package internal

import (
	"errors"
	"net"
	"net/http"
	"net/http/cookiejar"
	"net/url"
	"time"
)

var (
	// ErrNoCookieJar is the error type for missing cookie jar
	ErrNoCookieJar = errors.New("cookie jar is not available")
)

// Client is a small wrapper around *http.Client to provide new methods.
type Client struct {
	*http.Client
}

// NewClient creates http.Client with modified values for typical web scraper
func NewClient(cookiesDisabled bool) *Client {
	client := &http.Client{
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   30 * time.Second,
				KeepAlive: 30 * time.Second,
				DualStack: true,
			}).DialContext,
			MaxIdleConns:          0,    // Default: 100
			MaxIdleConnsPerHost:   1000, // Default: 2
			IdleConnTimeout:       90 * time.Second,
			TLSHandshakeTimeout:   10 * time.Second,
			ExpectContinueTimeout: 1 * time.Second,
		},
		Timeout: time.Second * 180, // Google's timeout
	}
	if !cookiesDisabled {
		client.Jar, _ = cookiejar.New(nil)
	}
	return &Client{Client: client}
}

// SetCookies handles the receipt of the cookies in a reply for the given URL
func (c *Client) SetCookies(URL string, cookies []*http.Cookie) error {
	if c.Jar == nil {
		return ErrNoCookieJar
	}
	u, err := url.Parse(URL)
	if err != nil {
		return err
	}
	c.Jar.SetCookies(u, cookies)
	return nil
}

// Cookies returns the cookies to send in a request for the given URL.
func (c *Client) Cookies(URL string) []*http.Cookie {
	if c.Jar == nil {
		return nil
	}
	parsedURL, err := url.Parse(URL)
	if err != nil {
		return nil
	}
	return c.Jar.Cookies(parsedURL)
}

// SetDefaultHeader sets header if not exists before
func SetDefaultHeader(header http.Header, key string, value string) http.Header {
	if header.Get(key) == "" {
		header.Set(key, value)
	}
	return header
}