//! Shared types for the SeismicAI earthquake simulation and early warning demo.
//!
//! This crate provides IPC types for seismic wave propagation simulation
//! using neural operators for fast ground motion prediction.

use serde::{Deserialize, Serialize};

// ============================================================================
// Geographic Types
// ============================================================================

/// Geographic location (latitude, longitude).
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub struct GeoLocation {
    /// Latitude in degrees (-90 to 90).
    pub latitude: f64,
    /// Longitude in degrees (-180 to 180).
    pub longitude: f64,
}

impl GeoLocation {
    pub fn new(latitude: f64, longitude: f64) -> Self {
        Self {
            latitude,
            longitude,
        }
    }

    /// Calculate distance to another location in kilometers (Haversine formula).
    pub fn distance_km(&self, other: &GeoLocation) -> f64 {
        const EARTH_RADIUS_KM: f64 = 6371.0;

        let lat1 = self.latitude.to_radians();
        let lat2 = other.latitude.to_radians();
        let dlat = (other.latitude - self.latitude).to_radians();
        let dlon = (other.longitude - self.longitude).to_radians();

        let a = (dlat / 2.0).sin().powi(2) + lat1.cos() * lat2.cos() * (dlon / 2.0).sin().powi(2);
        let c = 2.0 * a.sqrt().asin();

        EARTH_RADIUS_KM * c
    }

    /// Calculate azimuth to another location in degrees.
    pub fn azimuth_deg(&self, other: &GeoLocation) -> f64 {
        let lat1 = self.latitude.to_radians();
        let lat2 = other.latitude.to_radians();
        let dlon = (other.longitude - self.longitude).to_radians();

        let x = dlon.sin() * lat2.cos();
        let y = lat1.cos() * lat2.sin() - lat1.sin() * lat2.cos() * dlon.cos();

        x.atan2(y).to_degrees().rem_euclid(360.0)
    }
}

impl Default for GeoLocation {
    fn default() -> Self {
        // San Francisco, CA
        Self {
            latitude: 37.7749,
            longitude: -122.4194,
        }
    }
}

/// 3D position including depth.
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub struct Position3D {
    /// Geographic location.
    pub location: GeoLocation,
    /// Depth in kilometers (positive downward).
    pub depth_km: f64,
}

impl Position3D {
    pub fn new(latitude: f64, longitude: f64, depth_km: f64) -> Self {
        Self {
            location: GeoLocation::new(latitude, longitude),
            depth_km,
        }
    }

    /// Calculate 3D distance to another position in kilometers.
    pub fn distance_3d_km(&self, other: &Position3D) -> f64 {
        let horizontal = self.location.distance_km(&other.location);
        let vertical = (self.depth_km - other.depth_km).abs();
        (horizontal.powi(2) + vertical.powi(2)).sqrt()
    }
}

// ============================================================================
// Earthquake Source Types
// ============================================================================

/// Focal mechanism (beach ball) parameters.
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub struct FocalMechanism {
    /// Strike angle in degrees (0-360).
    pub strike: f64,
    /// Dip angle in degrees (0-90).
    pub dip: f64,
    /// Rake angle in degrees (-180 to 180).
    pub rake: f64,
}

impl FocalMechanism {
    pub fn new(strike: f64, dip: f64, rake: f64) -> Self {
        Self { strike, dip, rake }
    }

    /// Strike-slip mechanism (vertical fault, horizontal slip).
    pub fn strike_slip() -> Self {
        Self {
            strike: 0.0,
            dip: 90.0,
            rake: 0.0,
        }
    }

    /// Normal fault mechanism (extensional).
    pub fn normal() -> Self {
        Self {
            strike: 0.0,
            dip: 60.0,
            rake: -90.0,
        }
    }

    /// Reverse/thrust fault mechanism (compressional).
    pub fn reverse() -> Self {
        Self {
            strike: 0.0,
            dip: 30.0,
            rake: 90.0,
        }
    }

    /// Calculate slip vector direction in local coordinates.
    pub fn slip_direction(&self) -> (f64, f64, f64) {
        let strike_rad = self.strike.to_radians();
        let dip_rad = self.dip.to_radians();
        let rake_rad = self.rake.to_radians();

        let x =
            rake_rad.cos() * strike_rad.cos() + rake_rad.sin() * dip_rad.cos() * strike_rad.sin();
        let y =
            rake_rad.cos() * strike_rad.sin() - rake_rad.sin() * dip_rad.cos() * strike_rad.cos();
        let z = -rake_rad.sin() * dip_rad.sin();

        (x, y, z)
    }
}

impl Default for FocalMechanism {
    fn default() -> Self {
        Self::strike_slip()
    }
}

/// Earthquake source parameters.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct EarthquakeSource {
    /// Event identifier.
    pub event_id: String,
    /// Hypocenter location.
    pub hypocenter: Position3D,
    /// Moment magnitude (Mw).
    pub magnitude: f64,
    /// Focal mechanism.
    pub mechanism: FocalMechanism,
    /// Origin time in seconds from simulation start.
    pub origin_time: f64,
    /// Rupture area in km^2 (estimated from magnitude if not provided).
    pub rupture_area_km2: Option<f64>,
    /// Average slip in meters (estimated from magnitude if not provided).
    pub average_slip_m: Option<f64>,
    /// Rupture duration in seconds.
    pub rupture_duration_s: Option<f64>,
    /// Stress drop in MPa.
    pub stress_drop_mpa: Option<f64>,
}

impl EarthquakeSource {
    pub fn new(
        latitude: f64,
        longitude: f64,
        depth_km: f64,
        magnitude: f64,
        mechanism: FocalMechanism,
    ) -> Self {
        Self {
            event_id: format!("EQ_{:.4}_{:.4}_{:.1}", latitude, longitude, magnitude),
            hypocenter: Position3D::new(latitude, longitude, depth_km),
            magnitude,
            mechanism,
            origin_time: 0.0,
            rupture_area_km2: None,
            average_slip_m: None,
            rupture_duration_s: None,
            stress_drop_mpa: None,
        }
    }

    /// Estimate seismic moment in N*m from magnitude.
    pub fn seismic_moment(&self) -> f64 {
        10.0_f64.powf(1.5 * self.magnitude + 9.1)
    }

    /// Estimate rupture area in km^2 from magnitude (Wells & Coppersmith 1994).
    pub fn estimated_rupture_area(&self) -> f64 {
        self.rupture_area_km2
            .unwrap_or_else(|| 10.0_f64.powf(self.magnitude - 4.0))
    }

    /// Estimate rupture length in km.
    pub fn estimated_rupture_length(&self) -> f64 {
        10.0_f64.powf(0.5 * self.magnitude - 1.85)
    }

    /// Estimate rupture duration in seconds.
    pub fn estimated_rupture_duration(&self) -> f64 {
        self.rupture_duration_s
            .unwrap_or_else(|| 10.0_f64.powf(0.5 * self.magnitude - 2.5))
    }

    /// Corner frequency in Hz.
    pub fn corner_frequency(&self) -> f64 {
        1.0 / self.estimated_rupture_duration()
    }
}

impl Default for EarthquakeSource {
    fn default() -> Self {
        Self::new(37.0, -122.0, 10.0, 5.0, FocalMechanism::strike_slip())
    }
}

// ============================================================================
// Ground Motion Types
// ============================================================================

/// Ground motion parameters at a station.
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub struct GroundMotion {
    /// Peak Ground Acceleration in g.
    pub pga: f64,
    /// Peak Ground Velocity in cm/s.
    pub pgv: f64,
    /// Peak Ground Displacement in cm.
    pub pgd: f64,
    /// P-wave arrival time in seconds from origin.
    pub p_arrival_time: f64,
    /// S-wave arrival time in seconds from origin.
    pub s_arrival_time: f64,
    /// Duration of strong shaking (5-95% Arias intensity) in seconds.
    pub duration_5_95: f64,
    /// Spectral acceleration at 0.3s period in g.
    pub sa_03: f64,
    /// Spectral acceleration at 1.0s period in g.
    pub sa_10: f64,
    /// Spectral acceleration at 3.0s period in g.
    pub sa_30: f64,
    /// Modified Mercalli Intensity (estimated).
    pub mmi: f64,
}

impl GroundMotion {
    /// Calculate MMI from PGA (Wald et al., 1999).
    pub fn estimate_mmi_from_pga(pga_g: f64) -> f64 {
        let pga_cm_s2 = pga_g * 980.665;
        if pga_cm_s2 < 0.0017 {
            1.0
        } else {
            (3.66 * pga_cm_s2.log10() - 1.66).clamp(1.0, 12.0)
        }
    }

    /// Calculate MMI from PGV (Wald et al., 1999).
    pub fn estimate_mmi_from_pgv(pgv_cm_s: f64) -> f64 {
        if pgv_cm_s < 0.1 {
            1.0
        } else {
            (3.47 * pgv_cm_s.log10() + 2.35).clamp(1.0, 12.0)
        }
    }

    /// Create ground motion from basic parameters.
    pub fn from_pga_pgv(pga: f64, pgv: f64, p_arrival: f64, s_arrival: f64) -> Self {
        let mmi = f64::midpoint(
            Self::estimate_mmi_from_pga(pga),
            Self::estimate_mmi_from_pgv(pgv),
        );
        Self {
            pga,
            pgv,
            pgd: pgv * 0.1, // Rough estimate
            p_arrival_time: p_arrival,
            s_arrival_time: s_arrival,
            duration_5_95: 10.0 + (s_arrival - p_arrival) * 2.0,
            sa_03: pga * 2.5, // Amplification factor estimate
            sa_10: pga * 1.0,
            sa_30: pga * 0.3,
            mmi,
        }
    }
}

impl Default for GroundMotion {
    fn default() -> Self {
        Self {
            pga: 0.0,
            pgv: 0.0,
            pgd: 0.0,
            p_arrival_time: 0.0,
            s_arrival_time: 0.0,
            duration_5_95: 0.0,
            sa_03: 0.0,
            sa_10: 0.0,
            sa_30: 0.0,
            mmi: 1.0,
        }
    }
}

// ============================================================================
// Station Types
// ============================================================================

/// Seismic instrument type.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
pub enum InstrumentType {
    /// Strong motion accelerometer.
    #[default]
    Accelerometer,
    /// Broadband seismometer.
    Broadband,
    /// Short-period seismometer.
    ShortPeriod,
    /// MEMS accelerometer (low-cost).
    Mems,
    /// Rotational sensor.
    Rotational,
}

/// Site class based on Vs30 (average shear-wave velocity in top 30m).
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
pub enum SiteClass {
    /// Hard rock (Vs30 > 1500 m/s).
    A,
    /// Rock (760 < Vs30 <= 1500 m/s).
    B,
    /// Very dense soil / soft rock (360 < Vs30 <= 760 m/s).
    #[default]
    C,
    /// Stiff soil (180 < Vs30 <= 360 m/s).
    D,
    /// Soft soil (Vs30 <= 180 m/s).
    E,
}

impl SiteClass {
    /// Get approximate Vs30 for this site class.
    pub fn typical_vs30(&self) -> f64 {
        match self {
            SiteClass::A => 2000.0,
            SiteClass::B => 1000.0,
            SiteClass::C => 500.0,
            SiteClass::D => 270.0,
            SiteClass::E => 150.0,
        }
    }

    /// Get site amplification factor.
    pub fn amplification_factor(&self) -> f64 {
        match self {
            SiteClass::A => 0.8,
            SiteClass::B => 1.0,
            SiteClass::C => 1.2,
            SiteClass::D => 1.6,
            SiteClass::E => 2.5,
        }
    }
}

/// Seismic station configuration.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StationConfig {
    /// Station code.
    pub code: String,
    /// Station name.
    pub name: String,
    /// Station location.
    pub location: GeoLocation,
    /// Instrument type.
    pub instrument: InstrumentType,
    /// Site class.
    pub site_class: SiteClass,
    /// Vs30 in m/s (if measured).
    pub vs30: Option<f64>,
    /// Basin depth (Z1.0) in km.
    pub z1_0: Option<f64>,
    /// Basin depth (Z2.5) in km.
    pub z2_5: Option<f64>,
    /// Network code.
    pub network: String,
    /// Whether station is operational.
    pub operational: bool,
}

impl StationConfig {
    pub fn new(code: &str, latitude: f64, longitude: f64) -> Self {
        Self {
            code: code.to_string(),
            name: format!("Station {}", code),
            location: GeoLocation::new(latitude, longitude),
            instrument: InstrumentType::Accelerometer,
            site_class: SiteClass::C,
            vs30: None,
            z1_0: None,
            z2_5: None,
            network: "XX".to_string(),
            operational: true,
        }
    }

    /// Get Vs30 (use measured or site class default).
    pub fn get_vs30(&self) -> f64 {
        self.vs30.unwrap_or_else(|| self.site_class.typical_vs30())
    }
}

impl Default for StationConfig {
    fn default() -> Self {
        Self::new("STA01", 37.8, -122.4)
    }
}

// ============================================================================
// Velocity Model Types
// ============================================================================

/// 1D velocity model layer.
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub struct VelocityLayer {
    /// Depth to top of layer in km.
    pub depth_km: f64,
    /// Thickness of layer in km.
    pub thickness_km: f64,
    /// P-wave velocity in km/s.
    pub vp: f64,
    /// S-wave velocity in km/s.
    pub vs: f64,
    /// Density in g/cm^3.
    pub density: f64,
    /// P-wave quality factor (attenuation).
    pub qp: f64,
    /// S-wave quality factor (attenuation).
    pub qs: f64,
}

impl VelocityLayer {
    pub fn new(depth_km: f64, thickness_km: f64, vp: f64, vs: f64, density: f64) -> Self {
        Self {
            depth_km,
            thickness_km,
            vp,
            vs,
            density,
            qp: 500.0,
            qs: 250.0,
        }
    }

    /// Vp/Vs ratio.
    pub fn vp_vs_ratio(&self) -> f64 {
        self.vp / self.vs
    }

    /// Poisson's ratio.
    pub fn poisson_ratio(&self) -> f64 {
        let ratio = self.vp_vs_ratio();
        (ratio.powi(2) - 2.0) / (2.0 * (ratio.powi(2) - 1.0))
    }

    /// Shear modulus in GPa.
    pub fn shear_modulus(&self) -> f64 {
        self.density * self.vs.powi(2)
    }
}

/// 1D layered velocity model.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VelocityModel {
    /// Model name.
    pub name: String,
    /// Layers from surface to depth.
    pub layers: Vec<VelocityLayer>,
    /// Reference latitude.
    pub reference_lat: f64,
    /// Reference longitude.
    pub reference_lon: f64,
}

impl VelocityModel {
    pub fn new(name: &str) -> Self {
        Self {
            name: name.to_string(),
            layers: Vec::new(),
            reference_lat: 0.0,
            reference_lon: 0.0,
        }
    }

    /// Add a layer to the model.
    pub fn add_layer(&mut self, layer: VelocityLayer) {
        self.layers.push(layer);
    }

    /// Get velocity at depth.
    pub fn velocity_at_depth(&self, depth_km: f64) -> Option<(f64, f64)> {
        let mut cumulative_depth = 0.0;
        for layer in &self.layers {
            cumulative_depth += layer.thickness_km;
            if depth_km <= cumulative_depth {
                return Some((layer.vp, layer.vs));
            }
        }
        self.layers.last().map(|l| (l.vp, l.vs))
    }

    /// Calculate travel time for P-wave.
    pub fn p_wave_travel_time(&self, distance_km: f64, depth_km: f64) -> f64 {
        // Simplified calculation using average velocity
        let avg_vp = self.layers.iter().map(|l| l.vp).sum::<f64>() / self.layers.len() as f64;
        let path_length = (distance_km.powi(2) + depth_km.powi(2)).sqrt();
        path_length / avg_vp
    }

    /// Calculate travel time for S-wave.
    pub fn s_wave_travel_time(&self, distance_km: f64, depth_km: f64) -> f64 {
        let avg_vs = self.layers.iter().map(|l| l.vs).sum::<f64>() / self.layers.len() as f64;
        let path_length = (distance_km.powi(2) + depth_km.powi(2)).sqrt();
        path_length / avg_vs
    }
}

impl Default for VelocityModel {
    fn default() -> Self {
        let mut model = Self::new("Generic");
        model.add_layer(VelocityLayer::new(0.0, 5.0, 5.5, 3.2, 2.6));
        model.add_layer(VelocityLayer::new(5.0, 15.0, 6.5, 3.7, 2.8));
        model.add_layer(VelocityLayer::new(20.0, 15.0, 7.8, 4.5, 3.2));
        model
    }
}

// ============================================================================
// Simulation Configuration
// ============================================================================

/// Wave propagation simulation configuration.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SimulationConfig {
    /// Time step in seconds.
    pub dt: f64,
    /// Total simulation duration in seconds.
    pub duration: f64,
    /// Spatial resolution in km.
    pub dx: f64,
    /// Domain size in km (x, y, z).
    pub domain_size: (f64, f64, f64),
    /// Maximum frequency in Hz.
    pub max_frequency: f64,
    /// Include anelastic attenuation.
    pub include_attenuation: bool,
    /// Include site effects.
    pub include_site_effects: bool,
    /// Use neural operator for acceleration.
    pub use_neural_operator: bool,
    /// Number of Fourier modes for FNO.
    pub fno_modes: usize,
    /// Hidden dimension for neural networks.
    pub hidden_dim: usize,
}

impl Default for SimulationConfig {
    fn default() -> Self {
        Self {
            dt: 0.01,
            duration: 60.0,
            dx: 0.5,
            domain_size: (100.0, 100.0, 50.0),
            max_frequency: 10.0,
            include_attenuation: true,
            include_site_effects: true,
            use_neural_operator: true,
            fno_modes: 16,
            hidden_dim: 64,
        }
    }
}

// ============================================================================
// Early Warning Configuration
// ============================================================================

/// Warning alert level.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize, Default)]
pub enum AlertLevel {
    /// No alert.
    #[default]
    None,
    /// Information only.
    Advisory,
    /// Prepare for shaking.
    Watch,
    /// Shaking imminent.
    Warning,
    /// Severe shaking expected.
    Severe,
}

impl AlertLevel {
    /// Get alert level from MMI.
    pub fn from_mmi(mmi: f64) -> Self {
        if mmi < 3.0 {
            AlertLevel::None
        } else if mmi < 4.0 {
            AlertLevel::Advisory
        } else if mmi < 5.0 {
            AlertLevel::Watch
        } else if mmi < 7.0 {
            AlertLevel::Warning
        } else {
            AlertLevel::Severe
        }
    }

    /// Get alert level from PGA.
    pub fn from_pga(pga: f64) -> Self {
        if pga < 0.01 {
            AlertLevel::None
        } else if pga < 0.05 {
            AlertLevel::Advisory
        } else if pga < 0.1 {
            AlertLevel::Watch
        } else if pga < 0.3 {
            AlertLevel::Warning
        } else {
            AlertLevel::Severe
        }
    }
}

/// Early warning system configuration.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WarningConfig {
    /// Minimum magnitude to issue warning.
    pub min_magnitude: f64,
    /// Minimum number of stations for detection.
    pub min_stations: usize,
    /// Alert threshold (seconds of warning time).
    pub alert_threshold_seconds: f64,
    /// Enable sound alerts.
    pub enable_sound: bool,
    /// Enable push notifications.
    pub enable_notifications: bool,
    /// Alert radius in km.
    pub alert_radius_km: f64,
}

impl Default for WarningConfig {
    fn default() -> Self {
        Self {
            min_magnitude: 4.0,
            min_stations: 3,
            alert_threshold_seconds: 3.0,
            enable_sound: true,
            enable_notifications: true,
            alert_radius_km: 100.0,
        }
    }
}

/// Earthquake early warning alert.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EarthquakeWarning {
    /// Event identifier.
    pub event_id: String,
    /// Alert level.
    pub alert_level: AlertLevel,
    /// Estimated magnitude.
    pub estimated_magnitude: f64,
    /// Estimated location.
    pub estimated_location: GeoLocation,
    /// Estimated depth in km.
    pub estimated_depth_km: f64,
    /// Number of stations detecting event.
    pub detecting_stations: usize,
    /// Time to S-wave arrival in seconds.
    pub time_to_shaking: f64,
    /// Expected peak ground motion.
    pub expected_ground_motion: GroundMotion,
    /// Warning issued time (seconds from simulation start).
    pub warning_time: f64,
    /// Origin time (seconds from simulation start).
    pub origin_time: f64,
    /// Confidence level (0-1).
    pub confidence: f64,
}

impl Default for EarthquakeWarning {
    fn default() -> Self {
        Self {
            event_id: String::new(),
            alert_level: AlertLevel::None,
            estimated_magnitude: 0.0,
            estimated_location: GeoLocation::default(),
            estimated_depth_km: 10.0,
            detecting_stations: 0,
            time_to_shaking: 0.0,
            expected_ground_motion: GroundMotion::default(),
            warning_time: 0.0,
            origin_time: 0.0,
            confidence: 0.0,
        }
    }
}

// ============================================================================
// Simulation Results
// ============================================================================

/// Wave field snapshot.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WaveFieldSnapshot {
    /// Time of snapshot in seconds.
    pub time: f64,
    /// X-displacement field.
    pub displacement_x: Vec<Vec<f32>>,
    /// Y-displacement field.
    pub displacement_y: Vec<Vec<f32>>,
    /// Z-displacement field.
    pub displacement_z: Vec<Vec<f32>>,
    /// Grid X coordinates.
    pub grid_x: Vec<f32>,
    /// Grid Y coordinates.
    pub grid_y: Vec<f32>,
}

/// Seismogram at a station.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Seismogram {
    /// Station code.
    pub station_code: String,
    /// Time samples in seconds.
    pub time: Vec<f64>,
    /// East-West component (acceleration in g).
    pub east: Vec<f64>,
    /// North-South component (acceleration in g).
    pub north: Vec<f64>,
    /// Vertical component (acceleration in g).
    pub vertical: Vec<f64>,
    /// Sample rate in Hz.
    pub sample_rate: f64,
}

impl Seismogram {
    pub fn new(station_code: &str, num_samples: usize, sample_rate: f64) -> Self {
        let time: Vec<f64> = (0..num_samples).map(|i| i as f64 / sample_rate).collect();
        Self {
            station_code: station_code.to_string(),
            time,
            east: vec![0.0; num_samples],
            north: vec![0.0; num_samples],
            vertical: vec![0.0; num_samples],
            sample_rate,
        }
    }

    /// Calculate PGA from all components.
    pub fn pga(&self) -> f64 {
        let max_e = self.east.iter().map(|v| v.abs()).fold(0.0_f64, f64::max);
        let max_n = self.north.iter().map(|v| v.abs()).fold(0.0_f64, f64::max);
        let max_v = self
            .vertical
            .iter()
            .map(|v| v.abs())
            .fold(0.0_f64, f64::max);
        (max_e.powi(2) + max_n.powi(2) + max_v.powi(2)).sqrt()
    }

    /// Calculate horizontal PGA.
    pub fn pga_horizontal(&self) -> f64 {
        self.east
            .iter()
            .zip(self.north.iter())
            .map(|(e, n)| (e.powi(2) + n.powi(2)).sqrt())
            .fold(0.0_f64, f64::max)
    }
}

/// Complete simulation result.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SimulationResult {
    /// Earthquake source.
    pub source: EarthquakeSource,
    /// Station ground motions.
    pub ground_motions: Vec<(StationConfig, GroundMotion)>,
    /// Seismograms (optional, may be large).
    pub seismograms: Option<Vec<Seismogram>>,
    /// Wave field snapshots (optional).
    pub snapshots: Option<Vec<WaveFieldSnapshot>>,
    /// Early warning issued.
    pub warning: Option<EarthquakeWarning>,
    /// Computation time in milliseconds.
    pub computation_time_ms: f64,
}

// ============================================================================
// Sample Data Functions
// ============================================================================

/// Create a sample local earthquake (shallow, nearby).
pub fn sample_local_earthquake() -> EarthquakeSource {
    EarthquakeSource::new(
        37.8044, // Near Berkeley, CA
        -122.2712,
        8.0, // 8 km depth
        4.5, // M4.5
        FocalMechanism::strike_slip(),
    )
}

/// Create a sample regional earthquake (moderate, distant).
pub fn sample_regional_earthquake() -> EarthquakeSource {
    EarthquakeSource::new(
        36.5, // Central California
        -121.0,
        15.0, // 15 km depth
        6.0,  // M6.0
        FocalMechanism::reverse(),
    )
}

/// Create a sample major earthquake.
pub fn sample_major_earthquake() -> EarthquakeSource {
    EarthquakeSource::new(
        37.4, // Near San Jose
        -122.1,
        10.0, // 10 km depth
        7.0,  // M7.0
        FocalMechanism::strike_slip(),
    )
}

/// Create a sample dense station network.
pub fn sample_dense_network() -> Vec<StationConfig> {
    let mut stations = Vec::new();
    let center_lat = 37.8;
    let center_lon = -122.4;

    for i in 0..10 {
        for j in 0..10 {
            let lat = center_lat - 0.5 + (i as f64) * 0.1;
            let lon = center_lon - 0.5 + (j as f64) * 0.1;
            let code = format!("S{:02}{:02}", i, j);
            let mut station = StationConfig::new(&code, lat, lon);
            station.network = "CI".to_string();
            stations.push(station);
        }
    }

    stations
}

/// Create a sample sparse station network.
pub fn sample_sparse_network() -> Vec<StationConfig> {
    vec![
        StationConfig::new("BK.BKS", 37.8764, -122.2356),
        StationConfig::new("BK.CMB", 38.0346, -120.3865),
        StationConfig::new("BK.SAO", 36.7640, -121.4472),
        StationConfig::new("CI.SLA", 35.8900, -117.2833),
        StationConfig::new("NC.KRP", 40.4916, -124.2834),
    ]
}

/// Create a California velocity model.
pub fn sample_california_velocity_model() -> VelocityModel {
    let mut model = VelocityModel::new("California Generic");
    model.reference_lat = 37.0;
    model.reference_lon = -122.0;

    // Simplified California crust
    model.add_layer(VelocityLayer::new(0.0, 2.0, 4.0, 2.3, 2.4));
    model.add_layer(VelocityLayer::new(2.0, 5.0, 5.5, 3.2, 2.6));
    model.add_layer(VelocityLayer::new(7.0, 8.0, 6.3, 3.6, 2.8));
    model.add_layer(VelocityLayer::new(15.0, 10.0, 6.7, 3.9, 2.9));
    model.add_layer(VelocityLayer::new(25.0, 10.0, 7.8, 4.5, 3.2));

    model
}

/// Create default simulation configuration.
pub fn sample_simulation_config() -> SimulationConfig {
    SimulationConfig::default()
}

/// Create default warning configuration.
pub fn sample_warning_config() -> WarningConfig {
    WarningConfig::default()
}

// ============================================================================
// Tests
// ============================================================================

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

    #[test]
    fn test_geo_location_distance() {
        let sf = GeoLocation::new(37.7749, -122.4194);
        let la = GeoLocation::new(34.0522, -118.2437);
        let distance = sf.distance_km(&la);
        // SF to LA is about 560 km
        assert!((distance - 560.0).abs() < 10.0);
    }

    #[test]
    fn test_geo_location_azimuth() {
        let origin = GeoLocation::new(0.0, 0.0);
        let north = GeoLocation::new(1.0, 0.0);
        let east = GeoLocation::new(0.0, 1.0);

        let azimuth_to_north = origin.azimuth_deg(&north);
        let azimuth_to_east = origin.azimuth_deg(&east);

        assert!((azimuth_to_north - 0.0).abs() < 1.0);
        assert!((azimuth_to_east - 90.0).abs() < 1.0);
    }

    #[test]
    fn test_focal_mechanism() {
        let ss = FocalMechanism::strike_slip();
        assert_eq!(ss.dip, 90.0);
        assert_eq!(ss.rake, 0.0);

        let reverse = FocalMechanism::reverse();
        assert_eq!(reverse.rake, 90.0);

        let normal = FocalMechanism::normal();
        assert_eq!(normal.rake, -90.0);
    }

    #[test]
    fn test_earthquake_source() {
        let eq = EarthquakeSource::new(37.0, -122.0, 10.0, 6.0, FocalMechanism::strike_slip());

        // M6.0 should have seismic moment around 10^18 N*m
        let moment = eq.seismic_moment();
        assert!(moment > 1e17 && moment < 1e19);

        // Rupture area should be reasonable
        let area = eq.estimated_rupture_area();
        assert!(area > 1.0 && area < 1000.0);
    }

    #[test]
    fn test_ground_motion_mmi() {
        let mmi_pga = GroundMotion::estimate_mmi_from_pga(0.1);
        assert!(mmi_pga > 5.0 && mmi_pga < 8.0);

        let mmi_pgv = GroundMotion::estimate_mmi_from_pgv(10.0);
        assert!(mmi_pgv > 5.0 && mmi_pgv < 8.0);
    }

    #[test]
    fn test_site_class() {
        assert!(SiteClass::A.typical_vs30() > SiteClass::E.typical_vs30());
        assert!(SiteClass::E.amplification_factor() > SiteClass::A.amplification_factor());
    }

    #[test]
    fn test_velocity_model() {
        let model = sample_california_velocity_model();
        assert!(!model.layers.is_empty());

        let (vp, vs) = model.velocity_at_depth(10.0).unwrap();
        assert!(vp > vs);
        assert!(vp / vs > 1.5 && vp / vs < 2.0);
    }

    #[test]
    fn test_velocity_layer() {
        let layer = VelocityLayer::new(0.0, 5.0, 6.0, 3.5, 2.7);

        let poisson = layer.poisson_ratio();
        assert!(poisson > 0.2 && poisson < 0.35);

        let vp_vs = layer.vp_vs_ratio();
        assert!((vp_vs - 6.0 / 3.5).abs() < 0.01);
    }

    #[test]
    fn test_alert_level() {
        assert_eq!(AlertLevel::from_mmi(2.0), AlertLevel::None);
        assert_eq!(AlertLevel::from_mmi(6.0), AlertLevel::Warning);
        assert_eq!(AlertLevel::from_mmi(8.0), AlertLevel::Severe);

        assert_eq!(AlertLevel::from_pga(0.005), AlertLevel::None);
        assert_eq!(AlertLevel::from_pga(0.2), AlertLevel::Warning);
        assert_eq!(AlertLevel::from_pga(0.5), AlertLevel::Severe);
    }

    #[test]
    fn test_seismogram() {
        let mut seis = Seismogram::new("TEST", 1000, 100.0);
        seis.east[500] = 0.1;
        seis.north[500] = 0.1;

        let pga_h = seis.pga_horizontal();
        assert!((pga_h - (0.02_f64).sqrt()).abs() < 0.001);
    }

    #[test]
    fn test_sample_networks() {
        let dense = sample_dense_network();
        assert_eq!(dense.len(), 100);

        let sparse = sample_sparse_network();
        assert!(sparse.len() < 10);
    }

    #[test]
    fn test_sample_earthquakes() {
        let local = sample_local_earthquake();
        assert!(local.magnitude < 5.0);

        let regional = sample_regional_earthquake();
        assert!(regional.magnitude >= 5.0);

        let major = sample_major_earthquake();
        assert!(major.magnitude >= 7.0);
    }

    #[test]
    fn test_serialization() {
        let eq = sample_local_earthquake();
        let json = serde_json::to_string(&eq).unwrap();
        let _: EarthquakeSource = serde_json::from_str(&json).unwrap();

        let station = StationConfig::default();
        let json = serde_json::to_string(&station).unwrap();
        let _: StationConfig = serde_json::from_str(&json).unwrap();
    }

    #[test]
    fn test_position_3d() {
        let p1 = Position3D::new(37.0, -122.0, 10.0);
        let p2 = Position3D::new(37.0, -122.0, 20.0);

        let dist = p1.distance_3d_km(&p2);
        assert!((dist - 10.0).abs() < 0.1);
    }

    #[test]
    fn test_config_defaults() {
        let sim_config = SimulationConfig::default();
        assert!(sim_config.duration > 0.0);
        assert!(sim_config.use_neural_operator);

        let warn_config = WarningConfig::default();
        assert!(warn_config.min_magnitude > 0.0);
    }
}