package clientapi

import (
	"errors"
	"net/http"

	"github.com/dariuszjaniak/warp/server/internal/httputil"
	"github.com/dariuszjaniak/warp/server/internal/syncapi"
	"github.com/dariuszjaniak/warp/server/internal/userapi"
)

// slidingSyncPath is MSC4186's endpoint. It is still unstable: the MSC has
// not been merged, and the prefix is what every client implementing it
// sends.
const slidingSyncPath = "/_matrix/client/unstable/org.matrix.simplified_msc3575/sync"

// handleSlidingSync implements POST slidingSyncPath.
func (c *ClientAPI) handleSlidingSync(w http.ResponseWriter, r *http.Request, auth userapi.Authenticated) error {
	query := r.URL.Query()
	timeout, err := durationParam(query.Get("timeout"))
	if err != nil {
		return err
	}
	var body syncapi.SlidingBody
	if _, err := httputil.DecodeOptionalJSON(w, r, &body); err != nil {
		return err
	}

	resp, err := c.sync.SlidingSync(r.Context(), syncapi.SlidingRequest{
		User:        auth.UserID,
		Localpart:   auth.Localpart,
		Device:      auth.DeviceID,
		Pos:         query.Get("pos"),
		Timeout:     timeout,
		SetPresence: query.Get("set_presence"),
		Body:        body,
	})
	if err != nil {
		if ctxErr := r.Context().Err(); ctxErr != nil && errors.Is(err, ctxErr) {
			return nil //nolint:nilerr // the client is gone; there is nobody to answer
		}
		return syncError(err)
	}
	httputil.NoCache(w)
	httputil.WriteJSON(w, http.StatusOK, resp)
	return nil
}