//! cimery project file — JSON save/load of SceneParams.
//!
//! Format: `cimery/projects/*.cimery.json`
//! Sprint 12: SceneParams only. Sprint 13+: Feature IRs + Alignment.

use serde::{Deserialize, Serialize};
use super::bridge_scene::{GirderSectionType, SceneParams};

// ─── Serialisable form of SceneParams ────────────────────────────────────────

#[allow(dead_code)]
#[derive(Serialize, Deserialize)]
struct SectionTypeStr(String);

#[derive(Serialize, Deserialize)]
pub struct ProjectFile {
    pub version:               u32,
    pub name:                  String,
    pub span_m:                f64,
    pub girder_count:          usize,
    pub girder_spacing:        f32,
    pub girder_height:         f32,
    pub slab_thickness:        f32,
    pub section_type:          String,   // "psc_i" | "steel_box"
    pub show_alignment:        bool,
    /// Sprint 19
    #[serde(default = "default_true")]
    pub show_cross_beams:      bool,
    #[serde(default = "default_cross_beam_interval")]
    pub cross_beam_interval_m: f64,
    #[serde(default = "default_true")]
    pub show_expansion_joints: bool,
    /// Sprint 26: 다경간
    #[serde(default = "default_span_count")]
    pub span_count:            usize,
    #[serde(default = "default_pier_type")]
    pub pier_type:             String,   // "single" | "multi"
    /// Sprint 27: 경사각 [deg]
    #[serde(default)]
    pub skew_deg:              f32,
    /// Sprint 29: 격벽 표시
    #[serde(default = "default_true")]
    pub show_diaphragms:       bool,
    /// Sprint 30: 솟음(Camber) 중앙값 [mm]
    #[serde(default)]
    pub camber_mid_mm:         f32,
    /// Sprint 31: 데크 헌치(Haunch) 깊이 [mm]
    #[serde(default)]
    pub haunch_depth:          f32,
    /// Sprint 39: 변단면 거더 중앙부 높이 감소 [mm]
    #[serde(default)]
    pub variable_depth_mm:     f32,
}

fn default_true() -> bool { true }
fn default_cross_beam_interval() -> f64 { 5.0 }
fn default_span_count() -> usize { 1 }
fn default_pier_type() -> String { "single".into() }

impl ProjectFile {
    pub fn from_params(name: &str, p: &SceneParams) -> Self {
        Self {
            version:               2,
            name:                  name.to_owned(),
            span_m:                p.span_m,
            girder_count:          p.girder_count,
            girder_spacing:        p.girder_spacing,
            girder_height:         p.girder_height,
            slab_thickness:        p.slab_thickness,
            section_type:          match p.section_type {
                GirderSectionType::PscI     => "psc_i".into(),
                GirderSectionType::SteelBox => "steel_box".into(),
            },
            show_alignment:        p.show_alignment,
            show_cross_beams:      p.show_cross_beams,
            cross_beam_interval_m: p.cross_beam_interval_m,
            show_expansion_joints: p.show_expansion_joints,
            span_count:            p.span_count,
            pier_type:             match p.pier_type {
                cimery_core::PierType::MultiColumn => "multi".into(),
                _                                  => "single".into(),
            },
            skew_deg:              p.skew_deg,
            show_diaphragms:       p.show_diaphragms,
            camber_mid_mm:         p.camber_mid_mm,
            haunch_depth:          p.haunch_depth,
            variable_depth_mm:     p.variable_depth_mm,
        }
    }

    pub fn to_params(&self) -> SceneParams {
        SceneParams {
            span_m:                self.span_m,
            girder_count:          self.girder_count,
            girder_spacing:        self.girder_spacing,
            girder_height:         self.girder_height,
            slab_thickness:        self.slab_thickness,
            section_type:          match self.section_type.as_str() {
                "steel_box" => GirderSectionType::SteelBox,
                _           => GirderSectionType::PscI,
            },
            show_alignment:        self.show_alignment,
            show_cross_beams:      self.show_cross_beams,
            cross_beam_interval_m: self.cross_beam_interval_m,
            show_expansion_joints: self.show_expansion_joints,
            span_count:            self.span_count,
            pier_type:             match self.pier_type.as_str() {
                "multi" => cimery_core::PierType::MultiColumn,
                _       => cimery_core::PierType::SingleColumn,
            },
            skew_deg:              self.skew_deg,
            show_diaphragms:       self.show_diaphragms,
            camber_mid_mm:         self.camber_mid_mm,
            haunch_depth:          self.haunch_depth,
            variable_depth_mm:     self.variable_depth_mm,
        }
    }

    pub fn save(&self, path: &std::path::Path) -> std::io::Result<()> {
        let json = serde_json::to_string_pretty(self)
            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
        std::fs::write(path, json)
    }

    pub fn load(path: &std::path::Path) -> std::io::Result<Self> {
        let json = std::fs::read_to_string(path)?;
        serde_json::from_str(&json)
            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))
    }
}

/// Default project save path (relative to cimery workspace root).
pub fn default_save_path(name: &str) -> std::path::PathBuf {
    let mut p = std::path::PathBuf::from("projects");
    std::fs::create_dir_all(&p).ok();
    p.push(format!("{}.cimery.json", name));
    p
}

/// IFC 파일 기본 저장 경로.
pub fn default_ifc_path(name: &str) -> std::path::PathBuf {
    let mut p = std::path::PathBuf::from("projects");
    std::fs::create_dir_all(&p).ok();
    p.push(format!("{}.ifc", name));
    p
}

/// SceneParams → cimery-ifc::BridgeExportParams 변환.
///
/// viewer 의 SceneParams 에 있는 모든 파라미터를 IFC 익스포터 입력으로 매핑.
/// 선형(alignment)·camber 는 IFC Phase 3 로드맵(미반영).
pub fn scene_params_to_ifc(p: &SceneParams, name: &str) -> cimery_ifc::BridgeExportParams {
    use cimery_ifc::{BridgeExportParams, IfcSectionKind};
    BridgeExportParams {
        name:           name.to_owned(),
        span_m:         p.span_m,
        span_count:     p.span_count,
        girder_count:   p.girder_count,
        girder_spacing: p.girder_spacing as f64,
        girder_height:  p.girder_height as f64,
        slab_thickness: p.slab_thickness as f64,
        bearing_height: 60.0,
        section_kind:   match p.section_type {
            GirderSectionType::PscI     => IfcSectionKind::PscI,
            GirderSectionType::SteelBox => IfcSectionKind::SteelBox,
        },
        skew_deg:       p.skew_deg as f64,
        haunch_depth:   p.haunch_depth as f64,
        show_parapets:  true,
        show_joints:    p.show_expansion_joints,
        camber_mid_mm:  p.camber_mid_mm as f64,
    }
}