<?php
session_start();
require_once '../../../assets/utils/db_auth.php';
require_once '../../../assets/utils/classes/PurchaseOrderManager.php';
require_once '../../../assets/utils/classes/PurchaseRequestManager.php';
require_role($user_role, ['owner', 'admin', 'staff']);

$request_id    = (int)($data['request_id']  ?? 0);
$contact_id    = (int)($data['contact_id']  ?? 0);
$convert_items = $data['convert_items'] ?? [];
$discount      = (float)($data['discount']     ?? 0);
$shipping_fee  = (float)($data['shipping_fee'] ?? 0);

if (!$request_id) {
    $answer['message'] = 'Purchase request ID is required.';
    exit(json_encode($answer));
}
if (!$contact_id) {
    $answer['message'] = 'Supplier (contact_id) is required for the PO.';
    exit(json_encode($answer));
}

$prm = new PurchaseRequestManager($pdo2, $company_id);

// Load PR — must be Approved
$pr = $prm->getById($request_id);
if (!$pr || (int)$pr['status'] !== 2) {
    $answer['message'] = 'Purchase request not found or not in Approved status.';
    exit(json_encode($answer));
}

$pr_items = $pr['items'];
if (empty($pr_items)) {
    $answer['message'] = 'Purchase request has no items.';
    exit(json_encode($answer));
}

if ((float)$pr['total_remaining'] <= 0.000001) {
    $answer['message'] = 'Purchase request is already fully converted.';
    exit(json_encode($answer));
}

// Index by item_id for validation
$pr_by_id = [];
foreach ($pr_items as $pi) {
    $pr_by_id[(int)$pi['item_id']] = $pi;
}

// Default to all remaining
if (empty($convert_items)) {
    $convert_items = [];
    foreach ($pr_items as $pi) {
        $remaining = (float)$pi['remaining_qty'];
        if ($remaining > 0.000001) {
            $convert_items[] = ['item_id' => (int)$pi['item_id'], 'quantity' => $remaining];
        }
    }
}

// Validate quantities and build PO items
$po_items  = [];
$validated = [];

foreach ($convert_items as $ci) {
    $item_id = (int)($ci['item_id'] ?? 0);
    $qty     = (float)($ci['quantity'] ?? 0);

    if ($qty <= 0) continue;
    if (!isset($pr_by_id[$item_id])) {
        $answer['message'] = "Item #{$item_id} not found in this purchase request.";
        exit(json_encode($answer));
    }

    $pi        = $pr_by_id[$item_id];
    $remaining = (float)$pi['remaining_qty'];

    if ($qty - $remaining > 0.000001) {
        $name = $pi['product_name'] ?: $pi['product_sku'];
        $answer['message'] = "Cannot convert {$qty} for \"{$name}\": only {$remaining} remaining.";
        exit(json_encode($answer));
    }

    $unit_price  = (float)$pi['unit_price'];
    $total_price = round($qty * $unit_price, 4);
    $tax_amount  = round($total_price * (float)($pi['tax_amount'] / max((float)$pi['total_price'], 0.000001)), 4);

    $po_items[] = [
        'item_id'      => $item_id - 1,
        'product_sku'  => $pi['product_sku'],
        'product_name' => $pi['product_name'],
        'quantity'     => $qty,
        'unit_price'   => $unit_price,
        'total_price'  => $total_price,
        'tax_amount'   => $tax_amount,
        'received_qty' => 0,
        'stock_in_id'  => 0,
    ];
    $validated[] = ['item_id' => $item_id, 'quantity' => $qty];
}

if (empty($po_items)) {
    $answer['message'] = 'No valid items to convert.';
    exit(json_encode($answer));
}

$po_data = [
    'source'        => 'purchase_request',
    'source_id'     => $request_id,
    'contact_id'    => $contact_id,
    'department_id' => (int)($pr['department_id'] ?? 0),
    'po_date'       => date('Y-m-d'),
    'expected_date' => $pr['required_date'] ?: '',
    'warehouse_id'  => 0,
    'items'         => $po_items,
    'discount'      => $discount,
    'shipping_fee'  => $shipping_fee,
    'notes'         => $pr['notes'] ?? '',
];

try {
    $new_po_id = null;

    dbTransaction($pdo2, function($pdo) use (
        $po_data, $company_id, $logging, $request_id, $validated, $prm, &$new_po_id
    ) {
        $po        = new PurchaseOrderManager($pdo, $company_id);
        $new_po_id = $po->savePo($po_data, $logging);

        $prm2 = new PurchaseRequestManager($pdo, $company_id);
        $prm2->incrementConvertedQty($request_id, $validated);
    });

    $answer['success'] = 1;
    $answer['message'] = 'Purchase order created.';
    $answer['po_id']   = $new_po_id;

} catch (PDOException $e) {
    $answer['message'] = 'Database error, please try again.';
    http_response_code(500);
} catch (Exception $e) {
    $answer['message'] = $e->getMessage();
    http_response_code(400);
}

exit(json_encode($answer));