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

from sql.functions import AtTimeZone, Function

from trytond import backend
from trytond.pyson import PYSONEncoder

from .field import Field


class SQLite_Date(Function):
    __slots__ = ()
    _function = 'DATE'


class SQLite_DateTime(Function):
    __slots__ = ()
    _function = 'DATETIME'


class SQLite_Time(Function):
    __slots__ = ()
    _function = 'TIME'


class Date(Field):
    '''
    Define a date field (``date``).
    '''
    _type = 'date'
    _sql_type = 'DATE'
    _py_type = datetime.date

    def sql_format(self, value):
        if isinstance(value, str):
            year, month, day = list(map(int, value.split("-", 2)))
            value = datetime.date(year, month, day)
        elif isinstance(value, datetime.datetime):
            if value.time() != datetime.time():
                raise ValueError("Date field can not have time")
        return super().sql_format(value)

    def sql_cast(self, expression, timezone=None):
        if backend.name == 'sqlite':
            return SQLite_Date(expression)
        if timezone:
            expression = AtTimeZone(expression, 'utc')
            expression = AtTimeZone(expression, timezone)
        return super(Date, self).sql_cast(expression)


class FormatMixin(Field):

    def definition(self, model, language):
        encoder = PYSONEncoder()
        definition = super().definition(model, language)
        definition['format'] = encoder.encode(self.format)
        return definition


class Timestamp(FormatMixin, Field):
    '''
    Define a timestamp field (``datetime``).
    '''
    _type = 'timestamp'
    _sql_type = 'TIMESTAMP'
    _py_type = datetime.datetime
    format = '%H:%M:%S.%f'

    def sql_format(self, value):
        if isinstance(value, str):
            datepart, timepart = value.split(" ")
            year, month, day = map(int, datepart.split("-", 2))
            timepart_full = timepart.split(".", 1)
            hours, minutes, seconds = map(int, timepart_full[0].split(":"))
            if len(timepart_full) == 2:
                microseconds = int(timepart_full[1])
            else:
                microseconds = 0
            value = datetime.datetime(
                year, month, day, hours, minutes, seconds, microseconds)
        return super().sql_format(value)

    def sql_cast(self, expression):
        if backend.name == 'sqlite':
            return SQLite_DateTime(expression)
        return super().sql_cast(expression)


class DateTime(Timestamp):
    '''
    Define a datetime field (``datetime``).
    '''
    _type = 'datetime'
    _sql_type = 'DATETIME'

    def __init__(self, string='', format='%H:%M:%S', help='', required=False,
            readonly=False, domain=None, states=None, select=False,
            on_change=None, on_change_with=None, depends=None,
            context=None, loading='eager'):
        '''
        :param format: The validation format as used by strftime.
        '''
        super(DateTime, self).__init__(string=string, help=help,
            required=required, readonly=readonly, domain=domain, states=states,
            select=select, on_change=on_change, on_change_with=on_change_with,
            depends=depends, context=context, loading=loading)
        self.format = format

    __init__.__doc__ += Field.__init__.__doc__

    def sql_format(self, value):
        value = super().sql_format(value)
        if isinstance(value, datetime.datetime):
            value = value.replace(microsecond=0)
        return value


class Time(FormatMixin, Field):
    '''
    Define a time field (``time``).
    '''
    _type = 'time'
    _sql_type = 'TIME'
    _py_type = datetime.time

    def __init__(self, string='', format='%H:%M:%S', help='', required=False,
            readonly=False, domain=None, states=None, select=False,
            on_change=None, on_change_with=None, depends=None,
            context=None, loading='eager'):
        '''
        :param format: The validation format as used by strftime.
        '''
        super().__init__(string=string, help=help,
            required=required, readonly=readonly, domain=domain, states=states,
            select=select, on_change=on_change, on_change_with=on_change_with,
            depends=depends, context=context, loading=loading)
        self.format = format

    def sql_format(self, value):
        if isinstance(value, str):
            hours, minutes, seconds = map(int, value.split(":"))
            value = datetime.time(hours, minutes, seconds)
        value = super().sql_format(value)
        if isinstance(value, datetime.time):
            value = value.replace(microsecond=0)
        return value

    def sql_cast(self, expression):
        if backend.name == 'sqlite':
            return SQLite_Time(expression)
        return super(Time, self).sql_cast(expression)


class TimeDelta(Field):
    '''
    Define a timedelta field (``timedelta``).
    '''
    _type = 'timedelta'
    _sql_type = 'INTERVAL'
    _py_type = datetime.timedelta

    def __init__(self, string='', converter=None, help='', required=False,
            readonly=False, domain=None, states=None, select=False,
            on_change=None, on_change_with=None, depends=None,
            context=None, loading='eager'):
        '''
        :param converter: The name of the context key containing
            the time converter.
        '''
        super(TimeDelta, self).__init__(string=string, help=help,
            required=required, readonly=readonly, domain=domain, states=states,
            select=select, on_change=on_change, on_change_with=on_change_with,
            depends=depends, context=context, loading=loading)
        self.converter = converter

    def sql_format(self, value):
        if isinstance(value, (int, float)):
            value = datetime.timedelta(seconds=value)
        elif isinstance(value, str):
            if not value.find(':'):
                raise ValueError(
                    "TimeDelta requires a string '%H:%M:%S.%f' or '%H:%M'")
            hours, minutes, seconds = (value.split(":") + ['00'])[:3]
            value = datetime.timedelta(
                hours=int(hours), minutes=int(minutes), seconds=float(seconds))
        return super().sql_format(value)

    @classmethod
    def get(cls, ids, model, name, values=None):
        result = {}
        for row in values:
            value = row[name]
            if (value is not None
                    and not isinstance(value, datetime.timedelta)):
                if value >= datetime.timedelta.max.total_seconds():
                    value = datetime.timedelta.max
                elif value <= datetime.timedelta.min.total_seconds():
                    value = datetime.timedelta.min
                else:
                    value = datetime.timedelta(seconds=value)
                result[row['id']] = value
            else:
                result[row['id']] = value
        return result

    def definition(self, model, language):
        definition = super().definition(model, language)
        definition['converter'] = self.converter
        return definition