//! Phase 88: Ring0Context - OS API 抽象化レイヤー
//!
//! Ring0 は Box を知らない、Nyash を知らない純粋な OS API 層。

mod errors;
mod std_impls;
mod traits;

pub use errors::{IoError, TimeError};
pub use std_impls::{NoopMem, StdIo, StdLog, StdTime};
pub use traits::{IoApi, LogApi, LogLevel, MemApi, MemStats, TimeApi};

use std::sync::{Arc, OnceLock};

/// Phase 88: Ring0 コンテキスト
///
/// OS API レイヤーを trait で抽象化し、1つの構造体に束ねる。
pub struct Ring0Context {
    pub mem: Arc<dyn MemApi>,
    pub io: Arc<dyn IoApi>,
    pub time: Arc<dyn TimeApi>,
    pub log: Arc<dyn LogApi>,
}

impl Ring0Context {
    /// 新規 Ring0Context を作成
    pub fn new(
        mem: Arc<dyn MemApi>,
        io: Arc<dyn IoApi>,
        time: Arc<dyn TimeApi>,
        log: Arc<dyn LogApi>,
    ) -> Self {
        Self { mem, io, time, log }
    }
}

impl std::fmt::Debug for Ring0Context {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Ring0Context")
            .field("mem", &"<dyn MemApi>")
            .field("io", &"<dyn IoApi>")
            .field("time", &"<dyn TimeApi>")
            .field("log", &"<dyn LogApi>")
            .finish()
    }
}

/// デフォルト Ring0Context を作成（std ベース）
pub fn default_ring0() -> Ring0Context {
    Ring0Context {
        mem: Arc::new(NoopMem),
        io: Arc::new(StdIo),
        time: Arc::new(StdTime),
        log: Arc::new(StdLog),
    }
}

// ===== グローバル Ring0Context =====

pub static GLOBAL_RING0: OnceLock<Arc<Ring0Context>> = OnceLock::new();

/// グローバル Ring0Context を初期化
pub fn init_global_ring0(ctx: Ring0Context) {
    GLOBAL_RING0
        .set(Arc::new(ctx))
        .expect("[Phase 88] Ring0Context already initialized");
}

/// グローバル Ring0Context を取得
pub fn get_global_ring0() -> Arc<Ring0Context> {
    GLOBAL_RING0
        .get()
        .expect("[Phase 88] Ring0Context not initialized")
        .clone()
}

// ===== テスト =====

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_ring0_context_creation() {
        let ring0 = default_ring0();
        ring0.log.info("test message");
    }

    #[test]
    fn test_io_api() {
        let ring0 = default_ring0();
        let result = ring0.io.stdout_write(b"test\n");
        assert!(result.is_ok());
    }

    #[test]
    fn test_time_api() {
        let ring0 = default_ring0();
        let now = ring0.time.now();
        assert!(now.is_ok());

        let instant = ring0.time.monotonic_now();
        assert!(instant.is_ok());
    }

    #[test]
    fn test_log_levels() {
        let ring0 = default_ring0();
        ring0.log.debug("debug message");
        ring0.log.info("info message");
        ring0.log.warn("warn message");
        ring0.log.error("error message");
    }
}