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

from collections import defaultdict
from decimal import Decimal

from sql import Literal, Null, With
from sql.aggregate import Max, Min, Sum
from sql.conditionals import Case, Coalesce
from sql.functions import Ceil, CurrentTimestamp, DateTrunc, Log, Power, Round

try:
    import pygal
except ImportError:
    pygal = None
from dateutil.relativedelta import relativedelta

from trytond.i18n import lazy_gettext
from trytond.model import ModelSQL, ModelView, fields, sum_tree
from trytond.modules.currency.fields import Monetary
from trytond.pool import Pool
from trytond.pyson import Eval, If
from trytond.tools import grouped_slice, pairwise_longest, reduce_ids
from trytond.transaction import Transaction


class Abstract(ModelSQL, ModelView):

    company = fields.Many2One(
        'company.company', lazy_gettext('stock.msg_stock_reporting_company'))
    cost = Monetary(
        lazy_gettext('stock.msg_stock_reporting_cost'),
        currency='currency', digits='currency')
    revenue = Monetary(
        lazy_gettext('stock.msg_stock_reporting_revenue'),
        currency='currency', digits='currency')
    profit = Monetary(
        lazy_gettext('stock.msg_stock_reporting_profit'),
        currency='currency', digits='currency')
    margin = fields.Numeric(
        lazy_gettext('stock.msg_stock_reporting_margin'),
        digits=(14, 4),
        states={
            'invisible': ~Eval('margin'),
            })
    margin_trend = fields.Function(fields.Char(
            lazy_gettext('stock.msg_stock_reporting_margin_trend')),
        'get_trend')
    time_series = None

    currency = fields.Many2One(
        'currency.currency',
        lazy_gettext('stock.msg_stock_reporting_currency'))

    @classmethod
    def table_query(cls):
        from_item, tables, withs = cls._joins()
        return from_item.select(*cls._columns(tables, withs),
            where=cls._where(tables, withs),
            group_by=cls._group_by(tables, withs),
            with_=withs.values())

    @classmethod
    def _joins(cls):
        pool = Pool()
        Company = pool.get('company.company')
        Currency = pool.get('currency.currency')
        Move = pool.get('stock.move')
        Location = pool.get('stock.location')

        tables = {}
        tables['move'] = move = Move.__table__()
        tables['move.company'] = company = Company.__table__()
        tables['move.company.currency'] = currency = Currency.__table__()
        tables['move.from_location'] = from_location = Location.__table__()
        tables['move.to_location'] = to_location = Location.__table__()
        withs = {}
        withs['currency_rate'] = currency_rate = With(
            query=Currency.currency_rate_sql())
        withs['currency_rate_company'] = currency_rate_company = With(
            query=Currency.currency_rate_sql())

        from_item = (move
            .join(currency_rate, type_='LEFT',
                condition=(move.currency == currency_rate.currency)
                & (currency_rate.start_date <= move.effective_date)
                & ((currency_rate.end_date == Null)
                    | (currency_rate.end_date > move.effective_date))
                )
            .join(company,
                condition=move.company == company.id)
            .join(currency,
                condition=company.currency == currency.id)
            .join(currency_rate_company,
                condition=(company.currency == currency_rate_company.currency)
                & (currency_rate_company.start_date <= move.effective_date)
                & ((currency_rate_company.end_date == Null)
                    | (currency_rate_company.end_date > move.effective_date))
                )
            .join(from_location,
                condition=(move.from_location == from_location.id))
            .join(to_location,
                condition=(move.to_location == to_location.id)))
        return from_item, tables, withs

    @classmethod
    def _columns(cls, tables, withs):
        move = tables['move']
        from_location = tables['move.from_location']
        to_location = tables['move.to_location']
        currency = tables['move.company.currency']

        sign = Case(
            (from_location.type.in_(cls._to_location_types())
                & to_location.type.in_(cls._from_location_types()),
                -1),
            else_=1)
        cost = cls._column_cost(tables, withs, sign)
        revenue = cls._column_revenue(tables, withs, sign)
        profit = revenue - cost
        margin = Case(
            (revenue != 0, profit / revenue),
            else_=Null)
        return [
            cls._column_id(tables, withs).as_('id'),
            Literal(0).as_('create_uid'),
            CurrentTimestamp().as_('create_date'),
            cls.write_uid.sql_cast(Literal(Null)).as_('write_uid'),
            cls.write_date.sql_cast(Literal(Null)).as_('write_date'),
            move.company.as_('company'),
            cls.cost.sql_cast(
                Round(cost, currency.digits)).as_('cost'),
            cls.revenue.sql_cast(
                Round(revenue, currency.digits)).as_('revenue'),
            cls.profit.sql_cast(
                Round(profit, currency.digits)).as_('profit'),
            cls.margin.sql_cast(
                Round(margin, cls.margin.digits[1])).as_('margin'),
            currency.id.as_('currency'),
            ]

    @classmethod
    def _column_id(cls, tables, withs):
        move = tables['move']
        return Min(move.id)

    @classmethod
    def _column_cost(cls, tables, withs, sign):
        move = tables['move']
        return Sum(
            sign * cls.cost.sql_cast(move.internal_quantity)
            * Coalesce(move.cost_price, 0))

    @classmethod
    def _column_revenue(cls, tables, withs, sign):
        move = tables['move']
        currency = withs['currency_rate']
        currency_company = withs['currency_rate_company']
        return Sum(
            sign * cls.revenue.sql_cast(move.quantity)
            * Coalesce(move.unit_price, 0)
            * Coalesce(currency_company.rate / currency.rate, 0))

    @classmethod
    def _group_by(cls, tables, withs):
        move = tables['move']
        currency = tables['move.company.currency']
        return [move.company, currency.id, currency.digits]

    @classmethod
    def _where(cls, tables, withs):
        context = Transaction().context
        move = tables['move']
        from_location = tables['move.from_location']
        to_location = tables['move.to_location']

        where = move.company == context.get('company')
        where &= ((
                from_location.type.in_(cls._from_location_types())
                & to_location.type.in_(cls._to_location_types()))
            | (
                from_location.type.in_(cls._to_location_types())
                & to_location.type.in_(cls._from_location_types())))
        where &= move.state == 'done'
        from_date = context.get('from_date')
        if from_date:
            where &= move.effective_date >= from_date
        to_date = context.get('to_date')
        if to_date:
            where &= move.effective_date <= to_date
        return where

    @classmethod
    def _from_location_types(cls):
        return ['storage', 'drop']

    @classmethod
    def _to_location_types(cls):
        types = ['customer']
        if Transaction().context.get('include_lost'):
            types += ['lost_found']
        return types

    @property
    def time_series_all(self):
        delta = self._period_delta()
        for ts, next_ts in pairwise_longest(self.time_series or []):
            yield ts
            if delta and next_ts:
                date = ts.date + delta
                while date < next_ts.date:
                    yield None
                    date += delta

    @classmethod
    def _period_delta(cls):
        context = Transaction().context
        return {
            'year': relativedelta(years=1),
            'month': relativedelta(months=1),
            'day': relativedelta(days=1),
            }.get(context.get('period'))

    def get_trend(self, name):
        name = name[:-len('_trend')]
        if pygal:
            chart = pygal.Line()
            chart.add('', [getattr(ts, name) or 0 if ts else 0
                    for ts in self.time_series_all])
            return chart.render_sparktext()

    @classmethod
    def view_attributes(cls):
        return super().view_attributes() + [
            ('/tree/field[@name="profit"]', 'visual',
                If(Eval('profit', 0) < 0, 'danger', '')),
            ('/tree/field[@name="margin"]', 'visual',
                If(Eval('margin', 0) < 0, 'danger', '')),
            ]


class AbstractTimeseries(Abstract):

    date = fields.Date("Date")

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls._order = [('date', 'ASC')]

    @classmethod
    def _columns(cls, tables, withs):
        return super()._columns(tables, withs) + [
            cls._column_date(tables, withs).as_('date')]

    @classmethod
    def _column_date(cls, tables, withs):
        context = Transaction().context
        move = tables['move']
        date = DateTrunc(context.get('period'), move.effective_date)
        date = cls.date.sql_cast(date)
        return date

    @classmethod
    def _group_by(cls, tables, withs):
        return super()._group_by(tables, withs) + [
            cls._column_date(tables, withs)]


class Context(ModelView):
    "Stock Reporting Margin Context"
    __name__ = 'stock.reporting.margin.context'

    company = fields.Many2One('company.company', "Company", required=True)
    from_date = fields.Date("From Date",
        domain=[
            If(Eval('to_date') & Eval('from_date'),
                ('from_date', '<=', Eval('to_date')),
                ()),
            ])
    to_date = fields.Date("To Date",
        domain=[
            If(Eval('from_date') & Eval('to_date'),
                ('to_date', '>=', Eval('from_date')),
                ()),
            ])
    period = fields.Selection([
            ('year', "Year"),
            ('month', "Month"),
            ('day', "Day"),
            ], "Period", required=True)
    include_lost = fields.Boolean(
        "Include Lost",
        help="If checked, the cost of product moved "
        "to a lost and found location is included.")

    @classmethod
    def default_company(cls):
        return Transaction().context.get('company')

    @classmethod
    def default_from_date(cls):
        pool = Pool()
        Date = pool.get('ir.date')
        context = Transaction().context
        if 'from_date' in context:
            return context['from_date']
        return Date.today() - relativedelta(years=1)

    @classmethod
    def default_to_date(cls):
        pool = Pool()
        Date = pool.get('ir.date')
        context = Transaction().context
        if 'to_date' in context:
            return context['to_date']
        return Date.today()

    @classmethod
    def default_period(cls):
        return Transaction().context.get('period', 'month')

    @classmethod
    def default_include_lost(cls):
        return Transaction().context.get('include_lost', False)


class Main(Abstract, ModelView):
    "Stock Reporting Margin"
    __name__ = 'stock.reporting.margin.main'

    time_series = fields.Function(fields.One2Many(
            'stock.reporting.margin.main.time_series', None, "Time Series"),
        'get_time_series')

    def get_rec_name(self, name):
        return ''

    def get_time_series(self, name):
        pool = Pool()
        Timeseries = pool.get('stock.reporting.margin.main.time_series')
        return [t.id for t in Timeseries.search([])]


class MainTimeseries(AbstractTimeseries, ModelView):
    "Stock Reporting Margin"
    __name__ = 'stock.reporting.margin.main.time_series'


class ProductMixin:
    __slots__ = ()

    product = fields.Many2One(
        'product.product', "Product",
        context={
            'company': Eval('company', -1),
            },
        depends={'company'})
    internal_quantity = fields.Float("Internal Quantity")
    quantity = fields.Function(fields.Float(
            "Quantity", digits='unit'), 'get_quantity')
    unit = fields.Many2One('product.uom', "Unit")

    @classmethod
    def _joins(cls):
        pool = Pool()
        Product = pool.get('product.product')
        Template = pool.get('product.template')
        from_item, tables, withs = super()._joins()
        if 'move.product' not in tables:
            product = Product.__table__()
            tables['move.product'] = product
            move = tables['move']
            from_item = (from_item
                .join(product, condition=move.product == product.id))
        if 'move.product.template' not in tables:
            template = Template.__table__()
            tables['move.product.template'] = template
            product = tables['move.product']
            from_item = (from_item
                .join(template, condition=product.template == template.id))
        return from_item, tables, withs

    @classmethod
    def _columns(cls, tables, withs):
        move = tables['move']
        from_location = tables['move.from_location']
        to_location = tables['move.to_location']
        template = tables['move.product.template']
        sign = Case(
            (from_location.type.in_(cls._to_location_types())
                & to_location.type.in_(cls._from_location_types()),
                -1),
            else_=1)
        return super()._columns(tables, withs) + [
            move.product.as_('product'),
            Sum(sign * move.internal_quantity).as_('internal_quantity'),
            template.default_uom.as_('unit'),
            ]

    @classmethod
    def _group_by(cls, tables, withs):
        move = tables['move']
        template = tables['move.product.template']
        return super()._group_by(tables, withs) + [
            move.product, template.default_uom]

    def get_rec_name(self, name):
        return self.product.rec_name

    @classmethod
    def search_rec_name(cls, name, clause):
        return [('product.rec_name', *clause[1:])]

    def get_quantity(self, name):
        return self.unit.round(self.internal_quantity)


class Product(ProductMixin, Abstract, ModelView):
    "Stock Reporting Margin per Product"
    __name__ = 'stock.reporting.margin.product'

    time_series = fields.One2Many(
        'stock.reporting.margin.product.time_series', 'product', "Time Series")

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls._order.insert(0, ('product', 'ASC'))

    @classmethod
    def _column_id(cls, tables, withs):
        move = tables['move']
        return move.product


class ProductTimeseries(ProductMixin, AbstractTimeseries, ModelView):
    "Stock Reporting Margin per Product"
    __name__ = 'stock.reporting.margin.product.time_series'


class CategoryMixin:
    __slots__ = ()

    category = fields.Many2One('product.category', "Category")

    @classmethod
    def _joins(cls):
        pool = Pool()
        Product = pool.get('product.product')
        TemplateCategory = pool.get('product.template-product.category.all')
        from_item, tables, withs = super()._joins()
        if 'move.product' not in tables:
            product = Product.__table__()
            tables['move.product'] = product
            move = tables['move']
            from_item = (from_item
                .join(product, condition=move.product == product.id))
        if 'move.product.template_category' not in tables:
            template_category = TemplateCategory.__table__()
            tables['move.product.template_category'] = template_category
            product = tables['move.product']
            from_item = (from_item
                .join(template_category,
                    condition=product.template == template_category.template))
        return from_item, tables, withs

    @classmethod
    def _columns(cls, tables, withs):
        template_category = tables['move.product.template_category']
        return super()._columns(tables, withs) + [
            template_category.category.as_('category')]

    @classmethod
    def _column_id(cls, tables, withs):
        pool = Pool()
        Category = pool.get('product.category')
        category = Category.__table__()
        move = tables['move']
        template_category = tables['move.product.template_category']
        # Get a stable number of category over time
        # by using number one order bigger.
        nb_category = category.select(
            Power(10, (Ceil(Log(Max(category.id))) + Literal(1))))
        return Min(move.id * nb_category + template_category.id)

    @classmethod
    def _group_by(cls, tables, withs):
        template_category = tables['move.product.template_category']
        return super()._group_by(tables, withs) + [template_category.category]

    @classmethod
    def _where(cls, tables, withs):
        template_category = tables['move.product.template_category']
        where = super()._where(tables, withs)
        where &= template_category.category != Null
        return where

    def get_rec_name(self, name):
        return self.category.rec_name if self.category else None

    @classmethod
    def search_rec_name(cls, name, clause):
        return [('category.rec_name', *clause[1:])]


class Category(CategoryMixin, Abstract, ModelView):
    "Stock Reporting Margin per Category"
    __name__ = 'stock.reporting.margin.category'

    time_series = fields.One2Many(
        'stock.reporting.margin.category.time_series', 'category',
        "Time Series")

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls._order.insert(0, ('category', 'ASC'))

    @classmethod
    def _column_id(cls, tables, withs):
        template_category = tables['move.product.template_category']
        return template_category.category


class CategoryTimeseries(CategoryMixin, AbstractTimeseries, ModelView):
    "Stock Reporting Margin per Category"
    __name__ = 'stock.reporting.margin.category.time_series'


class CategoryTree(ModelSQL, ModelView):
    "Stock Reporting Margin per Category"
    __name__ = 'stock.reporting.margin.category.tree'

    name = fields.Function(
        fields.Char("Name"), 'get_name', searcher='search_name')
    parent = fields.Many2One('stock.reporting.margin.category.tree', "Parent")
    children = fields.One2Many(
        'stock.reporting.margin.category.tree', 'parent', "Children")
    cost = fields.Function(Monetary(
            lazy_gettext('stock.msg_stock_reporting_cost'),
            currency='currency', digits='currency'),
        'get_total')
    revenue = fields.Function(Monetary(
            lazy_gettext('stock.msg_stock_reporting_revenue'),
            currency='currency', digits='currency'),
        'get_total')
    profit = fields.Function(Monetary(
            lazy_gettext('stock.msg_stock_reporting_profit'),
            currency='currency', digits='currency'),
        'get_total')
    margin = fields.Function(Monetary(
            lazy_gettext('stock.msg_stock_reporting_margin'),
            digits=(14, 4)),
        'get_margin')

    currency = fields.Function(fields.Many2One(
            'currency.currency',
            lazy_gettext('stock.msg_stock_reporting_currency')),
        'get_currency')

    @classmethod
    def __setup__(cls):
        super().__setup__()
        cls._order.insert(0, ('name', 'ASC'))

    @classmethod
    def table_query(cls):
        pool = Pool()
        Category = pool.get('product.category')
        return Category.__table__()

    @classmethod
    def get_name(cls, categories, name):
        pool = Pool()
        Category = pool.get('product.category')
        categories = Category.browse(categories)
        return {c.id: c.name for c in categories}

    @classmethod
    def search_name(cls, name, clause):
        pool = Pool()
        Category = pool.get('product.category')
        return [('id', 'in', Category.search([clause], query=True))]

    @classmethod
    def order_name(cls, tables):
        pool = Pool()
        Category = pool.get('product.category')
        table, _ = tables[None]
        if 'category' not in tables:
            category = Category.__table__()
            tables['category'] = {
                None: (category, table.id == category.id),
                }
        return Category.name.convert_order(
            'name', tables['category'], Category)

    def time_series_all(self):
        return []

    @classmethod
    def get_total(cls, categories, names):
        pool = Pool()
        ReportingCategory = pool.get('stock.reporting.margin.category')
        reporting_category = ReportingCategory.__table__()
        cursor = Transaction().connection.cursor()

        categories = cls.search([
                ('parent', 'child_of', [c.id for c in categories]),
                ])
        ids = [c.id for c in categories]
        reporting_categories = []
        for sub_ids in grouped_slice(ids):
            sub_ids = list(sub_ids)
            where = reduce_ids(reporting_category.id, sub_ids)
            cursor.execute(
                *reporting_category.select(reporting_category.id, where=where))
            reporting_categories.extend(r for r, in cursor)

        result = {}
        reporting_categories = ReportingCategory.browse(reporting_categories)
        for name in names:
            values = defaultdict(
                Decimal,
                {c.id: getattr(c, name) for c in reporting_categories})
            result[name] = sum_tree(categories, values)
        return result

    def get_margin(self, name):
        digits = self.__class__.margin.digits
        if self.profit is not None and self.revenue:
            return (self.profit / self.revenue).quantize(
                Decimal(1) / 10 ** digits[1])

    def get_currency(self, name):
        pool = Pool()
        Company = pool.get('company.company')
        company = Transaction().context.get('company')
        if company is not None and company >= 0:
            return Company(company).currency.id

    @classmethod
    def view_attributes(cls):
        return super().view_attributes() + [
            ('/tree/field[@name="profit"]', 'visual',
                If(Eval('profit', 0) < 0, 'danger', '')),
            ('/tree/field[@name="margin"]', 'visual',
                If(Eval('margin', 0) < 0, 'danger', '')),
            ]
