Cdebase ported to Python

7 files changed, 736 insertions, 0 deletions

diff --git a/bcdd/BCalcWrapper.py b/bcdd/BCalcWrapper.py
new file mode 100644
index 0000000..9337809
--- /dev/null
+++ b/bcdd/BCalcWrapper.py
@@ -0,0 +1,32 @@
+'''
+Wrapper class for libbcalcDDS.dll
+'''
+
+from ctypes import cdll
+
+from .Exceptions import DllNotFoundException
+
+
+class BCalcWrapper(object):
+
+    DENOMINATIONS = [ 'C', 'D', 'H', 'S', 'N' ]
+    PLAYERS = [ 'N', 'E', 'S', 'W' ]
+
+    def __init__(self):
+        try:
+            self.libbcalcdds = cdll.LoadLibrary('./libbcalcdds.dll')
+        except OSError:
+            try:
+                self.libbcalcdds = cdll.LoadLibrary('./libbcalcdds.so')
+            except OSError:
+                self.libbcalcdds = None
+        if self.libbcalcdds is None:
+            raise DllNotFoundException()
+
+    def __getattr__(self, attrname):
+        def _dynamic_method(*args):
+            return getattr(self.libbcalcdds, 'bcalcDDS_' + attrname)(*args)
+        return _dynamic_method
+
+    def declarerToLeader(self, player):
+        return (player + 1) % 4
diff --git a/bcdd/DDTable.py b/bcdd/DDTable.py
new file mode 100644
index 0000000..cc08424
--- /dev/null
+++ b/bcdd/DDTable.py
@@ -0,0 +1,94 @@
+from ctypes import c_char_p
+from copy import copy
+
+from .BCalcWrapper import BCalcWrapper
+from .Exceptions import DDTableInvalidException, FieldNotFoundException
+
+
+class DDTable(object):
+
+    def _get_empty_table(self):
+        table = []
+        row = [-1] * 5
+        for col in range(0, 4):
+            table.append(copy(row))
+        return table
+
+    def _validate_table(self, table):
+        for row in table:
+            for t in row:
+                if (t > 13) or (t < 0):
+                    raise DDTableInvalidException(
+                        'Invalid number of tricks: %d' % (t)
+                    )
+        return table
+
+    _banner_displayed = False
+
+    def __init__(self, board):
+        self._board = board;
+        self._wrapper = BCalcWrapper()
+
+    def get_bcalc_table(self):
+        if not DDTable._banner_displayed:
+            print('Double dummy analysis provided by BCalc.')
+            print('BCalc is awesome, check it out: http://bcalc.w8.pl')
+            DDTable._banner_displayed = True
+        result = self._get_empty_table()
+        deal = self._board.get_layout()
+        solver = self._wrapper.new(b"PBN", deal.encode(), 0, 0)
+        for denom in range(0, 5):
+            self._wrapper.setTrumpAndReset(solver, denom)
+            for player in range(0, 4):
+                leader = self._wrapper.declarerToLeader(player)
+                self._wrapper.setPlayerOnLeadAndReset(solver, leader)
+                result[player][denom] = 13 - self._wrapper.getTricksToTake(
+                    solver)
+                error = self._wrapper.getLastError(solver)
+                if error:
+                    raise DDTableInvalidException(
+                        'BCalc error: ' + str(c_char_p(error)))
+        self._wrapper.delete(solver);
+        return self._validate_table(result)
+
+    def get_jfr_table(self):
+        result = self._get_empty_table()
+        ability = self._board.get_ability()
+        abilities = self._board.validate_ability(ability)
+        for player_ability in abilities:
+            player = player_ability.groups(1)[0]
+            player_id = BCalcWrapper.PLAYERS.index(player)
+            denom_id = 4
+            for tricks in player_ability.group(2):
+                result[player_id][denom_id] = int(tricks, 16)
+                denom_id -= 1
+        return self._validate_table(result)
+
+    def get_pbn_table(self):
+        table = self._board.get_optimum_result_table()
+        parsed_table = self._board.validate_optimum_result_table(table)
+        result = self._get_empty_table()
+        for line_match in parsed_table:
+            player = line_match.group(1)[0]
+            denom = line_match.group(2)[0]
+            tricks = int(line_match.group(3))
+            player_id = BCalcWrapper.PLAYERS.index(player)
+            denom_id = BCalcWrapper.DENOMINATIONS.index(denom)
+            result[player_id][denom_id] = tricks
+        return self._validate_table(result)
+
+    def get_dd_table(self):
+        try:
+            return self.get_jfr_table()
+        except FieldNotFoundException:
+            try:
+                return self.get_pbn_table()
+            except FieldNotFoundException:
+                return self.get_bcalc_table()
+
+    def print_table(self, dd_table):
+        print('\t' + '\t'.join(BCalcWrapper.DENOMINATIONS))
+        for i in range(0, 4):
+            print('%s%s' % (
+                self._wrapper.PLAYERS[i],
+                ''.join(['\t' + str(tricks) for tricks in dd_table[i]])))
diff --git a/bcdd/Exceptions.py b/bcdd/Exceptions.py
new file mode 100644
index 0000000..16970b5
--- /dev/null
+++ b/bcdd/Exceptions.py
@@ -0,0 +1,14 @@
+class DllNotFoundException(Exception):
+    pass
+
+
+class FieldNotFoundException(Exception):
+    pass
+
+
+class ParScoreInvalidException(FieldNotFoundException):
+    pass
+
+
+class DDTableInvalidException(FieldNotFoundException):
+    pass
diff --git a/bcdd/PBNBoard.py b/bcdd/PBNBoard.py
new file mode 100644
index 0000000..3dbb751
--- /dev/null
+++ b/bcdd/PBNBoard.py
@@ -0,0 +1,229 @@
+import re
+
+from .BCalcWrapper import BCalcWrapper
+from .Exceptions import FieldNotFoundException
+
+
+class PBNField(object):
+
+    def __init__(self, key=None, value=None, raw_data=None):
+        self.key = key
+        self.value = value
+        self.raw_field = '[%s "%s"]' % (self.key, str(self.value)) \
+                         if self.key is not None else raw_data
+
+class PBNBoard(object):
+
+    line_pattern = re.compile(r'\[(.*) "(.*)"\]')
+    ability_pattern = re.compile(r'\b([NESW]):([0-9A-D]{5})\b')
+    optimum_result_table_pattern = re.compile(
+        r'^([NESW])\s+([CDHSN])T?\s+(\d+)$')
+
+    def __init__(self, lines):
+        self._has_optimum_result_table = None
+        self._has_ability = None
+        self.fields = []
+        for line in lines:
+            field = PBNField(raw_data=line)
+            line_parse = self.line_pattern.match(line)
+            if line_parse:
+                field.key = line_parse.group(1)
+                field.value = line_parse.group(2)
+            self.fields.append(field)
+
+    def has_field(self, key):
+        for field in self.fields:
+            if key == field.key:
+                return True
+        return False
+
+    def get_field(self, key):
+        for field in self.fields:
+            if key == field.key:
+                return field.value
+        raise FieldNotFoundException(key + ' field not found')
+
+    def delete_field(self, key):
+        to_remove = []
+        for field in self.fields:
+            if key == field.key:
+                to_remove.append(field)
+        for remove in to_remove:
+            self.fields.remove(remove)
+
+    def get_event(self):
+        return self.get_field('Event')
+
+    def write_event(self, name):
+        for i in range(0, len(self.fields)):
+            if 'Board' == self.fields[i].key:
+                self.fields.insert(i, PBNField(key='Event', value=name))
+                break
+
+    def get_layout(self):
+        return self.get_field('Deal')
+
+    def get_number(self):
+        return self.get_field('Board')
+
+    def get_vulnerable(self):
+        return self.get_field('Vulnerable')
+
+    def get_dealer(self):
+        return self.get_field('Dealer')
+
+    def validate_ability(self, ability):
+        matches = self.ability_pattern.match(ability)
+        if len(match) != 4:
+            self._has_ability = False
+            raise DDTableInvalidException('Invalid Ability line: ' + ability)
+        players = []
+        for match in matches:
+            if match.group(1) in players:
+                self._has_ability = False
+                raise DDTableInvalidException(
+                    'Duplicate entry in Ability: ' + match.group(0))
+            else:
+                players.append(match.group(1))
+        self._has_ability = False
+        return matches
+
+    def get_ability(self):
+        return self.get_field('Ability')
+
+    def delete_ability(self):
+        self.delete_field('Ability')
+
+    def write_ability(self, dd_table):
+        sb = ''
+        for i in range(0, 4):
+            sb += BCalcWrapper.PLAYERS[i]
+            sb += ':'
+            sb += ''.join(['%X' % (j) for j in dd_table[i]])[::-1]
+            sb += ' '
+        self.fields.append(PBNField(key='Ability', value=sb.strip()))
+
+    def get_minimax(self):
+        return self.get_field('Minimax')
+
+    def delete_minimax(self):
+        self.delete_field('Minimax')
+
+    def write_minimax(self, contract):
+        minimax = '7NS0' if contract.score == 0 \
+                  else '%d%s%s%s%d' % (
+                          contract.level,
+                          contract.denomination,
+                          'D' if contract.doubled else '',
+                          contract.declarer,
+                          contract.score)
+        self.fields.append(PBNField(key='Minimax', value=minimax))
+
+    def get_optimum_score(self):
+        return self.get_field('OptimumScore')
+
+    def delete_optimum_score(self):
+        self.delete_field('OptimumScore')
+
+    def write_optimum_score(self, contract):
+        self.fields.append(
+            PBNField(key='OptimumScore',
+                     value='NS %d' % (contract.score)))
+
+    def get_optimum_result(self):
+        return self.get_field('OptimumResult')
+
+    def validate_optimum_result_table(self, table):
+        matches = []
+        duplicates = []
+        for line in table:
+            match = self.optimum_result_table_pattern.match(line)
+            if not match:
+                self._has_optimum_result_table = False
+                raise DDTableInvalidException(
+                    'Invalid OptimumResultTable line: ' + line)
+            position = match.group(1) + ' - ' + match.group(2)
+            if position in duplicates:
+                self._has_optimum_result_table = False
+                raise DDTableInvalidException(
+                    'Duplicate OptimumResultTable line: ' + line)
+            else:
+                duplicates.append(position)
+            matches.append(match)
+        self._has_optimum_result_table = True
+        return matches
+
+    def get_optimum_result_table(self):
+        field_found = False
+        result = []
+        for field in self.fields:
+            if 'OptimumResultTable' == field.key:
+                field_found = True
+            else:
+                if field_found:
+                    if field.key is None:
+                        result.append(field.raw_field)
+                    else:
+                        break
+        if not field_found:
+            self._has_optimum_result_table = False
+            raise FieldNotFoundException('OptimumResultTable field not found')
+        return result
+
+    def delete_optimum_result_table(self):
+        field_found = False
+        to_remove = []
+        for field in self.fields:
+            if 'OptimumResultTable' == field.key:
+                field_found = True
+                to_remove.append(field)
+            else:
+                if field_found:
+                    if field.key is None:
+                        to_remove.append(field)
+                    else:
+                        break
+        for remove in to_remove:
+            self.fields.remove(remove)
+
+    def write_optimum_result_table(self, dd_table):
+        self.fields.append(PBNField(
+            key='OptimumResultTable',
+            value=r'Declarer;Denomination\2R;Result\2R'))
+        for i in range(0, 4):
+            for j in range(0, 5):
+                self.fields.append(PBNField(
+                    raw_data='%s %s%s %d' % (
+                        BCalcWrapper.PLAYERS[i],
+                        BCalcWrapper.DENOMINATIONS[j],
+                        'T' if BCalcWrapper.DENOMINATIONS[j] == 'N' else '',
+                        dd_table[i][j])))
+
+    def save_par_contract(self, contract):
+        # we're not writing DDS custom fields, just parse them
+        self.delete_optimum_score()
+        self.write_optimum_score(contract)
+        self.delete_minimax()
+        self.write_minimax(contract)
+
+    def save_dd_table(self, dd_table):
+        if self._has_optimum_result_table is None:
+            try:
+                optimum_result_table = self.validate_optimum_result_table(
+                    self.get_optimum_result_table())
+                self._has_optimum_result_table = True
+            except FieldNotFoundException:
+                self._has_optimum_result_table = False
+        if not self._has_optimum_result_table:
+            self.delete_optimum_result_table()
+            self.write_optimum_result_table(dd_table)
+        if self._has_ability is None:
+            try:
+                ability = self.validate_ability(
+                    self.get_ability())
+                self._has_ability = True
+            except FieldNotFoundException:
+                self._has_ability = False
+        if not self._has_ability:
+            self.delete_ability()
+            self.write_ability(dd_table)
diff --git a/bcdd/PBNFile.py b/bcdd/PBNFile.py
new file mode 100644
index 0000000..16f4d6d
--- /dev/null
+++ b/bcdd/PBNFile.py
@@ -0,0 +1,41 @@
+import shutil
+import tempfile
+
+from .PBNBoard import PBNBoard
+
+class PBNFile(object):
+
+    def __init__(self, filename):
+        self._filename = filename
+        self.output_file = None
+        self.boards = []
+        lines = []
+        with open(self._filename) as pbn_file:
+            contents = pbn_file.readlines()
+        for line in contents:
+            line = line.strip()
+            if not line:
+                if len(lines) > 0:
+                    self.boards.append(PBNBoard(lines))
+                    lines = []
+            else:
+                lines.append(line)
+        if len(lines) > 0:
+            self.boards.append(PBNBoard(lines))
+        if not self.boards[0].has_field('Event'):
+            self.boards[0].write_event('')
+
+    def write_board(self, board):
+        if self.output_file is None:
+            self.output_file = tempfile.NamedTemporaryFile(
+                mode='w', encoding='utf-8', delete=False)
+        for field in board.fields:
+            self.output_file.write(field.raw_field + '\n')
+        self.output_file.write('\n')
+
+    def save(self):
+        if self.output_file is None:
+            raise IOError('No boards written to PBN file, unable to save it.')
+        tmp_path = self.output_file.name
+        self.output_file.close()
+        shutil.move(tmp_path, self._filename)
diff --git a/bcdd/ParContract.py b/bcdd/ParContract.py
new file mode 100644
index 0000000..918efae
--- /dev/null
+++ b/bcdd/ParContract.py
@@ -0,0 +1,155 @@
+import functools
+
+from .BCalcWrapper import BCalcWrapper as bcw
+from .Exceptions import ParScoreInvalidException
+
+
+class ParContract(object):
+    def __init__(self, level=0, denom='', declarer='', doubled=False, score=0):
+        self.level = level
+        self.denomination = denom
+        self.declarer = declarer
+        self.doubled = doubled
+        self.score = score
+
+    def validate(self):
+        if self.score == 0:
+            return self
+        if (self.level < 1) or (self.level > 7):
+            raise ParScoreInvalidException(
+                'Invalid par contract level: %d' % (self.level))
+        if self.denomination not in 'CDHSN':
+            raise ParScoreInvalidException(
+                'Invalid par contract denomination: ' + self.denomination)
+        if self.declarer not in 'NESW':
+            raise ParScoreInvalidException(
+                'Invalid par contract declarer: ' + self.declarer)
+        return self
+
+    def __repr__(self):
+        if self.score == 0:
+            return 'PASS'
+        return '%d%s%s %s %+d' % (
+            self.level,
+            self.denomination,
+            'x' if self.doubled else '',
+            self.declarer,
+            self.score)
+
+    def __eq__(self, other):
+        return hash(self) == hash(other)
+
+    def __hash__(self):
+        return self.score + self.level + 10000 * (
+            ord(self.denomination[0]) if self.denomination else 0)
+
+    def calculate_score(self, tricks, vulnerable=False):
+        if self.level == 0:
+            return 0
+        score = 0
+        if self.level + 6 > tricks:
+            undertricks = self.level + 6 - tricks
+            if self.doubled:
+                while True:
+                    if undertricks == 1:
+                        # first undertrick: 100 non-vul, 200 vul
+                        score -= 200 if vulnerable else 100
+                    else:
+                        if (undertricks <= 3) and not vulnerable:
+                            # second non-vul undertrick: 200
+                            score -= 200
+                        else:
+                            # further undertricks: 300
+                            score -= 300
+                    undertricks -= 1
+                    if undertricks == 0:
+                        break;
+            else:
+                score = -100 if vulnerable else -50
+                score *= undertricks
+        else:
+            par_tricks = self.level
+            while True:
+                if (self.denomination == 'N') and (par_tricks == 1):
+                    # first non-trump trick: 40
+                    score += 40
+                else:
+                    # other tricks
+                    score += 30 if self.denomination in 'NSH' else 20
+                par_tricks -= 1
+                if par_tricks == 0:
+                    break
+            overtricks = tricks - self.level - 6
+            if self.doubled:
+                score *= 2
+                score += 50
+            # game premium
+            score += (500 if vulnerable else 300) if (score >= 100) else 50
+            if self.doubled:
+                score += overtricks * (200 if vulnerable else 100)
+            else:
+                score += overtricks * (20 if self.denomination in 'CD' else 30)
+            if self.level == 7:
+                # grand slam premium
+                score += 1500 if vulnerable else 1000
+            elif self.level == 6:
+                # small slam premium
+                score += 750 if vulnerable else 500
+        if self.declarer in 'EW':
+            score = -score
+        return score
+
+    def __gt__(self, other):
+        denomination = bcw.DENOMINATIONS.index(self.denomination) \
+                       if self.denomination in bcw.DENOMINATIONS \
+                          else -1
+        other_denomination = bcw.DENOMINATIONS.index(
+            other.denomination) \
+            if other.denomination in bcw.DENOMINATIONS else -1
+        return (self.level > other.level) \
+            or ((self.level == other.level) \
+                and (denomination > other_denomination))
+
+    def get_defense(self, dd_table, vulnerable):
+        declarer_index = bcw.PLAYERS.index(self.declarer) \
+                         if self.declarer in bcw.PLAYERS else -1
+        denomination_index = bcw.DENOMINATIONS.index(self.denomination) \
+                             if self.denomination in bcw.DENOMINATIONS else -1
+        if (self.level != 0) \
+           and (self.level + 6
+                <= dd_table[declarer_index][denomination_index]):
+            defenders_indexes = []
+            defenders_indexes.append((declarer_index + 1) % 4);
+            defenders_indexes.append((declarer_index + 3) % 4);
+            possible_defense = []
+            score_squared = self.score * self.score
+            for i in range(0, 5):
+                level = self.level
+                if i <= denomination_index:
+                    level += 1
+                if level <= 7:
+                    for defender in defenders_indexes:
+                        if level + 6 > dd_table[defender][i]:
+                            defense = ParContract(
+                                level,
+                                bcw.DENOMINATIONS[i],
+                                bcw.PLAYERS[defender],
+                                True,
+                                0)
+                            defense.score = defense.calculate_score(
+                                dd_table[defender][i],
+                                vulnerable)
+                            if score_squared > self.score * defense.score:
+                                possible_defense.append(defense)
+            if possible_defense:
+                possible_defense.sort(
+                    key=lambda x: abs(x.score - self.score))
+                optimum_defense = possible_defense[-1]
+                possible_defense = [defense for defense in possible_defense
+                                    if defense.score == optimum_defense.score]
+                for defense in possible_defense:
+                    # Lowest from the most profitable sacrifices
+                    if optimum_defense > defense:
+                        optimum_defense = defense
+                return optimum_defense
+        return None
diff --git a/bcdd/ParScore.py b/bcdd/ParScore.py
new file mode 100644
index 0000000..b0c9674
--- /dev/null
+++ b/bcdd/ParScore.py
@@ -0,0 +1,171 @@
+import re
+
+from .BCalcWrapper import BCalcWrapper as bcw
+from .ParContract import ParContract
+from .Exceptions import FieldNotFoundException
+
+
+class ParScore(object):
+    _pbn_contract_pattern = re.compile(r'(\d)([CDHSN])(X?)\s+([NESW])')
+    _pbn_score_pattern = re.compile(r'(NS|EW)\s+(-?\d})')
+    _jfr_contract_pattern = re.compile(r'^(\d)([CDHSN])(D?)([NESW])(-?\d+)$')
+
+    def __init__(self, board):
+        self._board = board
+
+    def get_pbn_par_contract(self):
+        contract_field = self._board.get_optimum_result()
+        if 'Pass' == contract_field:
+            return ParContract()
+        contract_match = self._pbn_contract_pattern.match(contract_field)
+        if not contract_match:
+            raise ParScoreInvalidException(
+                'Invalid format for OptimumResult field: ' + contract_field)
+        score_field = self._board.get_optimum_score()
+        score_match = self._pbn_score_pattern.match(score_field)
+        if not score_match:
+            raise ParScoreInvalidException(
+                'Invalid format for OptimumScore field: ' + scoreField)
+        score = int(score_match.group(2))
+        if 'EW' == score_match.group(1):
+            score = -score
+        contract = ParContract(
+            int(contract_match.group(1)),
+            contract_match.group(2)[0],
+            contract_match.group(4)[0],
+            'X' == contract_match.group(3),
+            score)
+        return contract.validate()
+
+    def get_jfr_par_contract(self):
+        par_string = self._board.get_minimax()
+        par_match = self._jfr_contract_pattern.match(par_string)
+        if not par_match:
+            raise ParScoreInvalidException(
+                'Invalid format for Minimax field: ' + par_string)
+        if '0' == par_match.group(4):
+            return ParContract() # pass-out
+        contract = ParContract(
+            int(par_match.group(1)),
+            par_match.Group(2)[0],
+            par_match.Group(4)[0],
+            'D' == par_match.group(3),
+            int(par_match.groups(5)))
+        return contract.validate()
+
+    def _determine_vulnerability(self, vulnerability, declarer):
+        vulnerability = vulnerability.upper()
+        return vulnerability in ['ALL', 'BOTH'] \
+            or (vulnerability not in ['LOVE', 'NONE'] \
+                and declarer in vulnerability)
+
+    def _get_highest_makeable_contract(self, dd_table,
+                                       for_ns=True, for_ew=True):
+        contract = ParContract()
+        tricks = 0
+        for i in range(3, -1, -1):
+            if ((i % 2 == 0) and for_ns) \
+               or ((i % 2 == 1) and for_ew):
+                for j in range(0, 5):
+                    level = dd_table[i][j] - 6
+                    denomination = bcw.DENOMINATIONS.index(
+                        contract.denomination) \
+                        if contract.denomination in bcw.DENOMINATIONS \
+                           else -1
+                    if (level > contract.level) \
+                       or ((level == contract.level) \
+                           and (j > denomination)):
+                        contract.level = level
+                        contract.denomination = bcw.DENOMINATIONS[j]
+                        contract.declarer = bcw.PLAYERS[i]
+                        tricks = dd_table[i][j]
+        vulnerability = self._board.get_vulnerable().upper()
+        vulnerable = self._determine_vulnerability(
+            vulnerability, contract.declarer)
+        contract.score = contract.calculate_score(tricks, vulnerable)
+        return contract
+
+    def get_dd_table_par_contract(self, dd_table):
+        dealer = self._board.get_dealer()
+        vulnerability = self._board.get_vulnerable().upper()
+        ns_highest = self._get_highest_makeable_contract(
+            dd_table, True, False);
+        ew_highest = self._get_highest_makeable_contract(
+            dd_table, False, True)
+        if ns_highest == ew_highest:
+            return ns_highest.validate() \
+                if dealer in ['N', 'S'] else ew_highest.validate()
+        highest = max(ns_highest, ew_highest)
+        other_side_highest = min(ew_highest, ns_highest)
+        ns_playing = highest.declarer in ['N', 'S']
+        defense_vulnerability = self._determine_vulnerability(
+            vulnerability, 'E' if ns_playing else 'N')
+        highest_defense = highest.get_defense(dd_table, defense_vulnerability)
+        if highest_defense is not None:
+            # Highest contract has profitable defense
+            return highest_defense.validate()
+        denomination_index = bcw.DENOMINATIONS.index(highest.denomination) \
+                             if highest.denomination in bcw.DENOMINATIONS \
+                                else -1
+        declarer_index = bcw.PLAYERS.index(highest.declarer) \
+                         if highest.declarer in bcw.PLAYERS else -1
+        player_indexes = [declarer_index, (declarer_index + 2) % 4]
+        vulnerable = self._determine_vulnerability(
+            vulnerability, highest.declarer)
+        score_squared = highest.score * highest.score
+        possible_optimums = []
+        for i in range(0, 5):
+            for player in player_indexes:
+                level = highest.level
+                if i > denomination_index:
+                    level -= 1
+                while level > 0:
+                    contract = ParContract(
+                        level,
+                        bcw.DENOMINATIONS[i],
+                        bcw.PLAYERS[player],
+                        False, 0)
+                    contract.score = contract.calculate_score(
+                        dd_table[player][i], vulnerable)
+                    if other_side_highest > contract:
+                        # Contract is lower than other side's contract
+                        break
+                    if (highest.score * contract.score) > 0:
+                        # Contract makes
+                        if abs(contract.score) >= abs(highest.score):
+                            # Contract is profitable
+                            defense = contract.get_defense(
+                                dd_table, defense_vulnerability)
+                            if defense is not None \
+                               and (contract.score * contract.score) \
+                               > (contract.score * defense.score):
+                                # Contract has defense
+                                possible_optimums.append(defense)
+                                # So lower contracts will too.
+                                break
+                            else:
+                                # Contract does not have defense
+                                possible_optimums.append(contract)
+                        else:
+                            # Contract is not profitable
+                            break
+                    level -= 1
+        for contract in possible_optimums:
+            if abs(contract.score) > abs(highest.score):
+                # Contract is more profitable
+                highest = contract
+            else:
+                if contract.score == highest.score:
+                    if highest > contract:
+                        # Equally profitable, but lower
+                        highest = contract
+        return highest.validate()
+
+    def get_par_contract(self, dd_table):
+        try:
+            return self.get_jfr_par_contract()
+        except FieldNotFoundException:
+            try:
+                return self.get_pbn_par_contract()
+            except FieldNotFoundException:
+                return self.get_dd_table_par_contract(dd_table)