#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 warnings

from sql import Column
from sql.conditionals import Case

from ...config import CONFIG
from .field import Field, SQLType


class Selection(Field):
    '''
    Define a selection field (``str``).
    '''
    _type = 'selection'

    def __init__(self, selection, string='', sort=True,
            selection_change_with=None, translate=True, 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 selection: A list or a function name that returns a list.
            The list must be a list of tuples. First member is the value
            to store and the second is the value to display.
        :param sort: A boolean to sort or not the selections.
        '''
        super(Selection, 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)
        if hasattr(selection, 'copy'):
            self.selection = selection.copy()
        else:
            self.selection = selection
        self.selection_change_with = set()
        if selection_change_with:
            warnings.warn('selection_change_with argument is deprecated, '
                'use the depends decorator',
                DeprecationWarning, stacklevel=2)
            self.selection_change_with |= set(selection_change_with)
        self.sort = sort
        self.translate_selection = translate
    __init__.__doc__ += Field.__init__.__doc__

    def sql_type(self):
        db_type = CONFIG['db_type']
        if db_type == 'mysql':
            return SQLType('CHAR', 'VARCHAR(255)')
        return SQLType('VARCHAR', 'VARCHAR')

    def convert_order(self, name, tables, Model):
        if getattr(Model, 'order_%s' % name, None):
            return super(Selection, self).convert_order(name, tables, Model)

        table, _ = tables[None]
        selections = Model.fields_get([name])[name]['selection']
        if not isinstance(selections, (tuple, list)):
            selections = getattr(Model, selections)()
        column = Column(table, name)
        whens = []
        for key, value in selections:
            whens.append((column == key, value))
        return [Case(*whens, else_=column)]