/*
 * Copyright 2021 PingCAP, 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
 *
 *     http://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,
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package endpoint

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"

	"github.com/pingcap/log"
	"go.uber.org/zap"

	me "github.com/pingcap/mimir/errors"
)

type StreamResponser struct {
	f func(ctx context.Context, request *http.Request) (io.ReadCloser, error)
}

func (s *StreamResponser) ServeHTTP(responser http.ResponseWriter, request *http.Request) {
	stream, err := s.f(request.Context(), request)
	if err != nil {
		ei, ok := err.(me.ErrorInfo)
		if !ok {
			ei = me.ErrInternal(err.Error())
		}
		responser.Header().Add("Content-Type", "application/json")
		responser.WriteHeader(ei.StatusCode())
		content, _ := json.Marshal(ei)
		responser.Write(content) // nolint:errcheck
		return
	}
	defer stream.Close()

	if _, err := io.Copy(responser, stream); err != nil && !errors.Is(err, context.Canceled) {
		log.Error("copy logs to responser", zap.Error(err))
	}
}