<?php
/**
 * api/tren.php — Tren waktu jumlah warga & cakupan bantuan (KF-23).
 * GET → seri bulanan (12 bulan terakhir): warga baru, kumulatif warga, bantuan baru.
 */
require_once __DIR__ . '/../config/db.php';
require_once __DIR__ . '/helpers.php';

$pdo = Database::getConnection();
requireApiAnyRole(['operator', 'pimpinan']);
if ($_SERVER['REQUEST_METHOD'] !== 'GET') sendError('Method not allowed', 405);

// Bangun 12 bulan terakhir
$months = [];
for ($i = 11; $i >= 0; $i--) {
    $months[date('Y-m', strtotime("-$i month"))] = ['warga' => 0, 'bantuan' => 0];
}

foreach ($pdo->query("SELECT DATE_FORMAT(created_at,'%Y-%m') ym, COUNT(*) c FROM warga_miskin GROUP BY ym") as $r) {
    if (isset($months[$r['ym']])) $months[$r['ym']]['warga'] = (int)$r['c'];
}
foreach ($pdo->query("SELECT DATE_FORMAT(created_at,'%Y-%m') ym, COUNT(*) c FROM bantuan_sosial GROUP BY ym") as $r) {
    if (isset($months[$r['ym']])) $months[$r['ym']]['bantuan'] = (int)$r['c'];
}

// warga sebelum jendela 12 bulan (untuk basis kumulatif)
$firstMonth = array_key_first($months);
$base = (int)$pdo->query("SELECT COUNT(*) FROM warga_miskin WHERE DATE_FORMAT(created_at,'%Y-%m') < '$firstMonth'")->fetchColumn();

$labels = []; $wargaBaru = []; $kumulatif = []; $bantuanBaru = [];
$run = $base;
foreach ($months as $ym => $v) {
    $labels[] = $ym;
    $wargaBaru[] = $v['warga'];
    $run += $v['warga'];
    $kumulatif[] = $run;
    $bantuanBaru[] = $v['bantuan'];
}

sendSuccess([
    'labels' => $labels,
    'warga_baru' => $wargaBaru,
    'kumulatif' => $kumulatif,
    'bantuan_baru' => $bantuanBaru,
], 'Tren Waktu');