<?php
session_start();
require_once 'db/config.php';

// Check if user is logged in
if (!isset($_SESSION['user_id'])) {
    header('Location: login.php');
    exit();
}

$user_id = $_SESSION['user_id'];
$pdo = db();

// Build query with filters
$sql = "SELECT * FROM expenses WHERE user_id = :user_id";
$params = ['user_id' => $user_id];

if (!empty($_GET['start_date'])) {
    $sql .= " AND expense_date >= :start_date";
    $params['start_date'] = $_GET['start_date'];
}
if (!empty($_GET['end_date'])) {
    $sql .= " AND expense_date <= :end_date";
    $params['end_date'] = $_GET['end_date'];
}
if (!empty($_GET['category'])) {
    $sql .= " AND category = :category";
    $params['category'] = $_GET['category'];
}

$sql .= " ORDER BY expense_date DESC";

$stmt = $pdo->prepare($sql);
$stmt->execute($params);
$expenses = $stmt->fetchAll(PDO::FETCH_ASSOC);

// Set headers for CSV download
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename="despesas.csv"');

// Open output stream
$output = fopen('php://output', 'w');

// Write CSV header
fputcsv($output, ['Data', 'Descricao', 'Valor', 'Categoria']);

// Write data
if ($expenses) {
    foreach ($expenses as $expense) {
        fputcsv($output, [
            $expense['expense_date'],
            $expense['description'],
            $expense['amount'],
            $expense['category']
        ]);
    }
}

fclose($output);
exit();