account-financial-reporting/mis_builder/models/mis_builder.py

# -*- encoding: utf-8 -*-
##############################################################################
#
#    mis_builder module for OpenERP, Management Information System Builder
#    Copyright (C) 2014 ACSONE SA/NV (<http://acsone.eu>)
#
#    This file is a part of mis_builder
#
#    mis_builder is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License v3 or later
#    as published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    mis_builder 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 Affero General Public License v3 or later for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    v3 or later along with this program.
#    If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

from datetime import datetime, timedelta
from dateutil import parser
import traceback
import re
import pytz

from openerp.osv import orm, fields
from openerp.tools.safe_eval import safe_eval
from openerp.tools.translate import _
from openerp import tools
from collections import OrderedDict


FUNCTION = [('credit', 'cred'),
            ('debit', 'deb'),
            ('balance', 'bal')
            ]

FUNCTION_LIST = [x[1] for x in FUNCTION]

PARAMETERS = ['s', 'i', '']
PARAMETERS_WITHOUT_BLANK = [x for x in PARAMETERS if x != '']
SEPARATOR = '_'

PARAMETERS_STR = ''.join(PARAMETERS)

FUNCTION_CONDITION = '|'.join(PARAMETERS_WITHOUT_BLANK)


class AutoStruct(object):

    def __init__(self, **kwargs):
        for k, v in kwargs.items():
            setattr(self, k, v)


def _get_selection_label(selection, value):
    for v, l in selection:
        if v == value:
            return l
    return ''


def _utc_midnight(d, tz_name, add_day=0):
    d = datetime.strptime(d, tools.DEFAULT_SERVER_DATE_FORMAT)
    if add_day:
        d = d + timedelta(days=add_day)
    utc_tz = pytz.timezone('UTC')
    context_tz = pytz.timezone(tz_name)
    local_timestamp = context_tz.localize(d, is_dst=False)
    return datetime.strftime(local_timestamp.astimezone(utc_tz),
                             tools.DEFAULT_SERVER_DATETIME_FORMAT)


def _python_var(var_str):
    return re.sub(r'\W|^(?=\d)', '_', var_str).lower()


def _get_sufix(is_solde=False, is_initial=False):
    if is_solde:
        return 's'
    elif is_initial:
        return 'i'
    else:
        return ''


def _get_prefix(function, is_solde=False, is_initial=False):
    return function + _get_sufix(is_solde=is_solde, is_initial=is_initial) \
        + SEPARATOR


def _python_account_var(function, account_code, is_solde=False,
                        is_initial=False):
    prefix = _get_prefix(function, is_solde=is_solde, is_initial=is_initial)
    return prefix + re.sub(r'\W', '_', account_code)


# TODO : To review
def _get_account_code(account_var):
    res = re.findall(r'_(\d+)', account_var)
    assert len(res) == 1
    return res[0]


# TODO : To review
def _get_account_vars_in_expr(expr, res_vars, is_solde=False, is_initial=False):
    pass


# TODO : Not use here, Check in upstream
# def _get_vars_in_expr(expr, varnames=None):
#     if not varnames:
#         return []
#     varnames_re = r'\b' + r'\b|\b'.join(varnames) + r'\b'
#     return re.findall(varnames_re, expr)


def _get_eval_expression(expr, domain_mapping):
    domain_list = []
    for function in FUNCTION_LIST:
        domain_list.extend(re.findall(r'\b%s[%s]?_\w+(\[.+?\])' % (function, PARAMETERS_STR), expr))
    for domain in domain_list:
        expr = expr.replace(domain, domain_mapping[domain])
    return expr


def _get_account_vars_in_report(report, domain_mapping, is_solde=False,
                                is_initial=False):
    res_vars = {}
    domain_count = 0
    for kpi in report.kpi_ids:
        for function in FUNCTION_LIST:
            prefix = _get_prefix(function, is_solde=is_solde, is_initial=is_initial)
            find_res = re.findall(r'\b%s\w+(?:\[.+?\])?' % prefix, kpi.expression)
            for item in find_res:
                match = re.match(r'\b(%s)(\w+)(\[.+?\])?' % prefix, item)
                var_tuple = match.groups()
                domain = "" if var_tuple[2] is None else var_tuple[2]
                key = ""
                if domain != "":
                    if domain not in domain_mapping:
                        key = 'd' + str(domain_count)
                        domain_count += 1
                        domain_mapping[domain] = key
                    else:
                        key = domain_mapping[domain]
                key_domain = (key, domain)
                if not res_vars.get(key_domain, False):
                    res_vars[key_domain] = set()
                res_vars[key_domain].add(var_tuple[1])
    return res_vars


def _is_valid_python_var(name):
    for item in FUNCTION_LIST:
        for param in PARAMETERS:
            if name.startswith(item + param + SEPARATOR):
                return False
    return re.match("[_A-Za-z][_a-zA-Z0-9]*$", name)


class mis_report_kpi(orm.Model):

    """ A KPI is an element of a MIS report.

    In addition to a name and description, it has an expression
    to compute it based on queries defined in the MIS report.
    It also has various informations defining how to render it
    (numeric or percentage or a string, a suffix, divider) and
    how to render comparison of two values of the KPI.
    KPI are ordered inside the MIS report, as some KPI expressions
    can depend on other KPI that need to be computed before.
    """

    _name = 'mis.report.kpi'

    _columns = {
        'name': fields.char(size=32, required=True,
                            string='Name'),
        'description': fields.char(required=True,
                                   string='Description',
                                   translate=True),
        'expression': fields.char(required=True,
                                  string='Expression'),
        'default_css_style': fields.char(
            string='Default CSS style'),
        'css_style': fields.char(string='CSS style expression'),
        'type': fields.selection([('num', _('Numeric')),
                                  ('pct', _('Percentage')),
                                  ('str', _('String'))],
                                 required=True,
                                 string='Type'),
        'divider': fields.selection([('1e-6', _('µ')),
                                     ('1e-3', _('m')),
                                     ('1', _('1')),
                                     ('1e3', _('k')),
                                     ('1e6', _('M'))],
                                    string='Factor'),
        'dp': fields.integer(string='Rounding'),
        'suffix': fields.char(size=16, string='Suffix'),
        'compare_method': fields.selection([('diff', _('Difference')),
                                            ('pct', _('Percentage')),
                                            ('none', _('None'))],
                                           required=True,
                                           string='Comparison Method'),
        'sequence': fields.integer(string='Sequence'),
        'report_id': fields.many2one('mis.report', string='Report'),
    }

    _defaults = {
        'type': 'num',
        'divider': '1',
        'dp': 0,
        'compare_method': 'pct',
        'sequence': 100,
    }

    _order = 'sequence'

    def _check_name(self, cr, uid, ids, context=None):
        for record_name in self.read(cr, uid, ids, ['name']):
            if not _is_valid_python_var(record_name['name']):
                return False
        return True

    _constraints = [
        (_check_name, 'The name must be a valid python identifier', ['name']),
    ]

    def onchange_name(self, cr, uid, ids, name, context=None):
        res = {}
        if name and not _is_valid_python_var(name):
            res['warning'] = {
                'title': 'Invalid name',
                'message': 'The name must be a valid python identifier'}
        return res

    def onchange_description(self, cr, uid, ids, description, name,
                             context=None):
        """ construct name from description """
        res = {}
        if description and not name:
            res = {'value': {'name': _python_var(description)}}
        return res

    def onchange_type(self, cr, uid, ids, kpi_type, context=None):
        res = {}
        if kpi_type == 'pct':
            res['value'] = {'compare_method': 'diff'}
        elif kpi_type == 'str':
            res['value'] = {'compare_method': 'none',
                            'divider': '',
                            'dp': 0}
        return res

    def _render(self, cr, uid, lang_id, kpi, value, context=None):
        """ render a KPI value as a unicode string, ready for display """
        if kpi.type == 'num':
            return self._render_num(cr, uid, lang_id, value, kpi.divider,
                                    kpi.dp, kpi.suffix, context=context)
        elif kpi.type == 'pct':
            return self._render_num(cr, uid, lang_id, value, 0.01,
                                    kpi.dp, '%', context=context)
        else:
            return unicode(value)

    def _render_comparison(self, cr, uid, lang_id, kpi, value, base_value,
                           average_value, average_base_value, context=None):
        """ render the comparison of two KPI values, ready for display """
        if value is None or base_value is None:
            return ''
        if kpi.type == 'pct':
            return self._render_num(cr, uid, lang_id, value - base_value, 0.01,
                                    kpi.dp, _('pp'), sign='+', context=context)
        elif kpi.type == 'num':
            if average_value:
                value = value / float(average_value)
            if average_base_value:
                base_value = base_value / float(average_base_value)
            if kpi.compare_method == 'diff':
                return self._render_num(cr, uid, lang_id, value - base_value,
                                        kpi.divider,
                                        kpi.dp, kpi.suffix, sign='+',
                                        context=context)
            elif kpi.compare_method == 'pct' and base_value != 0:
                return self._render_num(cr, uid, lang_id,
                                        value / base_value - 1, 0.01,
                                        kpi.dp, '%', sign='+', context=context)
        return ''

    def _render_num(self, cr, uid, lang_id, value, divider,
                    dp, suffix, sign='-', context=None):
        divider_label = _get_selection_label(
            self._columns['divider'].selection, divider)
        if divider_label == '1':
            divider_label = ''
        # format number following user language
        value = round(value / float(divider or 1), dp) or 0
        return '%s %s%s' % (self.pool['res.lang'].format(
            cr, uid, lang_id,
            '%%%s.%df' % (
                sign, dp),
            value,
            grouping=True,
            context=context),
            divider_label, suffix or '')


class mis_report_query(orm.Model):

    """ A query to fetch data for a MIS report.

    A query works on a model and has a domain and list of fields to fetch.
    At runtime, the domain is expanded with a "and" on the date/datetime field.
    """

    _name = 'mis.report.query'

    def _get_field_names(self, cr, uid, ids, name, args, context=None):
        res = {}
        for query in self.browse(cr, uid, ids, context=context):
            field_names = []
            for field in query.field_ids:
                field_names.append(field.name)
            res[query.id] = ', '.join(field_names)
        return res

    def onchange_field_ids(self, cr, uid, ids, field_ids, context=None):
        # compute field_names
        field_names = []
        for field in self.pool.get('ir.model.fields').read(
                cr, uid,
                field_ids[0][2],
                ['name'],
                context=context):
            field_names.append(field['name'])
        return {'value': {'field_names': ', '.join(field_names)}}

    _columns = {
        'name': fields.char(size=32, required=True,
                            string='Name'),
        'model_id': fields.many2one('ir.model', required=True,
                                    string='Model'),
        'field_ids': fields.many2many('ir.model.fields', required=True,
                                      string='Fields to fetch'),
        'field_names': fields.function(_get_field_names, type='char',
                                       string='Fetched fields name',
                                       store={'mis.report.query':
                                              (lambda self, cr, uid, ids, c={}:
                                               ids, ['field_ids'], 20), }),
        'date_field': fields.many2one('ir.model.fields', required=True,
                                      string='Date field',
                                      domain=[('ttype', 'in',
                                               ('date', 'datetime'))]),
        'domain': fields.char(string='Domain'),
        'report_id': fields.many2one('mis.report', string='Report'),
    }

    _order = 'name'

    def _check_name(self, cr, uid, ids, context=None):
        for record_name in self.read(cr, uid, ids, ['name']):
            if not _is_valid_python_var(record_name['name']):
                return False
        return True

    _constraints = [
        (_check_name, 'The name must be a valid python identifier', ['name']),
    ]


class mis_report(orm.Model):

    """ A MIS report template (without period information)

    The MIS report holds:
    * an implicit query fetching all the account balances;
      for each account, the balance is stored in a variable named
      bal_{code} where {code} is the account code
    * an implicit query fetching all the account balances solde;
      for each account, the balance solde is stored in a variable named
      bals_{code} where {code} is the account code
    * a list of explicit queries; the result of each query is
      stored in a variable with same name as a query, containing as list
      of data structures populated with attributes for each fields to fetch
    * a list of KPI to be evaluated based on the variables resulting
      from the balance and queries
    """

    _name = 'mis.report'

    _columns = {
        'name': fields.char(size=32, required=True,
                            string='Name', translate=True),
        'description': fields.char(required=False,
                                   string='Description', translate=True),
        'query_ids': fields.one2many('mis.report.query', 'report_id',
                                     string='Queries'),
        'kpi_ids': fields.one2many('mis.report.kpi', 'report_id',
                                   string='KPI\'s'),
    }

    # TODO: kpi name cannot be start with query name

    def create(self, cr, uid, vals, context=None):
        # TODO: explain this
        if 'kpi_ids' in vals:
            mis_report_kpi_obj = self.pool.get('mis.report.kpi')
            for idx, line in enumerate(vals['kpi_ids']):
                if line[0] == 0:
                    line[2]['sequence'] = idx + 1
                else:
                    mis_report_kpi_obj.write(
                        cr, uid, [line[1]], {'sequence': idx + 1},
                        context=context)
        return super(mis_report, self).create(cr, uid, vals, context=context)

    def write(self, cr, uid, ids, vals, context=None):
        # TODO: explain this
        res = super(mis_report, self).write(
            cr, uid, ids, vals, context=context)
        mis_report_kpi_obj = self.pool.get('mis.report.kpi')
        for report in self.browse(cr, uid, ids, context):
            for idx, kpi in enumerate(report.kpi_ids):
                mis_report_kpi_obj.write(
                    cr, uid, [kpi.id], {'sequence': idx + 1}, context=context)
        return res


class mis_report_instance_period(orm.Model):

    """ A MIS report instance has the logic to compute
    a report template for a given date period.

    Periods have a duration (day, week, fiscal period) and
    are defined as an offset relative to a pivot date.
    """

    def _get_dates(self, cr, uid, ids, field_names, arg, context=None):
        if isinstance(ids, (int, long)):
            ids = [ids]
        res = {}
        for c in self.browse(cr, uid, ids, context=context):
            d = parser.parse(c.report_instance_id.pivot_date)
            if c.type == 'd':
                date_from = d + timedelta(days=c.offset)
                date_to = date_from + timedelta(days=c.duration - 1)
                date_from = date_from.strftime(
                    tools.DEFAULT_SERVER_DATE_FORMAT)
                date_to = date_to.strftime(tools.DEFAULT_SERVER_DATE_FORMAT)
                period_ids = None
            elif c.type == 'w':
                date_from = d - timedelta(d.weekday())
                date_from = date_from + timedelta(days=c.offset * 7)
                date_to = date_from + timedelta(days=(7 * c.duration) - 1)
                date_from = date_from.strftime(
                    tools.DEFAULT_SERVER_DATE_FORMAT)
                date_to = date_to.strftime(tools.DEFAULT_SERVER_DATE_FORMAT)
                period_ids = None
            elif c.type == 'fp':
                period_obj = self.pool['account.period']
                all_period_ids = period_obj.search(
                    cr, uid,
                    [('special', '=', False),
                     '|', ('company_id', '=', False),
                     ('company_id', '=', c.company_id.id)],
                    order='date_start',
                    context=context)
                current_period_ids = period_obj.search(
                    cr, uid,
                    [('special', '=', False),
                     ('date_start', '<=', d),
                     ('date_stop', '>=', d),
                     '|', ('company_id', '=', False),
                     ('company_id', '=', c.company_id.id)],
                    context=context)
                if not current_period_ids:
                    raise orm.except_orm(_("Error!"),
                                         _("No current fiscal period for %s")
                                         % d)
                p = all_period_ids.index(current_period_ids[0]) + c.offset
                if p < 0 or p >= len(all_period_ids):
                    raise orm.except_orm(_("Error!"),
                                         _("No such fiscal period for %s "
                                           "with offset %d") % (d, c.offset))
                period_ids = all_period_ids[p:p + c.duration]
                periods = period_obj.browse(cr, uid, period_ids,
                                            context=context)
                date_from = periods[0].date_start
                date_to = periods[-1].date_stop
            else:
                raise orm.except_orm(_("Error!"),
                                     _("Unimplemented period type %s") %
                                     (c.type,))
            res[c.id] = {
                'date_from': date_from,
                'date_to': date_to,
                'period_from': period_ids and period_ids[0],
                'period_to': period_ids and period_ids[-1],
            }
        return res

    _name = 'mis.report.instance.period'

    _columns = {
        'name': fields.char(size=32, required=True,
                            string='Description', translate=True),
        'type': fields.selection([('d', _('Day')),
                                  ('w', _('Week')),
                                  ('fp', _('Fiscal Period')),
                                  # ('fy', _('Fiscal Year'))
                                  ],
                                 required=True,
                                 string='Period type'),
        'offset': fields.integer(string='Offset',
                                 help='Offset from current period'),
        'duration': fields.integer(string='Duration',
                                   help='Number of periods'),
        'date_from': fields.function(_get_dates,
                                     type='date',
                                     multi="dates",
                                     string="From"),
        'date_to': fields.function(_get_dates,
                                   type='date',
                                   multi="dates",
                                   string="To"),
        'period_from': fields.function(_get_dates,
                                       type='many2one', obj='account.period',
                                       multi="dates", string="From period"),
        'period_to': fields.function(_get_dates,
                                     type='many2one', obj='account.period',
                                     multi="dates", string="To period"),
        'sequence': fields.integer(string='Sequence'),
        'report_instance_id': fields.many2one('mis.report.instance',
                                              string='Report Instance'),
        'comparison_column_ids': fields.many2many(
            'mis.report.instance.period',
            'mis_report_instance_period_rel',
            'period_id',
            'compare_period_id',
            string='Compare with'),
        'company_id': fields.related('report_instance_id', 'company_id',
                                     type="many2one", relation="res.company",
                                     string="Company", readonly=True),
        'normalize_factor': fields.integer(
            string='Factor',
            help='Factor to use to normalize the period (used in comparison'),
    }

    _defaults = {
        'offset': -1,
        'duration': 1,
        'sequence': 100,
        'normalize_factor': 1,
    }

    _order = 'sequence'

    _sql_constraints = [
        ('duration', 'CHECK (duration>0)',
         'Wrong duration, it must be positive!'),
        ('normalize_factor', 'CHECK (normalize_factor>0)',
         'Wrong normalize factor, it must be positive!'),
        ('name_unique', 'unique(name, report_instance_id)',
         'Period name should be unique by report'),
    ]

    # TODO : To review
    def compute_domain(self, cr, uid, ids, account_, context=None):
        if isinstance(ids, (int, long)):
            ids = [ids]
        domain = []
        # extract all bal code
        account = _get_account_vars_in_expr(account_)
        account_s = _get_account_vars_in_expr(account_, is_solde=True)
        account_i = _get_account_vars_in_expr(account_, is_initial=True)

        all_code = []
        all_code.extend([_get_account_code(acc) for acc in account])
        all_code.extend([_get_account_code(acc) for acc in account_s])
        all_code.extend([_get_account_code(acc) for acc in account_i])

        domain.append(('account_id.code', 'in', all_code))

        # compute date/period
        period_ids = []
        date_from = None
        date_to = None

        period_obj = self.pool['account.period']

        for c in self.browse(cr, uid, ids, context=context):
            target_move = c.report_instance_id.target_move
            if target_move == 'posted':
                domain.append(('move_id.state', '=', target_move))
            if c.period_from:
                compute_period_ids = period_obj.build_ctx_periods(
                    cr, uid, c.period_from.id, c.period_to.id)
                period_ids.extend(compute_period_ids)
            else:
                if not date_from or date_from > c.date_from:
                    date_from = c.date_from
                if not date_to or date_to < c.date_to:
                    date_to = c.date_to
        if period_ids:
            if date_from:
                domain.append('|')
            domain.append(('period_id', 'in', period_ids))
        if date_from:
            domain.extend([('date', '>=', c.date_from),
                           ('date', '<=', c.date_to)])

        return domain

    def _fetch_account(self, cr, uid, company_id, account_vars, context=None,
                       is_solde=False, is_initial=False):
        account_obj = self.pool['account.account']
        account_move_line_obj = self.pool['account.move.line']
        # TODO: use child of company_id?
        # first fetch all codes and filter the one we need+
        balances = {}
        for key_domain, account_code in account_vars.iteritems():
            key, domain = key_domain
            account_ids = account_obj.search(
                cr, uid,
                ['|', ('company_id', '=', False),
                 ('company_id', '=', company_id),
                 ('code', 'in', list(account_code))],
                context=context)
            # fetch balances
            where_clause = ''
            where_clause_params = ()
            if domain != '':
                domain_eval = safe_eval(domain)
                query = account_move_line_obj._where_calc(cr, uid, domain_eval, context=context)
                from_clause, where_clause, where_clause_params = query.get_sql()
                assert from_clause == '"account_move_line"'
                where_clause = where_clause.replace("account_move_line", "l")
                where_clause_params = tuple(where_clause_params)
            account_datas = self.pool['account.account']._compute(cr, uid, account_ids,['balance', 'credit', 'debit'], arg=None, context=context, query=where_clause, query_params=where_clause_params)
            for id, fields in account_datas.iteritems():
                account_data = account_obj.read(cr, uid, [id], ['code'],
                                                context=context)[0]
                for item in FUNCTION:
                    var = _python_account_var(item[1], account_data['code'],
                                              is_solde=is_solde,
                                              is_initial=is_initial)
                    var = var + key
                    assert key not in balances
                    balances[var] = fields[item[0]]

        return balances

    def _get_context_period(self, cr, uid, report_period, is_solde=False,
                            is_initial=False, context=None):
        context_period = {}
        move_obj = self.pool['account.move']
        period_obj = self.pool['account.period']
        if not is_solde and not is_initial:
            if report_period.period_from:
                context_period.\
                    update({'period_from': report_period.period_from.id,
                            'period_to': report_period.period_to.id})
            else:
                context_period.update({'date_from': report_period.date_from,
                                       'date_to': report_period.date_to})
        else:
            period_to = report_period.period_to
            if is_initial:
                move_id = move_obj.search(
                    cr, uid, [('period_id.special', '=', False),
                              ('period_id.date_start', '<',
                               period_to.date_start)],
                    order="period_id desc", limit=1, context=context)
                if move_id:
                    computed_period_to = move_obj.browse(
                        cr, uid, move_id[0], context=context).period_id.id
                else:
                    computed_period_to = self.pool['account.period'].search(
                        cr, uid, [('company_id', '=',
                                   report_period.company_id.id)],
                        order='date_start desc', limit=1)[0]
                # Change start period to search correctly period from
                period_to = period_obj.browse(cr, uid, [computed_period_to],
                                              context=context)[0]
            move_id = move_obj.search(
                cr, uid, [('period_id.special', '=', True),
                          ('period_id.date_start', '<=',
                           period_to.date_start)],
                order="period_id desc", limit=1, context=context)
            if move_id:
                computed_period_from = move_obj.browse(
                    cr, uid, move_id[0], context=context).period_id.id
            else:
                computed_period_from = self.pool['account.period'].search(
                    cr, uid, [('company_id', '=',
                               report_period.company_id.id)],
                    order='date_start', limit=1)[0]
            context_period.update({'period_from': computed_period_from,
                                   'period_to': period_to.id})
        return context_period

    def _fetch_balances(self, cr, uid, c, account_vars, context=None):
        """ fetch the general account balances for the given period

        returns a dictionary {bal_<account.code>: account.balance}
        """
        if not account_vars:
            return {}

        if context is None:
            context = {}

        search_ctx = dict(context)
        search_ctx.update(self._get_context_period(cr, uid, c,
                                                   context=context))
        # fetch balances
        return self._fetch_account(cr, uid, c.company_id.id, account_vars,
                                   search_ctx)

    def _fetch_balances_solde(self, cr, uid, c, account_vars, context=None):
        """ fetch the general account balances solde at the end of
            the given period

            the period from is computed by searching the last special period
            with journal entries.
            If nothing is found, the first period is used.

        returns a dictionary {bals_<account.code>: account.balance.solde}
        """
        if context is None:
            context = {}
        balances = {}
        if not account_vars:
            return balances

        search_ctx = dict(context)
        if c.period_to:
            search_ctx.update(self._get_context_period(cr, uid, c,
                                                       is_solde=True,
                                                       context=context))
        else:
            return balances

        # fetch balances
        return self._fetch_account(cr, uid, c.company_id.id, account_vars,
                                   search_ctx, is_solde=True)

    def _fetch_balances_initial(self, cr, uid, c, account_vars, context=None):
        if context is None:
            context = {}
        balances = {}
        if not account_vars:
            return balances

        search_ctx = dict(context)
        if c.period_to:
            search_ctx.update(self._get_context_period(cr, uid, c,
                                                       is_initial=True,
                                                       context=context))
        else:
            return balances

        # fetch balances
        return self._fetch_account(cr, uid, c.company_id.id, account_vars,
                                   search_ctx, is_initial=True)

    def _fetch_queries(self, cr, uid, c, context):
        res = {}

        report = c.report_instance_id.report_id
        for query in report.query_ids:
            obj = self.pool[query.model_id.model]
            domain = query.domain and safe_eval(query.domain) or []
            if query.date_field.ttype == 'date':
                domain.extend([(query.date_field.name, '>=', c.date_from),
                               (query.date_field.name, '<=', c.date_to)])
            else:
                datetime_from = _utc_midnight(
                    c.date_from, context.get('tz', 'UTC'))
                datetime_to = _utc_midnight(
                    c.date_to, context.get('tz', 'UTC'), add_day=1)
                domain.extend([(query.date_field.name, '>=', datetime_from),
                               (query.date_field.name, '<', datetime_to)])
            if obj._columns.get('company_id', False):
                domain.extend(['|', ('company_id', '=', False),
                               ('company_id', '=', c.company_id.id)])
            field_names = [field.name for field in query.field_ids]
            obj_ids = obj.search(cr, uid, domain, context=context)
            obj_datas = obj.read(
                cr, uid, obj_ids, field_names, context=context)
            res[query.name] = [AutoStruct(**d) for d in obj_datas]

        return res

    def _compute(self, cr, uid, lang_id, c, account_vars, accounts_vars,
                 accounti_vars, domain_mapping, context=None):
        if context is None:
            context = {}

        kpi_obj = self.pool['mis.report.kpi']

        res = {}

        localdict = {
            'registry': self.pool,
            'sum': sum,
            'min': min,
            'max': max,
            'len': len,
            'avg': lambda l: sum(l) / float(len(l)),
        }
        localdict.update(self._fetch_balances(cr, uid, c, account_vars,
                                              context=context))
        localdict.update(self._fetch_balances_solde(cr, uid, c, accounts_vars,
                                                    context=context))
        localdict.update(self._fetch_balances_initial(cr, uid, c,
                                                      accounti_vars,
                                                      context=context))
        localdict.update(self._fetch_queries(cr, uid, c,
                                             context=context))

        for kpi in c.report_instance_id.report_id.kpi_ids:
            try:
                kpi_eval_expression = _get_eval_expression(kpi.expression,
                                                           domain_mapping)
                kpi_val_comment = kpi.expression
                kpi_val = safe_eval(kpi_eval_expression, localdict)
            except ZeroDivisionError:
                kpi_val = None
                kpi_val_rendered = '#DIV/0'
                kpi_val_comment += '\n\n%s' % (traceback.format_exc(),)
            except:
                kpi_val = None
                kpi_val_rendered = '#ERR'
                kpi_val_comment += '\n\n%s' % (traceback.format_exc(),)
            else:
                kpi_val_rendered = kpi_obj._render(
                    cr, uid, lang_id, kpi, kpi_val, context=context)

            localdict[kpi.name] = kpi_val
            try:
                kpi_style = None
                if kpi.css_style:
                    kpi_style = safe_eval(kpi.css_style, localdict)
            except:
                kpi_style = None

            res[kpi.name] = {
                'val': kpi_val,
                'val_r': kpi_val_rendered,
                'val_c': kpi_val_comment,
                'style': kpi_style,
                'default_style': kpi.default_css_style or None,
                'suffix': kpi.suffix,
                'dp': kpi.dp,
                'is_percentage': kpi.type == 'pct',
                'period_id': c.id,
                'period_name': c.name,
            }

        return res


class mis_report_instance(orm.Model):

    """ The MIS report instance combines compute and
    display a MIS report template for a set of periods """

    def _get_pivot_date(self, cr, uid, ids, field_name, arg, context=None):
        res = {}
        for r in self.browse(cr, uid, ids, context=context):
            if r.date:
                res[r.id] = r.date
            else:
                res[r.id] = fields.date.context_today(self, cr, uid,
                                                      context=context)
        return res

    _name = 'mis.report.instance'

    _columns = {
        'name': fields.char(size=32, required=True,
                            string='Name', translate=True),
        'description': fields.char(required=False,
                                   string='Description', translate=True),
        'date': fields.date(string='Base date',
                            help='Report base date '
                                 '(leave empty to use current date)'),
        'pivot_date': fields.function(_get_pivot_date,
                                      type='date',
                                      string="Pivot date"),
        'report_id': fields.many2one('mis.report',
                                     required=True,
                                     string='Report'),
        'period_ids': fields.one2many('mis.report.instance.period',
                                      'report_instance_id',
                                      required=True,
                                      string='Periods'),
        'target_move': fields.selection([('posted', 'All Posted Entries'),
                                         ('all', 'All Entries'),
                                         ], 'Target Moves', required=True),
        'company_id': fields.many2one('res.company', 'Company', required=True),
    }

    _defaults = {
        'target_move': 'posted',
        'company_id': lambda s, cr, uid, c:
        s.pool.get('res.company')._company_default_get(
            cr, uid,
            'mis.report.instance',
            context=c)
    }

    def create(self, cr, uid, vals, context=None):
        if not vals:
            return context.get('active_id', None)
        # TODO: explain this
        if 'period_ids' in vals:
            mis_report_instance_period_obj = self.pool.get(
                'mis.report.instance.period')
            for idx, line in enumerate(vals['period_ids']):
                if line[0] == 0:
                    line[2]['sequence'] = idx + 1
                else:
                    mis_report_instance_period_obj.write(
                        cr, uid, [line[1]], {'sequence': idx + 1},
                        context=context)
        return super(mis_report_instance, self).create(cr, uid, vals,
                                                       context=context)

    def write(self, cr, uid, ids, vals, context=None):
        # TODO: explain this
        res = super(mis_report_instance, self).write(
            cr, uid, ids, vals, context=context)
        mis_report_instance_period_obj = self.pool.get(
            'mis.report.instance.period')
        for instance in self.browse(cr, uid, ids, context):
            for idx, period in enumerate(instance.period_ids):
                mis_report_instance_period_obj.write(
                    cr, uid, [period.id], {'sequence': idx + 1},
                    context=context)
        return res

    def _format_date(self, cr, uid, lang_id, date, context=None):
        # format date following user language
        tformat = self.pool['res.lang'].read(
            cr, uid, lang_id, ['date_format'])[0]['date_format']
        return datetime.strftime(datetime.strptime(
            date,
            tools.DEFAULT_SERVER_DATE_FORMAT),
            tformat)

    def compute(self, cr, uid, _ids, context=None):
        assert isinstance(_ids, (int, long))
        if context is None:
            context = {}
        r = self.browse(cr, uid, _ids, context=context)
        context['state'] = r.target_move

        content = OrderedDict()
        # empty line name for header
        header = OrderedDict()
        header[''] = {'kpi_name': '', 'cols': [], 'default_style': ''}

        # initialize lines with kpi
        for kpi in r.report_id.kpi_ids:
            content[kpi.name] = {'kpi_name': kpi.description,
                                 'cols': [],
                                 'default_style': ''}

        report_instance_period_obj = self.pool.get(
            'mis.report.instance.period')
        kpi_obj = self.pool.get('mis.report.kpi')

        period_values = {}
        domain_mapping = {}
        account_vars = _get_account_vars_in_report(r.report_id,
                                                   domain_mapping)
        accounts_vars = _get_account_vars_in_report(r.report_id,
                                                    domain_mapping,
                                                    is_solde=True)
        accounti_vars = _get_account_vars_in_report(r.report_id,
                                                    domain_mapping,
                                                    is_initial=True)

        lang = self.pool['res.users'].read(
            cr, uid, uid, ['lang'], context=context)['lang']
        lang_id = self.pool['res.lang'].search(
            cr, uid, [('code', '=', lang)], context=context)

        for period in r.period_ids:
            # add the column header
            header['']['cols'].append(dict(
                name=period.name,
                date=(period.duration > 1 or period.type == 'w') and
                _('from %s to %s' %
                  (period.period_from and period.period_from.name
                   or self._format_date(cr, uid, lang_id, period.date_from,
                                        context=context),
                   period.period_to and period.period_to.name
                   or self._format_date(cr, uid, lang_id, period.date_to,
                                        context=context)))
                or period.period_from and period.period_from.name or
                period.date_from))
            # compute kpi values
            values = report_instance_period_obj._compute(
                cr, uid, lang_id, period, account_vars, accounts_vars,
                accounti_vars, domain_mapping, context=context)
            period_values[period.name] = values
            for key in values:
                content[key]['default_style'] = values[key]['default_style']
                content[key]['cols'].append(values[key])

        # add comparison column
        for period in r.period_ids:
            for compare_col in period.comparison_column_ids:
                # add the column header
                header['']['cols'].append(
                    dict(name='%s - %s' % (period.name, compare_col.name),
                         date=''))
                column1_values = period_values[period.name]
                column2_values = period_values[compare_col.name]
                for kpi in r.report_id.kpi_ids:
                    content[kpi.name]['cols'].append(
                        {'val_r': kpi_obj._render_comparison(
                            cr,
                            uid,
                            lang_id,
                            kpi,
                            column1_values[kpi.name]['val'],
                            column2_values[kpi.name]['val'],
                            period.normalize_factor,
                            compare_col.normalize_factor,
                            context=context)})

        return {'header': header,
                'content': content}