// Server-owned audit stream. The file contains every event; chat reads a bounded
// recent-history window with explicit gap notices for clients that fall behind.
class ERR_HQJournal
{
	protected ref array<string> m_Recent = {};
	protected ref array<string> m_Pending = {};
	protected int m_Sequence;
	protected int m_Message;
	protected static int s_Part;
	protected static int s_Session;
	protected string m_Session;

	void ERR_HQJournal()
	{
		s_Session++;
		m_Session = string.Format("%1-%2", System.GetUnixTime(), s_Session);
	}
	protected float m_RetryAt;
	protected int m_Lost;

	string Path()
	{
		if (s_Part == 0)
			return "$logs:rereintroduced-hq.log";
		return "$logs:rereintroduced-hq-" + s_Part.ToString() + ".log";
	}

	int Message()
	{
		return ++m_Message;
	}

	int Sequence()
	{
		return m_Sequence;
	}

	void Write(string kind, string message, int messageId = 0)
	{
		if (!Replication.IsServer())
			return;
		float seconds = GetGame().GetWorld().GetWorldTime() / 1000;
		string line = string.Format("#%1 t=%2s M%3 %4 %5", ++m_Sequence, Math.Round(seconds * 10) / 10.0, messageId, kind, message) + " [session=" + m_Session + "]";
		if (m_Recent.Count() >= 300)
			m_Recent.Remove(0);
		m_Recent.Insert(line);
		if (m_Pending.Count() < 4096)
			m_Pending.Insert(line);
		else
			m_Lost++;
	}

	void Read(int after, out array<string> lines, out int cursor, int limit = 8)
	{
		lines.Clear();
		cursor = Math.Clamp(after, 0, m_Sequence);
		int first = m_Sequence - m_Recent.Count();
		if (cursor < first)
		{
			lines.Insert(string.Format("HQ log: %1 older entries are outside chat history; see %2", first - cursor, Path()));
			cursor = first;
		}
		int characters;
		for (int i = cursor - first; i < m_Recent.Count() && lines.Count() < Math.Clamp(limit, 1, 40); i++)
		{
			// Bound each menu RPC without skipping unread records. Chat still
			// requests eight; the live menu can drain a busy journal faster.
			if (characters + m_Recent[i].Length() > 16000 && !lines.IsEmpty())
				break;
			lines.Insert(m_Recent[i]);
			characters += m_Recent[i].Length();
			cursor++;
		}
	}

	void Flush()
	{
		if (m_Pending.IsEmpty() || !Replication.IsServer())
			return;
		float now = GetGame().GetWorld().GetWorldTime();
		if (now < m_RetryAt)
			return;
		FileHandle file = FileIO.OpenFile(Path(), FileMode.APPEND);
		if (!file)
		{
			m_RetryAt = now + 30000;
			PrintFormat("Escapists AI [HQ log]: cannot open %1; retry in 30s, chat history remains available", Path(), level: LogLevel.ERROR);
			return;
		}
		foreach (string line : m_Pending)
			file.WriteLine(line);
		if (m_Lost > 0)
			file.WriteLine(string.Format("HQ log: %1 entries lost while file was unavailable and buffer full", m_Lost));
		bool rotate = file.GetLength() >= 5242880;
		file.Close();
		m_Pending.Clear();
		m_Lost = 0;
		if (rotate)
			s_Part++;
	}
}