// Copyright (c) 2019 The Jaeger Authors.
// Copyright (c) 2017 Uber Technologies, 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,
// 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 tracing

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

	"github.com/opentracing-contrib/go-stdlib/nethttp"
	"github.com/opentracing/opentracing-go"
)

// HTTPClient wraps an http.Client with tracing instrumentation.
type HTTPClient struct {
	Tracer opentracing.Tracer
	Client *http.Client
}

// GetJSON executes HTTP GET against specified url and tried to parse
// the response into out object.
func (c *HTTPClient) GetJSON(ctx context.Context, endpoint string, url string, out interface{}) error {
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return err
	}
	req = req.WithContext(ctx)
	req, ht := nethttp.TraceRequest(c.Tracer, req, nethttp.OperationName("HTTP GET: "+endpoint))
	defer ht.Finish()

	res, err := c.Client.Do(req)
	if err != nil {
		return err
	}

	defer res.Body.Close()

	if res.StatusCode >= 400 {
		body, err := io.ReadAll(res.Body)
		if err != nil {
			return err
		}
		return errors.New(string(body))
	}
	decoder := json.NewDecoder(res.Body)
	return decoder.Decode(out)
}
