# Copyright The IETF Trust 2017-2020, All Rights Reserved
# -*- coding: utf-8 -*-


import re
import requests
from collections import defaultdict, namedtuple

from django.conf import settings
from django.db.models import Q

import debug                            # pyflakes:ignore

from ietf.stats.models import AffiliationAlias, AffiliationIgnoredEnding, CountryAlias, MeetingRegistration
from ietf.name.models import CountryName
from ietf.person.models import Person, Email
from ietf.utils.log import log

import logging
logger = logging.getLogger('django')


def compile_affiliation_ending_stripping_regexp():
    parts = []
    for ending_re in AffiliationIgnoredEnding.objects.values_list("ending", flat=True):
        try:
            re.compile(ending_re)
        except re.error:
            pass

        parts.append(ending_re)

    re_str = ",? *({}) *$".format("|".join(parts))

    return re.compile(re_str, re.IGNORECASE)


def get_aliased_affiliations(affiliations):
    """Given non-unique sequence of affiliations, returns dictionary with
    aliases needed.

    We employ the following strategies, interleaved:

    - Stripping company endings like Inc., GmbH etc. from database

    - Looking up aliases stored directly in the database, like
      "Examplar International" -> "Examplar"

    - Case-folding so Examplar and EXAMPLAR is merged with the
      winner being the one with most occurrences (so input should not
      be made unique) or most upper case letters in case of ties.
      Case folding can be overridden by the aliases in the database."""

    res = {}

    ending_re = compile_affiliation_ending_stripping_regexp()

    known_aliases = { alias.lower(): name for alias, name in AffiliationAlias.objects.values_list("alias", "name") }

    affiliations_with_case_spellings = defaultdict(set)
    case_spelling_count = defaultdict(int)
    for affiliation in affiliations:
        original_affiliation = affiliation

        # check aliases from DB
        name = known_aliases.get(affiliation.lower())
        if name is not None:
            affiliation = name
            res[original_affiliation] = affiliation

        # strip ending
        name = ending_re.sub("", affiliation)
        if name != affiliation:
            affiliation = name
            res[original_affiliation] = affiliation

        # check aliases from DB
        name = known_aliases.get(affiliation.lower())
        if name is not None:
            affiliation = name
            res[original_affiliation] = affiliation

        affiliations_with_case_spellings[affiliation.lower()].add(original_affiliation)
        case_spelling_count[affiliation] += 1

    def affiliation_sort_key(affiliation):
        count = case_spelling_count[affiliation]
        uppercase_letters = sum(1 for c in affiliation if c.isupper())
        return (count, uppercase_letters)

    # now we just need to pick the most popular uppercase/lowercase
    # spelling for each affiliation with more than one
    for similar_affiliations in affiliations_with_case_spellings.values():
        if len(similar_affiliations) > 1:
            most_popular = sorted(similar_affiliations, key=affiliation_sort_key, reverse=True)[0]
            for affiliation in similar_affiliations:
                if affiliation != most_popular:
                    res[affiliation] = most_popular

    return res


def get_aliased_countries(countries):
    known_aliases = dict(CountryAlias.objects.values_list("alias", "country__name"))

    # add aliases for known countries
    for slug, name in CountryName.objects.values_list("slug", "name"):
        known_aliases[name.lower()] = name

    def lookup_alias(possible_alias):
        name = known_aliases.get(possible_alias)
        if name is not None:
            return name

        name = known_aliases.get(possible_alias.lower())
        if name is not None:
            return name

        return possible_alias

    known_re_aliases = {
        re.compile("\\b{}\\b".format(re.escape(alias))): name
        for alias, name in known_aliases.items()
    }

    # specific hack: check for zip codes from the US since in the
    # early days, the addresses often didn't include the country
    us_zipcode_re = re.compile(r"\b(AL|AK|AZ|AR|CA|CO|CT|DE|DC|FL|GA|HI|ID|IL|IN|IA|KS|KY|LA|ME|MD|MA|MI|MN|MS|MO|MT|NE|NV|NH|NJ|NM|NY|NC|ND|OH|OK|OR|PA|RI|SC|SD|TN|TX|UT|VT|VA|WA|WV|WI|WY|AS|GU|MP|PR|VI|UM|FM|MH|PW|Ca|Cal.|California|CALIFORNIA|Colorado|Georgia|Illinois|Ill|Maryland|Ma|Ma.|Mass|Massachuss?etts|Michigan|Minnesota|New Jersey|New York|Ny|N.Y.|North Carolina|NORTH CAROLINA|Ohio|Oregon|Pennsylvania|Tx|Texas|Tennessee|Utah|Vermont|Virginia|Va.|Washington)[., -]*[0-9]{5}\b")

    us_country_name = CountryName.objects.get(slug="US").name

    def last_text_part_stripped(split):
        for t in reversed(split):
            t = t.strip()
            if t:
                return t
        return ""

    known_countries = set(CountryName.objects.values_list("name", flat=True))

    res = {}

    for country in countries:
        if country in res or country in known_countries:
            continue

        original_country = country

        # aliased name
        country = lookup_alias(country)
        if country in known_countries:
            res[original_country] = country
            continue

        # contains US zipcode
        if us_zipcode_re.search(country):
            res[original_country] = us_country_name
            continue

        # do a little bit of cleanup
        if len(country) > 1 and country[-1] == "." and not country[-2].isupper():
            country = country.rstrip(".")

        country = country.strip("-,").strip()

        # aliased name
        country = lookup_alias(country)
        if country in known_countries:
            res[original_country] = country
            continue

        # country name at end, separated by comma
        last_part = lookup_alias(last_text_part_stripped(country.split(",")))
        if last_part in known_countries:
            res[original_country] = last_part
            continue

        # country name at end, separated by whitespace
        last_part = lookup_alias(last_text_part_stripped(country.split()))
        if last_part in known_countries:
            res[original_country] = last_part
            continue

        # country name anywhere
        country_lower = country.lower()
        found = False
        for alias_re, name in known_re_aliases.items():
            if alias_re.search(country) or alias_re.search(country_lower):
                res[original_country] = name
                found = True
                break

        if found:
            continue

        # unknown country
        res[original_country] = ""

    return res


def clean_country_name(country_name):
    if country_name:
        country_name = get_aliased_countries([country_name]).get(country_name, country_name)
        if country_name and CountryName.objects.filter(name=country_name).exists():
            return country_name

    return ""


def compute_hirsch_index(citation_counts):
    """Computes the h-index given a sequence containing the number of
    citations for each document."""

    i = 0

    for count in sorted(citation_counts, reverse=True):
        if i + 1 > count:
            break

        i += 1

    return i


def get_meeting_registration_data(meeting):
    """"Retrieve registration attendee data and summary statistics.  Returns number
    of Registration records created.
    
    MeetingRegistration records are created in realtime as people register for a 
    meeting. This function serves as an audit / reconciliation. Most records are
    expected to already exist. The function has been optimized with this in mind.
    """
    num_created = 0
    num_processed = 0
    try:
        response = requests.get(
            settings.STATS_REGISTRATION_ATTENDEES_JSON_URL.format(number=meeting.number),
            timeout=settings.DEFAULT_REQUESTS_TIMEOUT,
        )
    except requests.Timeout as exc:
        log(f'GET request timed out for [{settings.STATS_REGISTRATION_ATTENDEES_JSON_URL}]: {exc}')
        raise RuntimeError("Timeout retrieving data from registrations API") from exc
    if response.status_code == 200:
        decoded = []
        try:
            decoded = response.json()
        except ValueError:
            if response.content.strip() == 'Invalid meeting':
                logger.info('Invalid meeting: {}'.format(meeting.number))
                return (0,0,0)
            else:
                raise RuntimeError("Could not decode response from registrations API: '%s...'" % (response.content[:64], ))

        records = MeetingRegistration.objects.filter(meeting_id=meeting.pk).select_related('person')
        meeting_registrations = {(r.email, r.reg_type):r for r in records}
        for registration in decoded:
            person = None
            # capture the stripped registration values for later use
            first_name      = registration['FirstName'].strip()
            last_name       = registration['LastName'].strip()
            affiliation     = registration['Company'].strip()
            country_code    = registration['Country'].strip()
            address         = registration['Email'].strip()
            reg_type        = registration['RegType'].strip()
            ticket_type     = registration['TicketType'].strip()
            checkedin       = bool(registration['CheckedIn'].strip().lower() == 'true')

            if (address, reg_type) in meeting_registrations:
                object = meeting_registrations.pop((address, reg_type))
                created = False
            else:
                object, created = MeetingRegistration.objects.get_or_create(
                    meeting_id=meeting.pk,
                    email=address,
                    reg_type=reg_type)
            
            if (object.first_name != first_name[:200] or
                object.last_name != last_name[:200] or
                object.affiliation != affiliation or
                object.country_code != country_code or
                object.ticket_type != ticket_type or
                object.checkedin != checkedin):
                    object.first_name=first_name[:200]
                    object.last_name=last_name[:200]
                    object.affiliation=affiliation
                    object.country_code=country_code
                    object.ticket_type=ticket_type
                    object.checkedin=checkedin
                    object.save()

            # Add a Person object to MeetingRegistration object
            # if valid email is available
            if object and not object.person and address:
                # If the person already exists do not try to create a new one
                emails = Email.objects.filter(address=address)
                # there can only be on Email object with a unique email address (primary key)
                if emails.exists():
                    person = emails.first().person
                # Create a new Person object
                else:
                    logger.error("No Person record for registration. email={}".format(address))
                # update the person object to an actual value
                object.person = person
                object.save()
            
            if created:
                num_created += 1
            num_processed += 1

        # any registrations left in meeting_registrations no longer exist in reg
        # so must have been deleted
        for r in meeting_registrations:
            try:
                MeetingRegistration.objects.get(meeting=meeting,email=r[0],reg_type=r[1]).delete()
                logger.info('Removing deleted registration. email={}, reg_type={}'.format(r[0], r[1]))
            except MeetingRegistration.DoesNotExist:
                pass
    else:
        raise RuntimeError("Bad response from registrations API: %s, '%s'" % (response.status_code, response.content))
    num_total = MeetingRegistration.objects.filter(
        meeting_id=meeting.pk,
        reg_type__in=['onsite', 'remote']
    ).filter(
        Q(attended=True) | Q(checkedin=True)
    ).count()
    if meeting.attendees is None or num_total > meeting.attendees:
        meeting.attendees = num_total
        meeting.save()
    return num_created, num_processed, num_total

def repair_meetingregistration_person(meetings=None):
    repaired_records = 0
    qs = MeetingRegistration.objects.all()
    if meetings:
        qs = qs.filter(meeting__number__in=meetings)
    for mr in qs:
        if mr.email and not mr.person:
            email_person = Person.objects.filter(email__address=mr.email).first()
            if email_person:
                mr.person = email_person
                mr.save()
                repaired_records += 1            
    return repaired_records

class MeetingRegistrationIssuesSummary(object):
    pass

def find_meetingregistration_person_issues(meetings=None):
    summary = MeetingRegistrationIssuesSummary()

    summary.could_be_fixed = set()
    summary.maybe_address = set()
    summary.different_person = set()
    summary.no_person = set()
    summary.maybe_person = set()
    summary.no_email = set()
    summary.ok_records = 0

    qs = MeetingRegistration.objects.all()
    if meetings:
        qs = qs.filter(meeting__number__in=meetings)
    for mr in qs:
        if mr.person and mr.email and mr.email in mr.person.email_set.values_list('address',flat=True):
            summary.ok_records += 1
        elif mr.email:
            email_person = Person.objects.filter(email__address=mr.email).first()
            if mr.person:
                if not email_person:
                    summary.maybe_address.add(f'{mr.email} is not present in any Email object. The MeetingRegistration object implies this is an address for {mr.person} ({mr.person.pk})')
                elif email_person != mr.person:
                    summary.different_person.add(f'{mr} ({mr.pk}) has person {mr.person} ({mr.person.pk}) but an email {mr.email} attached to a different person {email_person} ({email_person.pk}).')
            elif email_person:
                summary.could_be_fixed.add(f'{mr} ({mr.pk}) has no person, but email {mr.email} matches {email_person} ({email_person.pk})')
            else:
                maybe_person_qs = Person.objects.filter(name__icontains=mr.last_name).filter(name__icontains=mr.first_name)
                if maybe_person_qs.exists():
                    summary.maybe_person.add(f'{mr} ({mr.pk}) has email address {mr.email} which cannot be associated with any Person. Consider these possible people {[(p,p.pk) for p in maybe_person_qs]}')
                else:
                    summary.no_person.add(f'{mr} ({mr.pk}) has email address {mr.email} which cannot be associated with any Person')
        else:
            summary.no_email.add(f'{mr} ({mr.pk}) provides no email address')

    return summary


FetchStats = namedtuple("FetchStats", "added processed total")


def fetch_attendance_from_meetings(meetings):
    stats = [
        FetchStats(*get_meeting_registration_data(meeting)) for meeting in meetings
    ]
    return stats