""" ntpq out parser and reporter
"""
import re
import socket
# pylint: disable=redefined-builtin
from ansible.module_utils.basic import AnsibleModule

# - name: Run the ntp health module against the out from the ntp status command
#   ntp_health:
#     output: "{{ output['stdout'][0] }}"  # the output of 'show ntp associations or show ntp peer-status'
#     ntp_servers: "{{ ntp_servers }}"     # a list of ntp servers
#     os: "{{ os }}"                       # netmiko style os (cisco_os, cisco_nxos, cisco_xe etc)
#     domain_name: "company.net"         # the domain name to add to ntp servers where their domain gets cut off
#   register: health
#   ignore_errors: true
#
# - debug: var=health



REGEXES = {
    "arista_eos": re.compile(r'''
        ^                                       # Beginning of line
        (?P<status>[\sx\.\-+#\*o])              # Capture the status
        (?P<remote>\S+)\s+                      # The remote name
        (?P<refid>(\d{1,3}.){3}\d{1,3})\s+      # The remote's refid followed by spaces
        (?P<stratum>\d{1,2})\s+                 # The stratum of the remote followed by spaces
        (?P<type>[lumb-])\s+                    # The type of remote, followed by spaces
        (?P<when>\d+)\s+                        # The last time the server was queried
        (?P<poll>\d+)\s+                        # Frequency of poll, followed by spaces
        (?P<reach>\d+)\s+                       # Reach, followed by spaces
        (?P<delay>[\d\.]*)\s+                   # Delay, followed by spaces
        (?P<offset>[\d\.-]*)\s+                 # Offset followed by spaces
        (?P<jitter>[\d\.]*)                     # Jitter
        $  ''',                                 # End of line
                             re.VERBOSE),
    "cisco_ios": re.compile(r'''
        ^                                       # Beginning of line
        (?P<status>[\sx\.\-+#\*o])              # Capture the status
        (?P<configured>\~)                        # Configured
        (?P<remote>(\d{1,3}.){3}\d{1,3})\s+     # The remote IP followed by spaces
        (?P<refid>(\d{1,3}.){3}\d{1,3})\s+      # The remote's refid followed by spaces
        (?P<stratum>\d{1,2})\s+                 # The stratum of the remote followed by spaces
        (?P<when>\d+)\s+                        # The last time the server was queried
        (?P<poll>\d+)\s+                        # Frequency of poll, followed by spaces
        (?P<reach>\d+)\s+                       # Reach, followed by spaces
        (?P<delay>[\d\.]*)\s+                   # Delay, followed by spaces
        (?P<offset>[\d\.-]*)\s+                 # Offset followed by spaces
        (?P<jitter>[\d\.]*)                     # Jitter
        $''',                                   # End of line
                            re.VERBOSE),
    "cisco_nxos": re.compile(r'''
        ^
        (?P<status>[\*\+=-])                    # Beginning of line
        (?P<remote>(\d{1,3}.){3}\d{1,3})\s+     # The remote IP followed by spaces
        (?P<local>(\d{1,3}.){3}\d{1,3})\s+      # The local IP followed by spaces
        (?P<stratum>\d{1,2})\s+                 # The stratum of the remote followed by spaces
        (?P<poll>\d+)\s+                        # Frequency of poll, followed by spaces
        (?P<reach>\d+)\s+                       # Delay, followed by spaces
        (?P<delay>[\d\.]*)                      # Reach
        (\s+(?P<vrf>\S+))?                      # spaces, VRF (optional)
        (\s+)?                                  # stoopid eol spaces
        $''',                                   # End of line
                             re.VERBOSE),
    "cisco_xr": re.compile(r'''
        ^                                       # Beginning of line
        (?P<status>[\sx\.\-+#\*o])              # Capture the status
        (?P<configured>\~)                      # Configured
        (?P<remote>(\d{1,3}.){3}\d{1,3})\s+     # The remote IP followed by spaces
        (vrf\s(?P<vrf>\S+)\s+)?                 # Optional VRF
        (?P<refid>(\d{1,3}.){3}\d{1,3})\s+      # The remote's refid followed by spaces
        (?P<stratum>\d{1,2})\s+                 # The stratum of the remote followed by spaces
        (?P<when>\d+)\s+                        # The last time the server was queried
        (?P<poll>\d+)\s+                        # Frequency of poll, followed by spaces
        (?P<reach>\d+)\s+                       # Reach, followed by spaces
        (?P<delay>[\d\.]*)\s+                   # Delay, followed by spaces
        (?P<offset>[\d\.-]*)\s+                 # Offset followed by spaces
        (?P<jitter>[\d\.]*)                     # Jitter
        $''',                                   # End of line
                            re.VERBOSE),
}

def nxos_vdc(os, output):
    """ Determine if this is a VDC and set desired accordingly

    Args:
        output (str): The output from the ntp status command

    Returns:
        dict: Mock desired since we cna resolve

    """
    if os == "cisco_nxos":
        if "System clock is not controlled by NTP in this VDC" in output:
            return True
    else:
        return False

def parse_output(params):
    """ Parses the output and returns structured data

    Args:
        output (str): The output from the ntp status command

    Returns:
        dict: A dictionary of entries

    """
    entries = []
    if params['os'] in REGEXES:
        for line in params['output'].splitlines():
            result = re.match(REGEXES[params['os']], line)
            if result:
                entry = result.groupdict()
                entries.append(entry)
        return None, entries
    else:
        return "No regex support for %s" % params['os'], None

def arista_resolve(entries, domain_name):
    """ Resolves entries to an IP address

    Args:
        entries (dict): The dict of entries

    Returns:
        dict: A dictionary of entries

    """
    for entry in entries:
        try:
            entry['remote'] = socket.gethostbyname("%s.%s" % (entry['remote'].split('.')[0], domain_name))
        except socket.gaierror:
            pass
    return entries

def xr_unwrap(output):
    """ Unwrap long XR entries

    Args:
        output (str): The str output

    Returns:
        str: Unwrapped output

    """
    lines = output.splitlines()
    i = len(lines) - 1
    newlist = []
    while i >= 0:
        hl_regex = re.compile(r'^\s+(\d{1,3}.){3}\d{1,3}')
        if hl_regex.match(lines[i]):
            newlist.insert(0, "%s %s" % (lines[i-1], lines[i]))
            i -= 2
        else:
            newlist.insert(0, lines[i])
            i -= 1
    lines = "\n".join(newlist)
    return lines

def find_failed(entries):
    """ Walk the entries and look for stratum 16

    Args:
        entries (dict): A dictionary of NTP server entries

    Return:
        dict: The dict of entries with an additonal k,v for each

    """
    for entry in entries:
        entry['stratum_ok'] = bool(entry['stratum'] != "16")
    return entries

def resolve_expected(entries):
    """ Resolve each in the list of entries to an IP address

    Args:
        entries (list): A list of NTP servers

    Returns:
        dict: A dict of name, ip
    """

    desired = {}
    for entry in entries:
        try:
            desired[entry] = socket.gethostbyname(entry)
        except socket.gaierror:
            desired[entry] = None
        except Exception as error: # pylint: disable=broad-except
            desired[entry] = str(error)
    return desired

def roll_up(summary):
    """ Assess each of the individual health check and produce a final health check

    Args:
        summary (dict): A dictionary of summary information

    Returns:
        dict: The same dict, with a health note and health

    """
    summary['healthy_failed_reasons'] = []
    if summary['missing']:
        note = "One or more NTP servers is missing from the output."
        summary['healthy_failed_reasons'].append(note)
    if summary['extra']:
        note = "One or more extra NTP servers found in the output."
        summary['healthy_failed_reasons'].append(note)
    if not summary['stratums_ok']:
        note = "One or more NTP servers found with a stratum of 16."
        summary['healthy_failed_reasons'].append(note)
    if not summary['desired_ok']:
        note = "One or more of the desired NTP servers did not resolve to an IP address."
        summary['healthy_failed_reasons'].append(note)
    if not summary['desired_no_dupes']:
        note = "Duplicate entries found in desired NTP server list."
        summary['healthy_failed_reasons'].append(note)
    if not bool(summary['chosen']):
        note = "No 'chosen' NTP server found in output."
        summary['healthy_failed_reasons'].append(note)
    if not summary['reachability_ok']:
        note = "One or more NTP server is experiencing reachability issues."
        summary['healthy_failed_reasons'].append(note)
    summary['healthy'] = not bool(summary['healthy_failed_reasons'])
    return summary

def summarize(entries, desired, output):
    """ Use both the output and parsed entries to produce summary information

    Args:
        output (str): The output from the ntpq -pn command
        entries (dict): A dictionary of NTP server entries
        desired (dict): The list of NTP servers, resolved to IPs

    Returns:
        summary (dict): The summary dictionary

    """
    summary = {}
    current_ntp_ip_list = set(x['remote'] for x in entries)
    desired_ntp_ip_list = set(desired.values())

    summary['chosen'] = next((x for x in entries if x['status'] == "*"), None)
    summary['current_ntp_ip_list'] = list(current_ntp_ip_list)
    summary['desired_no_dupes'] = len(desired_ntp_ip_list) == len(desired.values())
    summary['desired_ntp_ip_list'] = list(desired_ntp_ip_list)
    summary['desired_ok'] = all([bool(v) for v in desired.values()])
    summary['desired'] = desired
    summary['entries'] = entries
    summary['extra'] = list(current_ntp_ip_list - desired_ntp_ip_list)
    summary['missing'] = list(desired_ntp_ip_list - current_ntp_ip_list)
    summary['output'] = output.splitlines()
    summary['reachability_issues'] = [x for x in entries if x['reach'] != "377"]
    summary['reachability_ok'] = not bool(summary['reachability_issues'])
    summary['stratums_ok'] = all([x['stratum_ok'] for x in entries])
    summary = roll_up(summary)
    return summary

def main():
    """ Genisis
    """
    module = AnsibleModule(
        argument_spec=dict(
            ntp_servers=dict(required=True, type='list'),
            output=dict(required=True, type='str'),
            os=dict(required=True, type='str'),
            domain_name=dict(required=False, type='str'),
        ),
        supports_check_mode=True)

    try:
        # Look for VDC warning in NX-OS
        is_vdc = nxos_vdc(module.params['os'], module.params['output'])
        if is_vdc:
            module.exit_json(changed=False, results="Is a NXOS VDC")
        else:
            desired = resolve_expected(module.params['ntp_servers'])
        # Reuse the IOS regex
        if module.params['os'] in ["cisco_xe", "cisco_asa", "cisco_fwsm", "cisco_pix"]:
            module.params['os'] = "cisco_ios"
        # Unwrap XR output
        if module.params['os'] == 'cisco_xr':
            module.params['output'] = xr_unwrap(module.params['output'])
        # Move along
        error, entries = parse_output(module.params)
        if error:
            module.fail_json(msg=error)
        # Resolve arista names back to IPs
        if module.params['os'] == "arista_eos":
            entries = arista_resolve(entries, module.params['domain_name'])
        entries = find_failed(entries)
        summary = summarize(entries, desired, module.params['output'])
        if summary['healthy']:
            module.exit_json(changed=False, results=summary)
        else:
            module.fail_json(msg=(", ".join(summary['healthy_failed_reasons'])), results=summary)


    except Exception as error: # pylint: disable=broad-except
        error_type = error.__class__.__name__
        module.fail_json(msg=error_type + ": " + str(error))

if __name__ == "__main__":
    main()