import datetime
import json
import hashlib
import logging
import os
import six

from leapp.compat import string_types
from leapp.models import fields, Model, ErrorModel
from leapp.topics import ReportTopic
from leapp.libraries.stdlib.api import produce


class Report(Model):
    """
    Framework model used for reporting
    """

    __non_inheritable__ = True

    topic = ReportTopic

    report = fields.JSON()


def _add_to_dict(data, path, value, leaf_list=False):
    for p in path[:-1]:
        if p not in data:
            data[p] = {}
        data = data[p]

    if leaf_list:
        data[path[-1]] = data.get(path[-1], []) + [value]
    else:
        if path[-1] in data:
            raise ValueError('Path {} is already taken'.format('.'.join(path)))
        data[path[-1]] = value


class BasePrimitive(object):
    """
    Report primitive (field) base class for dict targets (implies unique path)
    """
    # deepest nested key in resulting report dict
    name = ''

    def __init__(self, value=None):
        if not isinstance(value, string_types):
            raise TypeError('Value of "{}" must be a string'.format(self.__class__.__name__))
        self._value = value

    @property
    def value(self):
        """Return report field value"""
        return self._value

    @property
    def path(self):
        """Return report field destination path (nested dict description)"""
        return (self.name, )

    def to_dict(self):
        return {self.name: self._value}

    def apply(self, report):
        """Add report entry to the report dict based on provided path"""
        _add_to_dict(report, self.path, self.value, leaf_list=False)


class BaseListPrimitive(BasePrimitive):
    """
    Report primitive (field) base class for list targets (we append value to a list)
    """

    def apply(self, report):
        """Add report entry to the report dict based on provided path"""
        _add_to_dict(report, self.path, self.value, leaf_list=True)


class Title(BasePrimitive):
    """Report title"""
    name = 'title'


class Summary(BasePrimitive):
    """Report summary"""
    name = 'summary'


class Severity(BasePrimitive):
    """Report severity"""
    name = 'severity'

    INFO = 'info'
    LOW = 'low'
    MEDIUM = 'medium'
    HIGH = 'high'

    def __init__(self, value=None):
        severities = (self.INFO, self.LOW, self.MEDIUM, self.HIGH)
        if value not in severities:
            raise ValueError('Severity should be one of: "{}"'.format(' '.join(severities)))
        self._value = value


class Audience(BasePrimitive):
    """Target audience of the report"""
    name = 'audience'

    def __init__(self, value=None):
        if not isinstance(value, string_types):
            raise TypeError('Value of "Audience" must be a string')
        audiences = ('sysadmin', 'developer')
        if value not in audiences:
            raise ValueError('Audience should be one of: "{}"'.format(' '.join(audiences)))
        self._value = value


class Flags(BasePrimitive):
    """Report flags"""
    name = 'flags'

    INHIBITOR = 'inhibitor'
    FAILURE = 'failure'

    def __init__(self, value=None):
        if not isinstance(value, list):
            raise TypeError('Value of "Flags" must be a list')
        self._value = value


class Key(BasePrimitive):
    """Stable identifier for report entries."""
    name = 'key'

    def __init__(self, uuid):
        # uuid is allowed to be string or unicode only, checking in py2/py3 friendly mode
        if not isinstance(uuid, six.string_types):
            raise ValueError('Key value should be a string.')

        self._value = uuid


class Tags(BasePrimitive):
    """Report tags"""
    name = 'tags'

    class _Value(object):
        def __init__(self, value):
            self.value = value

    ACCESSIBILITY = _Value('accessibility')
    AUTHENTICATION = _Value('authentication')
    BOOT = _Value('boot')
    COMMUNICATION = _Value('communication')
    DESKTOP = _Value('desktop environment')
    DRIVERS = _Value('drivers')
    EMAIL = _Value('email')
    ENCRYPTION = _Value('encryption')
    FILESYSTEM = _Value('filesystem')
    FIREWALL = _Value('firewall')
    HIGH_AVAILABILITY = _Value('high availability')
    KERNEL = _Value('kernel')
    MONITORING = _Value('monitoring')
    NETWORK = _Value('network')
    OS_FACTS = _Value('OS facts')
    PUBLIC_CLOUD = _Value('public cloud')
    PYTHON = _Value('python')
    REPOSITORY = _Value('repository')
    RHUI = _Value('rhui')
    SANITY = _Value('sanity')
    SECURITY = _Value('security')
    SELINUX = _Value('selinux')
    SERVICES = _Value('services')
    TIME_MANAGEMENT = _Value('time management')
    TOOLS = _Value('tools')
    UPGRADE_PROCESS = _Value('upgrade process')

    def __init__(self, value=None):
        if not isinstance(value, list):
            raise TypeError('Value of "Tags" must be a list')
        if not all([isinstance(v, Tags._Value) for v in value]):
            raise TypeError('Unsupported tag value passed for Report Tags.')
        # after the objects validation we need the actual values in the list
        self._value = [v.value for v in value]


class ExternalLink(BaseListPrimitive):
    """External link report detail field"""
    name = 'external'

    def __init__(self, url=None, title=None):
        if not all(isinstance(v, string_types) for v in (url, title)):
            raise TypeError('Values "url" and "title" of "ExternalLink" must be a string')
        self._value = {'url': url, 'title': title}

    @property
    def path(self):
        return ('detail', 'external')


class RelatedResource(BaseListPrimitive):
    """Report detail field for related resources (e.g. affected packages/files)"""
    name = 'related_resources'

    def __init__(self, scheme=None, identifier=None):
        if not all(isinstance(v, string_types) for v in (scheme, identifier)):
            raise TypeError('Values "scheme" and "identifier" of "RelatedResource" must be a string')
        self._value = {'scheme': scheme, 'title': identifier}

    @property
    def path(self):
        return ('detail', 'related_resources')


class BaseRemediation(BaseListPrimitive):
    """Remediation base class"""
    name = 'remediations'

    @property
    def path(self):
        return ('detail', 'remediations')


class RemediationCommand(BaseRemediation):
    def __init__(self, value=None):
        if not isinstance(value, list):
            raise TypeError('Value of "RemediationCommand" must be a list')
        self._value = {'type': 'command', 'context': value}

    def __repr__(self):
        return "[{}] {}".format(self._value['type'], ' '.join(self._value['context']))


class RemediationHint(BaseRemediation):
    def __init__(self, value=None):
        self._value = {'type': 'hint', 'context': value}

    def __repr__(self):
        return "[{}] {}".format(self._value['type'], self._value['context'])


class RemediationPlaybook(BaseRemediation):
    def __init__(self, value=None):
        self._value = {'type': 'playbook', 'context': value}

    def __repr__(self):
        return "[{}] {}".format(self._value['type'], self._value['context'])


class Remediation(object):
    def __init__(self, playbook=None, commands=None, hint=None):
        self._remediations = []
        if hint:
            self._remediations.append(RemediationHint(value=hint))
        if commands:
            for command in commands:
                self._remediations.append(RemediationCommand(value=command))
        if playbook:
            self._remediations.append(RemediationPlaybook(value=playbook))

    def apply(self, report):
        for remediation in self._remediations:
            remediation.apply(report)

    def __repr__(self):
        return "\n".join([repr(r) for r in self._remediations])

    def to_dict(self):
        return {'remediations': [r.to_dict() for r in self._remediations]}

    @classmethod
    def from_dict(cls, data):
        values = data.get('remediations', [])
        playbook = next((v['context'] for v in values if v['type'] == 'playbook'), None)
        hint = next((v['context'] for v in values if v['type'] == 'hint'), None)
        commands = [v['context'] for v in values if v['type'] == 'command']
        if values:
            return Remediation(playbook, commands, hint)


def _sanitize_entries(entries):
    if not any(isinstance(e, Title) for e in entries):
        raise ValueError('Title not provided in the report.')
    if not any(isinstance(e, Summary) for e in entries):
        raise ValueError('Summary not provided in the report.')
    if not any(isinstance(e, Severity) for e in entries):
        entries.append(Severity('info'))
    if not any(isinstance(e, Audience) for e in entries):
        entries.append(Audience('sysadmin'))
    _check_stable_key(entries, raise_if_undefined=os.getenv('LEAPP_DEVEL_FIXED_REPORT_KEY', '0') != '0')


def _check_stable_key(entries, raise_if_undefined=False):
    """
    Inserts a Key into the entries of the report if it doesn't exist.

    The resulting id is calculated from the mandatory report
    entries (severity, audience, title).
    Please note that the original entries list is modified.
    """
    def _find_entry(cls):
        entry = next((e for e in entries if isinstance(e, cls)), None)
        if entry:
            return entry._value

    logger = logging.getLogger('leapp.reporting')
    key = _find_entry(Key)
    if key is not None:
        # Key is already there, check that it's not an empty string
        if not key.strip():
            logger.error('An empty string is specified as Key')
            raise ValueError('Key can not be an empty string.')
        return

    if raise_if_undefined:
        raise ValueError('Stable Key report entry with specified unique value not provided')

    # No Key found - let's generate one!
    key_str = u'{severity}:{audience}:{title}'.format(severity=_find_entry(Severity),
                                                      audience=_find_entry(Audience),
                                                      title=_find_entry(Title))
    key_value = hashlib.sha1(key_str.encode('utf-8')).hexdigest()
    entries.append(Key(key_value))
    logger.warning('Stable Key report entry not provided, dynamically generating one - {}'.format(key_value))


def _create_report_object(entries):
    report = {}

    _sanitize_entries(entries)
    for entry in entries:
        entry.apply(report)

    return Report(report=report)


def create_report(entries):
    """
    Produce final report message
    """
    produce(_create_report_object(entries))


_DEPRECATION_SEVERITY_THRESHOLD = datetime.timedelta(days=180)


def create_report_from_deprecation(deprecation):
    """
    Convert deprecation json to report json
    """
    since = datetime.datetime.strptime(deprecation['since'], '%Y-%m-%d').date()

    severity = Severity.MEDIUM
    if since < (datetime.date.today() - _DEPRECATION_SEVERITY_THRESHOLD):
        severity = Severity.HIGH

    report = _create_report_object([
        Title('{message} at {filename}:{lineno}'.format(
            message=deprecation['message'].split('\n')[0],
            filename=deprecation['filename'],
            lineno=deprecation['lineno'])),
        Severity(severity),
        Audience('developer'),
        Summary('{reason}\nSince: {since}\nLocation: {filename}:{lineno}\nNear: {line}'.format(
            reason=deprecation['reason'],
            since=deprecation['since'],
            filename=deprecation['filename'],
            lineno=deprecation['lineno'],
            line=deprecation['line']
        )),
    ])
    return json.loads(report.dump()['report'])


def create_report_from_error(error_dict):
    """
    Convert error json to report json
    """
    error = ErrorModel.create(error_dict)
    entries = [Title(error.message), Summary(error.details or ""), Severity('high'), Audience('sysadmin')]
    report = _create_report_object(entries)
    return json.loads(report.dump()['report'])