#!/usr/bin/env php
<?php
/**
 * 批量压缩 public/uploads 下的图片（支持 2G+ 大批量）
 *
 * 安全机制:
 * - 压缩结果写入临时文件，校验通过后才覆盖原文件
 * - 配合 --snapshot 先全量备份，可一键恢复
 * - 单张失败不影响其他文件，原图不会被损坏
 *
 * 用法:
 *   php deploy/compress-uploads.php --dry-run
 *   php deploy/compress-uploads.php --snapshot          # 推荐：先快照再压缩
 *   bash deploy/compress-uploads.sh --safe            # 同上（shell 用 rsync 快照更快）
 */

declare(strict_types=1);

ini_set('memory_limit', '512M');
set_time_limit(0);

const DEFAULT_MAX_WIDTH = 800;
const DEFAULT_QUALITY = 65;
const BACKUP_DIR_NAME = '.compress_backup';
const SNAPSHOTS_DIR = '.compress_backup/snapshots';
const SUPPORTED_EXT = ['jpg', 'jpeg', 'png', 'webp', 'gif'];

$options = getopt('', [
    'dry-run',
    'backup',
    'snapshot',
    'no-backup',
    'max-width:',
    'quality:',
    'path:',
    'log:',
    'help',
]);

if (isset($options['help'])) {
    echo <<<HELP
批量压缩 uploads 图片（安全模式，适合 2G+ 大批量）

选项:
  --dry-run           仅预览，不写入
  --snapshot          压缩前先做全量快照（推荐，可一键恢复）
  --backup            每张覆盖前单独备份（与 --snapshot 二选一即可）
  --no-backup         不备份（不推荐，仅测试用）
  --max-width=800     最大宽度
  --quality=65        JPEG/WebP 质量
  --path=DIR          目标目录
  --log=FILE          写入日志文件
  --help              显示帮助

推荐流程（2G 数据）:
  1. php deploy/compress-uploads.php --dry-run
  2. bash deploy/compress-uploads.sh --safe
  3. 若有异常: bash deploy/restore-uploads.sh --latest

HELP;
    exit(0);
}

$dryRun = isset($options['dry-run']);
$doSnapshot = isset($options['snapshot']);
$doBackup = isset($options['backup']) && !isset($options['no-backup']);
$maxWidth = isset($options['max-width']) ? max(1, (int) $options['max-width']) : DEFAULT_MAX_WIDTH;
$quality = isset($options['quality']) ? min(100, max(1, (int) $options['quality'])) : DEFAULT_QUALITY;
$logFile = $options['log'] ?? null;

$projectRoot = dirname(__DIR__);
$uploadsDir = isset($options['path'])
    ? rtrim($options['path'], DIRECTORY_SEPARATOR)
    : $projectRoot . DIRECTORY_SEPARATOR . 'public' . DIRECTORY_SEPARATOR . 'uploads';

if (!is_dir($uploadsDir)) {
    logLine("ERROR: 目录不存在: {$uploadsDir}", $logFile);
    exit(1);
}

if (!extension_loaded('gd')) {
    logLine('ERROR: 需要 PHP GD 扩展', $logFile);
    exit(1);
}

$backupRoot = $uploadsDir . DIRECTORY_SEPARATOR . BACKUP_DIR_NAME;
$snapshotRoot = $uploadsDir . DIRECTORY_SEPARATOR . SNAPSHOTS_DIR;

// ---------- 预检 ----------
$preflight = scanUploads($uploadsDir);
logLine("========== 预检 ==========", $logFile);
logLine("目标目录: {$uploadsDir}", $logFile);
logLine("图片数量: {$preflight['count']}  总大小: " . formatBytes($preflight['total_bytes']), $logFile);
logLine("磁盘可用: " . formatBytes(diskFreeBytes($uploadsDir)), $logFile);
logLine("最大宽度: {$maxWidth}px | 质量: {$quality}%", $logFile);

if (!$dryRun && !$doSnapshot && !$doBackup) {
    logLine('WARN: 未启用 --snapshot 或 --backup，压缩失败时无法恢复。建议加 --snapshot', $logFile);
}

if (!$dryRun && $doSnapshot) {
    $needSpace = $preflight['total_bytes'] * 1.1; // 快照 + 10% 缓冲
    $freeSpace = diskFreeBytes($uploadsDir);
    if ($freeSpace > 0 && $freeSpace < $needSpace) {
        logLine('ERROR: 磁盘空间不足。需要约 ' . formatBytes((int) $needSpace)
            . '，可用 ' . formatBytes($freeSpace), $logFile);
        logLine('请清理磁盘或使用 bash deploy/compress-uploads.sh --safe（rsync 快照到其他盘）', $logFile);
        exit(1);
    }
}

// ---------- 全量快照 ----------
$snapshotId = null;
if ($doSnapshot && !$dryRun) {
    $snapshotId = date('Ymd_His');
    $snapshotDir = $snapshotRoot . DIRECTORY_SEPARATOR . $snapshotId;
    logLine("\n========== 创建全量快照: {$snapshotId} ==========", $logFile);
    logLine("快照目录: {$snapshotDir}", $logFile);
    logLine('（约 2G 需数分钟，请耐心等待）', $logFile);

    $snapResult = createSnapshot($uploadsDir, $snapshotDir, $logFile);
    if (!$snapResult['ok']) {
        logLine('ERROR: 快照失败 - ' . $snapResult['reason'], $logFile);
        exit(1);
    }
    logLine("快照完成: {$snapResult['files']} 个文件, " . formatBytes($snapResult['bytes']), $logFile);
    writeSnapshotMeta($snapshotDir, $preflight, $maxWidth, $quality);
    logLine("恢复命令: bash deploy/restore-uploads.sh --restore={$snapshotId}", $logFile);
}

// ---------- 压缩 ----------
$stats = ['scanned' => 0, 'processed' => 0, 'skipped' => 0, 'saved_bytes' => 0, 'errors' => 0];
$startTime = microtime(true);

logLine("\n========== 开始压缩" . ($dryRun ? ' [dry-run]' : '') . " ==========", $logFile);

foreach ($preflight['files'] as $item) {
    $path = $item['path'];
    $relative = $item['relative'];
    $ext = $item['ext'];

    $stats['scanned']++;
    $result = processImage($path, $ext, $maxWidth, $quality, $dryRun, $doBackup, $uploadsDir, $backupRoot);

    switch ($result['status']) {
        case 'ok':
            $stats['processed']++;
            $stats['saved_bytes'] += $result['saved'];
            $savedKb = round($result['saved'] / 1024, 1);
            logLine("[OK] {$relative}  {$result['before_w']}x{$result['before_h']}"
                . " -> {$result['after_w']}x{$result['after_h']}"
                . '  ' . formatBytes($result['before_size']) . ' -> ' . formatBytes($result['after_size'])
                . " (-{$savedKb}KB)", $logFile);
            break;
        case 'skip':
            $stats['skipped']++;
            break;
        case 'error':
            $stats['errors']++;
            logLine("[ERR] {$relative}  {$result['reason']}", $logFile);
            break;
    }

    if ($stats['scanned'] % 100 === 0) {
        $elapsed = round(microtime(true) - $startTime);
        logLine("--- 进度 {$stats['scanned']}/{$preflight['count']} | 已用 {$elapsed}s ---", $logFile);
    }
}

$elapsed = round(microtime(true) - $startTime);
logLine("\n========== 完成 (耗时 {$elapsed}s) ==========", $logFile);
logLine("扫描: {$stats['scanned']} | 压缩: {$stats['processed']} | 跳过: {$stats['skipped']} | 失败: {$stats['errors']}", $logFile);
logLine('共节省: ' . formatBytes($stats['saved_bytes']), $logFile);

if ($snapshotId) {
    logLine("\n若需恢复全部原图:", $logFile);
    logLine("  bash deploy/restore-uploads.sh --restore={$snapshotId}", $logFile);
}

exit($stats['errors'] > 0 ? 1 : 0);

// ======================== 核心逻辑 ========================

/**
 * @return array{status:string,reason?:string,before_w?:int,before_h?:int,after_w?:int,after_h?:int,before_size?:int,after_size?:int,saved?:int}
 */
function processImage(
    string $path,
    string $ext,
    int $maxWidth,
    int $quality,
    bool $dryRun,
    bool $doBackup,
    string $uploadsDir,
    string $backupRoot
): array {
    $beforeSize = filesize($path);
    if ($beforeSize === false || $beforeSize === 0) {
        return ['status' => 'error', 'reason' => '无法读取文件'];
    }

    $info = @getimagesize($path);
    if (!$info || empty($info[0]) || empty($info[1])) {
        return ['status' => 'skip', 'reason' => '非有效图片'];
    }

    [$beforeW, $beforeH] = [$info[0], $info[1]];

    if ($ext === 'gif' && isAnimatedGif($path)) {
        return ['status' => 'skip', 'reason' => '动画 GIF'];
    }

    $image = loadImage($path, $ext);
    if ($image === null) {
        return ['status' => 'error', 'reason' => 'GD 无法加载'];
    }

    if (in_array($ext, ['jpg', 'jpeg'], true)) {
        $image = applyExifOrientation($image, $path);
        $beforeW = imagesx($image);
        $beforeH = imagesy($image);
    }

    $afterW = $beforeW;
    $afterH = $beforeH;
    $needResize = $beforeW > $maxWidth;

    if ($needResize) {
        $afterW = $maxWidth;
        $afterH = max(1, (int) round($beforeH * ($maxWidth / $beforeW)));
        $resized = imagecreatetruecolor($afterW, $afterH);
        if ($resized === false) {
            imagedestroy($image);
            return ['status' => 'error', 'reason' => '创建画布失败'];
        }
        preserveTransparency($resized, $ext);
        imagecopyresampled($resized, $image, 0, 0, 0, 0, $afterW, $afterH, $beforeW, $beforeH);
        imagedestroy($image);
        $image = $resized;
    }

    $tmpFile = $path . '.compress_tmp.' . getmypid() . '.' . mt_rand(1000, 9999);
    if (!saveImage($image, $tmpFile, $ext, $quality)) {
        imagedestroy($image);
        @unlink($tmpFile);
        return ['status' => 'error', 'reason' => '保存临时文件失败'];
    }
    imagedestroy($image);

    $validate = validateCompressedFile($tmpFile, $ext, $afterW, $afterH);
    if (!$validate['ok']) {
        @unlink($tmpFile);
        return ['status' => 'error', 'reason' => '校验失败: ' . $validate['reason']];
    }

    $afterSize = filesize($tmpFile);
    if ($afterSize === false || $afterSize === 0) {
        @unlink($tmpFile);
        return ['status' => 'error', 'reason' => '临时文件为空'];
    }

    if ($afterSize >= $beforeSize && !$needResize) {
        @unlink($tmpFile);
        return ['status' => 'skip', 'reason' => '已足够小'];
    }

    if ($dryRun) {
        @unlink($tmpFile);
        return buildOkResult($beforeW, $beforeH, $afterW, $afterH, $beforeSize, $afterSize);
    }

    // 先备份原文件，再原子替换
    if ($doBackup) {
        $relative = ltrim(str_replace($uploadsDir, '', $path), DIRECTORY_SEPARATOR);
        $backupPath = $backupRoot . DIRECTORY_SEPARATOR . 'per_file' . DIRECTORY_SEPARATOR . $relative;
        if (!backupFile($path, $backupPath)) {
            @unlink($tmpFile);
            return ['status' => 'error', 'reason' => '单文件备份失败'];
        }
    }

    if (!@rename($tmpFile, $path)) {
        @unlink($tmpFile);
        return ['status' => 'error', 'reason' => '覆盖原文件失败'];
    }
    @chmod($path, 0644);

    // 替换后再验一次，异常则从 per_file 备份恢复
    $postCheck = @getimagesize($path);
    if (!$postCheck) {
        if ($doBackup && isset($backupPath) && file_exists($backupPath)) {
            copy($backupPath, $path);
        }
        return ['status' => 'error', 'reason' => '替换后校验失败，已回滚单文件'];
    }

    return buildOkResult($beforeW, $beforeH, $afterW, $afterH, $beforeSize, $afterSize);
}

function validateCompressedFile(string $path, string $ext, int $expectW, int $expectH): array
{
    $info = @getimagesize($path);
    if (!$info || empty($info[0]) || empty($info[1])) {
        return ['ok' => false, 'reason' => 'getimagesize 失败'];
    }

    if ((int) $info[0] !== $expectW || (int) $info[1] !== $expectH) {
        return ['ok' => false, 'reason' => "尺寸不符 {$info[0]}x{$info[1]} != {$expectW}x{$expectH}"];
    }

    $img = loadImage($path, $ext);
    if ($img === null) {
        return ['ok' => false, 'reason' => 'GD 无法重新加载'];
    }
    imagedestroy($img);

    return ['ok' => true];
}

function createSnapshot(string $uploadsDir, string $snapshotDir, ?string $logFile): array
{
    if (!is_dir($snapshotDir) && !mkdir($snapshotDir, 0755, true) && !is_dir($snapshotDir)) {
        return ['ok' => false, 'reason' => '无法创建快照目录'];
    }

    $files = 0;
    $bytes = 0;
    $iterator = new RecursiveIteratorIterator(
        new RecursiveDirectoryIterator($uploadsDir, FilesystemIterator::SKIP_DOTS)
    );

    foreach ($iterator as $fileInfo) {
        /** @var SplFileInfo $fileInfo */
        if (!$fileInfo->isFile()) {
            continue;
        }
        $src = $fileInfo->getPathname();
        $relative = ltrim(str_replace($uploadsDir, '', $src), DIRECTORY_SEPARATOR);

        if (strpos($relative, BACKUP_DIR_NAME) === 0) {
            continue;
        }

        $dst = $snapshotDir . DIRECTORY_SEPARATOR . $relative;
        $dstDir = dirname($dst);
        if (!is_dir($dstDir) && !mkdir($dstDir, 0755, true) && !is_dir($dstDir)) {
            return ['ok' => false, 'reason' => "无法创建 {$dstDir}"];
        }

        if (!copy($src, $dst)) {
            return ['ok' => false, 'reason' => "复制失败: {$relative}"];
        }

        $size = filesize($src);
        $files++;
        $bytes += $size ?: 0;

        if ($files % 200 === 0) {
            logLine("  快照进度: {$files} 文件, " . formatBytes($bytes), $logFile);
        }
    }

    return ['ok' => true, 'files' => $files, 'bytes' => $bytes];
}

function writeSnapshotMeta(string $snapshotDir, array $preflight, int $maxWidth, int $quality): void
{
    $meta = [
        'created_at' => date('c'),
        'image_count' => $preflight['count'],
        'total_bytes' => $preflight['total_bytes'],
        'max_width' => $maxWidth,
        'quality' => $quality,
    ];
    file_put_contents($snapshotDir . DIRECTORY_SEPARATOR . '.snapshot_meta.json', json_encode($meta, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE));
}

function scanUploads(string $uploadsDir): array
{
    $files = [];
    $totalBytes = 0;

    $iterator = new RecursiveIteratorIterator(
        new RecursiveDirectoryIterator($uploadsDir, FilesystemIterator::SKIP_DOTS)
    );

    foreach ($iterator as $fileInfo) {
        /** @var SplFileInfo $fileInfo */
        if (!$fileInfo->isFile()) {
            continue;
        }
        $path = $fileInfo->getPathname();
        $relative = ltrim(str_replace($uploadsDir, '', $path), DIRECTORY_SEPARATOR);

        if (strpos($relative, BACKUP_DIR_NAME) === 0) {
            continue;
        }

        $ext = strtolower($fileInfo->getExtension());
        if (!in_array($ext, SUPPORTED_EXT, true)) {
            continue;
        }

        $size = $fileInfo->getSize();
        $files[] = ['path' => $path, 'relative' => $relative, 'ext' => $ext, 'size' => $size];
        $totalBytes += $size;
    }

    return ['files' => $files, 'count' => count($files), 'total_bytes' => $totalBytes];
}

function backupFile(string $src, string $dst): bool
{
    if (file_exists($dst)) {
        return true;
    }
    $dir = dirname($dst);
    if (!is_dir($dir) && !mkdir($dir, 0755, true) && !is_dir($dir)) {
        return false;
    }
    return copy($src, $dst);
}

function buildOkResult(int $beforeW, int $beforeH, int $afterW, int $afterH, int $beforeSize, int $afterSize): array
{
    return [
        'status' => 'ok',
        'before_w' => $beforeW,
        'before_h' => $beforeH,
        'after_w' => $afterW,
        'after_h' => $afterH,
        'before_size' => $beforeSize,
        'after_size' => $afterSize,
        'saved' => max(0, $beforeSize - $afterSize),
    ];
}

/**
 * @return resource|\GdImage|null
 */
function loadImage(string $path, string $ext)
{
    switch ($ext) {
        case 'jpg':
        case 'jpeg':
            return @imagecreatefromjpeg($path) ?: null;
        case 'png':
            return @imagecreatefrompng($path) ?: null;
        case 'webp':
            return function_exists('imagecreatefromwebp') ? (@imagecreatefromwebp($path) ?: null) : null;
        case 'gif':
            return @imagecreatefromgif($path) ?: null;
        default:
            return null;
    }
}

/**
 * @param resource|\GdImage $image
 */
function saveImage($image, string $path, string $ext, int $quality): bool
{
    switch ($ext) {
        case 'jpg':
        case 'jpeg':
            return imagejpeg($image, $path, $quality);
        case 'png':
            $pngLevel = max(0, min(9, (int) round((100 - $quality) / 100 * 9)));
            return imagepng($image, $path, $pngLevel);
        case 'webp':
            return function_exists('imagewebp') ? imagewebp($image, $path, $quality) : false;
        case 'gif':
            return imagegif($image, $path);
        default:
            return false;
    }
}

/**
 * @param resource|\GdImage $image
 * @return resource|\GdImage
 */
function applyExifOrientation($image, string $path)
{
    if (!function_exists('exif_read_data')) {
        return $image;
    }
    $exif = @exif_read_data($path);
    if (!$exif || empty($exif['Orientation'])) {
        return $image;
    }
    switch ((int) $exif['Orientation']) {
        case 2: imageflip($image, IMG_FLIP_HORIZONTAL); break;
        case 3: $image = imagerotate($image, 180, 0) ?: $image; break;
        case 4: imageflip($image, IMG_FLIP_VERTICAL); break;
        case 5: imageflip($image, IMG_FLIP_HORIZONTAL); $image = imagerotate($image, -90, 0) ?: $image; break;
        case 6: $image = imagerotate($image, -90, 0) ?: $image; break;
        case 7: imageflip($image, IMG_FLIP_HORIZONTAL); $image = imagerotate($image, 90, 0) ?: $image; break;
        case 8: $image = imagerotate($image, 90, 0) ?: $image; break;
    }
    return $image;
}

/**
 * @param resource|\GdImage $image
 */
function preserveTransparency($image, string $ext): void
{
    if (!in_array($ext, ['png', 'gif', 'webp'], true)) {
        return;
    }
    imagealphablending($image, false);
    imagesavealpha($image, true);
    $transparent = imagecolorallocatealpha($image, 0, 0, 0, 127);
    imagefilledrectangle($image, 0, 0, imagesx($image), imagesy($image), $transparent);
}

function isAnimatedGif(string $path): bool
{
    $content = @file_get_contents($path, false, null, 0, 65536);
    return $content !== false && preg_match('/\x00\x21\xF9\x04.{4}\x00[\x2C\x21]/s', $content) === 1;
}

function diskFreeBytes(string $path): int
{
    $free = @disk_free_space($path);
    return $free !== false ? (int) $free : 0;
}

function formatBytes(int $bytes): string
{
    if ($bytes >= 1073741824) {
        return round($bytes / 1073741824, 2) . 'GB';
    }
    if ($bytes >= 1048576) {
        return round($bytes / 1048576, 2) . 'MB';
    }
    if ($bytes >= 1024) {
        return round($bytes / 1024, 1) . 'KB';
    }
    return $bytes . 'B';
}

function logLine(string $msg, ?string $logFile): void
{
    echo $msg . PHP_EOL;
    if ($logFile) {
        file_put_contents($logFile, $msg . PHP_EOL, FILE_APPEND | LOCK_EX);
    }
}