// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package rpc

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

func confirmStatusCode(t *testing.T, got, want int) {
	t.Helper()
	if got == want {
		return
	}
	if gotName := http.StatusText(got); len(gotName) > 0 {
		if wantName := http.StatusText(want); len(wantName) > 0 {
			t.Fatalf("response status code: got %d (%s), want %d (%s)", got, gotName, want, wantName)
		}
	}
	t.Fatalf("response status code: got %d, want %d", got, want)
}

func confirmRequestValidationCode(t *testing.T, method, contentType, body string, expectedStatusCode int) {
	t.Helper()

	s := NewServer()
	request := httptest.NewRequest(method, "http://url.com", strings.NewReader(body))
	if len(contentType) > 0 {
		request.Header.Set("Content-Type", contentType)
	}
	code, err := s.validateRequest(request)
	if code == 0 {
		if err != nil {
			t.Errorf("validation: got error %v, expected nil", err)
		}
	} else if err == nil {
		t.Errorf("validation: code %d: got nil, expected error", code)
	}
	confirmStatusCode(t, code, expectedStatusCode)
}

func TestHTTPErrorResponseWithDelete(t *testing.T) {
	confirmRequestValidationCode(t, http.MethodDelete, contentType, "", http.StatusMethodNotAllowed)
}

func TestHTTPErrorResponseWithPut(t *testing.T) {
	confirmRequestValidationCode(t, http.MethodPut, contentType, "", http.StatusMethodNotAllowed)
}

func TestHTTPErrorResponseWithMaxContentLength(t *testing.T) {
	body := make([]rune, defaultBodyLimit+1)
	confirmRequestValidationCode(t,
		http.MethodPost, contentType, string(body), http.StatusRequestEntityTooLarge)
}

func TestHTTPErrorResponseWithEmptyContentType(t *testing.T) {
	confirmRequestValidationCode(t, http.MethodPost, "", "", http.StatusUnsupportedMediaType)
}

func TestHTTPErrorResponseWithValidRequest(t *testing.T) {
	confirmRequestValidationCode(t, http.MethodPost, contentType, "", 0)
}

func confirmHTTPRequestYieldsStatusCode(t *testing.T, method, contentType, body string, expectedStatusCode int) {
	t.Helper()
	s := Server{}
	ts := httptest.NewServer(&s)
	defer ts.Close()

	request, err := http.NewRequest(method, ts.URL, strings.NewReader(body))
	if err != nil {
		t.Fatalf("failed to create a valid HTTP request: %v", err)
	}
	if len(contentType) > 0 {
		request.Header.Set("Content-Type", contentType)
	}
	resp, err := http.DefaultClient.Do(request)
	if err != nil {
		t.Fatalf("request failed: %v", err)
	}
	resp.Body.Close()
	confirmStatusCode(t, resp.StatusCode, expectedStatusCode)
}

func TestHTTPResponseWithEmptyGet(t *testing.T) {
	confirmHTTPRequestYieldsStatusCode(t, http.MethodGet, "", "", http.StatusOK)
}

// This checks that maxRequestContentLength is not applied to the response of a request.
func TestHTTPRespBodyUnlimited(t *testing.T) {
	const respLength = defaultBodyLimit * 3

	s := NewServer()
	defer s.Stop()
	s.RegisterName("test", largeRespService{respLength})
	ts := httptest.NewServer(s)
	defer ts.Close()

	c, err := DialHTTP(ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()

	var r string
	if err := c.Call(&r, "test_largeResp"); err != nil {
		t.Fatal(err)
	}
	if len(r) != respLength {
		t.Fatalf("response has wrong length %d, want %d", len(r), respLength)
	}
}

// Tests that an HTTP error results in an HTTPError instance
// being returned with the expected attributes.
func TestHTTPErrorResponse(t *testing.T) {
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "error has occurred!", http.StatusTeapot)
	}))
	defer ts.Close()

	c, err := DialHTTP(ts.URL)
	if err != nil {
		t.Fatal(err)
	}

	var r string
	err = c.Call(&r, "test_method")
	if err == nil {
		t.Fatal("error was expected")
	}

	httpErr, ok := err.(HTTPError)
	if !ok {
		t.Fatalf("unexpected error type %T", err)
	}

	if httpErr.StatusCode != http.StatusTeapot {
		t.Error("unexpected status code", httpErr.StatusCode)
	}
	if httpErr.Status != "418 I'm a teapot" {
		t.Error("unexpected status text", httpErr.Status)
	}
	if body := string(httpErr.Body); body != "error has occurred!\n" {
		t.Error("unexpected body", body)
	}

	if errMsg := httpErr.Error(); errMsg != "418 I'm a teapot: error has occurred!\n" {
		t.Error("unexpected error message", errMsg)
	}
}

func TestHTTPPeerInfo(t *testing.T) {
	s := newTestServer()
	defer s.Stop()
	ts := httptest.NewServer(s)
	defer ts.Close()

	c, err := Dial(ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	c.SetHeader("user-agent", "ua-testing")
	c.SetHeader("origin", "origin.example.com")

	// Request peer information.
	var info PeerInfo
	if err := c.Call(&info, "test_peerInfo"); err != nil {
		t.Fatal(err)
	}

	if info.RemoteAddr == "" {
		t.Error("RemoteAddr not set")
	}
	if info.Transport != "http" {
		t.Errorf("wrong Transport %q", info.Transport)
	}
	if info.HTTP.Version != "HTTP/1.1" {
		t.Errorf("wrong HTTP.Version %q", info.HTTP.Version)
	}
	if info.HTTP.UserAgent != "ua-testing" {
		t.Errorf("wrong HTTP.UserAgent %q", info.HTTP.UserAgent)
	}
	if info.HTTP.Origin != "origin.example.com" {
		t.Errorf("wrong HTTP.Origin %q", info.HTTP.UserAgent)
	}
}

func TestNewContextWithHeaders(t *testing.T) {
	expectedHeaders := 0
	server := httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		for i := 0; i < expectedHeaders; i++ {
			key, want := fmt.Sprintf("key-%d", i), fmt.Sprintf("val-%d", i)
			if have := request.Header.Get(key); have != want {
				t.Errorf("wrong request headers for %s, want: %s, have: %s", key, want, have)
			}
		}
		writer.WriteHeader(http.StatusOK)
		_, _ = writer.Write([]byte(`{}`))
	}))
	defer server.Close()

	client, err := Dial(server.URL)
	if err != nil {
		t.Fatalf("failed to dial: %s", err)
	}
	defer client.Close()

	newHdr := func(k, v string) http.Header {
		header := http.Header{}
		header.Set(k, v)
		return header
	}
	ctx1 := NewContextWithHeaders(context.Background(), newHdr("key-0", "val-0"))
	ctx2 := NewContextWithHeaders(ctx1, newHdr("key-1", "val-1"))
	ctx3 := NewContextWithHeaders(ctx2, newHdr("key-2", "val-2"))

	expectedHeaders = 3
	if err := client.CallContext(ctx3, nil, "test"); err != ErrNoResult {
		t.Error("call failed", err)
	}

	expectedHeaders = 2
	if err := client.CallContext(ctx2, nil, "test"); err != ErrNoResult {
		t.Error("call failed:", err)
	}
}