//! `tahuantinsuyu-engine` — bridge entre el modelo agnóstico y
//! `eternal-astrology`.
//!
//! Recibe un `Chart` del modelo + un `ChartKind` y devuelve un
//! [`RenderModel`] que describe la geometría a pintar **sin** acoplar
//! el canvas a tipos de la librería astronómica. El canvas habla
//! grados decimales, radios normalizados y kinds simbólicos.
//!
//! ## Por qué un RenderModel intermedio
//!
//! 1. El canvas no debería caer si cambia el shape de `NatalChart`
//!    upstream.
//! 2. Tests del canvas: podemos generar `RenderModel`s sintéticos sin
//!    arrancar eternal.
//! 3. Cada `ChartKind` produce el mismo shape genérico → el render
//!    coordina N módulos sin saber qué calcularon.
//!
//! ## Feature `eternal-bridge`
//!
//! - **on** (default): [`compute`] abre una `EphemerisSession` VSOP2013
//!   compartida y corre la pipeline real.
//! - **off**: [`compute`] cae a [`compute_mock`] — útil para tests +
//!   builds sin eternal checked out.

#![forbid(unsafe_code)]
#![warn(rust_2018_idioms)]

use serde::{Deserialize, Serialize};
use thiserror::Error;

pub use tahuantinsuyu_model::{Chart, ChartId, ChartKind};

#[cfg(feature = "eternal-bridge")]
mod bridge;

// =====================================================================
// RenderModel — lo que el canvas necesita pintar
// =====================================================================

/// Resultado agnóstico de un cómputo astrológico, listo para renderizar.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RenderModel {
    pub chart_id: ChartId,
    pub chart_kind: ChartKind,
    pub title: String,
    #[serde(default)]
    pub subtitle: Option<String>,
    pub compute_ms: u64,

    // ─── Ángulos del chart (grados eclípticos, 0..360) ───────────────
    /// Ascendente — punto fijo de rotación del lienzo. La rueda se gira
    /// de modo que el Asc cae a las 9 (lado izquierdo).
    pub ascendant_deg: f32,
    pub midheaven_deg: f32,
    pub descendant_deg: f32,
    pub imum_coeli_deg: f32,

    /// Capas a pintar. Orden = z-order ascendente.
    pub layers: Vec<Layer>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Layer {
    pub module_id: String,
    pub kind: LayerKind,
    /// Radio normalizado [0, 1] sobre el lienzo — el canvas lo convierte
    /// a píxeles. Permite stack de anillos.
    pub ring: f32,
    #[serde(default)]
    pub z: i32,
    pub geometry: Geometry,
    #[serde(default)]
    pub glyphs: Vec<Glyph>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum LayerKind {
    SignDial,
    Houses,
    Bodies,
    Aspects,
    Lots,
    FixedStars,
    Midpoints,
    Outer,
    Custom,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Geometry {
    GlyphsOnly,
    /// Anillo dividido en sectores. `cusps_deg` son los grados
    /// zodiacales donde van las divisiones radiales.
    Ring { cusps_deg: Vec<f32> },
    Lines(Vec<LineSeg>),
    Points(Vec<PointMark>),
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LineSeg {
    /// Grados zodiacales del extremo "a".
    pub from_deg: f32,
    /// Grados zodiacales del extremo "b".
    pub to_deg: f32,
    /// Categoría simbólica (`"conjunction"`, `"trine"`, …) — el theme la
    /// resuelve a color.
    pub kind: String,
    pub opacity: f32,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PointMark {
    pub deg: f32,
    pub label: String,
    pub tag: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Glyph {
    /// Grado eclíptico [0, 360).
    pub deg: f32,
    /// Glyph simbólico — el theme/canvas lo mapea a unicode o imagen.
    /// Ej: `"sun"`, `"moon"`, `"aries"`, `"asc"`, `"mc"`.
    pub symbol: String,
    #[serde(default)]
    pub annotation: Option<String>,
    #[serde(default)]
    pub retrograde: bool,
    #[serde(default)]
    pub house: Option<u8>,
}

// =====================================================================
// Errores
// =====================================================================

#[derive(Debug, Error)]
pub enum EngineError {
    #[error("bridge a eternal-astrology no disponible (recompilá con feature `eternal-bridge`)")]
    BridgeDisabled,
    #[error("model: {0}")]
    Model(#[from] tahuantinsuyu_model::ModelError),
    #[error("eternal: {0}")]
    Eternal(String),
    #[error("kind {0:?} todavía no implementado")]
    UnsupportedKind(ChartKind),
}

// =====================================================================
// API pública
// =====================================================================

/// Computa el RenderModel real contra eternal-astrology si el feature
/// está prendido; sino cae al mock.
pub fn compute(chart: &Chart) -> Result<RenderModel, EngineError> {
    compute_at_offset(chart, 0)
}

/// Variante con offset temporal en minutos sobre el instante del chart.
/// Útil para time-scrubbing: el jog-dial del canvas pasa el offset
/// acumulado y la engine recompone toda la pipeline (Asc, casas,
/// posiciones planetarias, aspectos) para ese instante desplazado.
pub fn compute_at_offset(chart: &Chart, offset_minutes: i64) -> Result<RenderModel, EngineError> {
    #[cfg(feature = "eternal-bridge")]
    {
        bridge::compute_at_offset(chart, offset_minutes)
    }
    #[cfg(not(feature = "eternal-bridge"))]
    {
        let _ = offset_minutes;
        Ok(compute_mock(chart))
    }
}

/// Variante con overlay de tránsitos al **instante actual** (reloj de
/// pared). Computa la carta natal igual que [`compute_at_offset`] y le
/// suma dos capas extras:
///
/// - `LayerKind::Outer` con `module_id = "transit"` — glifos
///   planetarios del cielo del momento, sobre un anillo externo.
/// - `LayerKind::Aspects` con `module_id = "transit"` — líneas natal ↔
///   transit (sólo aspectos mayores). Por convención, en cada
///   `LineSeg` el `from_deg` es la longitud natal y el `to_deg` la
///   longitud del planeta de tránsito.
///
/// Sin el feature `eternal-bridge` cae al mock (sin overlay).
pub fn compute_with_transits_at_now(
    chart: &Chart,
    offset_minutes: i64,
) -> Result<RenderModel, EngineError> {
    #[cfg(feature = "eternal-bridge")]
    {
        bridge::compute_with_transits_at_now(chart, offset_minutes)
    }
    #[cfg(not(feature = "eternal-bridge"))]
    {
        let _ = offset_minutes;
        Ok(compute_mock(chart))
    }
}

/// Stub determinista — útil para tests + para la UI sin eternal.
pub fn compute_mock(chart: &Chart) -> RenderModel {
    use std::time::Instant;
    let t0 = Instant::now();

    let sign_dial = Layer {
        module_id: "natal".into(),
        kind: LayerKind::SignDial,
        ring: 1.0,
        z: 0,
        geometry: Geometry::Ring {
            cusps_deg: (0..12).map(|i| (i as f32) * 30.0).collect(),
        },
        glyphs: (0..12)
            .map(|i| Glyph {
                deg: (i as f32) * 30.0 + 15.0,
                symbol: ZODIAC_GLYPHS[i].into(),
                annotation: None,
                retrograde: false,
                house: None,
            })
            .collect(),
    };

    RenderModel {
        chart_id: chart.id,
        chart_kind: chart.kind,
        title: chart.label.clone(),
        subtitle: chart.birth_data.birthplace_label.clone(),
        compute_ms: t0.elapsed().as_millis() as u64,
        ascendant_deg: 0.0,
        midheaven_deg: 270.0,
        descendant_deg: 180.0,
        imum_coeli_deg: 90.0,
        layers: vec![sign_dial],
    }
}

const ZODIAC_GLYPHS: [&str; 12] = [
    "aries",
    "taurus",
    "gemini",
    "cancer",
    "leo",
    "virgo",
    "libra",
    "scorpio",
    "sagittarius",
    "capricorn",
    "aquarius",
    "pisces",
];

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

#[cfg(test)]
mod tests {
    use super::*;
    use tahuantinsuyu_model::{
        Chart, ChartKind, ContactId, StoredBirthData, StoredChartConfig,
    };

    fn sample_chart() -> Chart {
        Chart {
            id: ChartId::new(),
            contact_id: ContactId::new(),
            kind: ChartKind::Natal,
            label: "test".into(),
            birth_data: StoredBirthData {
                year: 1987,
                month: 3,
                day: 14,
                hour: 5,
                minute: 22,
                second: 0.0,
                tz_offset_minutes: -240,
                latitude_deg: 10.4806,
                longitude_deg: -66.9036,
                altitude_m: 900.0,
                time_certainty: Default::default(),
                subject_name: None,
                birthplace_label: None,
            },
            config: StoredChartConfig::default(),
            related_chart_id: None,
            created_at_ms: 0,
        }
    }

    #[test]
    fn mock_emits_sign_dial() {
        let model = compute_mock(&sample_chart());
        assert_eq!(model.layers.len(), 1);
        assert!(matches!(model.layers[0].kind, LayerKind::SignDial));
        assert_eq!(model.layers[0].glyphs.len(), 12);
    }

    #[cfg(feature = "eternal-bridge")]
    #[test]
    fn real_compute_natal_demo() {
        let model = compute(&sample_chart()).expect("compute con eternal");
        assert!(model.layers.iter().any(|l| matches!(l.kind, LayerKind::SignDial)));
        assert!(model.layers.iter().any(|l| matches!(l.kind, LayerKind::Houses)));
        assert!(model.layers.iter().any(|l| matches!(l.kind, LayerKind::Bodies)));
        // El Asc debe ser un grado válido.
        assert!(model.ascendant_deg.is_finite());
        assert!((0.0..360.0).contains(&model.ascendant_deg));
    }
}