package pastebin

import (
	"bytes"
	"context"
	"io"
	"mime/multipart"
	"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{}

// 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{"pastebin"}) + `\b([a-zA-Z0-9_]{32})\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{"pastebin"}
}

// FromData will find and optionally verify Pastebin 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)

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

		s1 := detectors.Result{
			DetectorType: detector_typepb.DetectorType_Pastebin,
			Raw:          []byte(resMatch),
			SecretParts:  map[string]string{"key": resMatch},
		}

		if verify {
			body := &bytes.Buffer{}
			writer := multipart.NewWriter(body)
			fw, err := writer.CreateFormField("api_dev_key")
			if err != nil {
				continue
			}
			_, err = io.Copy(fw, strings.NewReader(resMatch))
			if err != nil {
				continue
			}
			fw, err = writer.CreateFormField("api_paste_code")
			if err != nil {
				continue
			}
			_, err = io.Copy(fw, strings.NewReader("test"))
			if err != nil {
				continue
			}
			fw, err = writer.CreateFormField("api_option")
			if err != nil {
				continue
			}
			_, err = io.Copy(fw, strings.NewReader("paste"))
			if err != nil {
				continue
			}
			_ = writer.Close()
			req, err := http.NewRequestWithContext(ctx, "POST", "https://pastebin.com/api/api_post.php", bytes.NewReader(body.Bytes()))
			if err != nil {
				continue
			}
			req.Header.Add("Content-Type", writer.FormDataContentType())
			res, err := client.Do(req)
			if err == nil {
				defer func() { _ = res.Body.Close() }()
				if res.StatusCode >= 200 && res.StatusCode < 300 {
					s1.Verified = true
				}
			}
		}

		results = append(results, s1)
	}

	return results, nil
}

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

func (s Scanner) Description() string {
	return "Pastebin is a website where users can store plain text. Pastebin keys can be used to access and manipulate stored data."
}
