package lib

import (
	"context"
	"encoding/xml"
	"net/http"
	"net/url"

	ihttp "git.ptzo.gdn/feditools/go-lib/http"
)

// HostMetaWebFingerTemplateRel matches a webfinger link relationship.
const HostMetaWebFingerTemplateRel = "lrdd"

type HostMeta struct {
	XMLNS string `xml:"xmlns,attr"`
	Links []Link `xml:"Link"`
}

func (h *HostMeta) WebFingerURI() WebFingerURI {
	for _, link := range h.Links {
		if link.Rel == HostMetaWebFingerTemplateRel {
			return WebFingerURI(link.Template)
		}
	}

	return ""
}

func FetchHostMeta(ctx context.Context, t *http.Client, domain string, config ...bool) (*HostMeta, error) {
	hostMetaURI := &url.URL{
		Scheme: "https",
		Host:   domain,
		Path:   "/.well-known/host-meta",
	}
	if len(config) > 0 && !config[0] {
		hostMetaURI.Scheme = "http"
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, hostMetaURI.String(), nil)
	if err != nil {
		return nil, NewErrorf("req: %s", err.Error())
	}
	req.Header.Add("Accept", ihttp.MimeAppXML.String())

	// do request
	resp, err := t.Do(req)
	if err != nil {
		return nil, NewErrorf("get: %s", err.Error())
	}

	hostMeta := new(HostMeta)
	if err := xml.NewDecoder(resp.Body).Decode(&hostMeta); err != nil {
		return nil, NewErrorf("decode: %s", err.Error())
	}

	return hostMeta, nil
}