#!/usr/bin/python3

import argparse
import os
import socket
import glob
import ssl
import sys
path = os.path.dirname(os.path.realpath(__file__))
path = os.path.realpath(os.path.join(path, '..', 'lib', 'python'))
if path.startswith('/opt'):
    # if installed into system path, do not muck with things
    sys.path.append(path)
import confluent.sshutil as sshutil
import confluent.certutil as certutil
import confluent.client as client
import confluent.config.configmanager as configmanager
import subprocess
import tempfile
import shutil
import eventlet.green.socket as socket
import eventlet
import greenlet

def fprint(txt):
    sys.stdout.write(txt)
    sys.stdout.flush()


def tftp_works():
    try:
        subprocess.check_call(['curl', '--connect-timeout', '2', '-sf', 'tftp://localhost/confluent/x86_64/ipxe.efi', '-o', '/dev/null'])
        return True
    except Exception:
        return False

def emprint(txt):
    if sys.stdout.isatty():
        print('\x1b[1m\x1b[4m' + txt + '\x1b[0m')
    else:
        print(txt)

def deployment_configured():
    return os.path.exists('/var/lib/confluent/public/site/confluent_uuid')

def webserver_listening():
    try:
        conn = socket.create_connection(('localhost', 443))
        return conn
    except Exception:
        return False


def certificates_missing_ips(conn):
    # check if the tls can verify by the right CAs, then further
    # check if all ip addresses are in the certificate offered
    ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
    ctx.check_hostname = False
    for cacert in glob.glob('/var/lib/confluent/public/site/tls/*.pem'):
        ctx.load_verify_locations(cacert)
    sock = ctx.wrap_socket(conn)
    crt = sock.getpeercert()
    sans = crt.get('subjectAltName', [])
    ips = certutil.get_ip_addresses()
    missing_ips = []
    for ip in ips:
        for san in sans:
            field, val = san
            if val[-1] == '\n':
                val = val[:-1]
            if ':' in val:
                # must normalize ipv6 to a sane value
                val = socket.getaddrinfo(val, 443, proto=socket.IPPROTO_TCP)[0][-1][0]
            if ip == val:
                break
        else:
            missing_ips.append(ip)
    return missing_ips


def web_download_works():
    try:
        subprocess.check_call(['curl', '-skf', 'https://localhost/confluent-public/site/confluent_uuid', '-o', '/dev/null'])
    except Exception:
        return False
    return True
            

def nics_missing_ipv6():
    # check for ability to create AF_INET6, for kernel disabled ipv6
    a = socket.socket(socket.AF_INET6)
    ipaddrs = subprocess.check_output(['ip', '-br', 'a']).split(b'\n')
    missingnics = []
    for line in ipaddrs:
        comps = line.split()
        if not comps:
            continue
        iname, state = comps[:2]
        if iname == b'lo':
            continue
        addrs = comps[2:]
        hasv6 = False
        hasv4 = False
        for addr in addrs:
            if b'.' in addr:
                hasv4 = True
            if addr.startswith(b'fe80::'):
                hasv6 = True
        if hasv4 and not hasv6:
            missingnics.append(iname.decode('utf8'))
    return missingnics

def insecure_boot_attempts():
    insecurenodes = set([])
    with open('/var/log/confluent/events') as eventin:
        line = True
        while line:
            line = eventin.readline()
            if 'insecure mode is disabled' in line:
                line = line.split()
                insecurenodes.add(line[7])
    for node in insecurenodes:
        currattr = subprocess.check_output(['nodeattrib', node, 'deployment.useinsecureprotocols'])
        currattr = currattr.split()
        if len(currattr) > 2 and currattr[2] == b'firmware':
            continue
        else:
            return True
    return False


def uuid_matches():
    with open('/var/lib/confluent/public/site/confluent_uuid', 'r') as uuidf:
        fsuuid = uuidf.read().strip()
    dbuuid = configmanager.get_global('confluent_uuid')
    return dbuuid == fsuuid

def lookup_node(node):
    try:
        return socket.getaddrinfo(node, 0)
    except greenlet.GreenletExit:
        return None
    except Exception:
        return None

if __name__ == '__main__':
    ap = argparse.ArgumentParser(description='Run configuration checks for a system running confluent service')
    ap.add_argument('-n', '--node', help='A node name to run node specific checks against')
    args, extra = ap.parse_known_args(sys.argv)
    if len(extra) > 1:
        ap.print_help()
        sys.exit(1)
    sys.stdout.write('OS Deployment: ')
    sys.stdout.flush()
    if deployment_configured():
        print("Initialized")
        sys.stdout.write('Confluent UUID: ')
        sys.stdout.flush()
        if uuid_matches():
            print('Consistent')
        else:
            emprint('Inconsistent between confluent database and /var/lib/confluent (Example resolution: confetty set /uuid resync=1)')
        fprint('Web Server: ')
        conn = webserver_listening()
        if conn:
            print('Running')
            fprint('Web Certificate: ')
            cert = certificates_missing_ips(conn)
            if cert:
                cert = ', '.join(cert)
                emprint('Addresses missing from certificate: {0} (Example resolution: osdeploy initialize -t)'.format(cert))
            else:
                print('OK')
                fprint('Checking web download: ')
                if web_download_works():
                    print('OK')
                else:
                    emprint('Failed to download /confluent-public/site/confluent_uuid')
        else:
            emprint('Not Running (Example resolution: systemctl enable httpd --now)')
        fprint('TFTP Status: ')
        if tftp_works():
            print('OK')
        else:
            emprint('TFTP failure, PXE will not work, though media and HTTP boot can still work. (Example resolution: osdeploy initialize -p)')
        fprint('SSH root user public key: ')
        if glob.glob('/var/lib/confluent/public/site/ssh/*.rootpubkey'):
            print('OK')
        else:
            emprint('No trusted ssh keys for root user, passwordless SSH from managers to nodes may not work (Example resolution: osdeploy initialize -u)')
        if sshutil.sshver() > 7.6:
            fprint('Checking SSH Certificate authority: ')
            try:
                sshutil.prep_ssh_key('/etc/confluent/ssh/ca')
                print('OK')
            except Exception:
                emprint('Failed to load SSH authority key, deployed servers will not have host certificates for known_hosts and users may be unable to ssh between nodes without a password (Example resolution: osdeploy initialize -s)')            
            fprint('Checking confluent SSH automation key: ')
            try:
                sshutil.prep_ssh_key('/etc/confluent/ssh/automation')
                print('OK')
            except subprocess.CalledProcessError:
                emprint('Failed to load confluent automation key, syncfiles and profile ansible plays will not work (Example resolution: osdeploy initialize -a)')
        fprint('Checking for blocked insecure boot: ')
        if insecure_boot_attempts():
            emprint('Some nodes are attempting network boot using PXE or HTTP boot, but the node is not configured to allow this (Example resolution: nodegroupattrib everything deployment.useinsecureprotocols=firmware)')
        else:
            print('OK')
        fprint('Checking IPv6 enablement: ')
        nics = nics_missing_ipv6()
        if nics:
            snics = ','.join(nics)
            emprint('Some interfaces ({0}) have ipv6 disabled, and may be unable to fully perform discovery or deployment (Example resolution: nmcli c m {1} ipv6.method link-local )'.format(snics, nics[0]))
        else:
            print('OK')
    else:
        print("Uninitialized, further OS deployment checks skipped, see `osdeploy initialize` to set up OS deployment feature")
    if args.node:
        print("Performing node checks for '{}'".format(args.node))
        print("Checking node attributes in confluent: ")
        sess = client.Command()
        uuidok = False
        macok = False
        for rsp in sess.read(f'/nodes/{args.node}/attributes/all'):
            if rsp.get('errorcode', None) == 404:
                emprint(f'There is no node named "{args.node}"')
                uuidok = True  # not really, but suppress the spurious error
            uuid = rsp.get('id.uuid', {}).get('value', None)
            if uuid:
                uuidok = True
            for key in rsp:
                if key.endswith('.hwaddr'):
                    mac = rsp[key].get('value', None)
                    if mac:
                        macok = trusted
        if not uuidok and not macok:
            emprint(f'{args.node} does not have a uuid or mac address defined in id.uuid or net.*hwaddr, deployment will not work')
        fprint("Checking name resolution: ")
        lk = eventlet.spawn(lookup_node, args.node)
        eventlet.sleep(0.1)
        tries = 5
        while not lk.dead and tries > 0:
            eventlet.sleep(1)
            tries -= 1
        deaddns = False
        if not tries:
            emprint('Name resolution takes too long, check state of /etc/resolv.conf and indicated nameservers, this can produce failure to netboot or failure to commence installation')
            lk.kill()
            deaddns = True
        result = lk.wait()
        if not result and not deaddns:
            emprint('Name resolution failed for node, it is normally a good idea for the node name to resolve to an IP')
        if result:
            print("OK")
    else:
        print("Skipping node checks, no node specified (Example: confluent_selfcheck -n n1)")