|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
namespace lucidtaz\minimax\engine; |
|
4
|
|
|
|
|
5
|
|
|
use BadMethodCallException; |
|
6
|
|
|
use LogicException; |
|
7
|
|
|
use lucidtaz\minimax\game\GameState; |
|
8
|
|
|
use lucidtaz\minimax\game\Player; |
|
9
|
|
|
use RuntimeException; |
|
10
|
|
|
|
|
11
|
|
|
/** |
|
12
|
|
|
* MiniMax game engine |
|
13
|
|
|
* |
|
14
|
|
|
* Construct an object of this class, give it the player to optimize for, and |
|
15
|
|
|
* call decide() when it is time for the player to make a move, in order to get |
|
16
|
|
|
* the Decision that the engine has taken for the player. |
|
17
|
|
|
*/ |
|
18
|
|
|
class Engine |
|
19
|
|
|
{ |
|
20
|
|
|
private $objectivePlayer; |
|
21
|
|
|
|
|
22
|
|
|
private $maxDepth; |
|
23
|
|
|
|
|
24
|
|
|
/** |
|
25
|
|
|
* @var ?Analytics Only available after run, contains statistics about the |
|
26
|
|
|
* execution. |
|
27
|
|
|
*/ |
|
28
|
|
|
private $analytics; |
|
29
|
|
|
|
|
30
|
|
|
/** |
|
31
|
|
|
* @param Player $objectivePlayer The player to play as |
|
32
|
|
|
* @param int $maxDepth How far ahead should the engine look? |
|
33
|
|
|
*/ |
|
34
|
16 |
|
public function __construct(Player $objectivePlayer, int $maxDepth = 3) |
|
35
|
|
|
{ |
|
36
|
16 |
|
$this->objectivePlayer = $objectivePlayer; |
|
37
|
16 |
|
$this->maxDepth = $maxDepth; |
|
38
|
16 |
|
} |
|
39
|
|
|
|
|
40
|
|
|
/** |
|
41
|
|
|
* Evaluate possible decisions and take the best one |
|
42
|
|
|
* @param GameState $state Current state of the game for which there needs |
|
43
|
|
|
* to be made a decision. This implicitly means that the objective player |
|
44
|
|
|
* currently must have its turn in the GameState. |
|
45
|
|
|
* @return GameState The state resulting after the engine made its decision. |
|
46
|
|
|
*/ |
|
47
|
16 |
|
public function decide(GameState $state): GameState |
|
48
|
|
|
{ |
|
49
|
16 |
|
if (!$state->getNextPlayer()->equals($this->objectivePlayer)) { |
|
50
|
1 |
|
throw new BadMethodCallException('It is not this players turn'); |
|
51
|
|
|
} |
|
52
|
15 |
|
if (empty($state->getPossibleMoves())) { |
|
53
|
1 |
|
throw new RuntimeException('There are no possible moves'); |
|
54
|
|
|
} |
|
55
|
|
|
|
|
56
|
14 |
|
$rootNode = new DecisionNode( |
|
57
|
14 |
|
$this->objectivePlayer, |
|
58
|
|
|
$state, |
|
59
|
14 |
|
$this->maxDepth, |
|
60
|
14 |
|
NodeType::MAX(), |
|
61
|
14 |
|
AlphaBeta::initial() |
|
62
|
|
|
); |
|
63
|
|
|
|
|
64
|
14 |
|
$moveWithEvaluation = $rootNode->traverseGameTree(); |
|
65
|
14 |
|
$this->analytics = $moveWithEvaluation->analytics; |
|
66
|
14 |
|
if ($moveWithEvaluation->move === null) { |
|
67
|
1 |
|
throw new LogicException('Could not find move even though there are moves. Is the maxdepth parameter correct?'); |
|
68
|
|
|
} |
|
69
|
13 |
|
return $moveWithEvaluation->move; |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
1 |
|
public function getAnalytics(): Analytics |
|
73
|
|
|
{ |
|
74
|
1 |
|
if ($this->analytics === null) { |
|
75
|
|
|
throw new BadMethodCallException('Please run decide() first.'); |
|
76
|
|
|
} |
|
77
|
1 |
|
return $this->analytics; |
|
78
|
|
|
} |
|
79
|
|
|
} |
|
80
|
|
|
|
LucidTaZ /
minimax
