<?php
header('Content-Type: application/json');
require_once __DIR__ . '/../db/config.php';
require_once __DIR__ . '/../includes/functions.php';
require_once __DIR__ . '/../includes/WablasService.php';

$input = file_get_contents('php://input');
$data = json_decode($input, true);

if (!$data) {
    echo json_encode(['success' => false, 'error' => 'No data provided']);
    exit;
}

try {
    $pdo = db();
    $pdo->beginTransaction();

    // Validate order_type against allowed ENUM values
    $allowed_types = ['dine-in', 'takeaway', 'delivery', 'drive-thru'];
    $order_type = isset($data['order_type']) && in_array($data['order_type'], $allowed_types) 
        ? $data['order_type'] 
        : 'dine-in';

    // Get outlet_id from input, default to 1 if missing
    $outlet_id = !empty($data['outlet_id']) ? intval($data['outlet_id']) : 1;

    $table_id = null;
    $table_number = null;

    if ($order_type === 'dine-in') {
        $tid = $data['table_number'] ?? null; // Front-end sends ID as table_number
        if ($tid) {
            // Validate table exists AND belongs to the correct outlet
            $stmt = $pdo->prepare(
                "SELECT t.id, t.name 
                FROM tables t
                JOIN areas a ON t.area_id = a.id
                WHERE t.id = ? AND a.outlet_id = ?"
            );
            $stmt->execute([$tid, $outlet_id]);
            $table = $stmt->fetch(PDO::FETCH_ASSOC);
            if ($table) {
                $table_id = $table['id'];
                $table_number = $table['name'];
            }
        }
        
        // If not found or not provided, leave null (Walk-in/Counter) or try to find a default table for this outlet
        if (!$table_id) {
             // Optional: try to find the first available table for this outlet
             $stmt = $pdo->prepare(
                "SELECT t.id, t.name 
                FROM tables t 
                JOIN areas a ON t.area_id = a.id
                WHERE a.outlet_id = ?
                LIMIT 1"
             );
             $stmt->execute([$outlet_id]);
             $table = $stmt->fetch(PDO::FETCH_ASSOC);
             if ($table) {
                 $table_id = $table['id'];
                 $table_number = $table['name'];
             }
        }
    }

    // Customer Handling
    $customer_id = !empty($data['customer_id']) ? intval($data['customer_id']) : null;
    $customer_name = $data['customer_name'] ?? null;
    $customer_phone = $data['customer_phone'] ?? null;
    
    // Fetch Loyalty Settings
    $settingsStmt = $pdo->query("SELECT is_enabled, points_per_order, points_for_free_meal FROM loyalty_settings WHERE id = 1");
    $loyaltySettings = $settingsStmt->fetch(PDO::FETCH_ASSOC);
    $loyalty_enabled = $loyaltySettings ? (bool)$loyaltySettings['is_enabled'] : true;
    $points_threshold = $loyaltySettings ? intval($loyaltySettings['points_for_free_meal']) : 70;
    $points_per_product = $loyaltySettings ? intval($loyaltySettings['points_per_order']) : 10;

    $current_points = 0;
    $points_deducted = 0;
    $points_awarded = 0;
    $award_history_id = null;
    $redeem_history_id = null;

    if ($customer_id) {
        $stmt = $pdo->prepare("SELECT name, phone, points FROM customers WHERE id = ?");
        $stmt->execute([$customer_id]);
        $cust = $stmt->fetch(PDO::FETCH_ASSOC);
        if ($cust) {
            $customer_name = $cust['name'];
            $customer_phone = $cust['phone'];
            $current_points = intval($cust['points']);
        } else {
            $customer_id = null;
        }
    }
    
    // Loyalty Redemption Logic (initial check)
    $redeem_loyalty = !empty($data['redeem_loyalty']) && $loyalty_enabled;
    if ($redeem_loyalty && $customer_id) {
        if ($current_points < $points_threshold) {
             throw new Exception("Insufficient loyalty points for redemption.");
        }
    }

    // Total amount will be recalculated on server to be safe
    $calculated_total = 0;

    // First, process items to calculate real total and handle loyalty
    $processed_items = [];
    $loyalty_items_indices = [];
    
    if (!empty($data['items']) && is_array($data['items'])) {
        foreach ($data['items'] as $item) {
            $pid = $item['product_id'] ?? ($item['id'] ?? null);
            if (!$pid) continue;

            $qty = intval($item['quantity'] ?? 1);
            $vid = $item['variant_id'] ?? null;

            // Fetch Product Price (Promo aware)
            $pStmt = $pdo->prepare("SELECT * FROM products WHERE id = ?");
            $pStmt->execute([$pid]);
            $product = $pStmt->fetch(PDO::FETCH_ASSOC);
            if (!$product) continue;

            $unit_price = get_product_price($product);

            $variant_name = null;
            // Add variant adjustment
            if ($vid) {
                $vStmt = $pdo->prepare("SELECT name, price_adjustment FROM product_variants WHERE id = ? AND product_id = ?");
                $vStmt->execute([$vid, $pid]);
                $variant = $vStmt->fetch(PDO::FETCH_ASSOC);
                if ($variant) {
                    $unit_price += floatval($variant['price_adjustment']);
                    $variant_name = $variant['name'];
                }
            }

            if ($product['is_loyalty']) {
                $loyalty_items_indices[] = count($processed_items);
            } elseif ($redeem_loyalty) {
                throw new Exception("Redemption is only allowed when all items in the cart are loyalty-eligible.");
            }

            $processed_items[] = [
                'product_id' => $pid,
                'product_name' => $product['name'],
                'variant_id' => $vid,
                'variant_name' => $variant_name,
                'quantity' => $qty,
                'unit_price' => $unit_price,
                'is_loyalty' => (bool)$product['is_loyalty']
            ];
        }
    }

    // Handle Loyalty Redemption (Make loyalty items free up to points limit)
    if ($redeem_loyalty && $customer_id) {
        if (empty($loyalty_items_indices)) {
            throw new Exception("No loyalty-eligible products in the order to redeem.");
        }

        $possible_redemptions = floor($current_points / $points_threshold);
        $redemptions_done = 0;

        while ($redemptions_done < $possible_redemptions) {
            // Find the most expensive loyalty item that is still paid
            $max_price = -1;
            $max_index = -1;
            foreach ($processed_items as $idx => $item) {
                if ($item['is_loyalty'] && $item['unit_price'] > 0 && $item['quantity'] > 0) {
                    if ($item['unit_price'] > $max_price) {
                        $max_price = $item['unit_price'];
                        $max_index = $idx;
                    }
                }
            }

            if ($max_index === -1) break; // No more loyalty items to redeem

            // Deduct points for ONE redemption
            $points_deducted += $points_threshold;
            $redemptions_done++;

            // Make ONE unit of the found product free
            if ($processed_items[$max_index]['quantity'] > 1) {
                $processed_items[$max_index]['quantity']--;
                $free_item = $processed_items[$max_index];
                $free_item['quantity'] = 1;
                $free_item['unit_price'] = 0;
                $processed_items[] = $free_item;
            } else {
                $processed_items[$max_index]['unit_price'] = 0;
            }
        }

        if ($redemptions_done > 0) {
            // Update customer points and count
            $deductStmt = $pdo->prepare("UPDATE customers SET points = points - ? WHERE id = ?");
            $deductStmt->execute([$points_deducted, $customer_id]);
            $pdo->prepare("UPDATE customers SET loyalty_redemptions_count = loyalty_redemptions_count + ? WHERE id = ?")
                ->execute([$redemptions_done, $customer_id]);

            // Record Loyalty History (Deduction)
            $historyStmt = $pdo->prepare("INSERT INTO loyalty_points_history (customer_id, points_change, reason) VALUES (?, ?, 'Redeemed Free Product(s)')");
            $historyStmt->execute([$customer_id, -$points_deducted]);
            $redeem_history_id = $pdo->lastInsertId();
            
            // --- OVERRIDE PAYMENT TYPE ---
            $ptStmt = $pdo->prepare("SELECT id FROM payment_types WHERE name = 'Loyalty Redeem' LIMIT 1");
            $ptStmt->execute();
            $loyaltyPt = $ptStmt->fetchColumn();
            if ($loyaltyPt) {
                $data['payment_type_id'] = $loyaltyPt;
            }
        } else {
             throw new Exception("No loyalty-eligible products in the order to redeem.");
        }
    }

    // Recalculate Subtotal and Earned Points
    foreach ($processed_items as $pi) {
        $calculated_total += $pi['unit_price'] * $pi['quantity'];
        // Award points for PAID loyalty items
        if ($pi['is_loyalty'] && $pi['unit_price'] > 0 && $pi['quantity'] > 0) {
            $points_awarded += $pi['quantity'] * $points_per_product;
        }
    }

    // Award Points
    if ($customer_id && $loyalty_enabled && $points_awarded > 0) {
        $awardStmt = $pdo->prepare("UPDATE customers SET points = points + ? WHERE id = ?");
        $awardStmt->execute([$points_awarded, $customer_id]);

        // Record Loyalty History (Award)
        $historyStmt = $pdo->prepare("INSERT INTO loyalty_points_history (customer_id, points_change, reason) VALUES (?, ?, 'Earned from Products')");
        $historyStmt->execute([$customer_id, $points_awarded]);
        $award_history_id = $pdo->lastInsertId();
    }

    $vat = isset($data['vat']) ? floatval($data['vat']) : 0.00;
    $final_total = max(0, $calculated_total + $vat);

    // User/Payment info
    $user = get_logged_user();
    $user_id = $user ? $user['id'] : null;
    $payment_type_id = !empty($data['payment_type_id']) ? intval($data['payment_type_id']) : null;
    
    // Commission Calculation
    $commission_amount = 0;
    $companySettings = get_company_settings();
    if (!empty($companySettings['commission_enabled']) && $user_id) {
        $userStmt = $pdo->prepare("SELECT commission_rate FROM users WHERE id = ?");
        $userStmt->execute([$user_id]);
        $commission_rate = (float)$userStmt->fetchColumn();
        if ($commission_rate > 0) {
            $commission_amount = $calculated_total * ($commission_rate / 100);
        }
    }

    // Check for Existing Order ID (Update Mode)
    $order_id = isset($data['order_id']) ? intval($data['order_id']) : null;
    $is_update = false;

    if ($order_id) {
        $checkStmt = $pdo->prepare("SELECT id FROM orders WHERE id = ?");
        $checkStmt->execute([$order_id]);
        if ($checkStmt->fetch()) {
            $is_update = true;
        } else {
            $order_id = null;
        }
    }

    if ($is_update) {
        $stmt = $pdo->prepare("UPDATE orders SET 
            outlet_id = ?, table_id = ?, table_number = ?, order_type = ?, 
            customer_id = ?, customer_name = ?, customer_phone = ?, 
            payment_type_id = ?, total_amount = ?, discount = ?, user_id = ?, 
            commission_amount = ?, status = 'pending' 
            WHERE id = ?");
        $stmt->execute([
            $outlet_id, $table_id, $table_number, $order_type, 
            $customer_id, $customer_name, $customer_phone, 
            $payment_type_id, $final_total, $vat, $user_id, 
            $commission_amount, $order_id
        ]);

        $delStmt = $pdo->prepare("DELETE FROM order_items WHERE order_id = ?");
        $delStmt->execute([$order_id]);
    } else {
        $stmt = $pdo->prepare("INSERT INTO orders (outlet_id, table_id, table_number, order_type, customer_id, customer_name, customer_phone, payment_type_id, total_amount, discount, user_id, commission_amount, status) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'pending')");
        $stmt->execute([$outlet_id, $table_id, $table_number, $order_type, $customer_id, $customer_name, $customer_phone, $payment_type_id, $final_total, $vat, $user_id, $commission_amount]);
        $order_id = $pdo->lastInsertId();
    }

    // Update loyalty history with order_id
    if ($order_id) {
        if ($award_history_id) {
            $pdo->prepare("UPDATE loyalty_points_history SET order_id = ? WHERE id = ?")->execute([$order_id, $award_history_id]);
        }
        if ($redeem_history_id) {
            $pdo->prepare("UPDATE loyalty_points_history SET order_id = ? WHERE id = ?")->execute([$order_id, $redeem_history_id]);
        }
    }

    // Insert Items and Update Stock
    $item_stmt = $pdo->prepare("INSERT INTO order_items (order_id, product_id, product_name, variant_id, variant_name, quantity, unit_price) VALUES (?, ?, ?, ?, ?, ?, ?)");
    $stock_stmt = $pdo->prepare("UPDATE products SET stock_quantity = stock_quantity - ? WHERE id = ?");
    
    $order_items_list = [];

    foreach ($processed_items as $pi) {
        $item_stmt->execute([$order_id, $pi['product_id'], $pi['product_name'], $pi['variant_id'], $pi['variant_name'], $pi['quantity'], $pi['unit_price']]);
        
        // Decrement Stock
        $stock_stmt->execute([$pi['quantity'], $pi['product_id']]);

        $pName = $pi['product_name'];
        if ($pi['variant_name']) {
            $pName .= " ({$pi['variant_name']})";
        }
        $order_items_list[] = "{$pi['quantity']} x $pName";
    }

    $pdo->commit();
    
    // --- Post-Transaction Actions (WhatsApp) ---
    if ($customer_id && $customer_phone) {
        try {
            $final_points = $current_points - $points_deducted + ($loyalty_enabled ? $points_awarded : 0);
            $wablas = new WablasService($pdo);
            $companySettings = get_company_settings();
            $company_name = $companySettings['company_name'] ?? 'Flatlogic POS';
            
            $stmt = $pdo->prepare("SELECT setting_value FROM integration_settings WHERE provider = 'wablas' AND setting_key = 'order_template'");
            $stmt->execute();
            $template = $stmt->fetchColumn();
            
            if (!$template) {
                $template = "Dear *{customer_name}*,

Thank you for dining with *{company_name}*! 🍽️

*Order Details:*
{order_details}

Total: *{total_amount}* OMR

You've earned *{points_earned} points* with this order.
💰 *Current Balance: {new_balance} points*

{loyalty_status}";
            }

            $loyalty_status = "";
            if ($loyalty_enabled) {
                $loyalty_status = ($final_points >= $points_threshold) 
                    ? "🎉 Congratulations! You have enough points for a *FREE MEAL* on your next visit!" 
                    : "You need *" . ($points_threshold - $final_points) . " more points* to unlock a free meal.";
            }

            $replacements = [
                '{customer_name}' => $customer_name,
                '{company_name}' => $company_name,
                '{order_id}' => $order_id,
                '{order_details}' => implode("\n", $order_items_list),
                '{total_amount}' => number_format($final_total, 3),
                '{points_earned}' => $loyalty_enabled ? $points_awarded : 0,
                '{points_redeemed}' => $points_deducted,
                '{new_balance}' => $final_points,
                '{loyalty_status}' => $loyalty_status
            ];
            
            $msg = str_replace(array_keys($replacements), array_values($replacements), $template);
            $wablas->sendMessage($customer_phone, $msg);
            
        } catch (Exception $w) {
            error_log("Wablas Exception: " . $w->getMessage());
        }
    }

    echo json_encode(['success' => true, 'order_id' => $order_id]);

} catch (Exception $e) {
    if ($pdo->inTransaction()) $pdo->rollBack();
    error_log("Order Error: " . $e->getMessage());
    echo json_encode(['success' => false, 'error' => $e->getMessage()]);
}