<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
namespace Std\Lib;

/**
 * ログのファイル（log/、logger()が書く）を読む・消す（管理画面用）
 *
 *   $logs = new Logs();
 *   foreach ($logs->list() as $f) echo $f['name'], ' ', $f['size'], "\n";
 *   $tail = $logs->tail('db_log.txt', 100, 'エラー');
 */
class Logs {
  private string $dir;

  /**
   * @param string|null $dir  ログのディレクトリ（既定はROOT/log、テスト用）
   */
  public function __construct(?string $dir = null) {
    $this->dir = rtrim($dir ?? ROOT.'/log', '/\\');
  }

  public function dir(): string {
    return $this->dir;
  }

  /**
   * ログのファイルの一覧（ディレクトリが無ければ空）
   *
   * @return array  name、size、mtime（名前の順）
   */
  public function list(): array {
    $out = [];
    foreach (@scandir($this->dir) ?: [] as $f) {
      $p = $this->path($f);
      if ($p === null) continue;
      $out[] = ['name' => $f, 'size' => (int)filesize($p), 'mtime' => (int)filemtime($p)];
    }
    return $out;
  }

  /**
   * ログのファイルのパス（ディレクトリの中の普通のファイルだけ）
   *
   * @param string $name  ファイル名
   * @return string|null  無い・不正な名前ならnull
   */
  public function path(string $name): ?string {
    if (!preg_match('/^[A-Za-z0-9_-][A-Za-z0-9._-]{0,200}$/', $name) || str_contains($name, '..')) return null;
    $p = $this->dir.'/'.$name;
    return is_file($p) && !is_link($p) ? $p : null;
  }

  /**
   * 最後の行（新しい順ではなく、ファイルの順）
   *
   * @param string $name  ファイル名
   * @param int $lines  行数
   * @param string $search  含む行だけ（大文字・小文字を区別しない、空なら全部）
   * @return array|null  lines（行の配列）、more（前にもっと有るか）。ファイルが無ければnull
   */
  public function tail(string $name, int $lines = 200, string $search = ''): ?array {
    $p = $this->path($name);
    if ($p === null) return null;
    $lines = max(1, min($lines, 10000));
    $fh = @fopen($p, 'rb');
    if (!$fh) return null;
    try {
      if ($search !== '') {
        // 検索は全部を読む（一致した最後の行だけ残す）
        $out = [];
        $more = false;
        while (($l = fgets($fh)) !== false) {
          $l = rtrim($l, "\r\n");
          if (mb_stripos($l, $search, 0, 'UTF-8') === false) continue;
          $out[] = $l;
          if (count($out) > $lines) {
            array_shift($out);
            $more = true;
          }
        }
        return ['lines' => $out, 'more' => $more];
      }
      // 後ろから読む
      $size = (int)fstat($fh)['size'];
      $pos = $size;
      $buf = '';
      $chunk = 65536;
      while ($pos > 0 && substr_count($buf, "\n") <= $lines) {
        $n = min($chunk, $pos);
        $pos -= $n;
        fseek($fh, $pos);
        $buf = (string)fread($fh, $n).$buf;
      }
      $all = explode("\n", rtrim($buf, "\n"));
      if ($buf === '') $all = [];
      $more = $pos > 0 || count($all) > $lines;
      if (count($all) > $lines) $all = array_slice($all, -$lines);
      return ['lines' => array_map(fn($l) => rtrim($l, "\r"), $all), 'more' => $more];
    } finally {
      fclose($fh);
    }
  }

  /**
   * ログを空にする
   */
  public function clear(string $name): bool {
    $p = $this->path($name);
    return $p !== null && @file_put_contents($p, '', LOCK_EX) !== false;
  }

  /**
   * ログのファイルを消す
   */
  public function delete(string $name): bool {
    $p = $this->path($name);
    return $p !== null && @unlink($p);
  }
}