package http

import (
	"context"
	"crypto/tls"
	"encoding/base64"
	"errors"
	"fmt"
	"io"
	"log"
	"net/url"
	"reflect"
	"sort"
	"strings"
	"sync"
	"time"
)

	Transport RoundTripper

	CheckRedirect func(req *Request, via []*Request) error

	Jar CookieJar

	Timeout time.Duration
}

var DefaultClient = &Client{}

	RoundTrip(*Request) (*Response, error)
}

	if lastReq.Scheme == "https" && newReq.Scheme == "http" {
		return ""
	}
	referer := lastReq.String()

		auth := lastReq.User.String() + "@"
		referer = strings.Replace(referer, auth, "", 1)
	}
	return referer
}

func (c *Client) send(req *Request, deadline time.Time) (resp *Response, didTimeout func() bool, err error) {
	if c.Jar != nil {
		for _, cookie := range c.Jar.Cookies(req.URL) {
			req.AddCookie(cookie)
		}
	}
	resp, didTimeout, err = send(req, c.transport(), deadline)
	if err != nil {
		return nil, didTimeout, err
	}
	if c.Jar != nil {
		if rc := resp.Cookies(); len(rc) > 0 {
			c.Jar.SetCookies(req.URL, rc)
		}
	}
	return resp, nil, nil
}

func (c *Client) deadline() time.Time {
	if c.Timeout > 0 {
		return time.Now().Add(c.Timeout)
	}
	return time.Time{}
}

func (c *Client) transport() RoundTripper {
	if c.Transport != nil {
		return c.Transport
	}
	return DefaultTransport
}

func send(ireq *Request, rt RoundTripper, deadline time.Time) (resp *Response, didTimeout func() bool, err error) {
	req := ireq // req is either the original request, or a modified fork

	if rt == nil {
		req.closeBody()
		return nil, alwaysFalse, errors.New("http: no Client.Transport or DefaultTransport")
	}

	if req.URL == nil {
		req.closeBody()
		return nil, alwaysFalse, errors.New("http: nil Request.URL")
	}

	if req.RequestURI != "" {
		req.closeBody()
		return nil, alwaysFalse, errors.New("http: Request.RequestURI can't be set in client requests")
	}

	forkReq := func() {
		if ireq == req {
			req = new(Request)
			*req = *ireq // shallow clone
		}
	}

	if req.Header == nil {
		forkReq()
		req.Header = make(Header)
	}

	if u := req.URL.User; u != nil && req.Header.Get("Authorization") == "" {
		username := u.Username()
		password, _ := u.Password()
		forkReq()
		req.Header = cloneOrMakeHeader(ireq.Header)
		req.Header.Set("Authorization", "Basic "+basicAuth(username, password))
	}

	if !deadline.IsZero() {
		forkReq()
	}
	stopTimer, didTimeout := setRequestCancel(req, rt, deadline)

	resp, err = rt.RoundTrip(req)
	if err != nil {
		stopTimer()
		if resp != nil {
			log.Printf("RoundTripper returned a response & error; ignoring response")
		}

			if string(tlsErr.RecordHeader[:]) == "HTTP/" {
				err = errors.New("http: server gave HTTP response to HTTPS client")
			}
		}
		return nil, didTimeout, err
	}
	if resp == nil {
		return nil, didTimeout, fmt.Errorf("http: RoundTripper implementation (%T) returned a nil *Response with a nil error", rt)
	}

		if resp.ContentLength > 0 && req.Method != "HEAD" {
			return nil, didTimeout, fmt.Errorf("http: RoundTripper implementation (%T) returned a *Response with content length %d but a nil Body", rt, resp.ContentLength)
		}
		resp.Body = io.NopCloser(strings.NewReader(""))
	}
	if !deadline.IsZero() {
		resp.Body = &cancelTimerBody{
			stop:          stopTimer,
			rc:            resp.Body,
			reqDidTimeout: didTimeout,
		}
	}
	return resp, nil, nil
}

func timeBeforeContextDeadline(t time.Time, ctx context.Context) bool {
	d, ok := ctx.Deadline()
	if !ok {
		return true
	}
	return t.Before(d)
}

func knownRoundTripperImpl(rt RoundTripper, req *Request) bool {
	switch t := rt.(type) {
	case *Transport:
		if altRT := t.alternateRoundTripper(req); altRT != nil {
			return knownRoundTripperImpl(altRT, req)
		}
		return true
	case *http2Transport, http2noDialH2RoundTripper:
		return true

	if reflect.TypeOf(rt).String() == "*http2.Transport" {
		return true
	}
	return false
}

func setRequestCancel(req *Request, rt RoundTripper, deadline time.Time) (stopTimer func(), didTimeout func() bool) {
	if deadline.IsZero() {
		return nop, alwaysFalse
	}
	knownTransport := knownRoundTripperImpl(rt, req)
	oldCtx := req.Context()

		if !timeBeforeContextDeadline(deadline, oldCtx) {
			return nop, alwaysFalse
		}

		var cancelCtx func()
		req.ctx, cancelCtx = context.WithDeadline(oldCtx, deadline)
		return cancelCtx, func() bool { return time.Now().After(deadline) }
	}
	initialReqCancel := req.Cancel // the user's original Request.Cancel, if any

	var cancelCtx func()
	if oldCtx := req.Context(); timeBeforeContextDeadline(deadline, oldCtx) {
		req.ctx, cancelCtx = context.WithDeadline(oldCtx, deadline)
	}

	cancel := make(chan struct{})
	req.Cancel = cancel

		type canceler interface{ CancelRequest(*Request) }
		if v, ok := rt.(canceler); ok {
			v.CancelRequest(req)
		}
	}

	stopTimerCh := make(chan struct{})
	var once sync.Once
	stopTimer = func() {
		once.Do(func() {
			close(stopTimerCh)
			if cancelCtx != nil {
				cancelCtx()
			}
		})
	}

	timer := time.NewTimer(time.Until(deadline))
	var timedOut atomicBool

	go func() {
		select {
		case <-initialReqCancel:
			doCancel()
			timer.Stop()
		case <-timer.C:
			timedOut.setTrue()
			doCancel()
		case <-stopTimerCh:
			timer.Stop()
		}
	}()

	return stopTimer, timedOut.isSet
}

func basicAuth(username, password string) string {
	auth := username + ":" + password
	return base64.StdEncoding.EncodeToString([]byte(auth))
}

func Get(url string) (resp *Response, err error) {
	return DefaultClient.Get(url)
}

func (c *Client) Get(url string) (resp *Response, err error) {
	req, err := NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}
	return c.Do(req)
}

func alwaysFalse() bool { return false }

var ErrUseLastResponse = errors.New("net/http: use last response")

func (c *Client) checkRedirect(req *Request, via []*Request) error {
	fn := c.CheckRedirect
	if fn == nil {
		fn = defaultCheckRedirect
	}
	return fn(req, via)
}

func redirectBehavior(reqMethod string, resp *Response, ireq *Request) (redirectMethod string, shouldRedirect, includeBody bool) {
	switch resp.StatusCode {
	case 301, 302, 303:
		redirectMethod = reqMethod
		shouldRedirect = true
		includeBody = false

		if reqMethod != "GET" && reqMethod != "HEAD" {
			redirectMethod = "GET"
		}
	case 307, 308:
		redirectMethod = reqMethod
		shouldRedirect = true
		includeBody = true

			shouldRedirect = false
			break
		}

			shouldRedirect = false
		}
	}
	return redirectMethod, shouldRedirect, includeBody
}

func urlErrorOp(method string) string {
	if method == "" {
		return "Get"
	}
	return method[:1] + strings.ToLower(method[1:])
}

func (c *Client) Do(req *Request) (*Response, error) {
	return c.do(req)
}

var testHookClientDoResult func(retres *Response, reterr error)

func (c *Client) do(req *Request) (retres *Response, reterr error) {
	if testHookClientDoResult != nil {
		defer func() { testHookClientDoResult(retres, reterr) }()
	}
	if req.URL == nil {
		req.closeBody()
		return nil, &url.Error{
			Op:  urlErrorOp(req.Method),
			Err: errors.New("http: nil Request.URL"),
		}
	}

	var (
		deadline      = c.deadline()
		reqs          []*Request
		resp          *Response
		copyHeaders   = c.makeHeadersCopier(req)
		reqBodyClosed = false // have we closed the current req.Body?

		redirectMethod string
		includeBody    bool
	)

		if !reqBodyClosed {
			req.closeBody()
		}
		var urlStr string
		if resp != nil && resp.Request != nil {
			urlStr = stripPassword(resp.Request.URL)
		} else {
			urlStr = stripPassword(req.URL)
		}
		return &url.Error{
			Op:  urlErrorOp(reqs[0].Method),
			URL: urlStr,
			Err: err,
		}
	}

		if len(reqs) > 0 {
			loc := resp.Header.Get("Location")
			if loc == "" {
				resp.closeBody()
				return nil, uerr(fmt.Errorf("%d response missing Location header", resp.StatusCode))
			}
			u, err := req.URL.Parse(loc)
			if err != nil {
				resp.closeBody()
				return nil, uerr(fmt.Errorf("failed to parse Location header %q: %v", loc, err))
			}
			host := ""

				if u, _ := url.Parse(loc); u != nil && !u.IsAbs() {
					host = req.Host
				}
			}
			ireq := reqs[0]
			req = &Request{
				Method:   redirectMethod,
				Response: resp,
				URL:      u,
				Header:   make(Header),
				Host:     host,
				Cancel:   ireq.Cancel,
				ctx:      ireq.ctx,
			}
			if includeBody && ireq.GetBody != nil {
				req.Body, err = ireq.GetBody()
				if err != nil {
					resp.closeBody()
					return nil, uerr(err)
				}
				req.ContentLength = ireq.ContentLength
			}

			copyHeaders(req)

			if ref := refererForURL(reqs[len(reqs)-1].URL, req.URL); ref != "" {
				req.Header.Set("Referer", ref)
			}
			err = c.checkRedirect(req, reqs)

			if err == ErrUseLastResponse {
				return resp, nil
			}

			const maxBodySlurpSize = 2 << 10
			if resp.ContentLength == -1 || resp.ContentLength <= maxBodySlurpSize {
				io.CopyN(io.Discard, resp.Body, maxBodySlurpSize)
			}
			resp.Body.Close()

				ue := uerr(err)
				ue.(*url.Error).URL = loc
				return resp, ue
			}
		}

		reqs = append(reqs, req)
		var err error
		var didTimeout func() bool

			reqBodyClosed = true
			if !deadline.IsZero() && didTimeout() {

					err:     err.Error() + " (Client.Timeout exceeded while awaiting headers)",
					timeout: true,
				}
			}
			return nil, uerr(err)
		}

		var shouldRedirect bool
		redirectMethod, shouldRedirect, includeBody = redirectBehavior(req.Method, resp, reqs[0])
		if !shouldRedirect {
			return resp, nil
		}

		req.closeBody()
	}
}

	var (
		ireqhdr  = cloneOrMakeHeader(ireq.Header)
		icookies map[string][]*Cookie
	)
	if c.Jar != nil && ireq.Header.Get("Cookie") != "" {
		icookies = make(map[string][]*Cookie)
		for _, c := range ireq.Cookies() {
			icookies[c.Name] = append(icookies[c.Name], c)
		}
	}

	preq := ireq // The previous request

		if c.Jar != nil && icookies != nil {
			var changed bool
			resp := req.Response // The response that caused the upcoming redirect
			for _, c := range resp.Cookies() {
				if _, ok := icookies[c.Name]; ok {
					delete(icookies, c.Name)
					changed = true
				}
			}
			if changed {
				ireqhdr.Del("Cookie")
				var ss []string
				for _, cs := range icookies {
					for _, c := range cs {
						ss = append(ss, c.Name+"="+c.Value)
					}
				}
				sort.Strings(ss) // Ensure deterministic headers
				ireqhdr.Set("Cookie", strings.Join(ss, "; "))
			}
		}

		for k, vv := range ireqhdr {
			if shouldCopyHeaderOnRedirect(k, preq.URL, req.URL) {
				req.Header[k] = vv
			}
		}

		preq = req // Update previous Request with the current request
	}
}

func defaultCheckRedirect(req *Request, via []*Request) error {
	if len(via) >= 10 {
		return errors.New("stopped after 10 redirects")
	}
	return nil
}

func Post(url, contentType string, body io.Reader) (resp *Response, err error) {
	return DefaultClient.Post(url, contentType, body)
}

func (c *Client) Post(url, contentType string, body io.Reader) (resp *Response, err error) {
	req, err := NewRequest("POST", url, body)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", contentType)
	return c.Do(req)
}

func PostForm(url string, data url.Values) (resp *Response, err error) {
	return DefaultClient.PostForm(url, data)
}

func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error) {
	return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
}

func Head(url string) (resp *Response, err error) {
	return DefaultClient.Head(url)
}

func (c *Client) Head(url string) (resp *Response, err error) {
	req, err := NewRequest("HEAD", url, nil)
	if err != nil {
		return nil, err
	}
	return c.Do(req)
}

func (c *Client) CloseIdleConnections() {
	type closeIdler interface {
		CloseIdleConnections()
	}
	if tr, ok := c.transport().(closeIdler); ok {
		tr.CloseIdleConnections()
	}
}

type cancelTimerBody struct {
	stop          func() // stops the time.Timer waiting to cancel the request
	rc            io.ReadCloser
	reqDidTimeout func() bool
}

func (b *cancelTimerBody) Read(p []byte) (n int, err error) {
	n, err = b.rc.Read(p)
	if err == nil {
		return n, nil
	}
	b.stop()
	if err == io.EOF {
		return n, err
	}
	if b.reqDidTimeout() {
		err = &httpError{
			err:     err.Error() + " (Client.Timeout or context cancellation while reading body)",
			timeout: true,
		}
	}
	return n, err
}

func (b *cancelTimerBody) Close() error {
	err := b.rc.Close()
	b.stop()
	return err
}

func shouldCopyHeaderOnRedirect(headerKey string, initial, dest *url.URL) bool {
	switch CanonicalHeaderKey(headerKey) {

		ihost := canonicalAddr(initial)
		dhost := canonicalAddr(dest)
		return isDomainOrSubdomain(dhost, ihost)

	return true
}

func isDomainOrSubdomain(sub, parent string) bool {
	if sub == parent {
		return true

	if !strings.HasSuffix(sub, parent) {
		return false
	}
	return sub[len(sub)-len(parent)-1] == '.'
}

func stripPassword(u *url.URL) string {
	_, passSet := u.User.Password()
	if passSet {
		return strings.Replace(u.String(), u.User.String()+"@", u.User.Username()+":***@", 1)
	}
	return u.String()