//! Abutment (교대) Feature builder.

use cimery_core::{AbutmentType, FeatureError, MaterialGrade, Mm, M, UnitExt};
use cimery_ir::{AbutmentIR, FeatureId, WingWallIR};

#[derive(Debug)]
pub struct Abutment {
    pub ir: AbutmentIR,
}

impl Abutment {
    pub fn builder() -> AbutmentBuilder { AbutmentBuilder::default() }
}

/// Builder for an Abutment Feature.
#[derive(Default)]
pub struct AbutmentBuilder {
    station:                 Option<M>,
    skew_angle:              Option<f64>,
    abutment_type:           Option<AbutmentType>,
    breast_wall_height:      Option<Mm>,
    breast_wall_thickness:   Option<Mm>,
    breast_wall_width:       Option<Mm>,
    footing_length:          Option<Mm>,
    footing_width:           Option<Mm>,
    footing_thickness:       Option<Mm>,
    wing_length:             Option<Mm>,   // simplified: same left & right
    material:                Option<MaterialGrade>,
}

impl AbutmentBuilder {
    /// #[param(unit="m")] Station along alignment
    pub fn station(mut self, v: M) -> Self { self.station = Some(v); self }
    /// #[param(unit="deg", range=-45.0..=45.0, default=0.0)]
    pub fn skew_angle(mut self, v: f64) -> Self { self.skew_angle = Some(v); self }
    /// #[param(enum=AbutmentType, default=ReverseT)]
    pub fn abutment_type(mut self, t: AbutmentType) -> Self { self.abutment_type = Some(t); self }
    /// #[param(unit="mm", range=2000.0..=12_000.0)] Breast wall height
    pub fn breast_wall_height(mut self, v: Mm) -> Self { self.breast_wall_height = Some(v); self }
    /// #[param(unit="mm", range=500.0..=3000.0, default=800.0)]
    pub fn breast_wall_thickness(mut self, v: Mm) -> Self { self.breast_wall_thickness = Some(v); self }
    /// #[param(unit="mm")] Breast wall transverse width
    pub fn breast_wall_width(mut self, v: Mm) -> Self { self.breast_wall_width = Some(v); self }
    /// #[param(unit="mm", range=2000.0..=8000.0, default=4000.0)] Footing along span
    pub fn footing_length(mut self, v: Mm) -> Self { self.footing_length = Some(v); self }
    /// #[param(unit="mm")] Footing transverse width
    pub fn footing_width(mut self, v: Mm) -> Self { self.footing_width = Some(v); self }
    /// #[param(unit="mm", range=500.0..=2000.0, default=1000.0)]
    pub fn footing_thickness(mut self, v: Mm) -> Self { self.footing_thickness = Some(v); self }
    /// #[param(unit="mm")] Wing wall length (both sides equal)
    pub fn wing_length(mut self, v: Mm) -> Self { self.wing_length = Some(v); self }
    /// #[param(enum=MaterialGrade, default=C30)]
    pub fn material(mut self, m: MaterialGrade) -> Self { self.material = Some(m); self }

    pub fn build(self) -> Result<Abutment, FeatureError> {
        let station  = self.station
            .ok_or_else(|| FeatureError::missing("abutment.station"))?.value();
        let bw_h     = self.breast_wall_height
            .ok_or_else(|| FeatureError::missing("abutment.breast_wall_height"))?.value();
        let bw_w     = self.breast_wall_width
            .ok_or_else(|| FeatureError::missing("abutment.breast_wall_width"))?.value();
        let bw_t     = self.breast_wall_thickness.unwrap_or(800.0.mm()).value();
        let foot_l   = self.footing_length.unwrap_or(4000.0.mm()).value();
        let foot_w   = self.footing_width.unwrap_or_else(|| Mm(bw_w + 1000.0)).value();
        let foot_t   = self.footing_thickness.unwrap_or(1000.0.mm()).value();
        let wing_l   = self.wing_length.unwrap_or_else(|| Mm(bw_h * 0.8)).value();
        let wing_h   = bw_h * 0.5;   // simplified: half the breast wall height
        let wing_t   = bw_t;

        if bw_h < 1000.0 {
            return Err(FeatureError::validation("abutment.breast_wall_height",
                format!("minimum 1000 mm, got {bw_h:.0} mm")));
        }

        let wing = WingWallIR { length: wing_l, height: wing_h, thickness: wing_t };

        Ok(Abutment { ir: AbutmentIR {
            id: FeatureId::new(),
            station,
            skew_angle:            self.skew_angle.unwrap_or(0.0),
            abutment_type:         self.abutment_type.unwrap_or(AbutmentType::ReverseT),
            breast_wall_height:    bw_h,
            breast_wall_thickness: bw_t,
            breast_wall_width:     bw_w,
            footing_length:        foot_l,
            footing_width:         foot_w,
            footing_thickness:     foot_t,
            wing_wall_left:        wing.clone(),
            wing_wall_right:       wing,
            material:              self.material.unwrap_or(MaterialGrade::C40),
        }})
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use cimery_core::{AbutmentType, UnitExt};

    #[test]
    fn build_reverse_t() {
        let a = Abutment::builder()
            .station(100.0.m())
            .abutment_type(AbutmentType::ReverseT)
            .breast_wall_height(5000.0.mm())
            .breast_wall_width(12000.0.mm())
            .build()
            .unwrap();
        assert_eq!(a.ir.abutment_type, AbutmentType::ReverseT);
        assert!((a.ir.breast_wall_height - 5000.0).abs() < f64::EPSILON);
    }

    #[test]
    fn too_short_breast_wall_fails() {
        let e = Abutment::builder()
            .station(0.0.m())
            .breast_wall_height(500.0.mm())   // < 1000
            .breast_wall_width(10000.0.mm())
            .build().unwrap_err();
        assert!(matches!(e, FeatureError::Validation { .. }));
    }
}