// SPDX-License-Identifier: AGPL-3.0-only

//! Formatting of the periodic simulation statistics report.

use std::fmt::Write as _;

use shared::protocol::authority::ServerStats;

/// Renders one measurement window's diagnostics as a multi-line panel.
#[must_use]
pub fn format_panel(stats: &ServerStats) -> String {
    let mut out = String::with_capacity(256);

    // `write!` into a String cannot fail, so the results are discarded rather than propagated.
    let _ = writeln!(out, "── server statistics ──");
    let _ = writeln!(
        out,
        "tick   {:.1} tps  mean {:.2} ms  max {:.2} ms  budget {:.0}%  uptime {} s",
        stats.measured_tps,
        stats.mean_tick_ms,
        stats.max_tick_ms,
        stats.tick_budget_percent,
        stats.uptime_secs
    );
    let _ = write!(
        out,
        "world  chunks {} resident / {} in flight  clients {}  entities {}  players {}",
        stats.loaded_chunks,
        stats.chunks_in_flight,
        stats.connected_clients,
        stats.entities,
        stats.players
    );

    out
}

#[cfg(test)]
#[path = "tests/stats.rs"]
mod tests;