package mijia

import (
	"bytes"
	"compress/gzip"
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"testing"
	"time"

	"github.com/mdp/qrterminal/v3"
)

var errQRWriterFailed = errors.New("QR writer failed")

type failThenBlockWriter struct {
	calls       atomic.Int32
	failOnCall  int32
	blockWrites chan struct{}
}

func (writer *failThenBlockWriter) Write(payload []byte) (int, error) {
	call := writer.calls.Add(1)
	if call == writer.failOnCall {
		return 0, errQRWriterFailed
	}
	if call > writer.failOnCall {
		<-writer.blockWrites
	}
	return len(payload), nil
}

func TestRecordingWriterStopsAfterFirstError(t *testing.T) {
	underlying := &failThenBlockWriter{failOnCall: 1, blockWrites: make(chan struct{})}
	writer := &recordingWriter{w: underlying}
	done := make(chan struct{})
	go func() {
		qrterminal.GenerateHalfBlock("https://qr.example/login", qrterminal.L, writer)
		close(done)
	}()

	select {
	case <-done:
	case <-time.After(time.Second):
		close(underlying.blockWrites)
		<-done
		t.Fatal("GenerateHalfBlock blocked after the first write failure")
	}
	if calls := underlying.calls.Load(); calls != 1 {
		t.Fatalf("underlying Write calls = %d, want 1", calls)
	}
	if !errors.Is(writer.err, errQRWriterFailed) {
		t.Fatalf("recorded error = %v, want %v", writer.err, errQRWriterFailed)
	}
}

func TestParseServiceResponse(t *testing.T) {
	var result struct {
		Code int `json:"code"`
	}
	if err := parseServiceResponse([]byte(`&&&START&&&{"code":0}`), &result); err != nil {
		t.Fatal(err)
	}
	if result.Code != 0 {
		t.Fatalf("code = %d", result.Code)
	}
}

func TestParseLongPollResponseAcceptsNumericIdentifiers(t *testing.T) {
	var result longPollData
	if err := parseServiceResponse([]byte(`&&&START&&&{"code":0,"nonce":1784441289426,"userId":123456789,"cUserId":987654321}`), &result); err != nil {
		t.Fatal(err)
	}
	if result.Nonce != "1784441289426" {
		t.Fatalf("nonce = %q, want 1784441289426", result.Nonce)
	}
	if result.UserID != "123456789" {
		t.Fatalf("userId = %q, want 123456789", result.UserID)
	}
	if result.CUserID != "987654321" {
		t.Fatalf("cUserId = %q, want 987654321", result.CUserID)
	}
}

func TestSaveAuthDataUses0600AndStableFields(t *testing.T) {
	directory := t.TempDir()
	client, err := NewClient(directory)
	if err != nil {
		t.Fatal(err)
	}
	client.setAuthData(AuthData{UA: "agent", DeviceID: "device", Extra: map[string]string{"yetAnotherServiceToken": "extra"}})
	if err := client.saveAuthData(); err != nil {
		t.Fatal(err)
	}
	info, err := os.Stat(filepath.Join(directory, "auth.json"))
	if err != nil {
		t.Fatal(err)
	}
	if info.Mode().Perm() != 0o600 {
		t.Fatalf("permissions = %o, want 600", info.Mode().Perm())
	}
	contents, err := os.ReadFile(filepath.Join(directory, "auth.json"))
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Contains(contents, []byte(`"deviceId"`)) || !bytes.Contains(contents, []byte(`"yetAnotherServiceToken"`)) {
		t.Fatalf("saved JSON = %s", contents)
	}
}

func TestLoginSilentlyRefreshesPassToken(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/serviceLogin":
			writeGzipResponse(t, writer, `&&&START&&&{"code":0,"location":"`+serverURL(request)+`/refresh","ssecurity":"`+testSsecurity+`"}`)
		case "/refresh":
			http.SetCookie(writer, &http.Cookie{Name: "serviceToken", Value: "new-token", Path: "/"})
			http.SetCookie(writer, &http.Cookie{Name: "cUserId", Value: "new-c-user", Path: "/"})
			writeGzipResponse(t, writer, "ok")
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()
	client := testClient(t, server.Client())
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.updateAuthData(func(authData *AuthData) { authData.PassToken = "pass-token" })

	auth, err := client.Login(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if auth.ServiceToken != "new-token" || auth.CUserID != "new-c-user" {
		t.Fatalf("auth = %#v", auth)
	}
}

func TestRefreshRejectsMissingNewServiceTokenWithoutSaving(t *testing.T) {
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/v2/message/v2/check_new_msg":
			_, _ = io.WriteString(writer, `{"code":-10030,"message":"expired"}`)
		case "/serviceLogin":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"location":"`+server.URL+`/refresh","ssecurity":"`+testSsecurity+`"}`)
		case "/refresh":
			http.SetCookie(writer, &http.Cookie{Name: "cUserId", Value: "new-c-user", Path: "/"})
			_, _ = io.WriteString(writer, "ok")
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client := testClient(t, server.Client())
	client.baseURL = server.URL
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.availabilityValid = false
	client.updateAuthData(func(authData *AuthData) { authData.PassToken = "pass-token" })
	if err := client.saveAuthData(); err != nil {
		t.Fatal(err)
	}
	before, err := os.ReadFile(client.authPath)
	if err != nil {
		t.Fatal(err)
	}

	err = client.refreshToken(context.Background())
	if !errors.Is(err, ErrReauthenticationRequired) {
		t.Fatalf("refreshToken() error = %v, want ErrReauthenticationRequired", err)
	}
	var loginErr *LoginError
	if !errors.As(err, &loginErr) {
		t.Fatalf("refreshToken() error = %v, want LoginError", err)
	}
	after, readErr := os.ReadFile(client.authPath)
	if readErr != nil {
		t.Fatal(readErr)
	}
	if !bytes.Equal(after, before) {
		t.Fatalf("auth file changed after failed refresh\nbefore: %s\nafter: %s", before, after)
	}
	if auth := client.AuthData(); auth.ServiceToken != "service-token" || auth.CUserID != "c-user" {
		t.Fatalf("auth changed after failed refresh: %#v", auth)
	}
}

func TestRefreshWithoutNewTokenRequiresReauthentication(t *testing.T) {
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/v2/message/v2/check_new_msg":
			_, _ = io.WriteString(writer, `{"code":-10030,"message":"expired"}`)
		case "/serviceLogin":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":70016,"location":"`+server.URL+`/qr"}`)
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client := testClient(t, server.Client())
	client.baseURL = server.URL
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.availabilityValid = false

	err := client.refreshToken(context.Background())
	if !errors.Is(err, ErrReauthenticationRequired) {
		t.Fatalf("refreshToken() error = %v, want ErrReauthenticationRequired", err)
	}
	var loginErr *LoginError
	if !errors.As(err, &loginErr) {
		t.Fatalf("refreshToken() error = %v, want LoginError", err)
	}
	if loginErr.Code != -1 || loginErr.Message != "刷新Token失败，请重新登录" {
		t.Fatalf("LoginError = %#v", loginErr)
	}
}

func TestQRLoginTimeoutDoesNotRequireReauthentication(t *testing.T) {
	ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(-time.Second))
	defer cancel()

	client := testClient(t, http.DefaultClient)
	_, err := client.completeQRLogin(ctx, qrLoginData{LP: "https://example.invalid/long-poll"})
	var loginErr *LoginError
	if !errors.As(err, &loginErr) {
		t.Fatalf("completeQRLogin() error = %v, want LoginError", err)
	}
	if loginErr.Code != -1 {
		t.Fatalf("LoginError.Code = %d, want -1", loginErr.Code)
	}
	if errors.Is(err, ErrReauthenticationRequired) {
		t.Fatalf("completeQRLogin() error = %v, do not want ErrReauthenticationRequired", err)
	}
}

func TestAuthDataReturnsDeepCopy(t *testing.T) {
	client := testClient(t, http.DefaultClient)
	client.updateAuthData(func(authData *AuthData) { authData.Extra = map[string]string{"cookie": "original"} })

	snapshot := client.AuthData()
	snapshot.Extra["cookie"] = "changed"
	if got := client.AuthData().Extra["cookie"]; got != "original" {
		t.Fatalf("stored extra cookie = %q, want original", got)
	}
}

func TestLoginRejectsOversizedQRCode(t *testing.T) {
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/serviceLogin":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":70016,"location":"`+server.URL+`/prepare"}`)
		case "/loginUrl":
			loginURL := strings.Repeat("x", 10000)
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"loginUrl":"`+loginURL+`","lp":"`+server.URL+`/lp"}`)
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client, err := NewClient(t.TempDir(), WithHTTPClient(server.Client()))
	if err != nil {
		t.Fatal(err)
	}
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.loginURL = server.URL + "/loginUrl"
	client.qrWriter = io.Discard

	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	if _, err := client.Login(ctx); err == nil || !strings.Contains(err.Error(), "QR code") {
		t.Fatalf("Login() error = %v, want QR encoding error", err)
	}
}

func TestLoginQRCoreFlow(t *testing.T) {
	var output bytes.Buffer
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/serviceLogin":
			location := server.URL + `/prepare?sid=mijia&foo=bar`
			_, _ = io.WriteString(writer, `&&&START&&&{"code":70016,"location":"`+location+`"}`)
		case "/loginUrl":
			query := request.URL.Query()
			for _, key := range []string{"theme", "bizDeviceType", "_hasLogo", "_qrsize", "_dc", "sid", "foo"} {
				if _, ok := query[key]; !ok {
					t.Errorf("login query missing %q: %s", key, request.URL.RawQuery)
				}
			}
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"loginUrl":"https://qr.example/login","qr":"https://qr.example/image","lp":"`+server.URL+`/lp"}`)
		case "/lp":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"psecurity":"p","nonce":"n","ssecurity":"`+testSsecurity+`","passToken":"pass","userId":"user","cUserId":"cuser","location":"`+server.URL+`/callback"}`)
		case "/callback":
			http.SetCookie(writer, &http.Cookie{Name: "serviceToken", Value: "service", Path: "/"})
			http.SetCookie(writer, &http.Cookie{Name: "yetAnotherServiceToken", Value: "another", Path: "/"})
			_, _ = io.WriteString(writer, "ok")
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client, err := NewClient(t.TempDir(), WithHTTPClient(server.Client()))
	if err != nil {
		t.Fatal(err)
	}
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.loginURL = server.URL + "/loginUrl"
	client.qrWriter = &output
	auth, err := client.Login(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if auth.ServiceToken != "service" || auth.Psecurity != "p" || auth.ExpireTime <= auth.SaveTime {
		t.Fatalf("auth = %#v", auth)
	}
	if auth.YetAnotherServiceToken != "another" {
		t.Fatalf("yetAnotherServiceToken = %q", auth.YetAnotherServiceToken)
	}
	if !strings.Contains(output.String(), "qr.example/login") {
		t.Fatalf("QR output does not contain login URL")
	}

	contents, err := os.ReadFile(client.authPath)
	if err != nil {
		t.Fatal(err)
	}
	var saved AuthData
	if err := json.Unmarshal(contents, &saved); err != nil || saved.ServiceToken != "service" {
		t.Fatalf("saved auth = %#v, error = %v", saved, err)
	}
}

func TestLoginReturnsQROutputErrorBeforeLongPoll(t *testing.T) {
	var longPollRequests atomic.Int32
	qrWriter := &failThenBlockWriter{failOnCall: 2, blockWrites: make(chan struct{})}
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/serviceLogin":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":70016,"location":"`+server.URL+`/prepare"}`)
		case "/loginUrl":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"loginUrl":"https://qr.example/login","qr":"https://qr.example/image","lp":"`+server.URL+`/lp"}`)
		case "/lp":
			longPollRequests.Add(1)
			_, _ = io.WriteString(writer, `&&&START&&&{"code":70016}`)
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client, err := NewClient(t.TempDir(), WithHTTPClient(server.Client()), WithQRWriter(qrWriter))
	if err != nil {
		t.Fatal(err)
	}
	client.serviceLoginURL = server.URL + "/serviceLogin"
	client.loginURL = server.URL + "/loginUrl"

	done := make(chan error, 1)
	go func() {
		_, loginErr := client.Login(context.Background())
		done <- loginErr
	}()
	select {
	case err = <-done:
	case <-time.After(time.Second):
		close(qrWriter.blockWrites)
		<-done
		t.Fatal("Login() blocked after QR output failed")
	}
	if !errors.Is(err, errQRWriterFailed) {
		t.Fatalf("Login() error = %v, want %v", err, errQRWriterFailed)
	}
	if requests := longPollRequests.Load(); requests != 0 {
		t.Fatalf("long-poll requests = %d, want 0", requests)
	}
}

func TestQRLoginRejectsIncompleteCallbackWithoutSaving(t *testing.T) {
	var server *httptest.Server
	server = httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		switch request.URL.Path {
		case "/lp":
			_, _ = io.WriteString(writer, `&&&START&&&{"code":0,"ssecurity":"`+testSsecurity+`","passToken":"pass","userId":"user","cUserId":"cuser","location":"`+server.URL+`/callback"}`)
		case "/callback":
			_, _ = io.WriteString(writer, "ok")
		default:
			http.NotFound(writer, request)
		}
	}))
	defer server.Close()

	client := testClient(t, server.Client())
	_, err := client.completeQRLogin(context.Background(), qrLoginData{LP: server.URL + "/lp"})
	var loginErr *LoginError
	if !errors.As(err, &loginErr) {
		t.Fatalf("completeQRLogin() error = %v, want LoginError", err)
	}
	if _, statErr := os.Stat(client.authPath); !errors.Is(statErr, os.ErrNotExist) {
		t.Fatalf("auth file stat error = %v, want not exist", statErr)
	}
}

func serverURL(request *http.Request) string {
	return "http://" + request.Host
}

func writeGzipResponse(t *testing.T, writer http.ResponseWriter, body string) {
	t.Helper()
	writer.Header().Set("Content-Encoding", "gzip")
	gzipWriter := gzip.NewWriter(writer)
	if _, err := io.WriteString(gzipWriter, body); err != nil {
		t.Errorf("write gzip response: %v", err)
	}
	if err := gzipWriter.Close(); err != nil {
		t.Errorf("close gzip response: %v", err)
	}
}