<?php
session_start();
require_once("../core/auth.php");
require_once("../config/db.php");
require_once("../core/utils.php");

header('Content-Type: application/json; charset=utf-8');

if (!isset($_POST['hn'])) {
    echo json_encode(["status" => "error", "message" => "Missing parameters"]);
    exit;
}

$hn_raw = decrypt_param($_POST['hn']); 
$hn = mysqli_real_escape_string($conn1, $hn_raw);
$show_all = isset($_POST['show_all']) && $_POST['show_all'] === 'true';

$results = [];

try {
    // 1. Find all visits for this patient that have Health Checkup Diagnosis
    $sql_visits = "SELECT o.vstdate, o.vn 
                   FROM ovstdiag od
                   JOIN ovst o ON o.vn = od.vn
                   LEFT JOIN icd101 i ON i.code = od.icd10
                   WHERE o.hn = '$hn' 
                     AND (od.icd10 LIKE 'Z10%' OR od.icd10 LIKE 'Z00%' OR i.name LIKE '%Occupational%' OR i.name LIKE '%checkup%')
                     " . ($show_all ? "" : "AND o.vstdate >= DATE_SUB(CURDATE(), INTERVAL 2 YEAR)") . "
                   GROUP BY o.vstdate, o.vn
                   ORDER BY o.vstdate DESC
                   " . ($show_all ? "" : "LIMIT 20");
                   
    $res_visits = mysqli_query($conn1, $sql_visits);
    
    if (!$res_visits || mysqli_num_rows($res_visits) == 0) {
        echo json_encode(["status" => "success", "data" => []]);
        exit;
    }
    
    $visits = [];
    $prev_date = null;
    
    while ($row = mysqli_fetch_assoc($res_visits)) {
        $vn = $row['vn'];
        
        $visit_data = [
            'vstdate' => $row['vstdate'],
            'vstdate_thai' => thai_date2($row['vstdate']),
            'vn' => $vn,
            'gap_days' => 0,
            'labs' => [],
            'xrays' => []
        ];
        
        // 2. Fetch Labs for this visit
        $sql_lab = "SELECT i.lab_items_name, l.lab_order_result, i.lab_items_normal_value 
                    FROM lab_order l 
                    JOIN lab_head h ON h.lab_order_number = l.lab_order_number 
                    JOIN lab_items i ON i.lab_items_code = l.lab_items_code 
                    WHERE h.vn = '$vn' AND (l.lab_order_result IS NOT NULL AND l.lab_order_result != '')
                    ORDER BY i.lab_items_name";
        $res_lab = mysqli_query($conn1, $sql_lab);
        if ($res_lab) {
            while ($lrow = mysqli_fetch_assoc($res_lab)) {
                $lrow['is_abnormal'] = isAbnormalLab($lrow['lab_order_result'], $lrow['lab_items_normal_value']);
                $visit_data['labs'][] = $lrow;
            }
        }
        
        // 3. Fetch X-Rays for this visit
        $sql_xray = "SELECT xh.xray_list as item_name, xr.report_text as result 
                     FROM xray_report xr 
                     JOIN xray_head xh ON xh.vn = xr.vn 
                     WHERE xh.vn = '$vn'";
        $res_xray = mysqli_query($conn1, $sql_xray);
        if ($res_xray) {
            while ($xrow = mysqli_fetch_assoc($res_xray)) {
                $visit_data['xrays'][] = $xrow;
            }
        }
        
        // 4. Only include this visit if it has at least some results to compare
        if (!empty($visit_data['labs']) || !empty($visit_data['xrays'])) {
            $visits[] = $visit_data;
        }
    }
    
    // 5. Calculate gaps (We fetched DESC, so index 0 is newest, index 1 is older)
    for ($i = 0; $i < count($visits) - 1; $i++) {
        $newer_date = new DateTime($visits[$i]['vstdate']);
        $older_date = new DateTime($visits[$i + 1]['vstdate']);
        $interval = $older_date->diff($newer_date);
        $visits[$i]['gap_days'] = $interval->days;
        
        if ($interval->y > 0) {
            $text = "ห่างจากครั้งก่อน " . $interval->y . " ปี";
            if ($interval->m > 0) $text .= " " . $interval->m . " เดือน";
            if ($interval->d > 0) $text .= " " . $interval->d . " วัน";
            $visits[$i]['gap_text'] = $text;
        } else {
            $visits[$i]['gap_text'] = "ห่างจากครั้งก่อน " . $interval->days . " วัน";
        }
    }
    
    echo json_encode(["status" => "success", "data" => $visits]);

} catch (Exception $e) {
    echo json_encode(["status" => "error", "message" => $e->getMessage()]);
}
?>