asupersync 0.3.1

//! Configuration for the lab runtime.
//!
//! The lab configuration controls deterministic execution:
//! - Random seed for scheduling decisions
//! - Entropy seed for capability-based randomness
//! - Whether to panic on obligation leaks
//! - Trace buffer size
//! - Futurelock detection settings
//! - Chaos injection settings
//!
//! # Basic Usage
//!
//! ```ignore
//! use asupersync::lab::{LabConfig, LabRuntime};
//!
//! // Default configuration (seed=42)
//! let config = LabConfig::default();
//!
//! // Explicit seed for reproducibility
//! let config = LabConfig::new(12345);
//!
//! // Time-based seed for variety (useful in CI)
//! let config = LabConfig::from_time();
//! ```
//!
//! # Chaos Testing
//!
//! Enable chaos injection to stress-test error handling paths:
//!
//! ```ignore
//! use asupersync::lab::{LabConfig, LabRuntime};
//! use asupersync::lab::chaos::ChaosConfig;
//!
//! // Quick: use presets
//! let config = LabConfig::new(42).with_light_chaos();  // CI-friendly
//! let config = LabConfig::new(42).with_heavy_chaos();  // Thorough
//!
//! // Custom: fine-grained control
//! let chaos = ChaosConfig::new(42)
//!     .with_delay_probability(0.3)
//!     .with_cancel_probability(0.05);
//! let config = LabConfig::new(42).with_chaos(chaos);
//!
//! // Check if chaos is enabled
//! assert!(config.has_chaos());
//! ```
//!
//! # Futurelock Detection
//!
//! Detect tasks that hold obligations but stop being polled:
//!
//! ```ignore
//! let config = LabConfig::new(42)
//!     .futurelock_max_idle_steps(5000)  // Trigger after 5000 idle steps
//!     .panic_on_futurelock(true);       // Panic when detected
//! ```
//!
//! # Builder Style
//!
//! `LabConfig` uses a fluent, move-based builder style. Each method consumes
//! `self` and returns an updated configuration so you can chain options safely.
//!
//! # Configuration Examples
//!
//! ## Deterministic Multi-Worker Simulation
//!
//! ```ignore
//! use asupersync::lab::{LabConfig, LabRuntime};
//!
//! let config = LabConfig::new(7)
//!     .worker_count(4)
//!     .trace_capacity(16_384);
//! let mut lab = LabRuntime::new(config);
//! lab.run_until_quiescent();
//! ```
//!
//! ## Replay Capture for Debugging
//!
//! ```ignore
//! use asupersync::lab::{LabConfig, LabRuntime};
//!
//! let config = LabConfig::new(42).with_default_replay_recording();
//! let mut lab = LabRuntime::new(config);
//! lab.run_until_quiescent();
//! ```
//!
//! ## Entropy Decoupling
//!
//! ```ignore
//! use asupersync::lab::LabConfig;
//!
//! // Keep scheduling deterministic but vary entropy-derived behavior.
//! let config = LabConfig::new(42).entropy_seed(7);
//! ```
//!
//! # Migration Guide (Struct Updates → Builder Style)
//!
//! ```ignore
//! use asupersync::lab::LabConfig;
//!
//! // Old style: struct update
//! let config = LabConfig {
//!     seed: 42,
//!     worker_count: 4,
//!     ..LabConfig::new(42)
//! };
//!
//! // New style: builder methods
//! let config = LabConfig::new(42).worker_count(4);
//! ```

use crate::lab::chaos::ChaosConfig;
use crate::trace::RecorderConfig;
use crate::util::DetRng;

/// Configuration for the lab runtime.
#[derive(Debug, Clone)]
#[allow(clippy::struct_excessive_bools)]
pub struct LabConfig {
    /// Random seed for deterministic scheduling.
    pub seed: u64,
    /// Seed for deterministic entropy sources.
    ///
    /// By default this matches `seed`, but can be overridden to decouple
    /// scheduler decisions from entropy generation.
    pub entropy_seed: u64,
    /// Number of virtual workers to model in the lab scheduler.
    ///
    /// This does not spawn threads; it controls deterministic multi-worker simulation.
    /// Values less than 1 are clamped to 1.
    pub worker_count: usize,
    /// Whether to panic on obligation leaks.
    pub panic_on_obligation_leak: bool,
    /// Trace buffer capacity.
    pub trace_capacity: usize,
    /// Max lab steps a task may go unpolled while holding obligations.
    ///
    /// `0` disables the futurelock detector.
    pub futurelock_max_idle_steps: u64,
    /// Whether to panic when a futurelock is detected.
    pub panic_on_futurelock: bool,
    /// Maximum number of steps before forced termination.
    pub max_steps: Option<u64>,
    /// Chaos injection configuration.
    ///
    /// When enabled, the runtime will inject faults at various points
    /// to stress-test the system's resilience.
    pub chaos: Option<ChaosConfig>,
    /// Replay recording configuration.
    ///
    /// When enabled, the runtime will record all non-determinism sources
    /// for later replay.
    pub replay_recording: Option<RecorderConfig>,
    /// When true, the runtime auto-advances virtual time to the next timer
    /// deadline whenever all tasks are idle (no runnable tasks in scheduler).
    ///
    /// This enables "instant timeout testing" — a 24-hour wall-clock scenario
    /// completes in <1 second of real time because sleep/timeout deadlines
    /// are jumped to instantly rather than waited for.
    pub auto_advance_time: bool,
    /// Whether to enable real-time cancellation protocol oracle verification.
    ///
    /// When enabled, the runtime will continuously verify that the cancellation
    /// protocol is followed correctly during execution.
    pub enable_cancellation_oracle: bool,
    /// Whether to panic when cancellation protocol violations are detected.
    ///
    /// When false, violations are logged as warnings instead of panicking.
    pub panic_on_cancellation_violation: bool,
}

impl LabConfig {
    /// Creates a new lab configuration with the given seed.
    #[must_use]
    pub const fn new(seed: u64) -> Self {
        Self {
            seed,
            entropy_seed: seed,
            worker_count: 1,
            panic_on_obligation_leak: true,
            trace_capacity: 4096,
            futurelock_max_idle_steps: 10_000,
            panic_on_futurelock: true,
            max_steps: Some(100_000),
            chaos: None,
            replay_recording: None,
            auto_advance_time: false,
            enable_cancellation_oracle: true,
            panic_on_cancellation_violation: true,
        }
    }

    /// Creates a lab configuration from the current time (for quick testing).
    #[must_use]
    pub fn from_time() -> Self {
        use std::time::{SystemTime, UNIX_EPOCH};
        let seed = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .map_or(42, |d| d.as_nanos().min(u128::from(u64::MAX)) as u64);
        Self::new(seed)
    }

    /// Sets whether to panic on obligation leaks.
    #[must_use]
    pub const fn panic_on_leak(mut self, value: bool) -> Self {
        self.panic_on_obligation_leak = value;
        self
    }

    /// Sets the trace buffer capacity.
    #[must_use]
    pub const fn trace_capacity(mut self, capacity: usize) -> Self {
        self.trace_capacity = capacity;
        self
    }

    /// Sets the number of virtual workers to model.
    ///
    /// Values less than 1 are clamped to 1.
    #[must_use]
    pub const fn worker_count(mut self, count: usize) -> Self {
        self.worker_count = if count == 0 { 1 } else { count };
        self
    }

    /// Sets the entropy seed used for capability-based randomness.
    #[must_use]
    pub const fn entropy_seed(mut self, seed: u64) -> Self {
        self.entropy_seed = seed;
        self
    }

    /// Sets the maximum idle steps before the futurelock detector triggers.
    #[must_use]
    pub const fn futurelock_max_idle_steps(mut self, steps: u64) -> Self {
        self.futurelock_max_idle_steps = steps;
        self
    }

    /// Sets whether to panic when a futurelock is detected.
    #[must_use]
    pub const fn panic_on_futurelock(mut self, value: bool) -> Self {
        self.panic_on_futurelock = value;
        self
    }

    /// Sets the maximum number of steps.
    #[must_use]
    pub const fn max_steps(mut self, steps: u64) -> Self {
        self.max_steps = Some(steps);
        self
    }

    /// Disables the step limit.
    #[must_use]
    pub const fn no_step_limit(mut self) -> Self {
        self.max_steps = None;
        self
    }

    /// Enables chaos injection with the given configuration.
    ///
    /// The chaos seed will be derived from the main seed for determinism.
    #[must_use]
    pub fn with_chaos(mut self, config: ChaosConfig) -> Self {
        // Derive chaos seed from main seed for determinism
        let chaos_seed = self.seed.wrapping_add(0xCAFE_BABE);
        self.chaos = Some(config.with_seed(chaos_seed));
        self
    }

    /// Enables light chaos (suitable for CI).
    #[must_use]
    pub fn with_light_chaos(self) -> Self {
        self.with_chaos(ChaosConfig::light())
    }

    /// Enables heavy chaos (thorough testing).
    #[must_use]
    pub fn with_heavy_chaos(self) -> Self {
        self.with_chaos(ChaosConfig::heavy())
    }

    /// Returns true if chaos injection is enabled.
    #[must_use]
    pub fn has_chaos(&self) -> bool {
        self.chaos.as_ref().is_some_and(ChaosConfig::is_enabled)
    }

    /// Enables replay recording with the given configuration.
    #[must_use]
    pub fn with_replay_recording(mut self, config: RecorderConfig) -> Self {
        self.replay_recording = Some(config);
        self
    }

    /// Enables replay recording with default configuration.
    #[must_use]
    pub fn with_default_replay_recording(self) -> Self {
        self.with_replay_recording(RecorderConfig::enabled())
    }

    /// Enables automatic time advancement when all tasks are idle.
    ///
    /// When enabled, `run_with_auto_advance()` will jump virtual time to the
    /// next timer deadline whenever the scheduler has no runnable tasks,
    /// enabling instant timeout testing.
    #[must_use]
    pub const fn with_auto_advance(mut self) -> Self {
        self.auto_advance_time = true;
        self
    }

    /// Returns true if replay recording is enabled.
    #[must_use]
    pub fn has_replay_recording(&self) -> bool {
        self.replay_recording.as_ref().is_some_and(|c| c.enabled)
    }

    /// Enables or disables real-time cancellation protocol oracle verification.
    #[must_use]
    pub const fn with_cancellation_oracle(mut self, enable: bool) -> Self {
        self.enable_cancellation_oracle = enable;
        self
    }

    /// Sets whether to panic on cancellation protocol violations.
    ///
    /// When false, violations are logged as warnings instead of panicking.
    #[must_use]
    pub const fn panic_on_cancellation_violation(mut self, value: bool) -> Self {
        self.panic_on_cancellation_violation = value;
        self
    }

    /// Enables cancellation oracle in warning mode (logs violations but doesn't panic).
    #[must_use]
    pub const fn with_cancellation_oracle_warnings(mut self) -> Self {
        self.enable_cancellation_oracle = true;
        self.panic_on_cancellation_violation = false;
        self
    }

    /// Returns true if real-time cancellation protocol oracle verification is enabled.
    #[must_use]
    pub const fn has_cancellation_oracle(&self) -> bool {
        self.enable_cancellation_oracle
    }

    /// Creates a deterministic RNG from this configuration.
    #[must_use]
    pub fn rng(&self) -> DetRng {
        DetRng::new(self.seed)
    }
}

impl Default for LabConfig {
    fn default() -> Self {
        Self::new(42)
    }
}

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

    fn init_test(name: &str) {
        crate::test_utils::init_test_logging();
        crate::test_phase!(name);
    }

    #[test]
    fn default_config() {
        init_test("default_config");
        let config = LabConfig::default();
        let ok = config.seed == 42;
        crate::assert_with_log!(ok, "seed", 42, config.seed);
        crate::assert_with_log!(
            config.entropy_seed == 42,
            "entropy_seed",
            42,
            config.entropy_seed
        );
        crate::assert_with_log!(
            config.worker_count == 1,
            "worker_count",
            1,
            config.worker_count
        );
        crate::assert_with_log!(
            config.panic_on_obligation_leak,
            "panic_on_obligation_leak",
            true,
            config.panic_on_obligation_leak
        );
        crate::assert_with_log!(
            config.panic_on_futurelock,
            "panic_on_futurelock",
            true,
            config.panic_on_futurelock
        );
        crate::test_complete!("default_config");
    }

    #[test]
    fn rng_is_deterministic() {
        init_test("rng_is_deterministic");
        let config = LabConfig::new(12345);
        let mut rng1 = config.rng();
        let mut rng2 = config.rng();

        let a = rng1.next_u64();
        let b = rng2.next_u64();
        crate::assert_with_log!(a == b, "rng equal", b, a);
        crate::test_complete!("rng_is_deterministic");
    }

    #[test]
    fn worker_count_clamps_to_one() {
        init_test("worker_count_clamps_to_one");
        let config = LabConfig::new(7).worker_count(0);
        crate::assert_with_log!(
            config.worker_count == 1,
            "worker_count",
            1,
            config.worker_count
        );
        crate::test_complete!("worker_count_clamps_to_one");
    }

    #[test]
    fn lab_config_debug() {
        init_test("lab_config_debug");
        let cfg = LabConfig::new(42);
        let dbg = format!("{cfg:?}");
        assert!(dbg.contains("LabConfig"));
        crate::test_complete!("lab_config_debug");
    }

    #[test]
    fn lab_config_clone() {
        init_test("lab_config_clone");
        let cfg = LabConfig::new(99).worker_count(3);
        let cfg2 = cfg;
        assert_eq!(cfg2.seed, 99);
        assert_eq!(cfg2.worker_count, 3);
        crate::test_complete!("lab_config_clone");
    }

    #[test]
    fn new_sets_fields() {
        init_test("new_sets_fields");
        let cfg = LabConfig::new(123);
        assert_eq!(cfg.seed, 123);
        assert_eq!(cfg.entropy_seed, 123);
        assert_eq!(cfg.worker_count, 1);
        assert!(cfg.panic_on_obligation_leak);
        assert_eq!(cfg.trace_capacity, 4096);
        assert_eq!(cfg.futurelock_max_idle_steps, 10_000);
        assert!(cfg.panic_on_futurelock);
        assert_eq!(cfg.max_steps, Some(100_000));
        assert!(cfg.chaos.is_none());
        assert!(cfg.replay_recording.is_none());
        assert!(!cfg.auto_advance_time);
        crate::test_complete!("new_sets_fields");
    }

    #[test]
    fn from_time_creates_valid_config() {
        init_test("from_time_creates_valid_config");
        let cfg = LabConfig::from_time();
        // seed should be set from system time (non-deterministic but valid)
        assert_eq!(cfg.entropy_seed, cfg.seed);
        assert_eq!(cfg.worker_count, 1);
        crate::test_complete!("from_time_creates_valid_config");
    }

    #[test]
    fn panic_on_leak_builder() {
        init_test("panic_on_leak_builder");
        let cfg = LabConfig::new(1).panic_on_leak(false);
        assert!(!cfg.panic_on_obligation_leak);
        let cfg = cfg.panic_on_leak(true);
        assert!(cfg.panic_on_obligation_leak);
        crate::test_complete!("panic_on_leak_builder");
    }

    #[test]
    fn trace_capacity_builder() {
        init_test("trace_capacity_builder");
        let cfg = LabConfig::new(1).trace_capacity(8192);
        assert_eq!(cfg.trace_capacity, 8192);
        crate::test_complete!("trace_capacity_builder");
    }

    #[test]
    fn entropy_seed_builder() {
        init_test("entropy_seed_builder");
        let cfg = LabConfig::new(42).entropy_seed(7);
        assert_eq!(cfg.seed, 42);
        assert_eq!(cfg.entropy_seed, 7);
        crate::test_complete!("entropy_seed_builder");
    }

    #[test]
    fn futurelock_max_idle_steps_builder() {
        init_test("futurelock_max_idle_steps_builder");
        let cfg = LabConfig::new(1).futurelock_max_idle_steps(5000);
        assert_eq!(cfg.futurelock_max_idle_steps, 5000);
        crate::test_complete!("futurelock_max_idle_steps_builder");
    }

    #[test]
    fn panic_on_futurelock_builder() {
        init_test("panic_on_futurelock_builder");
        let cfg = LabConfig::new(1).panic_on_futurelock(false);
        assert!(!cfg.panic_on_futurelock);
        crate::test_complete!("panic_on_futurelock_builder");
    }

    #[test]
    fn max_steps_builder() {
        init_test("max_steps_builder");
        let cfg = LabConfig::new(1).max_steps(500);
        assert_eq!(cfg.max_steps, Some(500));
        crate::test_complete!("max_steps_builder");
    }

    #[test]
    fn no_step_limit_builder() {
        init_test("no_step_limit_builder");
        let cfg = LabConfig::new(1).no_step_limit();
        assert_eq!(cfg.max_steps, None);
        crate::test_complete!("no_step_limit_builder");
    }

    #[test]
    fn with_auto_advance_builder() {
        init_test("with_auto_advance_builder");
        let cfg = LabConfig::new(1);
        assert!(!cfg.auto_advance_time);
        let cfg = cfg.with_auto_advance();
        assert!(cfg.auto_advance_time);
        crate::test_complete!("with_auto_advance_builder");
    }

    #[test]
    fn has_chaos_false_by_default() {
        init_test("has_chaos_false_by_default");
        let cfg = LabConfig::new(1);
        assert!(!cfg.has_chaos());
        crate::test_complete!("has_chaos_false_by_default");
    }

    #[test]
    fn with_light_chaos_enables() {
        init_test("with_light_chaos_enables");
        let cfg = LabConfig::new(1).with_light_chaos();
        assert!(cfg.has_chaos());
        assert!(cfg.chaos.is_some());
        crate::test_complete!("with_light_chaos_enables");
    }

    #[test]
    fn with_heavy_chaos_enables() {
        init_test("with_heavy_chaos_enables");
        let cfg = LabConfig::new(1).with_heavy_chaos();
        assert!(cfg.has_chaos());
        crate::test_complete!("with_heavy_chaos_enables");
    }

    #[test]
    fn has_replay_recording_false_by_default() {
        init_test("has_replay_recording_false_by_default");
        let cfg = LabConfig::new(1);
        assert!(!cfg.has_replay_recording());
        crate::test_complete!("has_replay_recording_false_by_default");
    }

    #[test]
    fn with_default_replay_recording_enables() {
        init_test("with_default_replay_recording_enables");
        let cfg = LabConfig::new(1).with_default_replay_recording();
        assert!(cfg.has_replay_recording());
        assert!(cfg.replay_recording.is_some());
        crate::test_complete!("with_default_replay_recording_enables");
    }

    #[test]
    fn builder_chaining() {
        init_test("builder_chaining");
        let cfg = LabConfig::new(99)
            .worker_count(4)
            .entropy_seed(7)
            .trace_capacity(2048)
            .panic_on_leak(false)
            .futurelock_max_idle_steps(3000)
            .panic_on_futurelock(false)
            .max_steps(5000)
            .with_auto_advance();
        assert_eq!(cfg.seed, 99);
        assert_eq!(cfg.worker_count, 4);
        assert_eq!(cfg.entropy_seed, 7);
        assert_eq!(cfg.trace_capacity, 2048);
        assert!(!cfg.panic_on_obligation_leak);
        assert_eq!(cfg.futurelock_max_idle_steps, 3000);
        assert!(!cfg.panic_on_futurelock);
        assert_eq!(cfg.max_steps, Some(5000));
        assert!(cfg.auto_advance_time);
        crate::test_complete!("builder_chaining");
    }

    #[test]
    fn worker_count_positive_value() {
        init_test("worker_count_positive_value");
        let cfg = LabConfig::new(1).worker_count(8);
        assert_eq!(cfg.worker_count, 8);
        crate::test_complete!("worker_count_positive_value");
    }

    #[test]
    fn with_chaos_derives_seed() {
        init_test("with_chaos_derives_seed");
        let cfg = LabConfig::new(42).with_chaos(ChaosConfig::light());
        let chaos = cfg.chaos.as_ref().unwrap();
        // Chaos seed derived from main seed + 0xCAFE_BABE
        let dbg = format!("{chaos:?}");
        assert!(!dbg.is_empty());
        crate::test_complete!("with_chaos_derives_seed");
    }
}