<?php

class Reports
{
    private PDO $pdo;
    private int $companyId;

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

    /**
     * Master Data Summary:
     * - Total Categories: Count of all categories in md_product_category for the company.
     * - Active Categories: Count of categories where status = 1.
     * - Inactive Categories: Count of categories where status = 0.
     */
    public function getTotalCategory(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_product_category 
                WHERE company_id = :company_id";
        return (int) $this->fetchScalar($sql);
    }

    public function getActiveCategory(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_product_category 
                WHERE company_id = :company_id 
                  AND `status` = 1";
        return (int) $this->fetchScalar($sql);
    }

    public function getInactiveCategory(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_product_category 
                WHERE company_id = :company_id 
                  AND `status` = 0";
        return (int) $this->fetchScalar($sql);
    }

    public function getTotalWarehouse(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_warehouse 
                WHERE company_id = :company_id
                AND `status` = 1";
        return (int) $this->fetchScalar($sql);
    }

    public function getTotalLocation(): int
    {
        $sql = "SELECT COUNT(DISTINCT `location`) 
                FROM md_warehouse 
                WHERE company_id = :company_id
                AND `status` = 1";
        return (int) $this->fetchScalar($sql);
    }

    /**
     * Total capacity = total count of active racks across all warehouses.
     * One rack = one storage position (holds one product unit).
     */
    public function getTotalCapacity(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_rack 
                WHERE company_id = :company_id";
        return (int) $this->fetchScalar($sql);
    }

    /**
     * Space Used = count of racks currently occupied (product_sku IS NOT NULL).
     */
    public function getSpaceUsed(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_rack 
                WHERE company_id = :company_id
                AND product_sku IS NOT NULL";
        return (int) $this->fetchScalar($sql);
    }

    /**
     * Product Count = total count of distinct products in the md_product table for the company.
     * Low Stock Count = count of products where current stock balance (total_in - total_out) is less than the min_stock defined in md_product.
     */
    public function getTotalProduct(): int
    {
        $sql = "SELECT COUNT(*) 
                FROM md_product 
                WHERE company_id = :company_id";
        return (int) $this->fetchScalar($sql);
    }

    public function getTotalProductInStock(): int
{
        $sql = "SELECT COUNT(DISTINCT product_sku)
                FROM warehouse_balance
                WHERE company_id = :company_id
                AND (total_in - total_out) > 0";
        return (int) $this->fetchScalar($sql);
    }

    public function getLowStockCount(): int
    {
        $products = $this->getStockBalance();
        $count = 0;
        foreach ($products as $product) {
            $balance = (float) $product["total_in"] - (float) $product["total_out"];
            if ($balance < (float) $product["min_stock"]) {
                $count++;
            }
        }
        return $count;
    }

    public function getStockBalance(): array
    {
        $sql = "SELECT 
                    a.product_sku,
                    SUM(a.total_in) AS total_in, 
                    SUM(a.total_out) AS total_out, 
                    b.min_stock
                FROM warehouse_balance a
                LEFT JOIN md_product b 
                    ON a.company_id = b.company_id 
                AND a.product_sku = b.sku
                WHERE a.company_id = :company_id
                GROUP BY a.product_sku, b.min_stock";
        return $this->fetchAll($sql);
    }

    // FETCH HELPERS
    // These helper methods abstract away the common pattern of preparing, executing, and fetching results from the database.
    private function fetchScalar(string $sql)
    {
        $sth = $this->pdo->prepare($sql);
        $sth->execute([":company_id" => $this->companyId]);
        return $sth->fetchColumn();
    }

    private function fetchAll(string $sql): array
    {
        $sth = $this->pdo->prepare($sql);
        $sth->execute([":company_id" => $this->companyId]);
        return $sth->fetchAll(PDO::FETCH_ASSOC);
    }
}


?>