/*
	Copyright NetFoundry Inc.

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	https://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*/

package oidc_auth

import (
	"encoding"
	"errors"
	"net/http"

	"github.com/michaelquigley/pfxlog"
	"github.com/openziti/edge-api/rest_model"
	"github.com/openziti/foundation/v2/errorz"
	"github.com/openziti/ziti/v2/controller/apierror"
)

// render will attempt to send a responses on the provided http.ResponseWriter. All error output will be directed to the
// http.ResponseWriter. The provided http.ResponseWriter will have had its header sent after calling this function.
func render(w http.ResponseWriter, contentType string, status int, data encoding.BinaryMarshaler) {
	payload, err := data.MarshalBinary()

	if err != nil {
		pfxlog.Logger().WithError(err).Error("could not marshal data payload, attempting to respond with a marshalling error")
		internalErr := &rest_model.APIError{
			Code:    errorz.UnhandledCode,
			Message: "could not marshal, see cause",
			Cause: &rest_model.APIErrorCause{
				APIError: rest_model.APIError{
					Code:    "UNHANDLED",
					Message: err.Error(),
				},
			},
		}

		// if there is an err here, we are giving up as we have already tried to recover.
		internalErrPayload, internalErrMarshalErr := internalErr.MarshalBinary()

		if err != nil {
			pfxlog.Logger().WithError(internalErrMarshalErr).Error("could not write marshaling error, failed to marshal internal error, writing '{}'")
		}

		if len(internalErrPayload) == 0 {
			internalErrPayload = []byte("{}")
		}

		w.Header().Set(ContentTypeHeader, contentType)
		w.WriteHeader(http.StatusInternalServerError)

		_, err = w.Write(internalErrPayload)

		if err != nil {
			pfxlog.Logger().WithError(err).WithField("internalErrPayload", internalErrPayload).Error("could not write the internal error payload, giving up")
		}

		return
	}

	w.Header().Set(ContentTypeHeader, contentType)
	w.WriteHeader(status)
	_, err = w.Write(payload)

	if err != nil {
		pfxlog.Logger().WithError(err).Error("error writing payload")
	}
}

// renderJson will attempt to render the provided data as JSON.
func renderJson(w http.ResponseWriter, status int, data encoding.BinaryMarshaler) {
	render(w, JsonContentType, status, data)
}

func renderJsonError(w http.ResponseWriter, err error) {
	restErr, status := errorToRestApiError(err)
	renderJson(w, status, restErr)
}

func renderJsonApiError(w http.ResponseWriter, err *errorz.ApiError) {
	restErr, status := errorToRestApiError(err)
	renderJson(w, status, restErr)
}

func errorToRestApiError(err error) (*rest_model.APIError, int) {
	var typedErr *errorz.ApiError
	var maxBytesErr *http.MaxBytesError
	switch {
	case errors.As(err, &maxBytesErr):
		return &rest_model.APIError{
			Code:    apierror.RequestEntityTooLargeCode,
			Message: apierror.RequestEntityTooLargeMessage,
		}, http.StatusRequestEntityTooLarge
	case errors.As(err, &typedErr):
		restErr := &rest_model.APIError{
			Code:    typedErr.AppCode,
			Message: typedErr.Message,
		}

		if typedErr.Cause != nil {
			causeErr, _ := errorToRestApiError(typedErr.Cause)
			restErr.Cause = &rest_model.APIErrorCause{
				APIError: *causeErr,
			}
		}

		return restErr, typedErr.Status
	default:
		return &rest_model.APIError{
			Code:    "UNHANDLED",
			Message: err.Error(),
		}, http.StatusInternalServerError
	}

}