<?php
namespace Xxx\Tests\Support;

/*
 * In-memory copies of the site tables (xxx, queue, editors and
 * persistent_sessions), with FakeDb handlers for the queries that the
 * code sends. It knows only those queries, not SQL in general.
 *
 * Story rows have the columns id, title, author, email, date, story,
 * hidden, img, mime, comments and editor.
 */
class SiteData {
  public static array $tables = array();
  public static int $lastInsertId = 0;
  // The size of editors.password; NULL means that the column keeps any hash
  public static ?int $passwordLength = NULL;

  public static function install(array $tables = array()): void {
    self::$tables = $tables + array('xxx' => array(), 'queue' => array(), 'editors' => array(), 'persistent_sessions' => array());
    foreach (array('xxx', 'queue') as $table)
      self::$tables[$table] = array_map(array(self::class, 'story'), self::$tables[$table]);
    self::$lastInsertId = 0;

    $stories = '(xxx|queue)';
    FakeDb::on("/^SELECT \\* FROM $stories\\b/", array(self::class, 'selectStories'));
    FakeDb::on("/^SELECT COUNT\\(\\*\\) FROM $stories\\b/", function ($sql, $params) {
      return array(array('COUNT(*)' => (string)count(self::filterStories($sql, $params))));
    });
    FakeDb::on('/^SELECT MAX\(`date`\) FROM xxx/', function () {
      $dates = array_column(self::$tables['xxx'], 'date');
      return array(array('MAX(`date`)' => $dates ? max($dates) : NULL));
    });
    FakeDb::on("/^SELECT img, mime(, hidden)? FROM $stories\\b/i", function ($sql, $params) {
      $rows = self::filterStories($sql, $params);
      $columns = str_starts_with($sql, 'SELECT img, mime, hidden') ? array('img', 'mime', 'hidden') : array('img', 'mime');
      return array_map(function ($row) use ($columns) { return array_intersect_key($row, array_flip($columns)); }, array_slice($rows, 0, 1));
    });
    FakeDb::on("/^INSERT INTO $stories SET /", array(self::class, 'insertStory'));
    FakeDb::on("/^UPDATE $stories SET /", array(self::class, 'updateStory'));
    FakeDb::on("/^DELETE FROM $stories WHERE `id` = \\? LIMIT 1/", function ($sql, $params) {
      $table = self::tableOf($sql);
      self::$tables[$table] = array_values(array_filter(self::$tables[$table], function ($row) use ($params) {
        return (int)$row['id'] !== (int)$params[0];
      }));
      return TRUE;
    });
    FakeDb::on('/^SELECT LAST_INSERT_ID\(\)/', function () {
      return array(array('LAST_INSERT_ID()' => (string)self::$lastInsertId));
    });

    FakeDb::on('/^SELECT (\*|username|password) FROM editors WHERE username = \?/', function ($sql, $params) {
      return array_slice(array_values(array_filter(self::$tables['editors'], function ($row) use ($params) {
        return $row['username'] === $params[0];
      })), 0, 1);
    });
    FakeDb::on('/^UPDATE editors SET password = \? WHERE username = \?/', function ($sql, $params) {
      foreach (self::$tables['editors'] as &$row) {
        if ($row['username'] === $params[1])
          $row['password'] = self::cut($params[0]);
      }
      return TRUE;
    });
    FakeDb::on('/^INSERT INTO editors SET `username` = \?, `password` = \?, `email` = \?/', function ($sql, $params) {
      self::$tables['editors'][] = array('username' => $params[0], 'password' => self::cut($params[1]), 'email' => $params[2]);
      return TRUE;
    });
    FakeDb::on('/^DELETE FROM editors WHERE username = \?/', function ($sql, $params) {
      self::$tables['editors'] = array_values(array_filter(self::$tables['editors'], function ($row) use ($params) {
        return $row['username'] !== $params[0];
      }));
      return TRUE;
    });

    FakeDb::on('/^SELECT \* FROM persistent_sessions WHERE username = \? AND session = \?/', function ($sql, $params) {
      return array_slice(array_values(array_filter(self::$tables['persistent_sessions'], function ($row) use ($params) {
        return $row['username'] === $params[0] && $row['session'] === $params[1];
      })), 0, 1);
    });
    FakeDb::on('/^SELECT p\.username, p\.session FROM persistent_sessions p JOIN editors e ON e\.username = p\.username\s+WHERE p\.username = \? AND p\.session = \? AND p\.created > DATE_SUB\(now\(\), INTERVAL 1 YEAR\)/', function ($sql, $params) {
      $editors = array_column(self::$tables['editors'], 'username');
      $limit = gmdate('Y-m-d H:i:s', strtotime('-1 year'));
      return array_slice(array_values(array_map(function ($row) {
        return array('username' => $row['username'], 'session' => $row['session']);
      }, array_filter(self::$tables['persistent_sessions'], function ($row) use ($params, $editors, $limit) {
        return $row['username'] === $params[0] && $row['session'] === $params[1]
            && in_array($row['username'], $editors, TRUE) && ($row['created'] ?? $limit) > $limit;
      }))), 0, 1);
    });
    FakeDb::on('/^DELETE FROM persistent_sessions WHERE username = \?$/', function ($sql, $params) {
      self::$tables['persistent_sessions'] = array_values(array_filter(self::$tables['persistent_sessions'], function ($row) use ($params) {
        return $row['username'] !== $params[0];
      }));
      return TRUE;
    });
    FakeDb::on('/^INSERT INTO persistent_sessions \(username, session\) VALUES \(\?, \?\)/', function ($sql, $params) {
      self::$tables['persistent_sessions'][] = array('username' => $params[0], 'session' => $params[1], 'created' => gmdate('Y-m-d H:i:s'));
      return TRUE;
    });
    FakeDb::on('/^DELETE FROM persistent_sessions WHERE username = \? AND session = \?/', function ($sql, $params) {
      self::$tables['persistent_sessions'] = array_values(array_filter(self::$tables['persistent_sessions'], function ($row) use ($params) {
        return !($row['username'] === $params[0] && $row['session'] === $params[1]);
      }));
      return TRUE;
    });
    FakeDb::on('/^DELETE FROM persistent_sessions\s+WHERE created < DATE_SUB/', function () {
      $limit = gmdate('Y-m-d H:i:s', strtotime('-1 year'));
      self::$tables['persistent_sessions'] = array_values(array_filter(self::$tables['persistent_sessions'], function ($row) use ($limit) {
        return strlen($row['session']) === 64 && ($row['created'] ?? $limit) >= $limit;
      }));
      return TRUE;
    });
  }

  // A story row with every column, from the columns given
  public static function story(array $row): array {
    static $next = 1;
    $row += array('id' => $next, 'title' => 'Title', 'author' => 'Author', 'email' => '',
                  'date' => '2020-01-01 10:00:00', 'story' => '<p>Story.</p>', 'hidden' => '0',
                  'img' => NULL, 'mime' => NULL, 'comments' => '', 'editor' => 'original author');
    $next = max($next, (int)$row['id']) + 1;
    $row['id'] = (string)$row['id'];
    return $row;
  }

  public static function tableOf(string $sql): string {
    preg_match('/\b(FROM|INTO|UPDATE)\s+`?(xxx|queue)\b/', $sql, $match);
    return $match[2];
  }

  // The rows of the story table in $sql that its WHERE clause selects
  public static function filterStories(string $sql, array $params): array {
    $rows = self::$tables[self::tableOf($sql)];
    if (stripos($sql, 'hidden IS NOT TRUE') !== FALSE)
      $rows = array_filter($rows, function ($row) { return !$row['hidden']; });
    if (preg_match('/\bid = (\d+)/i', $sql, $match))
      $rows = array_filter($rows, function ($row) use ($match) { return (int)$row['id'] === (int)$match[1]; });
    else if (preg_match('/\bid = \?/i', $sql))
      $rows = array_filter($rows, function ($row) use ($params) { return (int)$row['id'] === (int)$params[0]; });
    if (preg_match('/title LIKE \?/', $sql)) {
      $term = strtolower(trim($params[0], '%'));
      $rows = array_filter($rows, function ($row) use ($term) {
        foreach (array('title', 'author', 'date', 'story') as $column) {
          if (str_contains(strtolower((string)$row[$column]), $term))
            return TRUE;
        }
        return FALSE;
      });
    }
    return array_values($rows);
  }

  public static function selectStories(string $sql, array $params): array {
    $rows = self::filterStories($sql, $params);
    if (preg_match('/ORDER BY (\w+) (asc|desc)/i', $sql, $match)) {
      $column = $match[1];
      usort($rows, function ($a, $b) use ($column) { return strcmp((string)$a[$column], (string)$b[$column]); });
      if (strtolower($match[2]) === 'desc')
        $rows = array_reverse($rows);
    }
    if (preg_match('/LIMIT (\d+)\s*,\s*(\d+)/', $sql, $match))
      $rows = array_slice($rows, (int)$match[1], (int)$match[2]);
    return $rows;
  }

  // The column => value pairs of "SET `a` = ?, `b` = ?"
  private static function assignments(string $sql, array $params): array {
    preg_match_all('/`(\w+)` = \?/', explode(' WHERE ', $sql)[0], $matches);
    return array_combine($matches[1], array_slice($params, 0, count($matches[1])));
  }

  public static function insertStory(string $sql, array $params) {
    $ids = array_merge(array_column(self::$tables['xxx'], 'id'), array_column(self::$tables['queue'], 'id'), array(0));
    $row = self::story(array('id' => max(array_map('intval', $ids)) + 1) + self::assignments($sql, $params));
    self::$tables[self::tableOf($sql)][] = $row;
    self::$lastInsertId = (int)$row['id'];
    return TRUE;
  }

  public static function updateStory(string $sql, array $params) {
    $id = (int)end($params);
    $table = self::tableOf($sql);
    foreach (self::$tables[$table] as &$row) {
      if ((int)$row['id'] === $id)
        $row = array_merge($row, self::assignments($sql, $params));
    }
    return TRUE;
  }

  private static function cut(string $value): string {
    return self::$passwordLength === NULL ? $value : substr($value, 0, self::$passwordLength);
  }

  // The rows of a story table, found by id
  public static function find(string $table, $id): ?array {
    foreach (self::$tables[$table] as $row) {
      if ((int)$row['id'] === (int)$id)
        return $row;
    }
    return NULL;
  }
}