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

if (!isset($_SESSION['admin_logged_in'])) {
    echo json_encode(['success' => false, 'message' => 'Unauthorized']);
    exit;
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    try {
        // Find CIDs that have duplicates
        $stmt = $pdo_bot->query("
            SELECT cid, COUNT(*) as c 
            FROM line_staff_register 
            GROUP BY cid 
            HAVING c > 1
        ");
        $duplicates = $stmt->fetchAll();
        
        $deleted_total = 0;

        foreach ($duplicates as $dup) {
            $cid = $dup['cid'];
            
            // Get all records for this CID ordered by date DESC, then id DESC
            $stmt = $pdo_bot->prepare("
                SELECT id 
                FROM line_staff_register 
                WHERE cid = ? 
                ORDER BY date DESC, id DESC
            ");
            $stmt->execute([$cid]);
            $records = $stmt->fetchAll();
            
            if (count($records) > 1) {
                // Keep the first one (most recent date)
                $keep_id = $records[0]['id'];
                
                // Delete the rest
                for ($i = 1; $i < count($records); $i++) {
                    $del_stmt = $pdo_bot->prepare("DELETE FROM line_staff_register WHERE id = ?");
                    $del_stmt->execute([$records[$i]['id']]);
                    $deleted_total++;
                }
            }
        }

        echo json_encode(['success' => true, 'deleted_count' => $deleted_total, 'message' => "ลบข้อมูลที่ซ้ำซ้อนสำเร็จ จำนวน $deleted_total รายการ"]);
    } catch (Exception $e) {
        echo json_encode(['success' => false, 'message' => 'Error: ' . $e->getMessage()]);
    }
}