package links

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"git.sr.ht/~emersion/gqlclient"
	oauth2 "netlandish.com/x/gobwebs-oauth2"
	"netlandish.com/x/gobwebs/auth"
	"netlandish.com/x/gobwebs/server"
)

// HTTPTransport custom http transport
type HTTPTransport struct {
	headers map[string]string
}

// AddHeader add headers for request
func (h *HTTPTransport) AddHeader(k, v string) {
	if h.headers == nil {
		h.headers = make(map[string]string)
	}
	h.headers[k] = v
}

// RoundTrip apply headers for request
func (h *HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	for k, v := range h.headers {
		req.Header.Set(k, v)
	}
	return http.DefaultTransport.RoundTrip(req)
}

// Execute ...
func Execute(ctx context.Context, op *gqlclient.Operation, result interface{}) error {
	var (
		client     *gqlclient.Client
		httpClient *http.Client
		origin     string
	)

	srv := server.ForContext(ctx)
	user := auth.ForContext(ctx)

	if ostr, ok := srv.Config.File.Get("links", "api-origin"); ok {
		origin = ostr
	} else {
		origin = "http://127.0.0.1:8080/query"
	}

	trans := &HTTPTransport{}
	issued := time.Now().UTC()
	expires := issued.Add(30 * time.Second)
	grant := oauth2.BearerToken{
		Version:  oauth2.TokenVersion,
		Issued:   oauth2.ToTimestamp(issued),
		Expires:  oauth2.ToTimestamp(expires),
		Grants:   "",
		ClientID: "",
	}

	if user != nil && user.IsAuthenticated() {
		grant.Type = TypeWebAuth
		grant.UserID = int(user.GetID())
	} else {
		grant.Type = TypeInternal
		// Add Lang Header
		lang := LangForContext(ctx)
		trans.AddHeader("Accept-Language", lang)
	}

	token := grant.Encode(ctx)
	trans.AddHeader("Authorization", fmt.Sprintf("Internal %s", token))
	httpClient = &http.Client{
		Transport: trans,
		Timeout:   30 * time.Second,
	}

	client = gqlclient.New(origin, httpClient)
	err := client.Execute(ctx, op, &result)
	if graphErrors, ok := err.(interface{ Unwrap() []error }); ok {
		errs := graphErrors.Unwrap()
		err = errs[0]
	}
	return err
}