package serverapi

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"strings"
)

// Client is a client aimed at a specific ServerAPI endpoint
type Client struct {
	endpoint string
	http     *http.Client
	token    string
}

// ClientOption is options for a Client
type ClientOption func(c *Client)

var defaultHeader = http.Header{
	"Content-Type": []string{"application/json; charset=utf-8"},
	"Accept":       []string{"application/json; charset=utf-8"},
}

// NewClient returns a new Client for making ServerAPI requests
func NewClient(endpoint string, opts ...ClientOption) *Client {
	endpoint = strings.TrimSuffix(endpoint, "/")
	c := &Client{
		endpoint: endpoint,
		http:     http.DefaultClient,
		token:    "",
	}
	for _, opt := range opts {
		opt(c)
	}
	return c
}

// WithHTTP is a ClientOption for setting the http.Client of a Client
func WithHTTP(http *http.Client) ClientOption {
	return func(c *Client) {
		c.http = http
	}
}

// WithToken is a ClientOption for setting the token of a Client
func WithToken(token string) ClientOption {
	return func(c *Client) {
		c.token = token
	}
}

func (c *Client) jsonGET(endpoint string, obj interface{}) error {
	req, err := c.newRequest(endpoint, http.MethodGet, nil)
	if err != nil {
		return err
	}
	res, err := c.http.Do(req)
	if err != nil {
		return fmt.Errorf("sending request: %v", err)
	}

	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return fmt.Errorf("reading body: %v", err)
	}

	return json.Unmarshal(body, obj)
}

func (c *Client) jsonPOST(endpoint string, obj interface{}) (int, error) {
	body, err := json.Marshal(obj)
	if err != nil {
		return -1, err
	}

	req, err := c.newRequest(endpoint, http.MethodPost, body)
	if err != nil {
		return -1, err
	}

	res, err := c.http.Do(req)
	if err != nil {
		return -1, fmt.Errorf("sending request: %v", err)
	}

	return res.StatusCode, nil
}

func (c *Client) newRequest(endpoint, method string, body []byte) (*http.Request, error) {
	req, err := http.NewRequest(method, endpoint, bytes.NewBuffer(body))
	if err != nil {
		return nil, fmt.Errorf("new JSON request: %v", err)
	}
	req.Header = defaultHeader
	req.Header.Add("X-ServerAPI-Token", c.token)
	return req, nil
}