package emailtemplates

import (
	"Yimaru-Backend/internal/domain"
	"html/template"
	"regexp"
	"strings"
	texttemplate "text/template"
)

var slugPattern = regexp.MustCompile(`^[a-z][a-z0-9_]*$`)

func normalizeSlug(slug string) (string, error) {
	value := strings.ToLower(strings.TrimSpace(slug))
	if value == "" {
		return "", errSlugRequired
	}
	if !slugPattern.MatchString(value) {
		return "", errInvalidSlug
	}
	return value, nil
}

func normalizeStatus(status *string) (string, error) {
	if status == nil || strings.TrimSpace(*status) == "" {
		return domain.EmailTemplateStatusActive, nil
	}
	value := strings.ToUpper(strings.TrimSpace(*status))
	switch value {
	case domain.EmailTemplateStatusActive, domain.EmailTemplateStatusInactive:
		return value, nil
	default:
		return "", errInvalidStatus
	}
}

func normalizeVariables(vars []string) []string {
	if len(vars) == 0 {
		return []string{}
	}
	out := make([]string, 0, len(vars))
	seen := make(map[string]struct{}, len(vars))
	for _, variable := range vars {
		trimmed := strings.TrimSpace(variable)
		if trimmed == "" {
			continue
		}
		if _, ok := seen[trimmed]; ok {
			continue
		}
		seen[trimmed] = struct{}{}
		out = append(out, trimmed)
	}
	return out
}

func newTextTemplate(name, content string) (*texttemplate.Template, error) {
	return texttemplate.New(name).Parse(content)
}

func newHTMLTemplate(name, content string) (*template.Template, error) {
	return template.New(name).Parse(content)
}