package browserstack

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/http/cookiejar"
	"strings"

	regexp "github.com/wasilibs/go-re2"
	"golang.org/x/net/publicsuffix"

	"github.com/trufflesecurity/trufflehog/v3/pkg/common"
	"github.com/trufflesecurity/trufflehog/v3/pkg/detectors"
	"github.com/trufflesecurity/trufflehog/v3/pkg/pb/detectorspb"
)

type Scanner struct {
	detectors.DefaultMultiPartCredentialProvider
	client *http.Client
}

// Ensure the Scanner satisfies the interface at compile time.
var _ detectors.Detector = (*Scanner)(nil)

const browserStackAPIURL = "https://www.browserstack.com/automate/plan.json"

var (
	// Make sure that your group is surrounded in boundary characters such as below to reduce false positives.
	keyPat  = regexp.MustCompile(detectors.PrefixRegex([]string{"hub-cloud.browserstack.com", "accessKey", "\"access_Key\":", "ACCESS_KEY", "key", "browserstackKey", "BS_AUTHKEY", "BROWSERSTACK_ACCESS_KEY"}) + `\b([0-9a-zA-Z]{20})\b`)
	userPat = regexp.MustCompile(detectors.PrefixRegex([]string{"hub-cloud.browserstack.com", "userName", "\"username\":", "USER_NAME", "user", "browserstackUser", "BS_USERNAME", "BROWSERSTACK_USERNAME"}) + `\b([a-zA-Z\d]{3,18}[._-]*[a-zA-Z\d]{6,11})\b`)
)

// Keywords are used for efficiently pre-filtering chunks.
// Use identifiers in the secret preferably, or the provider name.
func (s Scanner) Keywords() []string {
	return []string{"browserstack"}
}

func (s Scanner) getClient(cookieJar *cookiejar.Jar) *http.Client {
	if s.client != nil {
		s.client.Jar = cookieJar
		return s.client
	}
	// Using custom HTTP client instead of common.SaneHttpClient() here because, for unknown reasons, browserstack blocks those requests even with cookie jar attached
	return &http.Client{
		Jar: cookieJar,
	}
}

// FromData will find and optionally verify BrowserStack secrets in a given set of bytes.
func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (results []detectors.Result, err error) {
	dataStr := string(data)
	matches := keyPat.FindAllStringSubmatch(dataStr, -1)
	userMatches := userPat.FindAllStringSubmatch(dataStr, -1)

	for _, match := range matches {
		resMatch := strings.TrimSpace(match[1])

		for _, userMatch := range userMatches {

			resUserMatch := strings.TrimSpace(userMatch[1])

			s1 := detectors.Result{
				DetectorType: detectorspb.DetectorType_BrowserStack,
				Raw:          []byte(resMatch),
				RawV2:        []byte(resMatch + resUserMatch),
			}

			if verify {
				// browserstack (via cloudflare) requires cookies to be enabled
				jar, err := cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
				if err != nil {
					return nil, err
				}
				client := s.getClient(jar)

				isVerified, verificationErr := verifyBrowserStackCredentials(ctx, client, resUserMatch, resMatch)
				s1.Verified = isVerified
				s1.SetVerificationError(verificationErr, resMatch)
			}

			results = append(results, s1)
		}
	}

	return results, nil
}

func verifyBrowserStackCredentials(ctx context.Context, client *http.Client, username, accessKey string) (bool, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, browserStackAPIURL, nil)
	if err != nil {
		return false, err
	}
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("User-Agent", common.UserAgent())

	req.SetBasicAuth(username, accessKey)

	res, err := client.Do(req)
	if err != nil {
		return false, err
	}
	defer res.Body.Close()

	if res.StatusCode == http.StatusOK {
		return true, nil
	} else if res.StatusCode == http.StatusForbidden {
		// Sometimes browserstack (via Cloudflare) will block requests for security
		body, err := io.ReadAll(res.Body)
		if err != nil {
			return false, err
		}
		if strings.Contains(string(body), "blocked") {
			return false, fmt.Errorf("blocked by browserstack")
		}
	} else if res.StatusCode != http.StatusUnauthorized {
		return false, fmt.Errorf("unexpected HTTP response status %d", res.StatusCode)
	}

	return false, nil
}

func (s Scanner) Type() detectorspb.DetectorType {
	return detectorspb.DetectorType_BrowserStack
}

func (s Scanner) Description() string {
	return "BrowserStack is a cloud web and mobile testing platform. BrowserStack credentials can be used to access and manage testing environments."
}
