// Copyright (c) 2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package complianceportal_v1

import (
	"net/http"

	"go.gearno.de/x/ref"
	"go.probo.inc/probo/pkg/iam"
	"go.probo.inc/probo/pkg/server/api/complianceportal"
)

// SEOFromRequest derives html lang, a self-referencing canonical URL, and
// hreflang alternates (including x-default → English) for the SPA shell.
// Portals are host-routed (slug subdomain / custom domain); the request path
// is already relative to the portal root. The portal origin comes from
// request context (set by SNI middleware as scheme://host). When missing,
// canonical and hreflang are left empty so callers do not emit relative SEO
// links.
func SEOFromRequest(r *http.Request) (htmlLang, canonical string, hreflang []HreflangLink) {
	pathname := r.URL.Path
	if pathname == "" {
		pathname = "/"
	}

	locale, rest := splitLocaleFromAppPath(pathname)
	htmlLang = locale

	origin := ref.UnrefOrZero(complianceportal.CompliancePortalBaseURLFromContext(r.Context()))
	if origin == "" {
		return htmlLang, "", nil
	}

	canonical = localizedPageURL(origin, locale, rest)

	locales := iam.SupportedIdentityLocales

	hreflang = make([]HreflangLink, 0, len(locales)+1)
	for _, loc := range locales {
		hreflang = append(hreflang, HreflangLink{
			Lang: loc,
			Href: localizedPageURL(origin, loc, rest),
		})
	}

	hreflang = append(hreflang, HreflangLink{
		Lang: "x-default",
		Href: localizedPageURL(origin, defaultCompliancePortalLocale, rest),
	})

	return htmlLang, canonical, hreflang
}