import time, sys, json
from botocore.vendored import requests
from datetime import datetime, timedelta
#from auth import nvdToken


####  READ ME ###
##
# -- rename file from .txt to .py
# -- Checks the NVD Database for any new or updated vulnerabilities that have been released within the past 60 minutes. 
# -- This file has been modified to run in lambda, to which lambda needs run hourly.
# -- To test locally, uncomment lines 18, 117 and 118. Comment line 19
# -- Data has been redacted and the webhook would need to be updated with a working Slack Webhook
# -- Obtaining an API token from NVD is not required for this call. 24 calls within a day is well within their API Token-less requirements
# -- Vulnerabilities may be mssing a v3.1, v3.0 and/or v2 CVSS scores. A "missingScore" will replace the value in this case.
# -- Lastly - due to the amount of vulns that occur, the minimum CVSS rating is 8. Adjust this accordingly. 

#def main():
def lambda_handler(event, context):

    #currentHour, currentDate, currentMonth, currentYear = getDateTime()
    #lambda runs in UTC. I was having trouble setting the Z value in the url
    #to 00:00, so I set the deltaHours to 8 hours back instead of 1 to
    #compensate for this setback
    pHour, pDate, pMonth, pYear = getPreviousDateTime(8)
    x = 0
    # time.sleep(6)
    #while x < 50:
    results = askNVD(pHour, pDate, pMonth, pYear)
    messageText = ""
    for i in results:
        messageText += f"{i}\n"


    sendSlackMessage(messageText)


def getPreviousDateTime(deltaHours):
    lastHourDate = datetime.now() - timedelta(hours = deltaHours)
    pHour = lastHourDate.strftime("%H")
    pDate = lastHourDate.strftime("%d")
    pMonth = lastHourDate.strftime("%m")
    pYear = lastHourDate.strftime("%Y")
    return pHour, pDate, pMonth, pYear



def askNVD(pHour, pDate, pMonth, pYear):
    nvdToken = "4eebab29-2d4e-4f86-b1d2-290cea49eb3e"
    rootUrl = "https://services.nvd.nist.gov/rest/json/cves/2.0/?"
    customUrl = f'lastModStartDate={pYear}-{pMonth}-{pDate}T{pHour}:00:00.000%2D07:00&lastModEndDate={pYear}-{pMonth}-{pDate}T{pHour}:59:59.999%2D07:00'
    fullUrl = rootUrl + customUrl

    headers = {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
        'Authorization': 'Bearer {}'.format(nvdToken)
    }


    response = requests.get(fullUrl, headers=headers)#, json=data)
    jsonResponse = response.json()
    noResults = jsonResponse["resultsPerPage"]

    results = []
    myCount = 0
    while myCount < noResults:
        cveID = jsonResponse["vulnerabilities"][myCount]["cve"]["id"]
        cveDesc = jsonResponse["vulnerabilities"][myCount]["cve"]["descriptions"][0]["value"]
        cveDescTrunc = cveDesc[0:99]
        try:
            cveScore = jsonResponse["vulnerabilities"][myCount]["cve"]["metrics"]["cvssMetricV31"][0]["cvssData"]["baseScore"]
        except:
            try:
                cveScore = jsonResponse["vulnerabilities"][myCount]["cve"]["metrics"]["cvssMetricV30"][0]["cvssData"]["baseScore"]
            except:
                try:
                    cveScore = jsonResponse["vulnerabilities"][myCount]["cve"]["metrics"]["cvssMetricV2"][0]["cvssData"]["baseScore"]
                except:
                    cveScore = "missingScore"

        if cveScore != "missingScore":
            if float(cveScore) >= 8:
                cveUrl = f"https://nvd.nist.gov/vuln/detail/{cveID}"
                lineItem = f"<{cveUrl}|{cveID}> {cveScore} {cveDescTrunc}..."
                results.append(lineItem)

        myCount += 1

    return results


def sendSlackMessage(data):
    """Send a Slack message to a channel via a webhook.

    Args:
        payload (dict): Dictionary containing Slack message, i.e. {"text": "This is a test"}
        webhook (str): Full Slack webhook URL for your chosen channel.

    Returns:
        HTTP response code, i.e. <Response [503]>
    """
    webhook = "https://hooks.slack.com/services/[redacted]/[redacted]/[redacted]"
    
    payload = {
        "text": data,
        "username": "NVD",
        "icon_url": "https://cdn.vox-cdn.com/thumbor/cIgoJOxP3gYNl7z4wSzGsXygVtI=/0x0:2524x1730/1400x1400/filters:focal(1262x865:1263x866)/cdn.vox-cdn.com/uploads/chorus_asset/file/24528220/Screenshot_2023_03_22_at_09.43.05.png"
    }
    reqResults = requests.post(webhook, json.dumps(payload))
    print(reqResults)
    return




# if __name__ == "__main__":
#     main()