<?php
declare(strict_types=1);

$controlApiLibrary = defined('CONTROL_API_LIBRARY') && CONTROL_API_LIBRARY;

if (!$controlApiLibrary && session_status() !== PHP_SESSION_ACTIVE) {
    session_start();
}

require_once __DIR__ . '/../config/config.php';

if (!$controlApiLibrary && !signed_in()) {
    json_out([
        'ok' => false,
        'error' => 'login_required',
    ], 401);
}

function bytes_human(int|float $bytes): string
{
    $units = ['B', 'KB', 'MB', 'GB', 'TB'];
    $v = (float)$bytes;
    $i = 0;

    while ($v >= 1024 && $i < count($units) - 1) {
        $v /= 1024;
        $i++;
    }

    return ($i === 0 ? (string)(int)$v : number_format($v, 2)) . ' ' . $units[$i];
}

function command_short(string $value, int $limit = 120): string
{
    $value = trim(preg_replace('/\s+/', ' ', $value) ?? '');

    if ($value === '') {
        return 'N/A';
    }

    return mb_strlen($value) > $limit
        ? mb_substr($value, 0, $limit - 1) . '...'
        : $value;
}

function human_seconds(int $s): string
{
    $d = intdiv($s, 86400);
    $s %= 86400;

    $h = intdiv($s, 3600);
    $s %= 3600;

    $m = intdiv($s, 60);

    return ($d > 0 ? $d . 'd ' : '') . sprintf('%02dh %02dm', $h, $m);
}

function human_remaining_seconds(int $seconds): string
{
    if ($seconds <= 0) {
        return '-';
    }

    $hours = intdiv($seconds, 3600);
    $minutes = intdiv($seconds % 3600, 60);

    if ($hours > 0) {
        return sprintf('%dh %02dm', $hours, $minutes);
    }

    return sprintf('%dm', max(1, $minutes));
}

function dmesg_log(): array
{
    $path = '/tmp/dmesg.log';

    if (!is_readable($path)) {
        return [
            'path' => $path,
            'available' => false,
            'lines' => [],
            'line_count' => 0,
            'size_bytes' => 0,
            'updated_at' => null,
            'message' => 'dmesg log is not available yet.',
        ];
    }

    $size = filesize($path) ?: 0;
    $chunk = file_get_contents($path);
    if ($chunk === false) {
        return [
            'path' => $path,
            'available' => false,
            'lines' => [],
            'line_count' => 0,
            'size_bytes' => $size,
            'updated_at' => null,
            'message' => 'failed to open dmesg log.',
        ];
    }

    $lines = array_values(array_filter(
        preg_split('/\R/', $chunk) ?: [],
        static fn($line): bool => trim((string)$line) !== ''
    ));

    return [
        'path' => $path,
        'available' => true,
        'lines' => array_reverse($lines),
        'line_count' => count($lines),
        'size_bytes' => $size,
        'updated_at' => date('Y-m-d H:i:s', filemtime($path) ?: time()),
    ];
}

function fan_paths(): array
{
    $candidates = glob('/sys/devices/platform/cooling_fan/hwmon/hwmon*/pwm1') ?: [];
    $candidates = array_merge(
        $candidates,
        glob('/sys/class/hwmon/hwmon*/pwm1') ?: []
    );

    foreach ($candidates as $pwm) {
        $dir = dirname($pwm);

        return [
            'base' => $dir,
            'pwm' => $pwm,
            'enable' => $dir . '/pwm1_enable',
            'rpm' => $dir . '/fan1_input',
            'name' => first_readable([$dir . '/name']) ?: 'cooling_fan',
        ];
    }

    return [
        'base' => 'N/A',
        'pwm' => 'N/A',
        'enable' => 'N/A',
        'rpm' => 'N/A',
        'name' => 'N/A',
    ];
}

function read_int_file(string $file): int
{
    if ($file === '' || $file === 'N/A' || !is_readable($file)) {
        return 0;
    }

    $raw = trim((string)@file_get_contents($file));

    return is_numeric($raw) ? (int)$raw : 0;
}

function cpu_temp(): float
{
    $raw = first_readable([
        '/sys/class/thermal/thermal_zone0/temp',
        '/sys/devices/virtual/thermal/thermal_zone0/temp',
    ]);

    if ($raw !== '' && is_numeric($raw)) {
        return round(((float)$raw) / 1000, 2);
    }

    $vc = sh(['/usr/bin/vcgencmd', 'measure_temp'], false, 3)['out'];

    if (preg_match('/([0-9.]+)/', $vc, $m)) {
        return round((float)$m[1], 2);
    }

    return 0.0;
}

function fan_target_pwm(float $temp): int
{
    if ($temp >= 80) {
        return 255;
    }

    if ($temp <= 50) {
        return 0;
    }

    $ratio = ($temp - 50) / 30;

    return max(0, min(255, (int)round($ratio * 255)));
}

function fan_ramped_pwm(int $current, int $desired, float $temp): int
{
    if ($temp >= 80) {
        return $desired;
    }

    if ($desired > $current) {
        return min($desired, $current + 2);
    }

    if ($desired < $current) {
        return max($desired, $current - 2);
    }

    return $desired;
}

function write_sys_value(string $path, int $value): bool
{
    if ($path === '' || $path === 'N/A') {
        return false;
    }

    if (@file_put_contents($path, $value . "\n", LOCK_EX) !== false) {
        return true;
    }

    $cmd = 'printf ' . escapeshellarg($value . "\n") . ' > ' . escapeshellarg($path);
    return sh(['/bin/sh', '-lc', $cmd], true, 5)['code'] === 0;
}

function apply_fan_policy(): array
{
    $state = get_control_state();
    $paths = fan_paths();

    $temp = cpu_temp();

    $mode = (string)($state['mode'] ?? 'auto');
    if (!in_array($mode, ['auto', 'manual', 'off'], true)) {
        $mode = 'auto';
    }

    $manualPwm = max(0, min(255, (int)($state['manual_pwm'] ?? 120)));

    $currentPwm = read_int_file($paths['pwm']);
    $desired = match ($mode) {
        'manual' => $manualPwm,
        'off' => 0,
        default => fan_target_pwm($temp),
    };
    $target = $mode === 'auto'
        ? fan_ramped_pwm($currentPwm, $desired, $temp)
        : $desired;

    $enableOk = write_sys_value($paths['enable'], $mode === 'off' ? 0 : 1);
    $pwmOk = write_sys_value($paths['pwm'], $target);

    usleep(60000);

    $actualPwm = read_int_file($paths['pwm']);

    $rpm = read_int_file($paths['rpm']);

    return [
        'mode' => $mode,
        'target_pwm' => $target,
        'actual_pwm' => $actualPwm,
        'temp_c' => $temp,
        'rpm' => $rpm,
        'ok' => $enableOk && $pwmOk,
        'paths' => $paths,
        'enable_value' => first_readable([$paths['enable']]) ?: 'N/A',
    ];
}

function mem_info(): array
{
    $rows = [];

    foreach (@file('/proc/meminfo', FILE_IGNORE_NEW_LINES) ?: [] as $line) {
        if (preg_match('/^([^:]+):\s+(\d+)/', $line, $m)) {
            $rows[$m[1]] = (int)$m[2];
        }
    }

    $total = (int)($rows['MemTotal'] ?? 0);
    $available = (int)($rows['MemAvailable'] ?? 0);
    $used = max(0, $total - $available);

    $swapTotal = (int)($rows['SwapTotal'] ?? 0);
    $swapFree = (int)($rows['SwapFree'] ?? 0);

    return [
        'total_mb' => round($total / 1024),
        'used_mb' => round($used / 1024),
        'free_mb' => round($available / 1024),
        'percent' => $total > 0 ? round($used / $total * 100, 1) : 0,
        'swap_total_mb' => round($swapTotal / 1024),
        'swap_used_mb' => round(max(0, $swapTotal - $swapFree) / 1024),
    ];
}

function disk_info(string $path = '/var/www/control'): array
{
    $total = @disk_total_space($path) ?: 0;
    $free = @disk_free_space($path) ?: 0;

    if ($total <= 0 || $free <= 0) {
        $out = trim(sh(['/bin/df', '-kP', $path], false, 3)['out']);
        $lines = preg_split('/\R/', $out);
        $parts = isset($lines[1]) ? preg_split('/\s+/', trim($lines[1])) : [];

        if (count($parts) >= 6) {
            $total = (int)$parts[1] * 1024;
            $free = (int)$parts[3] * 1024;
        }
    }

    $used = max(0, $total - $free);

    return [
        'path' => '/',
        'total_kb' => (int)round($total / 1024),
        'used_kb' => (int)round($used / 1024),
        'free_kb' => (int)round($free / 1024),
        'percent' => $total > 0 ? round($used / $total * 100, 1) : 0,
    ];
}

function active_user_info(): array
{
    $out = trim(sh(['/usr/bin/who'], false, 3)['out']);

    if ($out === '') {
        return [
            'users' => 0,
            'sessions' => 0,
            'names' => '',
            'display' => '0 users / 0 sessions',
        ];
    }

    $lines = preg_split('/\R/', $out) ?: [];
    $lines = array_values(array_filter($lines, fn($line) => trim($line) !== ''));

    $names = [];

    foreach ($lines as $line) {
        $parts = preg_split('/\s+/', trim($line));
        if (!empty($parts[0])) {
            $names[$parts[0]] = true;
        }
    }

    $userNames = array_keys($names);

    return [
        'users' => count($userNames),
        'sessions' => count($lines),
        'names' => implode(', ', $userNames),
        'display' => count($userNames) . ' users / ' . count($lines) . ' sessions',
    ];
}

function os_info(): array
{
    $os = [];

    foreach (@file('/etc/os-release', FILE_IGNORE_NEW_LINES) ?: [] as $line) {
        if (preg_match('/^([A-Z_]+)=(.*)$/', $line, $m)) {
            $os[$m[1]] = trim($m[2], '"');
        }
    }

    $uptimeRaw = trim((string)@file_get_contents('/proc/uptime'));
    $uptimeSec = $uptimeRaw !== ''
        ? (int)floor((float)explode(' ', $uptimeRaw)[0])
        : 0;

    return [
        'hostname' => gethostname() ?: 'N/A',
        'os' => $os['PRETTY_NAME'] ?? 'N/A',
        'kernel' => php_uname('r'),
        'arch' => php_uname('m'),
        'model' => trim(@file_get_contents('/proc/device-tree/model') ?: '') ?: 'N/A',
        'uptime' => human_seconds($uptimeSec),
        'uptime_seconds' => $uptimeSec,
    ];
}

function network_info(): array
{
    $rows = [];

    foreach (glob('/sys/class/net/*') ?: [] as $dir) {
        $name = basename($dir);

        if ($name === 'lo') {
            continue;
        }

        $rx = (int)first_readable([$dir . '/statistics/rx_bytes']);
        $tx = (int)first_readable([$dir . '/statistics/tx_bytes']);

        $rows[] = [
            'name' => $name,
            'state' => first_readable([$dir . '/operstate']) ?: 'unknown',
            'carrier' => first_readable([$dir . '/carrier']) === '1' ? 'up' : 'down',
            'mac' => first_readable([$dir . '/address']) ?: 'N/A',
            'mtu' => first_readable([$dir . '/mtu']) ?: 'N/A',
            'rx_bytes' => $rx,
            'tx_bytes' => $tx,
            'rx_human' => bytes_human($rx),
            'tx_human' => bytes_human($tx),
            'ipv4' => trim(sh(['/usr/sbin/ip', '-4', '-o', 'addr', 'show', 'dev', $name], false, 3)['out']) ?: 'N/A',
        ];
    }

    return $rows;
}

function latest_sensor(): array
{
    $stmt = db()->query("
        SELECT *
        FROM sensor_logs
        ORDER BY id DESC
        LIMIT 1
    ");

    return $stmt->fetch() ?: [];
}

function sensor_history(int $limit = 240): array
{
    $limit = max(1, min(1500, $limit));

    $stmt = db()->query("
        SELECT
            sl.recorded_at AS time,
            sl.cpu_temp_c AS temp_c,
            sl.fan_rpm,
            sl.fan_efficiency,
            sl.rp1_temp_c,
            sl.cpu_voltage,
            sl.cpu_watts,
            sl.battery_voltage,
            sl.battery_percent,
            sl.pwm_value AS fan_pwm,
            sl.pwm_percent,
            sl.pwm_mode,
            sl.cpu_load_1,
            sl.cpu_load_5,
            sl.cpu_load_15,
            sl.disk_total_kb,
            sl.disk_used_kb,
            sl.disk_free_kb,
            sl.mem_total_mb,
            sl.mem_used_mb,
            CASE
                WHEN sl.mem_total_mb > 0 THEN ROUND(sl.mem_used_mb / sl.mem_total_mb * 100, 1)
                ELSE 0
            END AS mem_percent
        FROM sensor_logs sl
        ORDER BY sl.id DESC
        LIMIT {$limit}
    ");

    return array_reverse($stmt->fetchAll());
}

function battery_remaining_estimate(array $battery, array $history): array
{
    $percent = $battery['percent'] ?? null;
    if ($percent === null || $percent === '' || !is_numeric($percent)) {
        return [
            'display' => '-',
            'seconds' => null,
            'source' => 'battery_soc_missing',
            'avg_watts' => null,
        ];
    }

    $percent = max(0.0, min(100.0, (float)$percent));
    $wattValues = [];

    foreach (array_slice($history, -90) as $row) {
        $watts = $row['cpu_watts'] ?? null;
        if ($watts !== null && $watts !== '' && is_numeric($watts) && (float)$watts > 0) {
            $wattValues[] = (float)$watts;
        }
    }

    $avgWatts = $wattValues === []
        ? null
        : array_sum($wattValues) / count($wattValues);

    if (BATTERY_CAPACITY_WH > 0 && $avgWatts !== null && $avgWatts > 0) {
        $remainingWh = BATTERY_CAPACITY_WH * ($percent / 100);
        $seconds = (int)round(($remainingWh / $avgWatts) * 3600);

        return [
            'display' => human_remaining_seconds($seconds),
            'seconds' => $seconds,
            'source' => 'avg_watts',
            'avg_watts' => round($avgWatts, 3),
            'capacity_wh' => BATTERY_CAPACITY_WH,
        ];
    }

    $socRows = [];
    foreach ($history as $row) {
        $soc = $row['battery_percent'] ?? null;
        $time = strtotime((string)($row['time'] ?? ''));
        if ($soc !== null && $soc !== '' && is_numeric($soc) && $time > 0) {
            $socRows[] = [
                'time' => $time,
                'soc' => (float)$soc,
            ];
        }
    }

    if (count($socRows) >= 30) {
        $first = $socRows[0];
        $last = $socRows[count($socRows) - 1];
        $elapsed = max(1, (int)$last['time'] - (int)$first['time']);
        $drop = (float)$first['soc'] - (float)$last['soc'];

        if ($elapsed >= 120 && $drop >= 0.2) {
            $dropPerSecond = $drop / $elapsed;
            $seconds = (int)round($percent / $dropPerSecond);

            return [
                'display' => human_remaining_seconds($seconds),
                'seconds' => $seconds,
                'source' => 'soc_trend',
                'avg_watts' => $avgWatts === null ? null : round($avgWatts, 3),
            ];
        }
    }

    return [
        'display' => '-',
        'seconds' => null,
        'source' => BATTERY_CAPACITY_WH > 0 ? 'avg_watts_missing' : 'battery_capacity_missing',
        'avg_watts' => $avgWatts === null ? null : round($avgWatts, 3),
    ];
}

function add_battery_remaining_history(array $history): array
{
    $wattWindow = [];

    foreach ($history as $index => $row) {
        $watts = $row['cpu_watts'] ?? null;
        if ($watts !== null && $watts !== '' && is_numeric($watts) && (float)$watts > 0) {
            $wattWindow[] = (float)$watts;
            if (count($wattWindow) > 90) {
                array_shift($wattWindow);
            }
        }

        $percent = $row['battery_percent'] ?? null;
        $avgWatts = $wattWindow === []
            ? null
            : array_sum($wattWindow) / count($wattWindow);

        $history[$index]['battery_remaining_seconds'] = null;
        if (BATTERY_CAPACITY_WH > 0 && $avgWatts !== null && $avgWatts > 0 && is_numeric($percent)) {
            $safePercent = max(0.0, min(100.0, (float)$percent));
            $remainingWh = BATTERY_CAPACITY_WH * ($safePercent / 100);
            $history[$index]['battery_remaining_seconds'] = (int)round(($remainingWh / $avgWatts) * 3600);
        }
    }

    return $history;
}

function process_service_name(int $pid): string
{
    $cgroup = @file('/proc/' . $pid . '/cgroup', FILE_IGNORE_NEW_LINES) ?: [];

    foreach ($cgroup as $line) {
        if (preg_match('/([^\/:]+\.service)(?:\/|$)/', $line, $m)) {
            return $m[1];
        }
    }

    return 'N/A';
}

function process_args(int $pid): string
{
    $raw = @file_get_contents('/proc/' . $pid . '/cmdline');

    if (is_string($raw) && $raw !== '') {
        return command_short(str_replace("\0", ' ', trim($raw, "\0")));
    }

    $comm = trim((string)@file_get_contents('/proc/' . $pid . '/comm'));

    return $comm !== '' ? $comm : 'N/A';
}

function process_resource_data(int $limit = 6): array
{
    $limit = max(3, min(12, $limit));

    $ps = sh([
        '/bin/ps',
        '-eo',
        'pid=,ppid=,user=,pcpu=,pmem=,rss=,comm=,args=',
        '--sort=-pcpu',
    ], false, 4)['out'];

    $cpu = [];
    $mem = [];

    foreach (preg_split('/\R/', trim($ps)) ?: [] as $line) {
        $line = trim($line);

        if ($line === '') {
            continue;
        }

        $parts = preg_split('/\s+/', $line, 8);

        if (count($parts) < 8 || !ctype_digit($parts[0])) {
            continue;
        }

        $pid = (int)$parts[0];
        $row = [
            'pid' => $pid,
            'ppid' => (int)$parts[1],
            'user' => $parts[2],
            'cpu_percent' => round((float)$parts[3], 1),
            'mem_percent' => round((float)$parts[4], 1),
            'rss_mb' => round(((int)$parts[5]) / 1024, 1),
            'name' => $parts[6],
            'service' => process_service_name($pid),
            'command' => command_short($parts[7]),
        ];

        if ($row['cpu_percent'] > 0 || count($cpu) < $limit) {
            $cpu[] = $row;
        }

        $mem[] = $row;
    }

    usort($mem, fn($a, $b) => ($b['mem_percent'] <=> $a['mem_percent']) ?: ($b['rss_mb'] <=> $a['rss_mb']));

    return [
        'cpu' => array_slice($cpu, 0, $limit),
        'memory' => array_slice($mem, 0, $limit),
    ];
}

function notice_process_signature(array $processes): string
{
    $cpu = null;
    foreach (($processes['cpu'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $command = (string)($row['command'] ?? $row['name'] ?? '');
        $service = (string)($row['service'] ?? '');
        if (
            str_contains($command, '/bin/ps')
            || str_contains($command, 'api.php')
            || str_contains($command, 'php-fpm')
            || $service === 'fanpanel-apply.service'
        ) {
            continue;
        }

        $cpu = $row;
        break;
    }

    $mem = null;
    foreach (($processes['memory'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $mem = $row;
        break;
    }

    return hash('sha256', json_encode([
        'cpu' => $cpu === null ? null : [
            'pid' => $cpu['pid'] ?? null,
            'service' => $cpu['service'] ?? null,
            'command' => $cpu['command'] ?? $cpu['name'] ?? null,
        ],
        'mem' => $mem === null ? null : [
            'pid' => $mem['pid'] ?? null,
            'service' => $mem['service'] ?? null,
            'command' => $mem['command'] ?? $mem['name'] ?? null,
        ],
    ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
}

function trimmed_average(array $values, float $fallback): float
{
    $values = array_values(array_filter(
        $values,
        fn($value) => is_numeric($value) && (float)$value > 0
    ));

    if (count($values) < 5) {
        return $fallback;
    }

    sort($values, SORT_NUMERIC);
    $trim = (int)floor(count($values) * 0.1);
    if ($trim > 0 && count($values) > $trim * 2) {
        $values = array_slice($values, $trim, count($values) - ($trim * 2));
    }

    return array_sum($values) / max(1, count($values));
}

function notice_rolling_baseline(array $history, float $temp, float $rpm, float $pwm, array $state = []): array
{
    $rows = array_slice($history, -180);
    if (count($rows) > 3) {
        $rows = array_slice($rows, 0, -3);
    }

    $temps = [];
    $rpms = [];
    $pwms = [];

    foreach ($rows as $row) {
        $rowTemp = (float)($row['temp_c'] ?? 0);
        $rowRpm = (float)($row['fan_rpm'] ?? 0);
        $rowPwm = (float)($row['fan_pwm'] ?? 0);

        if ($rowTemp > 0) $temps[] = $rowTemp;
        if ($rowRpm > 0) $rpms[] = $rowRpm;
        if ($rowPwm > 0) $pwms[] = $rowPwm;
    }

    $fallbackTemp = (float)($state['baseline_temp'] ?? 0) > 0 ? (float)$state['baseline_temp'] : $temp;
    $fallbackRpm = (float)($state['baseline_rpm'] ?? 0) > 0 ? (float)$state['baseline_rpm'] : $rpm;
    $fallbackPwm = (float)($state['baseline_pwm'] ?? 0) > 0 ? (float)$state['baseline_pwm'] : $pwm;

    return [
        'temp' => trimmed_average($temps, $fallbackTemp),
        'rpm' => trimmed_average($rpms, $fallbackRpm),
        'pwm' => trimmed_average($pwms, $fallbackPwm),
        'samples' => count($rows),
    ];
}

function fan_spike_analysis(array $history, array $fan, array $system, array $processes = []): array
{
    $rpm = (float)($fan['rpm'] ?? 0);
    $pwm = (float)($fan['pwm'] ?? 0);
    $temp = (float)($system['temp_c'] ?? 0);
    $state = system_notice_state();
    $rollingBaseline = notice_rolling_baseline($history, $temp, $rpm, $pwm, $state);

    $currentState = (string)($state['state'] ?? 'normal');
    if (!in_array($currentState, ['normal', 'alert'], true)) {
        $currentState = 'normal';
    }

    $bootEpoch = (int)(time() - max(0, (int)($system['uptime_seconds'] ?? 0)));
    $alertStartedEpoch = strtotime((string)($state['alert_started_at'] ?? '')) ?: 0;
    if ($currentState === 'alert' && $bootEpoch > 0 && ($alertStartedEpoch === 0 || $alertStartedEpoch < $bootEpoch)) {
        $currentState = 'normal';
    }

    $rpmAvg = $currentState === 'alert' ? (float)($state['baseline_rpm'] ?? 0) : (float)$rollingBaseline['rpm'];
    $pwmAvg = $currentState === 'alert' ? (float)($state['baseline_pwm'] ?? 0) : (float)$rollingBaseline['pwm'];
    $tempAvg = $currentState === 'alert' ? (float)($state['baseline_temp'] ?? 0) : (float)$rollingBaseline['temp'];

    if ($rpmAvg <= 0) $rpmAvg = $rpm;
    if ($pwmAvg <= 0) $pwmAvg = $pwm;
    if ($tempAvg <= 0) $tempAvg = $temp;

    $rpmDelta = $rpm - $rpmAvg;
    $pwmDelta = $pwm - $pwmAvg;
    $tempDelta = $temp - $tempAvg;
    $rollingRpmDelta = $rpm - (float)$rollingBaseline['rpm'];
    $rollingTempDelta = $temp - (float)$rollingBaseline['temp'];

    $mode = (string)($fan['mode'] ?? '');
    if ($mode === 'off') {
        $offBaselineReason = 'fan_off_baseline';
        $hasOffBaseline = (string)($state['active_reason'] ?? '') === $offBaselineReason;

        $tempAvg = $hasOffBaseline && (float)($state['baseline_temp'] ?? 0) > 0
            ? (float)$state['baseline_temp']
            : $temp;
        $rpmAvg = $hasOffBaseline && (float)($state['baseline_rpm'] ?? 0) >= 0
            ? (float)$state['baseline_rpm']
            : $rpm;
        $pwmAvg = $hasOffBaseline && (float)($state['baseline_pwm'] ?? 0) >= 0
            ? (float)$state['baseline_pwm']
            : $pwm;

        if (!$hasOffBaseline) {
            save_system_notice_state('normal', $tempAvg, $rpmAvg, $pwmAvg, $offBaselineReason);
        }

        return [
            'active' => false,
            'summary' => 'Fan off baseline is fixed.',
            'rpm_delta' => round($rpm - $rpmAvg, 1),
            'pwm_delta' => round($pwm - $pwmAvg, 1),
            'temp_delta' => round($temp - $tempAvg, 1),
            'rpm_avg' => round($rpmAvg, 1),
            'pwm_avg' => round($pwmAvg, 1),
            'temp_avg' => round($tempAvg, 1),
            'notice_state' => 'normal',
            'baseline_source' => 'frozen_off',
            'baseline_samples' => (int)$rollingBaseline['samples'],
        ];
    }

    $rpmExpected = $mode !== 'off' && ($pwm >= 20 || $pwmAvg >= 20);

    $reasons = [];
    if ($rpmExpected && abs($rpmDelta) >= 1000) $reasons[] = 'RPM ' . signed_delta_text($rpmDelta);
    if (abs($tempDelta) >= 3.0) $reasons[] = 'TEMP ' . signed_delta_text($tempDelta, 'C');

    $spiking = false;

    if ($currentState === 'normal') {
        $spiking = $reasons !== [];
        if ($spiking) {
            save_system_notice_state(
                'alert',
                $tempAvg,
                $rpmAvg,
                $pwmAvg,
                implode(', ', $reasons),
                true,
                $tempDelta,
                $rpmDelta,
                notice_process_signature($processes)
            );
        } else {
            save_system_notice_state('normal', $rollingBaseline['temp'], $rollingBaseline['rpm'], $rollingBaseline['pwm']);
        }
    } else {
        $recovered = (abs($rpmDelta) <= 500 && abs($tempDelta) <= 1.5)
            || (abs($rollingRpmDelta) <= 500 && abs($rollingTempDelta) <= 1.5);
        if ($recovered || $reasons === []) {
            $currentState = 'normal';
            save_system_notice_state('normal', $rollingBaseline['temp'], $rollingBaseline['rpm'], $rollingBaseline['pwm']);
            $tempAvg = (float)$rollingBaseline['temp'];
            $rpmAvg = (float)$rollingBaseline['rpm'];
            $pwmAvg = (float)$rollingBaseline['pwm'];
            $rpmDelta = $rpm - $rpmAvg;
            $pwmDelta = $pwm - $pwmAvg;
            $tempDelta = $temp - $tempAvg;
        } else {
            save_system_notice_state(
                'alert',
                $tempAvg,
                $rpmAvg,
                $pwmAvg,
                implode(', ', $reasons),
                false,
                $tempDelta,
                $rpmDelta,
                notice_process_signature($processes)
            );
        }
    }

    $summary = 'No system notice detected in recent samples.';
    if ($spiking) {
        $summary = 'System notice: ' . implode(', ', $reasons);
    } elseif ($currentState === 'alert' && $reasons !== []) {
        $summary = 'System notice active: ' . implode(', ', $reasons);
    }

    return [
        'active' => $spiking,
        'summary' => $summary,
        'rpm_delta' => round($rpmDelta, 1),
        'pwm_delta' => round($pwmDelta, 1),
        'temp_delta' => round($tempDelta, 1),
        'rpm_avg' => round($rpmAvg, 1),
        'pwm_avg' => round($pwmAvg, 1),
        'temp_avg' => round($tempAvg, 1),
        'notice_state' => $spiking ? 'alert' : $currentState,
        'baseline_source' => $currentState === 'alert' ? 'frozen_alert' : 'rolling',
        'baseline_samples' => (int)$rollingBaseline['samples'],
    ];
}

function system_notice_state(): array
{
    $stmt = db()->query("
        SELECT
            state,
            baseline_temp,
            baseline_rpm,
            baseline_pwm,
            active_reason,
            active_temp_delta,
            active_rpm_delta,
            process_signature,
            alert_started_at,
            last_alert_at,
            updated_at
        FROM system_notice_state
        WHERE id = 1
        LIMIT 1
    ");

    return $stmt->fetch() ?: [];
}

function save_system_notice_state(
    string $state,
    float $baselineTemp,
    float $baselineRpm,
    float $baselinePwm,
    ?string $reason = null,
    bool $alertStarted = false,
    float $activeTempDelta = 0.0,
    float $activeRpmDelta = 0.0,
    ?string $processSignature = null
): void {
    $stmt = db()->prepare("
        INSERT INTO system_notice_state (
            id,
            state,
            baseline_temp,
            baseline_rpm,
            baseline_pwm,
            active_reason,
            active_temp_delta,
            active_rpm_delta,
            process_signature,
            alert_started_at,
            last_alert_at
        ) VALUES (
            1,
            :state,
            :baseline_temp,
            :baseline_rpm,
            :baseline_pwm,
            :active_reason,
            :active_temp_delta,
            :active_rpm_delta,
            :process_signature,
            IF(:alert_started = 1, CURRENT_TIMESTAMP, NULL),
            IF(:alert_started_last = 1, CURRENT_TIMESTAMP, NULL)
        )
        ON DUPLICATE KEY UPDATE
            state = VALUES(state),
            baseline_temp = VALUES(baseline_temp),
            baseline_rpm = VALUES(baseline_rpm),
            baseline_pwm = VALUES(baseline_pwm),
            active_reason = VALUES(active_reason),
            active_temp_delta = VALUES(active_temp_delta),
            active_rpm_delta = VALUES(active_rpm_delta),
            process_signature = VALUES(process_signature),
            alert_started_at = IF(:alert_started_update = 1, CURRENT_TIMESTAMP, alert_started_at),
            last_alert_at = IF(:alert_started_last_update = 1, CURRENT_TIMESTAMP, last_alert_at),
            updated_at = CURRENT_TIMESTAMP
    ");

    $stmt->execute([
        ':state' => in_array($state, ['normal', 'alert'], true) ? $state : 'normal',
        ':baseline_temp' => round($baselineTemp, 2),
        ':baseline_rpm' => round($baselineRpm, 2),
        ':baseline_pwm' => round($baselinePwm, 2),
        ':active_reason' => $reason,
        ':active_temp_delta' => round($activeTempDelta, 2),
        ':active_rpm_delta' => round($activeRpmDelta, 2),
        ':process_signature' => $processSignature,
        ':alert_started' => $alertStarted ? 1 : 0,
        ':alert_started_last' => $alertStarted ? 1 : 0,
        ':alert_started_update' => $alertStarted ? 1 : 0,
        ':alert_started_last_update' => $alertStarted ? 1 : 0,
    ]);
}

function add_fan_spike_log(array $spike, array $fan, array $system, array $processes): int
{
    $summary = (string)($spike['summary'] ?? '');
    $rpmDelta = round((float)($spike['rpm_delta'] ?? 0), 1);
    $pwmDelta = round((float)($spike['pwm_delta'] ?? 0), 1);
    $tempDelta = round((float)($spike['temp_delta'] ?? 0), 1);
    $spikeKey = 'fan:' . date('YmdHi');
    $loggedProcesses = notice_downward_only($tempDelta, $rpmDelta)
        ? ['cpu' => [], 'memory' => []]
        : $processes;

    $stmt = db()->prepare("
        INSERT IGNORE INTO fan_spike_logs (
            spike_key,
            summary,
            rpm_delta,
            pwm_delta,
            temp_delta,
            current_rpm,
            current_pwm,
            current_temp,
            cpu_process,
            memory_process
        ) VALUES (
            :spike_key,
            :summary,
            :rpm_delta,
            :pwm_delta,
            :temp_delta,
            :current_rpm,
            :current_pwm,
            :current_temp,
            :cpu_process,
            :memory_process
        )
    ");

    $stmt->execute([
        ':spike_key' => $spikeKey,
        ':summary' => $summary !== '' ? $summary : null,
        ':rpm_delta' => $rpmDelta,
        ':pwm_delta' => $pwmDelta,
        ':temp_delta' => $tempDelta,
        ':current_rpm' => $fan['rpm'] ?? null,
        ':current_pwm' => $fan['pwm'] ?? null,
        ':current_temp' => $system['temp_c'] ?? null,
        ':cpu_process' => json_encode($loggedProcesses['cpu'] ?? [], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES),
        ':memory_process' => json_encode($loggedProcesses['memory'] ?? [], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES),
    ]);

    if ($stmt->rowCount() <= 0) {
        return 0;
    }

    return (int)db()->lastInsertId();
}

function signed_delta_text(float $value, string $suffix = ''): string
{
    $sign = $value >= 0 ? '+' : '';

    return $sign . number_format($value, 1) . $suffix;
}

function signed_delta_compact(float $value, int $decimals, string $suffix = ''): string
{
    $sign = $value >= 0 ? '+' : '';

    return $sign . number_format($value, $decimals) . $suffix;
}

function push_process_name(array $row): string
{
    $service = (string)($row['service'] ?? '');
    if ($service !== '' && $service !== 'N/A') {
        return $service;
    }

    $command = (string)($row['command'] ?? $row['name'] ?? '');

    if (
        str_contains($command, '/codex ')
        || str_contains($command, '/codex')
        || str_contains($command, 'codex app-server')
    ) {
        return 'codex';
    }

    if (str_contains($command, '.vscode-server')) {
        return 'vscode-server';
    }

    if (str_contains($command, 'python3 -m homeassistant')) {
        return 'homeassistant';
    }

    if (str_contains($command, 'firefox')) {
        return 'firefox';
    }

    if ($command === '') {
        $command = (string)($row['name'] ?? '');
    }

    return $command !== '' ? $command : 'N/A';
}

function process_identity(array $row): string
{
    return implode('|', [
        (string)($row['pid'] ?? ''),
        (string)($row['service'] ?? ''),
        (string)($row['command'] ?? $row['name'] ?? ''),
    ]);
}

function expected_process_text(array $processes): string
{
    $cpu = null;
    foreach (($processes['cpu'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $command = (string)($row['command'] ?? $row['name'] ?? '');
        $service = (string)($row['service'] ?? '');
        if (
            str_contains($command, '/bin/ps')
            || str_contains($command, 'api.php')
            || str_contains($command, 'php-fpm')
            || $service === 'fanpanel-apply.service'
        ) {
            continue;
        }

        $cpu = $row;
        break;
    }

    if ($cpu !== null && (float)($cpu['cpu_percent'] ?? 0) >= 1.0) {
        return 'CPU ' . push_process_name($cpu);
    }

    $mem = null;
    foreach (($processes['memory'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $mem = $row;
        break;
    }

    if ($mem !== null) {
        return 'MEM ' . push_process_name($mem);
    }

    return 'CPU/MEM 원인 후보 없음';
}

function expected_process_detail_text(array $processes): string
{
    $cpu = null;
    foreach (($processes['cpu'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $command = (string)($row['command'] ?? $row['name'] ?? '');
        $service = (string)($row['service'] ?? '');
        if (
            str_contains($command, '/bin/ps')
            || str_contains($command, 'api.php')
            || str_contains($command, 'php-fpm')
            || $service === 'fanpanel-apply.service'
        ) {
            continue;
        }

        $cpu = $row;
        break;
    }

    $mem = null;
    foreach (($processes['memory'] ?? []) as $row) {
        if (!is_array($row)) {
            continue;
        }

        $mem = $row;
        break;
    }

    if ($cpu !== null && $mem !== null && process_identity($mem) === process_identity($cpu)) {
        return push_process_name($cpu);
    }

    $parts = [];

    if ($cpu !== null) {
        $parts[] = sprintf('CPU %.1f%% %s', (float)($cpu['cpu_percent'] ?? 0), push_process_name($cpu));
    }

    if ($mem !== null) {
        $parts[] = sprintf('RAM %.1f%% %s', (float)($mem['mem_percent'] ?? 0), push_process_name($mem));
    }

    return $parts === [] ? '원인 후보 없음' : implode(' / ', $parts);
}

function delta_state_text(float $value): string
{
    return $value >= 0 ? '높음' : '낮음';
}

function notice_downward_only(float $tempDelta, float $rpmDelta): bool
{
    $tempTriggered = abs($tempDelta) >= 3.0;
    $rpmTriggered = abs($rpmDelta) >= 1000;

    if (!$tempTriggered && !$rpmTriggered) {
        return false;
    }

    if ($tempTriggered && $tempDelta >= 0) {
        return false;
    }

    if ($rpmTriggered && $rpmDelta >= 0) {
        return false;
    }

    return true;
}

function send_fan_spike_push(array $spike, array $fan, array $system, array $processes): array
{
    $tempDelta = (float)($spike['temp_delta'] ?? 0);
    $rpmDelta = (float)($spike['rpm_delta'] ?? 0);
    $tempAvg = (float)($spike['temp_avg'] ?? 0);
    $rpmAvg = (float)($spike['rpm_avg'] ?? 0);
    $pwmAvg = (float)($spike['pwm_avg'] ?? 0);
    $reasons = [];

    if (abs($tempDelta) >= 3.0) {
        $reasons[] = '온도 평균보다 ' . ($tempDelta >= 0 ? '상승' : '하강');
    }

    if (abs($rpmDelta) >= 1000) {
        $reasons[] = '팬RPM 평균보다 ' . ($rpmDelta >= 0 ? '상승' : '하강');
    }

    if ($reasons === []) {
        $reasons[] = '순간 변화';
    }

    $body = '기록된 이유: '
        . implode(', ', $reasons)
        . "\n평균: "
        . number_format($tempAvg, 1)
        . '°C / '
        . number_format($rpmAvg, 0)
        . ' RPM / PWM '
        . number_format($pwmAvg, 0)
        . "\n현재: "
        . number_format((float)($system['temp_c'] ?? 0), 1)
        . '°C / '
        . number_format((float)($fan['rpm'] ?? 0), 0)
        . ' RPM / PWM '
        . number_format((float)($fan['pwm'] ?? 0), 0)
        . (notice_downward_only($tempDelta, $rpmDelta) ? '' : "\n원인 후보: " . expected_process_detail_text($processes));

    return send_push_payload([
        'title' => '시스템 유의사항',
        'body' => $body,
        'url' => '/',
        'tag' => 'system-notice-' . date('YmdHi'),
        'created_at' => date('Y-m-d H:i:s'),
        'data' => [
            'summary' => $spike['summary'] ?? '',
            'rpm_delta' => $spike['rpm_delta'] ?? 0,
            'pwm_delta' => $spike['pwm_delta'] ?? 0,
            'temp_delta' => $spike['temp_delta'] ?? 0,
            'expected_process' => expected_process_text($processes),
        ],
    ]);
}

function latest_system_notice_push_epoch(): int
{
    $stmt = db()->query("
        SELECT UNIX_TIMESTAMP(MAX(created_at))
        FROM push_event_logs
        WHERE event = 'send_success'
          AND meta LIKE '%\"tag\":\"system-notice-%'
    ");

    return (int)($stmt->fetchColumn() ?: 0);
}

function fan_spike_history(int $limit = 100): array
{
    $limit = max(1, min(500, $limit));

    $stmt = db()->query("
        SELECT
            id,
            created_at,
            summary,
            rpm_delta,
            pwm_delta,
            temp_delta,
            current_rpm,
            current_pwm,
            current_temp,
            cpu_process,
            memory_process
        FROM fan_spike_logs
        WHERE id IN (
            SELECT MAX(id)
            FROM fan_spike_logs
            GROUP BY DATE_FORMAT(created_at, '%Y-%m-%d %H:%i')
        )
        ORDER BY id DESC
        LIMIT {$limit}
    ");

    $rows = $stmt->fetchAll();

    foreach ($rows as &$row) {
        $row['cpu_process'] = json_decode((string)($row['cpu_process'] ?? '[]'), true) ?: [];
        $row['memory_process'] = json_decode((string)($row['memory_process'] ?? '[]'), true) ?: [];
    }

    unset($row);

    return $rows;
}

function dnsmasq_leases(): array
{
    $map = [];

    foreach (@file('/var/lib/misc/dnsmasq.leases', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES) ?: [] as $line) {
        $p = preg_split('/\s+/', trim($line));

        if (count($p) >= 4) {
            $mac = strtolower($p[1]);

            $map[$mac] = [
                'expire_ts' => (int)$p[0],
                'mac' => $mac,
                'ip' => $p[2],
                'hostname' => $p[3] === '*' ? 'N/A' : $p[3],
            ];
        }
    }

    return $map;
}

function iw_station_dump(string $iface): string
{
    if (!preg_match('/^[A-Za-z0-9_.:-]+$/', $iface)) {
        return '';
    }

    return sh(['/usr/sbin/iw', 'dev', $iface, 'station', 'dump'], true, 4)['out'];
}

function parse_live_wifi_rows(string $iface, string $band, string $text, array $leases): array
{
    $rows = [];
    $cur = null;

    foreach (explode("\n", $text) as $line) {
        $t = trim($line);

        if (preg_match('/^Station\s+([0-9a-f:]+)/i', $t, $m)) {
            if ($cur !== null) {
                $rows[] = $cur;
            }

            $mac = strtolower($m[1]);
            $lease = $leases[$mac] ?? [];
            $cur = [
                'band' => $band,
                'iface' => $iface,
                'mac' => $mac,
                'ip' => $lease['ip'] ?? 'N/A',
                'hostname' => $lease['hostname'] ?? 'N/A',
                'name' => $lease['hostname'] ?? $mac,
                'signal' => 'N/A',
                'tx_bitrate' => 'N/A',
                'rx_bitrate' => 'N/A',
                'connected_time' => 'N/A',
                'inactive_time' => 'N/A',
                'rx_bytes' => 0,
                'tx_bytes' => 0,
                'rx_packets' => 0,
                'tx_packets' => 0,
                'tx_failed' => 0,
            ];
            continue;
        }

        if ($cur === null) {
            continue;
        }

        if (preg_match('/^signal:\s+(.+)/', $t, $m)) $cur['signal'] = $m[1];
        elseif (preg_match('/^tx bitrate:\s+(.+)/', $t, $m)) $cur['tx_bitrate'] = $m[1];
        elseif (preg_match('/^rx bitrate:\s+(.+)/', $t, $m)) $cur['rx_bitrate'] = $m[1];
        elseif (preg_match('/^connected time:\s+(.+)/', $t, $m)) $cur['connected_time'] = $m[1];
        elseif (preg_match('/^inactive time:\s+(.+)/', $t, $m)) $cur['inactive_time'] = $m[1];
        elseif (preg_match('/^rx bytes:\s+(\d+)/', $t, $m)) $cur['rx_bytes'] = (int)$m[1];
        elseif (preg_match('/^tx bytes:\s+(\d+)/', $t, $m)) $cur['tx_bytes'] = (int)$m[1];
        elseif (preg_match('/^rx packets:\s+(\d+)/', $t, $m)) $cur['rx_packets'] = (int)$m[1];
        elseif (preg_match('/^tx packets:\s+(\d+)/', $t, $m)) $cur['tx_packets'] = (int)$m[1];
        elseif (preg_match('/^tx failed:\s+(\d+)/', $t, $m)) $cur['tx_failed'] = (int)$m[1];
    }

    if ($cur !== null) {
        $rows[] = $cur;
    }

    return $rows;
}

function wifi_time_ms(string $value): int
{
    if (preg_match('/(\d+)/', $value, $m)) {
        return (int)$m[1];
    }

    return PHP_INT_MAX;
}

function wifi_signal_dbm(string $value): int
{
    if (preg_match('/-?\d+/', $value, $m)) {
        return (int)$m[0];
    }

    return -999;
}

function dedupe_wifi_clients(array $clients): array
{
    $deduped = [];

    foreach ($clients as $client) {
        $mac = strtolower((string)($client['mac'] ?? ''));
        $key = $mac !== '' && $mac !== 'n/a'
            ? 'mac:' . $mac
            : 'row:' . ($client['band'] ?? '') . ':' . ($client['ip'] ?? '') . ':' . ($client['hostname'] ?? '');

        if (!isset($deduped[$key])) {
            $deduped[$key] = $client;
            continue;
        }

        $currentInactive = wifi_time_ms((string)($deduped[$key]['inactive_time'] ?? ''));
        $nextInactive = wifi_time_ms((string)($client['inactive_time'] ?? ''));
        $currentSignal = wifi_signal_dbm((string)($deduped[$key]['signal'] ?? ''));
        $nextSignal = wifi_signal_dbm((string)($client['signal'] ?? ''));

        if ($nextInactive < $currentInactive || ($nextInactive === $currentInactive && $nextSignal > $currentSignal)) {
            $deduped[$key] = $client;
        }
    }

    return array_values($deduped);
}

function wifi_data(): array
{
    $leases = dnsmasq_leases();
    $clients = [];

    foreach (['wlan0' => '2.4G', 'wlan1' => '5G'] as $iface => $band) {
        $clients = array_merge(
            $clients,
            parse_live_wifi_rows($iface, $band, iw_station_dump($iface), $leases)
        );
    }

    $clients = dedupe_wifi_clients($clients);

    return [
        'clients' => $clients,
        'count24' => count(array_filter($clients, fn($c) => $c['band'] === '2.4G')),
        'count5' => count(array_filter($clients, fn($c) => $c['band'] === '5G')),
        'leases' => array_values($leases),
    ];
}

function action_rows(int $limit = 80): array
{
    $limit = max(1, min(300, $limit));

    $stmt = db()->query("
        SELECT
            created_at AS ts,
            action_type AS action,
            CONCAT(
                action_type,
                IF(pwm_mode IS NULL, '', CONCAT(' ', pwm_mode)),
                IF(pwm_value IS NULL, '', CONCAT(' pwm ', pwm_value)),
                IF(note IS NULL OR note = '', '', CONCAT(' / ', note))
            ) AS message,
            success,
            actor_ip
        FROM fan_actions
        ORDER BY id DESC
        LIMIT {$limit}
    ");

    return $stmt->fetchAll();
}

function collect_snapshot(bool $applyFan = true): array
{
    if ($applyFan) {
        $policy = apply_fan_policy();
    } else {
        $state = get_control_state();
        $policy = [
            'mode' => (string)($state['mode'] ?? 'auto'),
            'target_pwm' => (int)($state['manual_pwm'] ?? 120),
            'actual_pwm' => 0,
            'temp_c' => 0.0,
            'rpm' => 0,
            'ok' => true,
            'paths' => [],
            'enable_value' => 'N/A',
        ];
    }

    $latest = latest_sensor();

    $pwm = isset($latest['pwm_value']) ? (int)$latest['pwm_value'] : 0;
    if ($latest === false || $latest === [] || !isset($latest['pwm_value'])) {
        $pwm = (int)$policy['actual_pwm'];
    }

    $rpm = (int)($latest['fan_rpm'] ?? 0);
    if ($rpm <= 0) {
        $rpm = (int)$policy['rpm'];
    }

    $temp = (float)($latest['cpu_temp_c'] ?? 0);
    if ($temp <= 0) {
        $temp = (float)$policy['temp_c'];
    }

    $load = sys_getloadavg() ?: [0, 0, 0];
    $mem = mem_info();
    $disk = disk_info('/');
    $os = os_info();
    $cpuPower = $applyFan ? cpu_power_status() : [
        'voltage' => isset($latest['cpu_voltage']) ? (float)$latest['cpu_voltage'] : null,
        'watts' => isset($latest['cpu_watts']) ? (float)$latest['cpu_watts'] : null,
    ];
    $battery = $applyFan ? battery_status() : [
        'voltage' => isset($latest['battery_voltage']) ? (float)$latest['battery_voltage'] : null,
        'percent' => isset($latest['battery_percent']) ? (float)$latest['battery_percent'] : null,
    ];

    if ($applyFan) {
        add_sensor_log([
            'cpu_temp_c' => $temp,
            'fan_rpm' => $rpm,
            'fan_efficiency' => fan_efficiency($rpm, $temp, $cpuPower['watts'] ?? null),
            'rp1_temp_c' => rp1_temp_c(),
            'cpu_voltage' => $cpuPower['voltage'],
            'cpu_watts' => $cpuPower['watts'],
            'battery_voltage' => $battery['voltage'],
            'battery_percent' => $battery['percent'],
            'pwm_value' => $pwm,
            'pwm_percent' => round($pwm / 255 * 100, 2),
            'pwm_mode' => $policy['mode'],
            'cpu_load_1' => round((float)$load[0], 2),
            'cpu_load_5' => round((float)$load[1], 2),
            'cpu_load_15' => round((float)$load[2], 2),
            'mem_total_mb' => $mem['total_mb'],
            'mem_used_mb' => $mem['used_mb'],
            'mem_free_mb' => $mem['free_mb'],
            'disk_total_kb' => $disk['total_kb'],
            'disk_used_kb' => $disk['used_kb'],
            'disk_free_kb' => $disk['free_kb'],
            'uptime_seconds' => $os['uptime_seconds'],
            'hostname' => $os['hostname'],
        ]);
    }

    $fan = [
        'mode' => $policy['mode'],
        'pwm' => $pwm,
        'percent' => round($pwm / 255 * 100, 1),
        'rpm' => $rpm,
        'enable' => $policy['enable_value'],
        'target_pwm' => $policy['target_pwm'],
        'policy_ok' => $policy['ok'],
        'paths' => $policy['paths'],
    ];

    $system = array_merge($os, [
        'temp_c' => $temp,
        'load' => [
            round((float)$load[0], 2),
            round((float)$load[1], 2),
            round((float)$load[2], 2),
        ],
        'active_users' => active_user_info(),
        'memory' => $mem,
        'disk' => $disk,
    ]);

    $history = add_battery_remaining_history(sensor_history(240));
    $battery['remaining'] = battery_remaining_estimate($battery, $history);

    $processes = process_resource_data(6);
    $fanSpike = fan_spike_analysis($history, $fan, $system, $processes);

    if (!empty($fanSpike['active'])) {
        $latestNoticePush = latest_system_notice_push_epoch();
        $spikeLogId = add_fan_spike_log($fanSpike, $fan, $system, $processes);
        if ($spikeLogId > 0) {
            $fanSpike['log_id'] = $spikeLogId;
            if ($latestNoticePush <= 0 || time() - $latestNoticePush >= 600) {
                $fanSpike['push'] = send_fan_spike_push($fanSpike, $fan, $system, $processes);
            } else {
                $fanSpike['push'] = [
                    'sent' => 0,
                    'failed' => 0,
                    'skipped' => 'system_notice_cooldown',
                    'cooldown_seconds' => 600,
                ];
            }
        }
    }

    $snapshot = [
        'ok' => true,
        'generated_at' => date('Y-m-d H:i:s'),
        'time_ms' => (int)round(microtime(true) * 1000),

        'fan' => $fan,
        'system' => $system,
        'battery' => $battery,

        'wifi' => wifi_data(),
        'history' => $history,
        'processes' => $processes,
        'fan_spike' => $fanSpike,
        'fan_spike_history' => fan_spike_history(100),
    ];

    return $snapshot;
}

function control_api_dispatch(): void
{
    $action = $_GET['action'] ?? $_POST['action'] ?? 'status';

    if (($_SERVER['REQUEST_METHOD'] ?? 'GET') === 'POST') {
        require_csrf();
    }

    try {
        if ($action === 'dmesg') {
            json_out([
                'ok' => true,
                'data' => dmesg_log(),
            ]);
        }

        if ($action === 'status') {
            json_out([
                'ok' => true,
                'data' => collect_snapshot(false),
            ]);
        }

        if ($action === 'push_devices') {
            json_out([
                'ok' => true,
                'data' => [
                    'devices' => push_device_rows(),
                ],
            ]);
        }

        if ($action === 'push_status') {
            json_out([
                'ok' => true,
                'data' => push_subscription_status((string)($_GET['endpoint'] ?? $_POST['endpoint'] ?? '')),
            ]);
        }

        if ($action === 'delete_push_device') {
            delete_push_device((string)($_POST['endpoint_hash'] ?? ''));

            json_out([
                'ok' => true,
                'data' => [
                    'devices' => push_device_rows(),
                ],
            ]);
        }

        if ($action === 'delete_push_endpoint') {
            delete_push_endpoint((string)($_POST['endpoint'] ?? ''));

            json_out([
                'ok' => true,
                'data' => [
                    'devices' => push_device_rows(),
                ],
            ]);
        }

        if ($action === 'fan') {
            $mode = (string)($_POST['mode'] ?? 'auto');
            $pwm = max(0, min(255, (int)($_POST['pwm'] ?? 120)));

            if (!in_array($mode, ['auto', 'manual', 'off'], true)) {
                json_out([
                    'ok' => false,
                    'error' => 'bad_mode',
                ], 400);
            }

            set_control_state($mode, $pwm);

            add_fan_action(
                'fan_set',
                $mode,
                $pwm,
                'web fan control',
                true
            );

            $data = collect_snapshot(true);

            json_out([
                'ok' => true,
                'data' => $data,
            ]);
        }

        if ($action === 'wifi') {
            $verb = (string)($_POST['verb'] ?? '');
            $unit = (string)($_POST['unit'] ?? '');
            $allowedUnits = [
                'hostapd-24g.service',
                'hostapd-5g.service',
                'dnsmasq.service',
            ];

            if (
                !in_array($unit, $allowedUnits, true)
                || !in_array($verb, ['restart', 'reload'], true)
            ) {
                json_out([
                    'ok' => false,
                    'error' => 'bad_wifi_request',
                ], 400);
            }

            $result = sh(['/usr/bin/systemctl', $verb, $unit], true, 25);
            $out = $result['out'];

            add_fan_action(
                'wifi_' . $verb,
                null,
                null,
                $unit . "\n" . mb_substr($out, 0, 1000),
                true
            );

            json_out([
                'ok' => true,
                'output' => $out,
                'data' => collect_snapshot(false),
            ]);
        }

        if ($action === 'collect') {
            json_out([
                'ok' => true,
                'data' => collect_snapshot(true),
            ]);
        }

        json_out([
            'ok' => false,
            'error' => 'unknown_action',
        ], 404);
    } catch (Throwable $e) {
        json_out([
            'ok' => false,
            'error' => 'exception',
            'message' => $e->getMessage(),
        ], 500);
    }
}

if (!$controlApiLibrary) {
    control_api_dispatch();
}