<?php
/**
 * EtlStockManager
 *
 * Manages etl_stock_summary — the materialized aggregate of td_stock_<warehouse_id>
 * by (company_id, warehouse_id, product_sku, month). Mirrors EtlManager for GL.
 *
 * etl_stock_summary is maintained two ways:
 *   1. Write-through — adjustBalance() in WarehouseManager updates it on every approve/delete.
 *   2. Batch repair  — checkAndRepair() scans td_stock_* for drift and rebuilds stale months.
 *
 * Gap detection is timestamp-based (identical to GL):
 *   A month is stale when any td_stock_N row (updated_at) is newer than the
 *   oldest etl_stock_summary entry for that warehouse+month (source_updated_at).
 *
 * checkAndRepair()               — scan all warehouses, rebuild stale months, save status
 * getGaps()                      — return [['warehouse_id'=>N,'period'=>'YYYY-MM'], ...]
 * rebuildPeriod(wh_id, period)   — DELETE + reinsert one (warehouse, month) slice
 * rebuildFull(wh_id)             — DELETE + rebuild all months for one warehouse
 * getDistinctPeriods(wh_id)      — distinct approved months in td_stock_N
 * getStatus()                    — read etl_stock_* keys from company_setting
 */
class EtlStockManager
{
    private PDO $pdo;
    private PDO $pdo1;
    private int $companyId;

    public function __construct(PDO $pdo, PDO $pdo1, int $company_id)
    {
        $this->pdo       = $pdo;
        $this->pdo1      = $pdo1;
        $this->companyId = $company_id;
    }

    // ── Public ───────────────────────────────────────────────────────────────

    public function checkAndRepair(): array
    {
        $gaps = $this->getGaps();

        foreach ($gaps as $gap) {
            $this->rebuildPeriod($gap['warehouse_id'], $gap['period']);
        }

        $gaps_found      = count($gaps);
        $periods_rebuilt = $gaps_found;
        $this->saveStatus('ok', $gaps_found, $periods_rebuilt);

        return ['gaps_found' => $gaps_found, 'periods_rebuilt' => $periods_rebuilt];
    }

    public function getGaps(): array
    {
        $stock_tables = $this->discoverStockTables();
        $gaps         = [];

        foreach ($stock_tables as $table) {
            $warehouse_id = (int)substr($table, strlen('td_stock_'));

            $sth = $this->pdo->prepare("
                SELECT DISTINCT DATE_FORMAT(s.date, '%Y-%m') AS period
                FROM `{$table}` s
                LEFT JOIN (
                    SELECT month, MAX(source_updated_at) AS etl_ts
                    FROM etl_stock_summary
                    WHERE company_id = :cid2 AND warehouse_id = :wh2
                    GROUP BY month
                ) etl ON etl.month = DATE_FORMAT(s.date, '%Y-%m')
                WHERE s.company_id = :cid
                  AND s.status = 1
                  AND (etl.month IS NULL OR s.updated_at > etl.etl_ts)
                ORDER BY period
            ");
            $sth->execute([
                ':cid'  => $this->companyId,
                ':cid2' => $this->companyId,
                ':wh2'  => $warehouse_id,
            ]);

            foreach ($sth->fetchAll(PDO::FETCH_COLUMN) as $period) {
                $gaps[] = ['warehouse_id' => $warehouse_id, 'period' => $period];
            }
        }

        return $gaps;
    }

    public function rebuildPeriod(int $warehouse_id, string $period): void
    {
        $table = 'td_stock_' . $warehouse_id;

        $this->pdo->prepare(
            "DELETE FROM etl_stock_summary
             WHERE company_id = :cid AND warehouse_id = :wh AND month = :month"
        )->execute([':cid' => $this->companyId, ':wh' => $warehouse_id, ':month' => $period]);

        $this->pdo->prepare("
            INSERT INTO etl_stock_summary
                (company_id, warehouse_id, product_sku, month, total_in, total_out, source_updated_at)
            SELECT
                company_id,
                :wh,
                product_sku,
                DATE_FORMAT(`date`, '%Y-%m')  AS month,
                ROUND(SUM(`in`),  4)          AS total_in,
                ROUND(SUM(`out`), 4)          AS total_out,
                MAX(updated_at)               AS source_updated_at
            FROM `{$table}`
            WHERE company_id = :cid
              AND status = 1
              AND DATE_FORMAT(`date`, '%Y-%m') = :month
            GROUP BY company_id, product_sku, DATE_FORMAT(`date`, '%Y-%m')
        ")->execute([':cid' => $this->companyId, ':wh' => $warehouse_id, ':month' => $period]);
    }

    public function rebuildFull(int $warehouse_id): array
    {
        $table = 'td_stock_' . $warehouse_id;

        $this->pdo->prepare(
            "DELETE FROM etl_stock_summary WHERE company_id = :cid AND warehouse_id = :wh"
        )->execute([':cid' => $this->companyId, ':wh' => $warehouse_id]);

        $this->pdo->prepare("
            INSERT INTO etl_stock_summary
                (company_id, warehouse_id, product_sku, month, total_in, total_out, source_updated_at)
            SELECT
                company_id,
                :wh,
                product_sku,
                DATE_FORMAT(`date`, '%Y-%m')  AS month,
                ROUND(SUM(`in`),  4)          AS total_in,
                ROUND(SUM(`out`), 4)          AS total_out,
                MAX(updated_at)               AS source_updated_at
            FROM `{$table}`
            WHERE company_id = :cid AND status = 1
            GROUP BY company_id, product_sku, DATE_FORMAT(`date`, '%Y-%m')
        ")->execute([':cid' => $this->companyId, ':wh' => $warehouse_id]);

        $sth = $this->pdo->prepare(
            "SELECT COUNT(DISTINCT month) FROM etl_stock_summary
             WHERE company_id = :cid AND warehouse_id = :wh"
        );
        $sth->execute([':cid' => $this->companyId, ':wh' => $warehouse_id]);
        $periods_rebuilt = (int)$sth->fetchColumn();

        $this->saveStatus('ok', 0, $periods_rebuilt);

        return ['periods_rebuilt' => $periods_rebuilt];
    }

    public function getDistinctPeriods(int $warehouse_id): array
    {
        $table = 'td_stock_' . $warehouse_id;
        $sth   = $this->pdo->prepare(
            "SELECT DISTINCT DATE_FORMAT(`date`, '%Y-%m') AS period
             FROM `{$table}`
             WHERE company_id = :cid AND status = 1
             ORDER BY period"
        );
        $sth->execute([':cid' => $this->companyId]);
        return $sth->fetchAll(PDO::FETCH_COLUMN);
    }

    public function getStatus(): array
    {
        $keys = [
            'etl_stock_last_ran',
            'etl_stock_last_result',
            'etl_stock_gaps_found',
            'etl_stock_periods_rebuilt',
        ];
        $sth = $this->pdo1->prepare(
            "SELECT setting_key, value FROM company_setting
             WHERE company_id = :cid AND setting_key IN ('" . implode("','", $keys) . "')"
        );
        $sth->execute([':cid' => $this->companyId]);
        $rows = $sth->fetchAll(PDO::FETCH_KEY_PAIR);

        $slot_hour = $this->companyId % 24;
        $last_ran  = $rows['etl_stock_last_ran'] ?? null;
        $next_run  = $last_ran
            ? date('Y-m-d', strtotime($last_ran . ' +1 day')) . sprintf(' %02d:30', $slot_hour)
            : date('Y-m-d') . sprintf(' %02d:30', $slot_hour);

        return [
            'slot_hour'       => $slot_hour,
            'last_ran'        => $last_ran,
            'last_result'     => $rows['etl_stock_last_result']      ?? null,
            'gaps_found'      => (int)($rows['etl_stock_gaps_found']       ?? 0),
            'periods_rebuilt' => (int)($rows['etl_stock_periods_rebuilt']  ?? 0),
            'next_run'        => $next_run,
        ];
    }

    // ── Private ──────────────────────────────────────────────────────────────

    private function discoverStockTables(): array
    {
        $sth = $this->pdo->prepare(
            "SELECT t.table_name
             FROM md_warehouse w
             JOIN information_schema.tables t
               ON t.table_schema = DATABASE()
              AND t.table_name = CONCAT('td_stock_', w.id)
             WHERE w.company_id = :cid"
        );
        $sth->execute([':cid' => $this->companyId]);
        return $sth->fetchAll(PDO::FETCH_COLUMN);
    }

    private function saveStatus(string $result, int $gaps_found, int $periods_rebuilt): void
    {
        $now  = date('Y-m-d H:i:s');
        $data = [
            'etl_stock_last_ran'        => $now,
            'etl_stock_last_result'     => $result,
            'etl_stock_gaps_found'      => (string)$gaps_found,
            'etl_stock_periods_rebuilt' => (string)$periods_rebuilt,
        ];
        $sth = $this->pdo1->prepare(
            "INSERT INTO company_setting (company_id, setting_key, value, updated_at)
             VALUES (:cid, :key, :val, :ts)
             ON DUPLICATE KEY UPDATE value = VALUES(value), updated_at = VALUES(updated_at)"
        );
        foreach ($data as $key => $val) {
            $sth->execute([':cid' => $this->companyId, ':key' => $key, ':val' => $val, ':ts' => $now]);
        }
    }
}