# -*- coding: utf-8; -*-
################################################################################
#
#  Rattail -- Retail Software Framework
#  Copyright © 2010-2021 Lance Edgar
#
#  This file is part of Rattail.
#
#  Rattail is free software: you can redistribute it and/or modify it under the
#  terms of the GNU General Public License as published by the Free Software
#  Foundation, either version 3 of the License, or (at your option) any later
#  version.
#
#  Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
#  details.
#
#  You should have received a copy of the GNU General Public License along with
#  Rattail.  If not, see <http://www.gnu.org/licenses/>.
#
################################################################################
"""
Handler for "customer order" batches
"""

from __future__ import unicode_literals, absolute_import, division

import re
import decimal

import six
import sqlalchemy as sa
from sqlalchemy import orm

from rattail.db import model
from rattail.batch import BatchHandler


class CustomerOrderBatchHandler(BatchHandler):
    """
    Handler for all "customer order" batches, regardless of "mode".  The
    handler must inspect the
    :attr:`~rattail.db.model.batch.custorder.CustomerOrderBatch.mode` attribute
    of each batch it deals with, in order to determine which logic to apply.

    .. attribute:: has_custom_product_autocomplete

       If true, this flag indicates that the handler provides custom
       autocomplete logic for use when selecting a product while
       creating a new order.
    """
    batch_model_class = model.CustomerOrderBatch
    has_custom_product_autocomplete = False
    nondigits_pattern = re.compile(r'\D')

    def init_batch(self, batch, progress=None, **kwargs):
        """
        Assign the "local" store to the batch, if applicable.
        """
        session = self.app.get_session(batch)
        batch.store = self.config.get_store(session)

    def new_order_requires_customer(self):
        """
        Returns a boolean indicating whether a *new* "customer order"
        in fact requires a proper customer account, or not.  Note that
        in all cases a new order requires a *person* to associate
        with, but technically the customer is optional, unless this
        returns true.
        """
        return self.config.getbool('rattail.custorders',
                                   'new_order_requires_customer',
                                   default=False)

    def allow_contact_info_choice(self):
        """
        Returns a boolean indicating whether the user is allowed at
        all, to choose from existing contact info options for the
        customer, vs. they just have to go with whatever the handler
        auto-provides.
        """
        return self.config.getbool('rattail.custorders',
                                   'new_orders.allow_contact_info_choice',
                                   default=True)

    def should_restrict_contact_info(self):
        """
        Returns a boolean indicating whether contact info should be
        "restricted" - i.e. user can only choose from existing contact
        info and cannot override by e.g. entering a new phone number.
        """
        return self.config.getbool('rattail.custorders',
                                   'new_orders.restrict_contact_info',
                                   default=False)

    def product_price_may_be_questionable(self):
        """
        Returns a boolean indicating whether "any" product's price may
        be questionable.  So this isn't saying that a price *is*
        questionable but rather that it *may* be, if the user
        indicates it.  (That checkbox is only shown for the user if
        this flag is true.)
        """
        return self.config.getbool('rattail.custorders',
                                   'product_price_may_be_questionable',
                                   default=False)

    def assign_contact(self, batch, customer=None, person=None, **kwargs):
        """
        Assign the customer and/or person "contact" for the order.
        """
        clientele = self.app.get_clientele_handler()
        customer_required = self.new_order_requires_customer()

        # nb. person is always required
        if customer and not person:
            person = clientele.get_person(customer)
        if not person:
            raise ValueError("Must specify a person")

        # customer may or may not be optional
        if person and not customer:
            customer = clientele.get_customer(person)
        if customer_required and not customer:
            raise ValueError("Must specify a customer account")

        # assign contact
        batch.customer = customer
        batch.person = person

        # cache contact name
        batch.contact_name = self.get_contact_display(batch)

        # update phone/email per new contact
        batch.phone_number = None
        batch.email_address = None
        if customer_required:
            batch.phone_number = clientele.get_first_phone_number(customer)
            batch.email_address = clientele.get_first_email_address(customer)
        else:
            batch.phone_number = person.first_phone_number()
            batch.email_address = person.first_email_address()

        # always reset "add to customer" flags
        batch.clear_param('add_phone_number')
        batch.clear_param('add_email_address')

        session = self.app.get_session(batch)
        session.flush()

    def get_contact(self, batch):
        """
        Should return the contact record (i.e. Customer or Person) for
        the batch.
        """
        customer_required = self.new_order_requires_customer()

        if customer_required:
            return batch.customer
        else:
            return batch.person

    def get_contact_id(self, batch):
        """
        Should return contact ID for the batch, i.e. customer ID.
        """
        contact = self.get_contact(batch)
        if isinstance(contact, model.Customer):
            return contact.id

    def get_contact_display(self, batch):
        """
        Should return contact display text for the batch,
        i.e. customer name.
        """
        contact = self.get_contact(batch)
        if contact:
            return six.text_type(contact)

        pending = batch.pending_customer
        if pending:
            return six.text_type(pending)

    def get_contact_phones(self, batch):
        """
        Retrieve all phone records on file for the batch contact, to
        be presented as options for user to choose from when making a
        new order.
        """
        phones = []
        contact = self.get_contact(batch)
        if contact:
            phones = contact.phones

        return [self.normalize_phone(phone)
                for phone in phones]

    def normalize_phone(self, phone):
        """
        Normalize the given phone record to simple data dict, for
        passing around via JSON etc.
        """
        return {
            'uuid': phone.uuid,
            'type': phone.type,
            'number': phone.number,
            'preference': phone.preference,
            'preferred': phone.preference == 1,
        }

    def get_contact_emails(self, batch):
        """
        Retrieve all email records on file for the batch contact, to
        be presented as options for user to choose from when making a
        new order.

        Note that the default logic will exclude invalid email addresses.
        """
        emails = []
        contact = self.get_contact(batch)
        if contact:
            emails = contact.emails

        # exclude invalid
        emails = [email for email in emails
                  if not email.invalid]

        return [self.normalize_email(email)
                for email in emails]

    def normalize_email(self, email):
        """
        Normalize the given email record to simple data dict, for
        passing around via JSON etc.
        """
        return {
            'uuid': email.uuid,
            'type': email.type,
            'address': email.address,
            'invalid': email.invalid,
            'preference': email.preference,
            'preferred': email.preference == 1,
        }

    def get_contact_notes(self, batch):
        """
        Get extra "contact notes" which should be made visible to the
        user who is entering the new order.
        """
        notes = []

        invalid = False
        contact = self.get_contact(batch)
        if contact:
            invalid = [email for email in contact.emails
                       if email.invalid]
        if invalid:
            notes.append("Customer has one or more invalid email addresses on file.")

        return notes

    def unassign_contact(self, batch, **kwargs):
        """
        Unassign the customer and/or person "contact" for the order.
        """
        batch.customer = None
        batch.person = None

        # note that if batch already has a "pending" customer on file,
        # we will "restore" it as the contact info for the batch
        pending = batch.pending_customer
        if pending:
            batch.contact_name = pending.display_name
            batch.phone_number = pending.phone_number
            batch.email_address = pending.email_address
        else:
            batch.contact_name = None
            batch.phone_number = None
            batch.email_address = None

        # always reset "add to customer" flags
        batch.clear_param('add_phone_number')
        batch.clear_param('add_email_address')

        session = self.app.get_session(batch)
        session.flush()
        session.refresh(batch)

    def validate_pending_customer_data(self, batch, user, data):
        pass

    def update_pending_customer(self, batch, user, data):
        model = self.model
        people = self.app.get_people_handler()

        # first validate all data
        self.validate_pending_customer_data(batch, user, data)

        # clear out any contact it may have
        self.unassign_contact(batch)

        # create pending customer if needed
        pending = batch.pending_customer
        if not pending:
            pending = model.PendingCustomer()
            pending.user = user
            pending.status_code = self.enum.PENDING_CUSTOMER_STATUS_PENDING
            batch.pending_customer = pending

        # update pending customer info
        if 'first_name' in data:
            pending.first_name = data['first_name']
        if 'last_name' in data:
            pending.last_name = data['last_name']
        if 'display_name' in data:
            pending.display_name = data['display_name']
        else:
            pending.display_name = people.normalize_full_name(pending.first_name,
                                                              pending.last_name)
        if 'phone_number' in data:
            pending.phone_number = self.app.format_phone_number(data['phone_number'])
        if 'email_address' in data:
            pending.email_address = data['email_address']

        # also update the batch w/ contact info
        batch.contact_name = pending.display_name
        batch.phone_number = pending.phone_number
        batch.email_address = pending.email_address

    def get_case_size_for_product(self, product):
        if product.case_size:
            return product.case_size

        cost = product.cost
        if cost:
            return cost.case_size

    def get_case_price_for_row(self, row):
        """
        Calculate and return the per-case price for the given row.

        NB. we do not store case price, only unit price.  maybe that
        should change some day..
        """
        if row.unit_price is not None:
            case_price = row.unit_price * (row.case_quantity or 1)
            return case_price.quantize(decimal.Decimal('0.01'))

    # TODO: this method should maybe not exist?  and caller just
    # invokes the handler directly instead?
    def customer_autocomplete(self, session, term, **kwargs):
        """
        Override the Customer autocomplete, to search by phone number
        as well as name.
        """
        autocompleter = self.app.get_autocompleter('customers.neworder')
        return autocompleter.autocomplete(session, term, **kwargs)

    # TODO: this method should maybe not exist?  and caller just
    # invokes the handler directly instead?
    def person_autocomplete(self, session, term, **kwargs):
        """
        Override the Person autocomplete, to search by phone number as
        well as name.
        """
        autocompleter = self.app.get_autocompleter('people.neworder')
        return autocompleter.autocomplete(session, term, **kwargs)

    def get_customer_info(self, batch, **kwargs):
        """
        Return a data dict containing misc. info pertaining to the
        customer/person for the order batch.
        """
        info = {
            'customer_uuid': None,
            'person_uuid': None,
            'phone_number': None,
            'email_address': None,
        }

        if batch.customer:
            info['customer_uuid'] = batch.customer.uuid
            phone = batch.customer.first_phone()
            if phone:
                info['phone_number'] = phone.number
            email = batch.customer.first_email()
            if email:
                info['email_address'] = email.address

        if batch.person:
            info['person_uuid'] = batch.person.uuid
            if not info['phone_number']:
                phone = batch.person.first_phone()
                if phone:
                    info['phone_number'] = phone.number
                email = batch.person.first_email()
                if email:
                    info['email_address'] = email.address

        return info

    def custom_product_autocomplete(self, session, term, **kwargs):
        """
        For the given term, this should return a (possibly empty) list
        of products which "match" the term.  Each element in the list
        should be a dict with "label" and "value" keys.
        """
        raise NotImplementedError("Please define the "
                                  "{}.custom_product_autocomplete() "
                                  "method.".format(__class__.__name__))

    def get_past_products(self, batch, **kwargs):
        """
        Should return a (possibly empty) list of products which have
        been ordered in the past by the customer who is associated
        with the given batch.
        """
        # TODO: should crawl the rattail order history here
        return []

    def get_product_info(self, batch, product, **kwargs):
        """
        Return a data dict containing misc. info pertaining to the
        given product, for the order batch.
        """
        products = self.app.get_products_handler()
        vendor = product.cost.vendor if product.cost else None
        info = {
            'uuid': product.uuid,
            'upc': six.text_type(product.upc),
            'upc_pretty': product.upc.pretty(),
            'brand_name': product.brand.name if product.brand else None,
            'description': product.description,
            'size': product.size,
            'full_description': product.full_description,
            'case_quantity': self.app.render_quantity(self.get_case_size_for_product(product)),
            'unit_price_display': products.render_price(product.regular_price),
            'department_name': product.department.name if product.department else None,
            'vendor_name': vendor.name if vendor else None,
            'image_url': products.get_image_url(product),
            'uom_choices': self.uom_choices_for_product(product),
        }

        case_price = None
        if product.regular_price and product.regular_price is not None:
            case_size = self.get_case_size_for_product(product)
            case_price = case_size * product.regular_price.price
            case_price = case_price.quantize(decimal.Decimal('0.01'))
        info['case_price'] = six.text_type(case_price) if case_price is not None else None
        info['case_price_display'] = self.app.render_currency(case_price)

        key = self.config.product_key()
        if key == 'upc':
            info['key'] = info['upc_pretty']
        else:
            info['key'] = getattr(product, key, info['upc_pretty'])

        return info

    def uom_choices_for_product(self, product):
        """
        Return a list of UOM choices for the given product.
        """
        choices = []

        # Each
        if not product or not product.weighed:
            unit_name = self.enum.UNIT_OF_MEASURE[self.enum.UNIT_OF_MEASURE_EACH]
            choices.append({'key': self.enum.UNIT_OF_MEASURE_EACH,
                            'value': unit_name})

        # Pound
        if not product or product.weighed:
            unit_name = self.enum.UNIT_OF_MEASURE[self.enum.UNIT_OF_MEASURE_POUND]
            choices.append({
                'key': self.enum.UNIT_OF_MEASURE_POUND,
                'value': unit_name,
            })

        # Case
        case_text = None
        case_size = self.get_case_size_for_product(product)
        if case_size is None:
            case_text = "{} (&times; ?? {})".format(
                self.enum.UNIT_OF_MEASURE[self.enum.UNIT_OF_MEASURE_CASE],
                unit_name)
        elif case_size > 1:
            case_text = "{} (&times; {} {})".format(
                self.enum.UNIT_OF_MEASURE[self.enum.UNIT_OF_MEASURE_CASE],
                self.app.render_quantity(case_size),
                unit_name)
        if case_text:
            choices.append({'key': self.enum.UNIT_OF_MEASURE_CASE,
                            'value': case_text})

        return choices

    def why_not_add_product(self, product, batch):
        """
        This method can inspect the given product, and batch, to
        determine if the product may be added to the batch as a new
        row.  Useful to e.g. prevent one customer from ordering too
        many things, etc.

        :returns: If there is a reason not to add the product, should
           return that reason as a string; otherwise ``None``.
        """

    def add_product(self, batch, product, order_quantity, order_uom,
                    **kwargs):
        """
        Add a new row to the batch, for the given product and order
        quantity.
        """
        row = self.make_row()
        row.item_entry = product.uuid
        row.product = product
        row.order_quantity = order_quantity
        row.order_uom = order_uom
        if 'price_needs_confirmation' in kwargs:
            row.price_needs_confirmation = kwargs['price_needs_confirmation']
        self.add_row(batch, row)
        return row

    def refresh_row(self, row):
        if not row.product:
            if row.item_entry:
                session = orm.object_session(row)
                # TODO: should do more than just query for uuid here
                product = session.query(model.Product).get(row.item_entry)
                if product:
                    row.product = product
            if not row.product:
                row.status_code = row.STATUS_PRODUCT_NOT_FOUND
                return

        product = row.product
        row.product_upc = product.upc
        row.product_brand = six.text_type(product.brand or "")
        row.product_description = product.description
        row.product_size = product.size
        row.product_weighed = product.weighed
        row.case_quantity = self.get_case_size_for_product(product)

        department = product.department
        row.department_number = department.number if department else None
        row.department_name = department.name if department else None

        cost = product.cost
        row.product_unit_cost = cost.unit_cost if cost else None

        regprice = product.regular_price
        row.unit_price = regprice.price if regprice else None

        # we need to know if total price is updated
        old_total = row.total_price

        # maybe update total price
        if row.unit_price is None:
            row.total_price = None
        elif not row.unit_price:
            row.total_price = 0
        else:
            row.total_price = row.unit_price * row.order_quantity
            if row.order_uom == self.enum.UNIT_OF_MEASURE_CASE:
                row.total_price *= (row.case_quantity or 1)

        # update total price for batch too, if it changed
        if row.total_price != old_total:
            batch = row.batch
            batch.total_price = ((batch.total_price or 0)
                                 + (row.total_price or 0)
                                 - (old_total or 0))

        row.status_code = row.STATUS_OK

    def remove_row(self, row):
        batch = row.batch

        if not row.removed:
            row.removed = True

            if row.total_price:
                batch.total_price = (batch.total_price or 0) - row.total_price

        self.refresh_batch_status(batch)

    def execute(self, batch, user=None, progress=None, **kwargs):
        """
        Default behavior here will create and return a new rattail
        Customer Order.  It also may "add contact info" e.g. to the
        customer record.  Override as needed.
        """
        order = self.make_new_order(batch, user=user, progress=progress, **kwargs)
        self.update_contact_info(batch, user)
        return order

    def update_contact_info(self, batch, user, **kwargs):
        """
        Update contact info from the batch, onto the customer record.
        """
        if batch.get_param('add_phone_number'):
            self.add_phone_number(batch, user)
        if batch.get_param('add_email_address'):
            self.add_email_address(batch, user)

    def add_phone_number(self, batch, user, **kwargs):
        """
        Add phone number from the batch to the customer record.

        Note that the default behavior does *not* do that, but instead
        will send an email alert to configured recipient(s) with the
        update request.
        """
        self.app.send_email('new_phone_requested', {
            'user': user,
            'user_display': user.display_name if user else "(unknown user)",
            'contact': self.get_contact(batch),
            'contact_id': self.get_contact_id(batch),
            'phone_number': batch.phone_number,
        })

    def add_email_address(self, batch, user, **kwargs):
        """
        Add email address from the batch to the customer record.

        Note that the default behavior does *not* do that, but instead
        will send an email alert to configured recipient(s) with the
        update request.
        """
        self.app.send_email('new_email_requested', {
            'user': user,
            'user_display': user.display_name if user else "(unknown user)",
            'contact': self.get_contact(batch),
            'contact_id': self.get_contact_id(batch),
            'email_address': batch.email_address,
        })

    def make_new_order(self, batch, user=None, progress=None, **kwargs):
        """
        Create and return a new rattail Customer Order based on the
        batch contents.
        """
        batch_fields = [
            'store',
            'id',
            'customer',
            'person',
            'pending_customer',
            'phone_number',
            'email_address',
            'total_price',
        ]

        order = model.CustomerOrder()
        order.created_by = user
        order.status_code = self.enum.CUSTORDER_STATUS_ORDERED
        for field in batch_fields:
            setattr(order, field, getattr(batch, field))

        row_fields = [
            'product',
            'product_upc',
            'product_brand',
            'product_description',
            'product_size',
            'product_weighed',
            'department_number',
            'department_name',
            'case_quantity',
            'order_quantity',
            'order_uom',
            'product_unit_cost',
            'unit_price',
            'discount_percent',
            'total_price',
            'price_needs_confirmation',
            'paid_amount',
            'payment_transaction_number',
        ]

        def convert(row, i):

            # add new order item
            item = model.CustomerOrderItem()
            item.sequence = i
            for field in row_fields:
                setattr(item, field, getattr(row, field))
            order.items.append(item)

            # set initial status and attach events
            self.set_initial_item_status(item, user)

        self.progress_loop(convert, batch.active_rows(), progress,
                           message="Converting batch rows to order items")

        session = orm.object_session(batch)
        session.add(order)
        session.flush()

        return order

    def set_initial_item_status(self, item, user, **kwargs):
        """
        Set the initial status for the given order item, and attach
        any events.

        The first logical status is ``CUSTORDER_ITEM_STATUS_INITIATED``
        and an item may stay there if there is some other step(s)
        which must occur before the item is ready to proceed.  For
        instance the default logic will leave it there if the price
        needs to be confirmed, but you can override as needed, for
        instance if you require payment up-front.

        The second status is ``CUSTORDER_ITEM_STATUS_READY`` which
        indicates the item is ready to proceed.  The default logic
        will auto-advance the item to this status if the price does
        *not* need to be confirmed.  Again you may need to override
        e.g. to prevent this until up-front payment is received.
        """
        # set "initiated" status
        item.status_code = self.enum.CUSTORDER_ITEM_STATUS_INITIATED
        item.add_event(self.enum.CUSTORDER_ITEM_EVENT_INITIATED, user)

        # but if the price is good...
        if not item.price_needs_confirmation:

            # then we set "ready" status
            item.status_code = self.enum.CUSTORDER_ITEM_STATUS_READY
            item.status_text = "everything looks normal"

            item.add_event(self.enum.CUSTORDER_ITEM_EVENT_READY, user,
                           note=item.status_text)