opcotech/elemo

package email

import (
    "bytes"
    "errors"
    "io"
)

const (
    MimeTypeHTML      = "text/html"
    MimeTypePlainText = "text/plain"
)

// Executor executes parsed templates.
type Executor interface {
    Execute(wr io.Writer, data any) error
}

// TemplateParserFunc parses email templates.
type TemplateParserFunc[T Executor] func(filenames ...string) (T, error)

// emailBody returns the rendered email body.
func emailBody[T Executor](path string, data any, parser TemplateParserFunc[T]) (string, error) {
    tmpl, err := parser(path)
    if err != nil {
        return "", errors.Join(ErrTemplateParse, err)
    }

    buf := new(bytes.Buffer)
    if err := tmpl.Execute(buf, data); err != nil {
        return "", errors.Join(ErrTemplateExecute, err)
    }

    return buf.String(), nil
}