# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.

__all__ = ['Wizard',
    'StateView', 'StateTransition', 'StateAction', 'StateReport',
    'Button']

import copy
import json

from trytond.i18n import gettext
from trytond.model import ModelSQL
from trytond.model.exceptions import AccessError
from trytond.model.fields import states_validate
from trytond.pool import Pool, PoolBase
from trytond.protocols.jsonrpc import JSONDecoder, JSONEncoder
from trytond.pyson import PYSONEncoder
from trytond.rpc import RPC
from trytond.tools import cached_property
from trytond.transaction import Transaction, check_access
from trytond.url import URLMixin


class Button(object):
    '''
    Define a button on wizard.
    '''

    def __init__(self, string, state,
            icon='', default=False, states=None, validate=None):
        self.string = string
        self.state = state
        self.icon = icon
        self.default = bool(default)
        self.__states = None
        self.states = states or {}
        self.validate = validate

    @property
    def states(self):
        return self.__states

    @states.setter
    def states(self, value):
        states_validate(value)
        self.__states = value


class State(object):
    '''
    A State of a wizard.
    '''
    name = None


class StateView(State):
    '''
    A view state of a wizard.
    '''

    def __init__(self, model_name, view, buttons):
        '''
        model_name is the name of the model
        view is the xml id of the view
        buttons is a list of Button
        '''
        self.model_name = model_name
        self.view = view
        self.buttons = buttons
        assert len(self.buttons) == len(set(b.state for b in self.buttons))
        assert len([b for b in self.buttons if b.default]) <= 1

    def get_view(self, wizard, state_name):
        '''
        Returns the view definition
        '''
        Model_ = Pool().get(self.model_name)
        ModelData = Pool().get('ir.model.data')
        if self.view:
            module, fs_id = self.view.split('.')
            view_id = ModelData.get_id(module, fs_id)
        else:
            view_id = None
        return Model_.fields_view_get(view_id=view_id, view_type='form')

    def get_defaults(self, wizard, state_name, fields):
        '''
        Returns defaults values for the fields
        '''
        pool = Pool()
        Model_ = pool.get(self.model_name)
        defaults = Model_.default_get(fields)
        default = getattr(wizard, 'default_%s' % state_name, None)
        if default:
            defaults.update(default(fields))
            self._complete_values(defaults)
        return defaults

    def get_values(self, wizard, state_name, fields):
        "Return values for the fields"
        values = {}
        value = getattr(wizard, 'value_%s' % state_name, None)
        if value:
            values.update(value(fields))
        self._complete_values(values)
        return values

    def _complete_values(self, values):
        pool = Pool()
        Model_ = pool.get(self.model_name)
        for field_name, value in list(values.items()):
            if '.' in field_name:
                continue
            field = Model_._fields[field_name]
            if value and field._type == 'many2one':
                Target = field.get_target()
                if 'rec_name' in Target._fields:
                    values.setdefault(
                        field_name + '.', {})['rec_name'] = Target(
                            value).rec_name

    def get_buttons(self, wizard, state_name):
        '''
        Returns button definitions translated
        '''
        Translation = Pool().get('ir.translation')

        def translation_key(button):
            return (','.join((wizard.__name__, state_name, button.state)),
                'wizard_button', Transaction().language, button.string)
        translation_keys = [translation_key(button) for button in self.buttons]
        translations = Translation.get_sources(translation_keys)
        encoder = PYSONEncoder()
        result = []
        for button in self.buttons:
            validate = (button.validate
                if button.validate is not None
                else button.state != wizard.end_state)
            result.append({
                    'state': button.state,
                    'icon': button.icon,
                    'default': button.default,
                    'validate': validate,
                    'string': (translations.get(translation_key(button))
                        or button.string),
                    'states': encoder.encode(button.states),
                    })
        return result


class StateTransition(State):
    '''
    A transition state of a wizard.
    '''


class StateAction(StateTransition):
    '''
    An action state of a wizard.
    '''

    def __init__(self, action_id):
        '''
        action_id is a string containing ``module.xml_id``
        '''
        super(StateAction, self).__init__()
        self.action_id = action_id

    def get_action(self):
        "Returns action definition"
        pool = Pool()
        ModelData = pool.get('ir.model.data')
        Action = pool.get('ir.action')
        module, fs_id = self.action_id.split('.')
        action_id = Action.get_action_id(
            ModelData.get_id(module, fs_id))
        action = Action(action_id)
        return action.get_action_value()


class StateReport(StateAction):
    'An report state of a wizard'

    def __init__(self, report_name):
        super(StateReport, self).__init__(None)
        self.report_name = report_name

    def get_action(self):
        'Return report definition'
        pool = Pool()
        ActionReport = pool.get('ir.action.report')
        action_reports = ActionReport.search([
                ('report_name', '=', self.report_name),
                ])
        assert action_reports, '%s not found' % self.report_name
        action_report = action_reports[0]
        action = action_report.action
        return action.get_action_value()


class Wizard(URLMixin, PoolBase):
    __no_slots__ = True  # To allow setting State
    start_state = 'start'
    end_state = 'end'

    @classmethod
    def __setup__(cls):
        super(Wizard, cls).__setup__()
        cls.__rpc__ = {
            'create': RPC(readonly=False),
            'delete': RPC(readonly=False),
            'execute': RPC(readonly=False, check_access=False),
            }

        # Copy states
        for attr in dir(cls):
            if not isinstance(getattr(cls, attr), State):
                continue
            state_name = attr
            state = getattr(cls, state_name)
            # Copy the original state definition to prevent side-effect with
            # the mutable attributes
            for parent_cls in cls.__mro__:
                parent_state = getattr(parent_cls, state_name, None)
                if isinstance(parent_state, State):
                    state = parent_state
            state = copy.deepcopy(state)
            setattr(cls, attr, state)

    @classmethod
    def __post_setup__(cls):
        super(Wizard, cls).__post_setup__()
        # Set states
        cls.states = {}
        for attr in dir(cls):
            if attr.startswith('_'):
                continue
            if isinstance(getattr(cls, attr), State):
                cls.states[attr] = getattr(cls, attr)

    @classmethod
    def __register__(cls, module_name):
        super(Wizard, cls).__register__(module_name)
        pool = Pool()
        Translation = pool.get('ir.translation')
        Translation.register_wizard(cls, module_name)

    @classmethod
    def check_access(cls):
        pool = Pool()
        ModelAccess = pool.get('ir.model.access')
        ActionWizard = pool.get('ir.action.wizard')
        User = pool.get('res.user')
        context = Transaction().context

        if Transaction().user == 0:
            return

        with check_access():
            model = context.get('active_model')
            if model:
                Model = pool.get(model)
            if model and model != 'ir.ui.menu':
                ModelAccess.check(model, 'read')
            models = ActionWizard.get_models(
                cls.__name__, action_id=context.get('action_id'))
            if model and models and model not in models:
                raise AccessError(gettext(
                        'ir.msg_access_wizard_model_error',
                        wizard=cls.__name__,
                        model=model))
            groups = set(User.get_groups())
            wizard_groups = ActionWizard.get_groups(cls.__name__,
                action_id=context.get('action_id'))
            if wizard_groups:
                if not groups & wizard_groups:
                    raise AccessError(gettext(
                            'ir.msg_access_wizard_error',
                            name=cls.__name__))
            elif model and model != 'ir.ui.menu':
                if (not callable(getattr(Model, 'table_query', None))
                        or Model.write.__func__ != ModelSQL.write.__func__):
                    ModelAccess.check(model, 'write')

            if model:
                ids = context.get('active_ids') or []
                id_ = context.get('active_id')
                if id_ not in ids and id_ is not None:
                    ids.append(id_)
                # Check read access
                Model.read(ids, ['id'])

    @classmethod
    def create(cls):
        "Create a session"
        Session = Pool().get('ir.session.wizard')
        cls.check_access()
        return (Session.create([{}])[0].id, cls.start_state, cls.end_state)

    @classmethod
    def delete(cls, session_id):
        "Delete the session"
        Session = Pool().get('ir.session.wizard')
        end = getattr(cls, cls.end_state, None)
        if end:
            wizard = cls(session_id)
            action = end(wizard)
        else:
            action = None
        Session.delete([Session(session_id)])
        return action

    @classmethod
    def execute(cls, session_id, data, state_name):
        '''
        Execute the wizard state.

        session_id is a Session id
        data is a dictionary with the session data to update
        state_name is the name of state to execute

        Returns a dictionary with:
            - ``actions``: a list of Action to execute
            - ``view``: a dictionary with:
                - ``fields_view``: a fields/view definition
                - ``defaults``: a dictionary with default values
                - ``values``: a dictionary with values
                - ``buttons``: a list of buttons
        '''
        transaction = Transaction()
        counter = transaction.counter
        cls.check_access()
        wizard = cls(session_id)
        for key, values in data.items():
            record = getattr(wizard, key)
            for field, value in values.items():
                if field == 'id':
                    continue
                setattr(record, field, value)
        result = wizard._execute(state_name)
        # Log before _save increases the counter
        if transaction.counter != counter and wizard.model:
            wizard.model.log(
                wizard.records, 'wizard',
                f'{cls.__name__}:{state_name}')
        wizard._save()
        return result

    def _execute(self, state_name):
        if state_name == self.end_state:
            return {}

        state = self.states[state_name]
        result = {}

        if isinstance(state, StateView):
            view = state.get_view(self, state_name)
            fields = list(view['fields'].keys())
            defaults = state.get_defaults(self, state_name, fields)
            values = state.get_values(self, state_name, fields)
            buttons = state.get_buttons(self, state_name)
            result['view'] = {
                'fields_view': view,
                'defaults': defaults,
                'values': values,
                'buttons': buttons,
                'state': state_name,
                }
        elif isinstance(state, StateTransition):
            do_result = None
            if isinstance(state, StateAction):
                action = state.get_action()
                do = getattr(self, 'do_%s' % state_name, None)
                if do:
                    do_result = do(action)
                else:
                    do_result = action, {}
            transition = getattr(self, 'transition_%s' % state_name, None)
            if transition:
                result = self._execute(transition())
            if do_result:
                result.setdefault('actions', []).append(do_result)
        return result

    def __init__(self, session_id):
        pool = Pool()
        Session = pool.get('ir.session.wizard')
        self._session_id = session_id
        session = Session(session_id)
        data = json.loads(session.data, object_hook=JSONDecoder())
        for state_name, state in self.states.items():
            if isinstance(state, StateView):
                Target = pool.get(state.model_name)
                data.setdefault(state_name, {})
                setattr(self, state_name, Target(**data[state_name]))

    def _save(self):
        "Save the session in database"
        Session = Pool().get('ir.session.wizard')
        data = {}
        for state_name, state in self.states.items():
            if isinstance(state, StateView):
                data[state_name] = getattr(self, state_name)._default_values
        session = Session(self._session_id)
        data = json.dumps(data, cls=JSONEncoder, separators=(',', ':'))
        if data != session.data.encode('utf-8'):
            Session.write([session], {
                    'data': data,
                    })

    @cached_property
    def model(self):
        pool = Pool()
        context = Transaction().context
        if context.get('active_model'):
            return pool.get(context['active_model'])

    @cached_property
    def record(self):
        context = Transaction().context
        if context.get('active_id') is not None:
            return self.model(context['active_id'])

    @cached_property
    def records(self):
        context = Transaction().context
        if context.get('active_ids'):
            return self.model.browse(context['active_ids'])
        return []
