<?php
/**
 * TaxReportManager
 *
 * Generates VAT and withholding tax reports from journal lines
 * tagged to tax accounts (output VAT, input VAT, WHT) in md_account.
 * Matches accounts where account_name contains 'vat' or 'tax' (case-insensitive).
 * Read-only — no writes.
 */
class TaxReportManager
{
    private PDO $pdo;
    private int $companyId;

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

    private function normalizeDate(string $date, bool $end_of_month = false): string
    {
        $date = trim($date);
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $date)) {
            return $date;
        }
        if (preg_match('/^\d{4}-\d{2}$/', $date)) {
            return $end_of_month ? date('Y-m-t', strtotime($date . '-01')) : $date . '-01';
        }
        return date('Y-m-d');
    }

    // ── VAT Report ────────────────────────────────────────────────────────────
    // Returns all GL lines for accounts whose account_category is 'sales_tax'
    // or 'purchase_tax'. Pass $categories = [] to get both; pass one or more
    // category strings to narrow (e.g. ['sales_tax']).

    public function getVATReport(string $from_date, string $to_date, array $categories = [], int $dept_id = 0): array
    {
        $from_date = $this->normalizeDate($from_date);
        $to_date   = $this->normalizeDate($to_date, true);

        $valid = ['sales_tax', 'purchase_tax'];
        $cats  = $categories ? array_intersect($categories, $valid) : $valid;

        if (empty($cats)) {
            return ['rows' => [], 'total_debit' => 0.0, 'total_credit' => 0.0,
                    'from_date' => $from_date, 'to_date' => $to_date,
                    'from_period' => substr($from_date, 0, 7), 'to_period' => substr($to_date, 0, 7)];
        }

        $placeholders = implode(',', array_map(fn($i) => ":cat$i", array_keys($cats)));
        $params       = [':cid' => $this->companyId, ':from_date' => $from_date, ':to_date' => $to_date];
        foreach (array_values($cats) as $i => $c) { $params[":cat$i"] = $c; }

        $sth = $this->pdo->prepare("
            SELECT
                g.id          AS gl_id,
                g.source_type,
                COALESCE(g.reference, '')                    AS reference,
                g.period,
                COALESCE(g.journal_date, DATE(g.created_at)) AS entry_date,
                a.account_code,
                a.account_name,
                a.account_category,
                i.department_id,
                COALESCE(d.dept_code, '') AS dept_code,
                COALESCE(d.dept_name, '') AS dept_name,
                i.debit,
                i.credit,
                COALESCE(i.description, '')                  AS description
            FROM td_gl_item i
            JOIN td_gl g      ON g.id = i.gl_id AND g.company_id = i.company_id
            JOIN md_account a ON a.company_id = i.company_id AND a.account_code = i.account_code
            LEFT JOIN md_department d ON d.company_id = i.company_id AND d.id = i.department_id
            WHERE i.company_id = :cid
              AND COALESCE(g.journal_date, DATE(g.created_at)) BETWEEN :from_date AND :to_date
              AND a.account_category IN ($placeholders)
              AND (:dept_id = 0 OR i.department_id = :dept_id)
            ORDER BY g.period ASC, g.journal_date ASC, g.id ASC
        ");
        $params[':dept_id'] = $dept_id;
        $sth->execute($params);
        $rows = $sth->fetchAll(PDO::FETCH_ASSOC);

        return [
            'rows'         => $rows,
            'total_debit'  => (float)array_sum(array_column($rows, 'debit')),
            'total_credit' => (float)array_sum(array_column($rows, 'credit')),
            'from_date'    => $from_date,
            'to_date'      => $to_date,
            'from_period'  => substr($from_date, 0, 7),
            'to_period'    => substr($to_date, 0, 7),
        ];
    }

    public function getOutputVAT(string $from_period, string $to_period, int $dept_id = 0): array
    {
        return $this->getVATReport($from_period, $to_period, ['sales_tax'], $dept_id);
    }

    public function getInputVAT(string $from_period, string $to_period, int $dept_id = 0): array
    {
        return $this->getVATReport($from_period, $to_period, ['purchase_tax'], $dept_id);
    }
}