<?php

declare(strict_types=1);

use PHPUnit\Framework\TestCase;
use sammo\Json;
use sammo\LiteHashDRBG;
use sammo\NpcPossessionSelector;
use sammo\RandUtil;

require_once __DIR__ . '/../src/sammo/NpcPossessionSelector.php';

final class NpcPossessionSelectorTest extends TestCase
{
    /** @return array<int, array{id: int, leadership: int, strength: int, intel: int, keepCnt: int}> */
    private function candidates(): array
    {
        $rows = [
            ['id' => 1, 'leadership' => 40, 'strength' => 50, 'intel' => 60, 'keepCnt' => 3],
            ['id' => 2, 'leadership' => 73, 'strength' => 44, 'intel' => 81, 'keepCnt' => 3],
            ['id' => 3, 'leadership' => 91, 'strength' => 32, 'intel' => 47, 'keepCnt' => 3],
            ['id' => 4, 'leadership' => 55, 'strength' => 88, 'intel' => 38, 'keepCnt' => 3],
            ['id' => 5, 'leadership' => 66, 'strength' => 67, 'intel' => 68, 'keepCnt' => 3],
            ['id' => 6, 'leadership' => 99, 'strength' => 20, 'intel' => 21, 'keepCnt' => 3],
            ['id' => 7, 'leadership' => 35, 'strength' => 93, 'intel' => 72, 'keepCnt' => 3],
            ['id' => 8, 'leadership' => 84, 'strength' => 75, 'intel' => 69, 'keepCnt' => 3],
        ];
        $result = [];
        foreach ($rows as $row) {
            $result[$row['id']] = $row;
        }
        return $result;
    }

    public function testSharedKernelPreservesThePreviousEndpointLoop(): void
    {
        $candidates = $this->candidates();
        $weights = [];
        foreach ($candidates as $id => $candidate) {
            $weights[$id] = pow(
                $candidate['leadership'] + $candidate['strength'] + $candidate['intel'],
                1.5,
            );
            self::assertSame($weights[$id], NpcPossessionSelector::weight($candidate));
        }
        $seed = NpcPossessionSelector::buildSeed(
            'npc-possession-differential-seed',
            7701,
            '2026-08-01 00:00:01',
        );

        $legacyRng = new RandUtil(new LiteHashDRBG($seed));
        $legacyPicked = [];
        $legacyDraws = [];
        $pickLimit = min(count($candidates), 5);
        while (count($legacyPicked) < $pickLimit) {
            $id = $legacyRng->choiceUsingWeight($weights);
            $legacyDraws[] = (int)$id;
            if (!array_key_exists($id, $legacyPicked)) {
                $legacyPicked[$id] = $candidates[$id];
            }
        }

        $sharedDraws = [];
        $sharedPicked = NpcPossessionSelector::select(
            $candidates,
            $weights,
            [],
            new RandUtil(new LiteHashDRBG($seed)),
            static function (int|string $id) use (&$sharedDraws): void {
                $sharedDraws[] = (int)$id;
            },
        );

        self::assertSame([1, 8, 1, 4, 5, 5, 8, 8, 5, 3], $legacyDraws);
        self::assertSame($legacyDraws, $sharedDraws);
        self::assertSame($legacyPicked, $sharedPicked);
    }

    public function testKeepAndReservedHelpersPreserveEndpointSemantics(): void
    {
        $candidates = $this->candidates();
        $weights = array_map(
            static fn(array $candidate): float => NpcPossessionSelector::weight($candidate),
            $candidates,
        );
        NpcPossessionSelector::removeReserved(
            $candidates,
            $weights,
            [
                Json::encode((object)[2 => ['keepCnt' => 3], 7 => ['keepCnt' => 3]]),
            ],
        );
        self::assertSame([1, 3, 4, 5, 6, 8], array_keys($candidates));
        self::assertSame([1, 3, 4, 5, 6, 8], array_keys($weights));

        $oldPick = array_intersect_key($this->candidates(), array_flip([1, 8, 4, 5, 3]));
        $partial = NpcPossessionSelector::applyKeep($oldPick, [1, 4]);
        self::assertFalse($partial['cancelled']);
        self::assertSame(2, $partial['picked'][1]['keepCnt']);
        self::assertSame(2, $partial['picked'][4]['keepCnt']);

        $all = NpcPossessionSelector::applyKeep($oldPick, [1, 8, 4, 5, 3]);
        self::assertTrue($all['cancelled']);
        self::assertSame([1, 8, 4, 5, 3], array_keys($all['picked']));
    }
}