<?php

declare(strict_types=1);

namespace LIT\MCP\Tests\Unit\Integrations\Divi\Design;

use Brain\Monkey\Functions;
use InvalidArgumentException;
use LIT\MCP\Integrations\Divi\Design\SnapshotStore;
use LIT\MCP\Integrations\Divi\Design\SnapshotTooLarge;
use LIT\MCP\Tests\Unit\TestCase;
use RuntimeException;

final class SnapshotStoreTest extends TestCase
{
    /** @var array<string, mixed> */
    private array $options = [];

    protected function setUp(): void
    {
        parent::setUp();
        $this->options = [];
        Functions\when('get_option')->alias(fn (string $name, mixed $default = false): mixed => $this->options[$name] ?? $default);
        Functions\when('update_option')->alias(function (string $name, mixed $value, mixed $autoload = null): bool {
            self::assertFalse($autoload, 'snapshots are never autoloaded');
            $this->options[$name] = $value;

            return true;
        });
        Functions\when('get_current_user_id')->justReturn(7);
    }

    public function testSavesListsAndReturnsTheNewestFirst(): void
    {
        $store = new SnapshotStore();
        $first = $store->save('presets', ['module' => ['a' => 1]], 'lit/divi-presets-set');
        $second = $store->save('presets', ['module' => ['a' => 2]], 'lit/divi-presets-set');
        $store->attachLog('presets', $second, 42);

        self::assertSame('lit_mcp_snapshots_presets', SnapshotStore::option('presets'));
        self::assertMatchesRegularExpression('/^presets-\d{8}T\d{6}Z-[0-9a-f]{6}$/', $first);
        $list = $store->list('presets');
        self::assertSame([$second, $first], array_column($list, 'id'));
        self::assertSame(42, $list[0]['log_id']);
        self::assertSame(7, $list[0]['user_id']);
        self::assertArrayNotHasKey('data', $list[0]);
        self::assertSame(['module' => ['a' => 1]], $store->get('presets', $first)['data']);
        self::assertNull($store->get('presets', 'presets-unknown'));
        self::assertSame([], $store->list('colors'));
    }

    public function testKeepsAtMostTwentyPerArea(): void
    {
        $store = new SnapshotStore();
        $ids = [];
        for ($i = 0; $i < 22; ++$i) {
            $ids[] = $store->save('presets', ['n' => $i], 'lit/divi-presets-set');
        }

        $list = $store->list('presets');
        self::assertCount(SnapshotStore::LIMIT, $list);
        self::assertSame($ids[21], $list[0]['id']);
        self::assertNull($store->get('presets', $ids[0]));
        self::assertNull($store->get('presets', $ids[1]));
    }

    /** Final review I-4: the option as a whole stays below TOTAL_BYTES; the oldest entries fall out first. */
    public function testKeepsTheOptionBelowTheTotalSize(): void
    {
        $store = new SnapshotStore();
        $big = ['x' => str_repeat('a', 1900000)];
        $ids = [];
        for ($i = 0; $i < 5; ++$i) {
            $ids[] = $store->save('presets', $big + ['n' => $i], 'lit/divi-presets-set');
        }

        $list = $store->list('presets');
        self::assertSame([$ids[4], $ids[3], $ids[2], $ids[1]], array_column($list, 'id'));
        self::assertLessThanOrEqual(SnapshotStore::TOTAL_BYTES, array_sum(array_column($list, 'size')));
    }

    public function testOldEntriesOverTheTotalSizeFallOutButTheNewestStays(): void
    {
        $store = new SnapshotStore();
        $store->save('presets', ['x' => str_repeat('a', 1900000)], 'lit/divi-presets-set');
        $this->options['lit_mcp_snapshots_presets'][0]['size'] = SnapshotStore::TOTAL_BYTES + 1;

        $newest = $store->save('presets', ['n' => 1], 'lit/divi-presets-set');

        self::assertSame([$newest], array_column($store->list('presets'), 'id'));
    }

    public function testRefusesSnapshotsAboveTheLimit(): void
    {
        $this->expectException(SnapshotTooLarge::class);

        (new SnapshotStore())->save('presets', ['x' => str_repeat('a', SnapshotStore::MAX_BYTES)], 'lit/divi-presets-set');
    }

    public function testUnknownAreaIsAProgrammingError(): void
    {
        $this->expectException(InvalidArgumentException::class);

        SnapshotStore::option('pages');
    }

    public function testAFailedOptionWriteThrows(): void
    {
        Functions\when('update_option')->justReturn(false);
        $this->expectException(RuntimeException::class);
        $this->expectExceptionMessage('snapshot presets could not be stored');

        (new SnapshotStore())->save('presets', ['a' => 1], 'lit/divi-presets-set');
    }

    public function testAnUnencodableSnapshotIsRefusedBeforeAnyWrite(): void
    {
        Functions\when('wp_json_encode')->justReturn(false);
        $written = false;
        Functions\when('update_option')->alias(function () use (&$written): bool {
            $written = true;

            return true;
        });

        try {
            (new SnapshotStore())->save('presets', ['a' => 1], 'lit/divi-presets-set');
            self::fail('an unencodable snapshot must be refused');
        } catch (RuntimeException $e) {
            self::assertSame('snapshot presets could not be encoded', $e->getMessage());
        }
        self::assertFalse($written, 'nothing may be written when the snapshot cannot be encoded');
    }

    public function testCorruptOptionReadsAsEmpty(): void
    {
        $this->options['lit_mcp_snapshots_presets'] = 'kaputt';

        self::assertSame([], (new SnapshotStore())->list('presets'));
    }
}