package appcues

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

	regexp "github.com/wasilibs/go-re2"

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

type Scanner struct {
	detectors.DefaultMultiPartCredentialProvider
}

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

var (
	client = common.SaneHttpClient()

	// Make sure that your group is surrounded in boundary characters such as below to reduce false positives.
	keyPat  = regexp.MustCompile(detectors.PrefixRegex([]string{"appcues"}) + `\b([a-z0-9-]{36})\b`)
	userPat = regexp.MustCompile(detectors.PrefixRegex([]string{"appcues"}) + `\b([a-z0-9-]{39})\b`)
	idPat   = regexp.MustCompile(detectors.PrefixRegex([]string{"appcues"}) + `\b([0-9]{5})\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{"appcues"}
}

// FromData will find and optionally verify Appcues 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)
	idMatches := idPat.FindAllStringSubmatch(dataStr, -1)

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

		for _, userMatch := range userMatches {

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

			for _, idMatch := range idMatches {

				resIdMatch := strings.TrimSpace(idMatch[1])

				s1 := detectors.Result{
					DetectorType: detector_typepb.DetectorType_Appcues,
					Raw:          []byte(resMatch),
					RawV2:        []byte(resMatch + resUserMatch),
				}
				if verify {
					isVerified, err := verifyMatch(ctx, client, resUserMatch, resMatch, resIdMatch)
					s1.Verified = isVerified
					s1.SetVerificationError(err, resUserMatch, resMatch, resIdMatch)
				}

				results = append(results, s1)
			}
		}
	}

	return results, nil
}

func verifyMatch(ctx context.Context, client *http.Client, resUserMatch, resMatch, resIdMatch string) (bool, error) {
	// Reference: https://api.appcues.com/v2/docs?_gl=1#responses
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("https://api.appcues.com/v2/accounts/%s/flows", resIdMatch), http.NoBody)
	if err != nil {
		return false, err
	}
	req.SetBasicAuth(resUserMatch, resMatch)
	res, err := client.Do(req)
	if err != nil {
		return false, err
	}
	defer func() {
		_, _ = io.Copy(io.Discard, res.Body)
		_ = res.Body.Close()
	}()
	switch res.StatusCode {
	case http.StatusOK:
		return true, nil
	case http.StatusUnauthorized, http.StatusForbidden, http.StatusBadRequest:
		return false, nil
	default:
		return false, fmt.Errorf("unexpected status code: %d", res.StatusCode)
	}
}

func (s Scanner) Type() detector_typepb.DetectorType {
	return detector_typepb.DetectorType_Appcues
}

func (s Scanner) Description() string {
	return "Appcues is a user engagement platform that helps create personalized user experiences. The detected credentials can be used to access and manage user engagement flows and data."
}
