#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 string import Template
import time
from itertools import izip
from sql import Flavor

from ..model import ModelView, ModelSQL, fields
from ..tools import datetime_strftime
from ..pyson import Eval, And
from ..transaction import Transaction
from ..pool import Pool
from ..config import CONFIG
from .. import backend

__all__ = [
    'SequenceType', 'Sequence', 'SequenceStrict',
    ]

sql_sequence = CONFIG.options['db_type'] == 'postgresql'


class SequenceType(ModelSQL, ModelView):
    "Sequence type"
    __name__ = 'ir.sequence.type'

    name = fields.Char('Sequence Name', required=True, translate=True)
    code = fields.Char('Sequence Code', required=True)


class Sequence(ModelSQL, ModelView):
    "Sequence"
    __name__ = 'ir.sequence'

    _strict = False
    name = fields.Char('Sequence Name', required=True, translate=True)
    code = fields.Selection('code_get', 'Sequence Code', required=True,
        states={
            'readonly': Eval('context', {}).contains('code'),
            })
    active = fields.Boolean('Active')
    prefix = fields.Char('Prefix')
    suffix = fields.Char('Suffix')
    type = fields.Selection([
        ('incremental', 'Incremental'),
        ('decimal timestamp', 'Decimal Timestamp'),
        ('hexadecimal timestamp', 'Hexadecimal Timestamp'),
        ], 'Type')
    number_next_internal = fields.Integer('Next Number',
        states={
            'invisible': ~Eval('type').in_(['incremental']),
            'required': And(Eval('type').in_(['incremental']),
                not sql_sequence),
            }, depends=['type'])
    number_next = fields.Function(number_next_internal, 'get_number_next',
        'set_number_next')
    number_increment = fields.Integer('Increment Number',
        states={
            'invisible': ~Eval('type').in_(['incremental']),
            'required': Eval('type').in_(['incremental']),
            }, depends=['type'])
    padding = fields.Integer('Number padding',
        states={
            'invisible': ~Eval('type').in_(['incremental']),
            'required': Eval('type').in_(['incremental']),
            }, depends=['type'])
    timestamp_rounding = fields.Float('Timestamp Rounding', required=True,
        states={
            'invisible': ~Eval('type').in_(
                ['decimal timestamp', 'hexadecimal timestamp']),
            }, depends=['type'])
    timestamp_offset = fields.Float('Timestamp Offset', required=True,
        states={
            'invisible': ~Eval('type').in_(
                ['decimal timestamp', 'hexadecimal timestamp']),
            }, depends=['type'])
    last_timestamp = fields.Integer('Last Timestamp',
        states={
            'invisible': ~Eval('type').in_(
                ['decimal timestamp', 'hexadecimal timestamp']),
            'required': Eval('type').in_(
                ['decimal timestamp', 'hexadecimal timestamp']),
            }, depends=['type'])

    @classmethod
    def __setup__(cls):
        super(Sequence, cls).__setup__()
        cls._sql_constraints += [
            ('check_timestamp_rounding', 'CHECK(timestamp_rounding > 0)',
                'Timestamp rounding should be greater than 0'),
            ]
        cls._error_messages.update({
                'missing': 'Missing sequence.',
                'invalid_prefix': ('Invalid prefix "%(prefix)s" on sequence '
                    '"%(sequence)s".'),
                'invalid_suffix': ('Invalid suffix "%(suffix)s" on sequence '
                    '"%(sequence)s".'),
                'future_last_timestamp': ('Last Timestamp cannot be in the '
                    'future on sequence "%s".'),
                })

    @classmethod
    def __register__(cls, module_name):
        TableHandler = backend.get('TableHandler')
        cursor = Transaction().cursor
        table = TableHandler(cursor, cls, module_name)

        # Migration from 2.0 rename number_next into number_next_internal
        table.column_rename('number_next', 'number_next_internal')

        super(Sequence, cls).__register__(module_name)

        # Migration from 2.0 create sql_sequence
        if sql_sequence and not cls._strict:
            sequences = cls.search([])
            for sequence in sequences:
                if sequence.type != 'incremental':
                    continue
                if not TableHandler.sequence_exist(cursor,
                        sequence._sql_sequence_name):
                    sequence.create_sql_sequence(sequence.number_next_internal)

    @staticmethod
    def default_active():
        return True

    @staticmethod
    def default_type():
        return 'incremental'

    @staticmethod
    def default_number_increment():
        return 1

    @staticmethod
    def default_number_next():
        return 1

    @staticmethod
    def default_padding():
        return 0

    @staticmethod
    def default_timestamp_rounding():
        return 1.0

    @staticmethod
    def default_timestamp_offset():
        return 946681200.0  # Offset for 2000-01-01

    @staticmethod
    def default_last_timestamp():
        return 0.0

    @staticmethod
    def default_code():
        return Transaction().context.get('code')

    def get_number_next(self, name):
        cursor = Transaction().cursor
        sql_name = self._sql_sequence_name
        if sql_sequence and not self._strict:
            cursor.execute('SELECT '
                'CASE WHEN NOT is_called THEN last_value '
                    'ELSE last_value + increment_by '
                'END FROM "%s"' % sql_name)
            return cursor.fetchone()[0]
        else:
            return self.number_next_internal

    @classmethod
    def set_number_next(cls, sequences, name, value):
        super(Sequence, cls).write(sequences, {
                'number_next_internal': value,
                })

    @classmethod
    def create(cls, vlist):
        sequences = super(Sequence, cls).create(vlist)
        for sequence, values in izip(sequences, vlist):
            if sql_sequence and not cls._strict:
                sequence.update_sql_sequence(values.get('number_next',
                        cls.default_number_next()))
        return sequences

    @classmethod
    def write(cls, sequences, values):
        result = super(Sequence, cls).write(sequences, values)
        if sql_sequence and not cls._strict:
            for sequence in sequences:
                sequence.update_sql_sequence(values.get('number_next'))
        return result

    @classmethod
    def delete(cls, sequences):
        if sql_sequence and not cls._strict:
            for sequence in sequences:
                sequence.delete_sql_sequence()
        return super(Sequence, cls).delete(sequences)

    @classmethod
    def code_get(cls):
        pool = Pool()
        SequenceType = pool.get('ir.sequence.type')
        sequence_types = SequenceType.search([])
        return [(x.code, x.name) for x in sequence_types]

    @classmethod
    def validate(cls, sequences):
        super(Sequence, cls).validate(sequences)
        cls.check_prefix_suffix(sequences)
        cls.check_last_timestamp(sequences)

    @classmethod
    def check_prefix_suffix(cls, sequences):
        "Check prefix and suffix"

        for sequence in sequences:
            for fix, error_message in ((sequence.prefix, 'invalid_prefix'),
                    (sequence.suffix, 'invalid_suffix')):
                try:
                    cls._process(sequence.prefix)
                    cls._process(sequence.suffix)
                except Exception:
                    cls.raise_user_error(error_message, {
                            'prefix': fix,
                            'sequence': sequence.rec_name,
                            })

    @classmethod
    def check_last_timestamp(cls, sequences):
        "Check last_timestamp"

        for sequence in sequences:
            next_timestamp = cls._timestamp(sequence)
            if sequence.last_timestamp > next_timestamp:
                cls.raise_user_error('future_last_timestamp', (
                        sequence.rec_name,))

    @property
    def _sql_sequence_name(self):
        'Return SQL sequence name'
        return '%s_%s' % (self._table, self.id)

    def create_sql_sequence(self, number_next=None):
        'Create the SQL sequence'
        cursor = Transaction().cursor
        param = Flavor.get().param
        if self.type != 'incremental':
            return
        if number_next is None:
            number_next = self.number_next
        cursor.execute('CREATE SEQUENCE "' + self._sql_sequence_name
            + '" INCREMENT BY ' + param + ' START WITH ' + param,
            (self.number_increment, number_next))

    def update_sql_sequence(self, number_next=None):
        'Update the SQL sequence'
        TableHandler = backend.get('TableHandler')
        cursor = Transaction().cursor
        param = Flavor.get().param
        exist = TableHandler.sequence_exist(cursor, self._sql_sequence_name)
        if self.type != 'incremental':
            if exist:
                self.delete_sql_sequence()
            return
        if not exist:
            self.create_sql_sequence(number_next)
            return
        if number_next is None:
            number_next = self.number_next
        cursor.execute('ALTER SEQUENCE "' + self._sql_sequence_name
            + '" INCREMENT BY ' + param + ' RESTART WITH ' + param,
            (self.number_increment, number_next))

    def delete_sql_sequence(self):
        'Delete the SQL sequence'
        cursor = Transaction().cursor
        if self.type != 'incremental':
            return
        cursor.execute('DROP SEQUENCE "%s"'
            % self._sql_sequence_name)

    @staticmethod
    def _process(string, date=None):
        pool = Pool()
        Date = pool.get('ir.date')
        if not date:
            date = Date.today()
        year = datetime_strftime(date, '%Y')
        month = datetime_strftime(date, '%m')
        day = datetime_strftime(date, '%d')
        return Template(string or '').substitute(
                year=year,
                month=month,
                day=day,
                )

    @staticmethod
    def _timestamp(sequence):
        return int((time.time() - sequence.timestamp_offset)
                / sequence.timestamp_rounding)

    @classmethod
    def _get_sequence(cls, sequence):
        if sequence.type == 'incremental':
            if sql_sequence and not cls._strict:
                cursor = Transaction().cursor
                cursor.execute('SELECT nextval(\'"%s"\')'
                    % sequence._sql_sequence_name)
                number_next, = cursor.fetchone()
            else:
                #Pre-fetch number_next
                number_next = sequence.number_next_internal

                with Transaction().set_user(0):
                    cls.write([sequence], {
                            'number_next_internal': (number_next
                                + sequence.number_increment),
                            })
            return '%%0%sd' % sequence.padding % number_next
        elif sequence.type in ('decimal timestamp', 'hexadecimal timestamp'):
            timestamp = sequence.last_timestamp
            while timestamp == sequence.last_timestamp:
                timestamp = cls._timestamp(sequence)
            with Transaction().set_user(0):
                cls.write([sequence], {
                    'last_timestamp': timestamp,
                    })
            if sequence.type == 'decimal timestamp':
                return '%d' % timestamp
            else:
                return hex(timestamp)[2:].upper()
        return ''

    @classmethod
    def get_id(cls, domain):
        '''
        Return sequence value for the domain
        '''
        if isinstance(domain, cls):
            domain = domain.id
        if isinstance(domain, (int, long)):
            domain = [('id', '=', domain)]

        # bypass rules on sequences
        with Transaction().set_context(user=False):
            with Transaction().set_user(0):
                try:
                    sequence, = cls.search(domain, limit=1)
                except TypeError:
                    cls.raise_user_error('missing')
            date = Transaction().context.get('date')
            return '%s%s%s' % (
                cls._process(sequence.prefix, date=date),
                cls._get_sequence(sequence),
                cls._process(sequence.suffix, date=date),
                )

    @classmethod
    def get(cls, code):
        return cls.get_id([('code', '=', code)])


class SequenceStrict(Sequence):
    "Sequence Strict"
    __name__ = 'ir.sequence.strict'
    _table = 'ir_sequence_strict'  # Needed to override Sequence._table
    _strict = True

    @classmethod
    def get_id(cls, clause):
        Transaction().cursor.lock(cls._table)
        return super(SequenceStrict, cls).get_id(clause)
