worse copy
	// of this one.
	FormatMarkdown BodyFormat = "markdown"
)

var bodyFormats = []BodyFormat{FormatRaw, FormatMarkdown}

// normalize maps an unset Format to the one that changes nothing, and accepts
// the casing a hand-written configuration file is likely to use.
func (f BodyFormat) normalize() BodyFormat {
	normalized := BodyFormat(strings.ToLower(strings.TrimSpace(string(f))))
	if normalized == "" {
		return FormatRaw
	}

	return normalized
}

// valid normalizes first, so a Config assembled in Go rather than loaded from
// a file does not fail validation on a Format nobody set.
func (f BodyFormat) valid() bool {
	return slices.Contains(bodyFormats, f.normalize())
}

func formatNames() string {
	names := make([]string, 0, len(bodyFormats))
	for _, format := range bodyFormats {
		names = append(names, string(format))
	}

	return strings.Join(names, ", ")
}