client.go

package lichess

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
)

// HTTPClient interface
type HTTPClient interface {
	Do(req *http.Request) (*http.Response, error)
}

type Client struct {
	BaseURL    *url.URL
	UserAgent  string
	APIKey     string
	HttpClient HTTPClient
}

func (c *Client) newRequest(method, path string, body interface{}) (*http.Request, error) {
	if c.BaseURL == nil {
		return nil, errors.New("BaseURL is undefined")
	}
	if c.APIKey == "" {
		return nil, errors.New("APIKey is undefined")
	}

	rel := &url.URL{Path: path}
	u := c.BaseURL.ResolveReference(rel)

	var buf io.ReadWriter
	if body != nil {
		buf = new(bytes.Buffer)
		err := json.NewEncoder(buf).Encode(body)
		if err != nil {
			return nil, err
		}
	}
	req, err := http.NewRequest(method, u.String(), buf)
	if err != nil {
		return nil, err
	}
	// Default request is json
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.Header.Set("User-Agent", c.UserAgent)
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", c.APIKey))
	return req, nil
}

func (c *Client) do(req *http.Request,
	v interface{}) (*http.Response, error) {
	resp, err := c.HttpClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	err = json.NewDecoder(resp.Body).Decode(v)
	return resp, err
}