<?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\Db\Convert;

use Std\Lib\Db\Convert;
use Std\Lib\Db\DbException;

/**
 * SQLのダンプのファイルに書く（MySQL、PostgreSQL、SQLiteの方言）
 *
 * mysql・psql・sqlite3のコマンド、又はDumpSourceで読める。
 */
final class DumpTarget implements Target {
  /** @var resource|null */
  private $fh = null;
  private array $warnings = [];
  private bool $drop = false;
  private int $perInsert = 200;

  /**
   * @param string $path  書くファイル（.gzなら圧縮）
   * @param string $dialect  mysql、pgsql、sqlite
   */
  public function __construct(private string $path, public readonly string $dialect) {
    if (!in_array($dialect, ['mysql', 'pgsql', 'sqlite'], true)) throw new \InvalidArgumentException("未対応の方言：{$dialect}");
  }

  public function warnings(): array {
    return array_values(array_unique($this->warnings));
  }

  private function out(string $s): void {
    $n = str_ends_with(strtolower($this->path), '.gz') ? gzwrite($this->fh, $s) : fwrite($this->fh, $s);
    if ($n === false) throw new DbException("ダンプのファイルに書けません：{$this->path}", 0, 'HY000');
  }

  public function begin(bool $drop): void {
    $this->drop = $drop;
    $gz = str_ends_with(strtolower($this->path), '.gz');
    if ($gz && !function_exists('gzopen')) throw new DbException("圧縮したダンプにはzlibが必要です：{$this->path}", 0, 'HY000');
    $fh = $gz ? @gzopen($this->path, 'wb6') : @fopen($this->path, 'wb');
    if ($fh === false) throw new DbException("ダンプのファイルを作れません：{$this->path}", 0, 'HY000');
    $this->fh = $fh;
    $this->out("-- LittleBeastのデータベースの変換（{$this->dialect}）\n-- ".gmdate('Y-m-d H:i:s')." UTC\n");
    if ($this->dialect === 'mysql') {
      $this->out("SET NAMES utf8mb4;\nSET FOREIGN_KEY_CHECKS = 0;\nSET SQL_MODE = 'NO_AUTO_VALUE_ON_ZERO';\nSET time_zone = '+00:00';\n");
    } else if ($this->dialect === 'pgsql') {
      $this->out("SET client_encoding = 'UTF8';\nSET standard_conforming_strings = on;\nSET TimeZone = 'UTC';\n");
    }
    $this->out("BEGIN;\n\n");
  }

  public function createTable(array $t): void {
    $q = fn(string $n) => Convert::quote($this->dialect, $n);
    if ($this->drop) $this->out('DROP TABLE IF EXISTS '.$q($t['name']).($this->dialect === 'pgsql' ? ' CASCADE' : '').";\n");
    $this->out(Convert::createTable($this->dialect, $t, $this->warnings).";\n\n");
  }

  public function insertRows(array $t, array $rows): void {
    $q = fn(string $n) => Convert::quote($this->dialect, $n);
    $head = 'INSERT INTO '.$q($t['name']).' ('.implode(', ', array_map(fn($c) => $q($c['name']), $t['columns'])).') VALUES';
    foreach (array_chunk($rows, $this->perInsert) as $chunk) {
      $vals = [];
      foreach ($chunk as $r) {
        $parts = [];
        foreach ($t['columns'] as $i => $c) $parts[] = $this->value($r[$i], $c, $t);
        $vals[] = '('.implode(', ', $parts).')';
      }
      $this->out($head."\n".implode(",\n", $vals).";\n");
    }
  }

  private function value(mixed $v, array $c, array $t): string {
    if ($v === null) return 'NULL';
    if (is_string($v) && $this->dialect === 'pgsql' && str_contains($v, "\0")) {
      $this->warnings[] = "PostgreSQLの文字列に0のバイトは入れられないので、消しました：{$t['name']}.{$c['name']}";
      $v = str_replace("\0", '', $v);
    }
    if (is_float($v) && $this->dialect !== 'pgsql' && (is_nan($v) || is_infinite($v))) {
      $this->warnings[] = "NaN・無限はNULLにしました：{$t['name']}.{$c['name']}";
    }
    return Convert::literal($this->dialect, $v, $c);
  }

  public function finishTable(array $t): void {
    $q = fn(string $n) => Convert::quote($this->dialect, $n);
    foreach ($t['indexes'] as $idx) $this->out(Convert::createIndex($this->dialect, $t, $idx).";\n");
    // 自動の番号の続き
    foreach ($t['columns'] as $c) {
      if (!$c['autoinc'] || count($t['pk']) !== 1 || strcasecmp($t['pk'][0], $c['name']) !== 0) continue;
      if ($this->dialect === 'pgsql') {
        $this->out("SELECT setval(pg_get_serial_sequence('".str_replace("'", "''", $q($t['name']))."', '".str_replace("'", "''", $c['name'])."'), "
          ."COALESCE(MAX({$q($c['name'])}), 1), MAX({$q($c['name'])}) IS NOT NULL) FROM {$q($t['name'])};\n");
      }
    }
    $this->out("\n");
  }

  public function abort(): void {
    if ($this->fh) {
      str_ends_with(strtolower($this->path), '.gz') ? @gzclose($this->fh) : @fclose($this->fh);
      $this->fh = null;
      @unlink($this->path);
    }
  }

  public function end(): void {
    $this->out("COMMIT;\n");
    if ($this->dialect === 'mysql') $this->out("SET FOREIGN_KEY_CHECKS = 1;\n");
    str_ends_with(strtolower($this->path), '.gz') ? gzclose($this->fh) : fclose($this->fh);
    $this->fh = null;
  }
}