|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
namespace lucidtaz\minimax; |
|
4
|
|
|
|
|
5
|
|
|
use Closure; |
|
6
|
|
|
|
|
7
|
|
|
class DecisionPoint |
|
8
|
|
|
{ |
|
9
|
|
|
private $objectivePlayer; |
|
10
|
|
|
private $state; |
|
11
|
|
|
private $depthLeft; |
|
12
|
|
|
private $ideal; |
|
13
|
|
|
|
|
14
|
|
|
/** |
|
15
|
|
|
* @param Player $objectivePlayer The Player to optimize for |
|
16
|
|
|
* @param GameState $state Current GameState to base decisions on |
|
17
|
|
|
* @param int $depthLeft Recursion limiter |
|
18
|
|
|
* @param Closure $ideal Function that takes two DecisionWithScore objects |
|
19
|
|
|
* and returns the ideal one. In some situations this is the best, in others |
|
20
|
|
|
* it is the worst. |
|
21
|
|
|
*/ |
|
22
|
11 |
|
public function __construct(Player $objectivePlayer, GameState $state, int $depthLeft, Closure $ideal) |
|
23
|
|
|
{ |
|
24
|
11 |
|
$this->objectivePlayer = $objectivePlayer; |
|
25
|
11 |
|
$this->state = $state; |
|
26
|
11 |
|
$this->depthLeft = $depthLeft; |
|
27
|
11 |
|
$this->ideal = $ideal; |
|
28
|
11 |
|
} |
|
29
|
|
|
|
|
30
|
11 |
|
public function decide(): DecisionWithScore |
|
31
|
|
|
{ |
|
32
|
11 |
|
if ($this->depthLeft == 0) { |
|
33
|
9 |
|
return $this->makeLeafResult(); |
|
34
|
|
|
} |
|
35
|
|
|
|
|
36
|
|
|
/* @var $possibleMoves Decision[] */ |
|
37
|
11 |
|
$possibleMoves = $this->state->getDecisions(); |
|
38
|
11 |
|
if (empty($possibleMoves)) { |
|
39
|
9 |
|
return $this->makeLeafResult(); |
|
40
|
|
|
} |
|
41
|
|
|
|
|
42
|
10 |
|
$bestDecisionWithScore = null; |
|
43
|
10 |
|
foreach ($possibleMoves as $move) { |
|
44
|
10 |
|
$bestDecisionWithScore = $this->considerMove($move, $bestDecisionWithScore); |
|
45
|
|
|
} |
|
46
|
|
|
|
|
47
|
10 |
|
return $bestDecisionWithScore; |
|
48
|
|
|
} |
|
49
|
|
|
|
|
50
|
11 |
|
private function makeLeafResult(): DecisionWithScore |
|
51
|
|
|
{ |
|
52
|
11 |
|
$result = new DecisionWithScore; |
|
53
|
11 |
|
$result->age = $this->depthLeft; |
|
54
|
11 |
|
$result->score = $this->state->evaluateScore($this->objectivePlayer); |
|
55
|
11 |
|
return $result; |
|
56
|
|
|
} |
|
57
|
|
|
|
|
58
|
10 |
|
private function considerMove(Decision $move, DecisionWithScore $bestDecisionWithScoreSoFar = null): DecisionWithScore |
|
59
|
|
|
{ |
|
60
|
10 |
|
$newState = $move->apply($this->state); |
|
61
|
|
|
|
|
62
|
10 |
|
$nextDecisionWithScore = $this->considerNextMove($newState); |
|
63
|
|
|
|
|
64
|
10 |
|
$replaced = false; |
|
65
|
10 |
|
$bestDecisionWithScore = $this->replaceIfBetter( |
|
66
|
|
|
$nextDecisionWithScore, |
|
67
|
|
|
$bestDecisionWithScoreSoFar, |
|
68
|
|
|
$replaced |
|
69
|
|
|
); |
|
70
|
10 |
|
if ($replaced) { |
|
71
|
10 |
|
$bestDecisionWithScore->decision = $move; |
|
72
|
|
|
} |
|
73
|
|
|
|
|
74
|
10 |
|
return $bestDecisionWithScore; |
|
75
|
|
|
} |
|
76
|
|
|
|
|
77
|
10 |
|
private function considerNextMove(GameState $newState): DecisionWithScore |
|
78
|
|
|
{ |
|
79
|
10 |
|
$nextPlayerIsFriendly = $newState->getNextPlayer()->isFriendsWith($this->objectivePlayer); |
|
80
|
10 |
|
$comparator = $nextPlayerIsFriendly ? DecisionWithScore::getBestComparator() : DecisionWithScore::getWorstComparator(); |
|
81
|
10 |
|
$nextDecisionPoint = new static($this->objectivePlayer, $newState, $this->depthLeft - 1, $comparator); |
|
82
|
10 |
|
return $nextDecisionPoint->decide(); |
|
83
|
|
|
} |
|
84
|
|
|
|
|
85
|
10 |
|
private function replaceIfBetter(DecisionWithScore $new, DecisionWithScore $current = null, &$replaced = false): DecisionWithScore |
|
86
|
|
|
{ |
|
87
|
10 |
|
if ($current === null) { |
|
88
|
10 |
|
$replaced = true; |
|
89
|
10 |
|
return $new; |
|
90
|
|
|
} |
|
91
|
|
|
|
|
92
|
9 |
|
$ideal = $this->ideal; |
|
93
|
9 |
|
$idealDecisionWithScore = $ideal($new, $current); |
|
94
|
9 |
|
if ($idealDecisionWithScore === $new) { |
|
95
|
7 |
|
$replaced = true; |
|
96
|
7 |
|
return $new; |
|
97
|
|
|
} |
|
98
|
|
|
|
|
99
|
9 |
|
$replaced = false; |
|
100
|
9 |
|
return $current; |
|
101
|
|
|
} |
|
102
|
|
|
} |
|
103
|
|
|
|
LucidTaZ /
minimax
