<?php

namespace Modules\EcommerceFinance\Services;

use Modules\EcommerceFinance\Contracts\BusinessMirrorDataset;
use RuntimeException;

class ClickHouseSchemaManager
{
    public function __construct(
        private readonly BusinessMirrorSchemaManager $sourceSchemas,
        private readonly ClickHouseClient $clickHouse,
        private readonly BusinessDataPlacement $placements,
    ) {
    }

    /** @return list<array<string,mixed>> */
    public function ensure(BusinessMirrorDataset $dataset): array
    {
        if (! in_array($this->placements->targetStore($dataset->key()), ['clickhouse', 'parquet'], true)) {
            throw new RuntimeException('business_data_dataset_not_columnar');
        }

        $columns = $this->sourceSchemas->columns($dataset);
        $definitions = ['`_mirror_key` String'];
        foreach ($columns as $column) {
            $definitions[] = $this->clickHouse->identifier((string) $column['column_name'])
                . ' Nullable(' . $this->type($column) . ')';
        }
        $definitions[] = '`_mirror_generation` UUID';
        $definitions[] = "`_mirror_synced_at` DateTime64(6, 'Asia/Shanghai')";
        $definitions[] = '`_mirror_version` UInt64';

        // Hash partitioning keeps every version of one business key in the same
        // partition. The generation must also be part of the replacement key:
        // otherwise a newer backfill generation would erase the retained one.
        $sql = sprintf(
            'CREATE TABLE IF NOT EXISTS %s (%s) '
            . 'ENGINE = ReplacingMergeTree(_mirror_version) '
            . 'PARTITION BY modulo(cityHash64(_mirror_key), 32) '
            . 'ORDER BY (_mirror_generation, _mirror_key) SETTINGS index_granularity = 8192',
            $this->clickHouse->qualifiedTable($dataset->targetTable()),
            implode(', ', $definitions),
        );
        $this->clickHouse->command($sql);
        $this->assertGenerationScopedSortingKey($dataset);

        return $columns;
    }

    public function tableExists(BusinessMirrorDataset $dataset): bool
    {
        return (int) $this->clickHouse->scalar(
            'SELECT count() FROM system.tables WHERE database = {database:String} AND name = {table:String}',
            [
                'database' => (string) config('business_data.clickhouse.database', 'caiwu_business_analytics'),
                'table' => $dataset->targetTable(),
            ],
        ) === 1;
    }

    private function assertGenerationScopedSortingKey(BusinessMirrorDataset $dataset): void
    {
        $sortingKey = (string) $this->clickHouse->scalar(
            'SELECT sorting_key FROM system.tables '
            . 'WHERE database = {database:String} AND name = {table:String}',
            [
                'database' => (string) config('business_data.clickhouse.database', 'caiwu_business_analytics'),
                'table' => $dataset->targetTable(),
            ],
        );
        $normalized = strtolower((string) preg_replace('/[`()\s]+/', '', $sortingKey));
        if ($normalized !== '_mirror_generation,_mirror_key') {
            throw new RuntimeException('business_data_columnar_generation_key_mismatch');
        }
    }

    /** @param array<string,mixed> $column */
    private function type(array $column): string
    {
        $type = strtolower((string) ($column['data_type'] ?? ''));
        $precision = min(max((int) ($column['numeric_precision'] ?? 20), 1), 76);
        $scale = min(max((int) ($column['numeric_scale'] ?? 0), 0), $precision);

        return match ($type) {
            'bit', 'boolean' => 'UInt8',
            // SQL Server tinyint is unsigned (0..255), unlike MySQL tinyint.
            'tinyint' => 'UInt8',
            'smallint' => 'Int16',
            'int', 'integer' => 'Int32',
            'bigint' => 'Int64',
            'decimal', 'numeric', 'money', 'smallmoney' => sprintf('Decimal(%d, %d)', $precision, $scale),
            'float', 'real', 'double', 'double precision' => 'Float64',
            'date' => 'Date32',
            'datetime', 'datetime2', 'smalldatetime', 'timestamp without time zone', 'timestamp with time zone' => "DateTime64(6, 'Asia/Shanghai')",
            'uniqueidentifier', 'uuid' => 'UUID',
            default => 'String',
        };
    }
}