# -*- coding: utf-8 -*-
# This file is part of the investment-module from m-ds.de for Tryton.
# The COPYRIGHT file at the top level of this repository contains the
# full copyright notices and license terms.

from trytond.model import ModelView, ModelSQL, fields
from trytond.transaction import Transaction
from trytond.pool import Pool, PoolMeta
from trytond.pyson import Eval
from sql.functions import Function
from datetime import timedelta
from decimal import Decimal


class Concat2(Function):
    """ concat columns
    """
    __slots__ = ()
    _function = 'concat'

# end Concat2


class GraphDef(metaclass=PoolMeta):
    __name__ = 'diagram.graphdef'

    asset = fields.Many2One(string='Asset',
        model_name='investment.asset',
        states={
            'invisible': Eval('dtype', '') != 'investment.asset',
            'required': Eval('dtype', '') == 'investment.asset',
        }, depends=['dtype'])

    @classmethod
    def _get_dtypes(cls):
        """ return list of types
        """
        l1 = super(GraphDef, cls)._get_dtypes()
        l1.append('investment.asset')
        return l1

    def get_recname_value(self):
        """ value by dtype
        """
        if self.dtype == 'investment.asset':
            return getattr(self.asset, 'rec_name', '-')
        return super(GraphDef, self).get_recname_value()

    def get_field_key(self):
        """ get to read value from json
        """
        if self.dtype == 'investment.asset':
            return 'asset%d' % self.asset.id
        return super(GraphDef, self).get_field_key()

    def get_scaling_for_investment_asset(self):
        """ get scaling for currency
        """
        Rate = Pool().get('investment.rate')

        if self.scaling == 'fix':
            return None

        if self.scaling == 'alldata':
            query = [('asset.id', '=', self.asset.id)]
        elif self.scaling == 'view':
            query = [
                ('asset.id', '=', self.asset.id),
                ('date', '>=', self.chart.used_start_date()),
                ('date', '<=', self.chart.used_end_date()),
                ]
        elif self.scaling == 'six':
            query = [
                ('asset.id', '=', self.asset.id),
                ('date', '>=', self.chart.used_start_date() - timedelta(days=180)),
                ('date', '<=', self.chart.used_end_date()),
                ]

        min_rec = Rate.search(query, limit=1, order=[('rate', 'ASC')])
        max_rec = Rate.search(query, limit=1, order=[('rate', 'DESC')])
        min_val = min_rec[0].rate if len(min_rec) > 0 else None
        max_val = max_rec[0].rate if len(max_rec) > 0 else None

        return self.compute_scaling_factor(min_val, max_val)

# end GraphDef


class ChartPoint(metaclass=PoolMeta):
    __name__ = 'diagram.point'

    @classmethod
    def get_interpolated_val(cls, keyname, query_date):
        """ query two neighbour-values to
            interpolate missing value
        """
        Rate = Pool().get('investment.rate')

        if keyname is None:
            return None

        # check if query is for us
        if keyname.startswith('asset'):
            asset_id = int(keyname[len('asset'):])

            before = Rate.search([
                ('date', '<', query_date),
                ('asset.id', '=', asset_id),
                ], limit=1, order=[('date', 'DESC')])

            after = Rate.search([
                ('date', '>', query_date),
                ('asset.id', '=', asset_id),
                ], limit=1, order=[('date', 'ASC')])

            if (len(before) == 1) and (len(after) == 1):
                result = cls.interpolate_linear(
                        (after[0].date, after[0].rate),
                        (before[0].date, before[0].rate),
                        query_date
                    )
                return result
            elif len(before) == 1:
                return before[0].rate
            elif len(after) == 1:
                return after[0].rate
        return super(ChartPoint, cls).get_interpolated_val(keyname, query_date)

    @classmethod
    def get_table_parts(cls):
        """ return a list of tables to union,
            table must contain the columns:
                date, key, val
        """
        pool = Pool()
        Rate = pool.get('investment.rate')
        tab_rate = Rate.__table__()

        tabparts = super(ChartPoint, cls).get_table_parts()

        # rate
        tabparts.append(tab_rate.select(
                tab_rate.date,
                Concat2('asset', tab_rate.asset).as_('key'),
                tab_rate.rate.as_('val'),
            ))
        return tabparts

# end ChartPoint