// Copyright (c) 2024 RustyTorch++ Team
// Licensed under the Apache License, Version 2.0

//! # RTX-FEA: GPU-Accelerated Finite Element Analysis
//!
//! A production-ready finite element analysis library with comprehensive GPU acceleration
//! using CUDA. This crate provides all the essential components for modern FEA simulations.
//!
//! ## Features
//!
//! - **GPU-Accelerated**: Leverages cudarc 0.17.3 for CUDA operations
//! - **Comprehensive Elements**: Support for Tri3/6, Quad4/8/9, Tet4/10, Hex8/20/27, and more
//! - **Advanced Materials**: Linear elastic, hyperelastic, and plasticity models
//! - **Efficient Assembly**: Sparse matrix assembly with GPU optimization
//! - **Robust Solvers**: Direct and iterative solvers with GPU acceleration
//! - **Mesh Management**: Advanced mesh operations including refinement and partitioning
//!
//! ## Maturity
//!
//! Validated: element stiffness and mass matrices, shape functions across the
//! element library, global assembly, constraint handling, the generalized
//! eigensolver, and modal analysis end to end against closed-form bar
//! frequencies. See `tests/element_matrices_physical.rs`,
//! `tests/shape_function_invariants.rs`, `tests/eigenvalue_closed_form.rs`
//! and `tests/modal_closed_form.rs`.
//!
//! Validated since: manufactured solutions across the element library and
//! the nonlinear path — `NonlinearStaticAnalysis` runs full Newton on the
//! consistent tangent (orders 1.76/1.95 by MMS) and [`mor`] provides
//! POD-Galerkin reduction with ECSW hyper-reduction on top of it.
//!
//! Not yet: `Pyramid13` and pyramid quadrature are unimplemented and report
//! so; plane-stress condensation of nonlinear materials refuses explicitly.
//! The only test modules still behind `#[cfg(disabled)]` are the GPU solver
//! tests, which need CUDA hardware — everything else is enabled, with
//! fixtures corrected where they encoded abandoned designs.
//!
//! ## Quick Start
//!
//! Natural frequencies of a fixed-free bar:
//!
//! ```rust
//! use rtx_fea::analysis::{Analysis, AnalysisConfig, AnalysisData, ModalAnalysis};
//! use rtx_fea::assembly::DofComponent;
//! use rtx_fea::boundary::{BoundaryCondition, BoundaryConditionSet, DirichletBC};
//! use rtx_fea::materials::{LinearElastic, MaterialDatabase};
//! use rtx_fea::mesh::{Element, ElementType, MaterialId, Mesh, Node};
//!
//! // A 4 x 1 grid of quadrilaterals spanning a 1.0 x 0.05 strip.
//! let mut mesh = Mesh::new(2)?;
//! let mut columns = Vec::new();
//! for i in 0..=4 {
//!     let x = f64::from(i) * 0.25;
//!     columns.push([
//!         mesh.add_node(Node::new_2d(x, 0.0)),
//!         mesh.add_node(Node::new_2d(x, 0.05)),
//!     ]);
//! }
//! for i in 0..4 {
//!     let nodes = vec![columns[i][0], columns[i + 1][0], columns[i + 1][1], columns[i][1]];
//!     mesh.add_element(Element::new(ElementType::Quad4, nodes, MaterialId(0))?)?;
//! }
//!
//! let mut materials = MaterialDatabase::new();
//! materials.add_material(MaterialId(0), LinearElastic::new(200e9, 0.3).with_density(8000.0), None);
//!
//! // Clamp the left edge. Without constraints the stiffness matrix is
//! // singular and the analysis reports that rather than returning noise.
//! let mut boundary_conditions = BoundaryConditionSet::new();
//! boundary_conditions.add_condition(BoundaryCondition::Dirichlet(DirichletBC::fixed(
//!     columns[0].to_vec(),
//!     vec![DofComponent::DisplacementX, DofComponent::DisplacementY],
//!     0.0,
//! )));
//!
//! let mut analysis = ModalAnalysis::new(mesh, materials, 3, AnalysisConfig::default())
//!     .with_boundary_conditions(boundary_conditions);
//! let results = analysis.run()?;
//!
//! let AnalysisData::Vector(frequencies) = &results.additional_data["frequencies"] else {
//!     panic!("frequencies should be a vector")
//! };
//! assert_eq!(frequencies.len(), 3);
//! assert!(frequencies.iter().all(|f| f.is_finite() && *f > 0.0));
//! # Ok::<(), Box<dyn std::error::Error>>(())
//! ```
//!
//! ## Module Organization
//!
//! - [`mesh`]: Mesh data structures, generation, and operations
//! - [`elements`]: Finite element formulations and shape functions
//! - [`materials`]: Constitutive models and material behavior
//! - [`assembly`]: Global matrix assembly and equation systems
//! - [`boundary`]: Boundary conditions and constraints
//! - [`solvers`]: Linear and nonlinear equation solvers
//! - [`kernels`]: GPU kernels and CUDA operations
//! - [`analysis`]: High-level analysis drivers
//!
//! ## Examples
//!
//! The crate includes comprehensive examples:
//!
//! - `linear_elasticity`: Basic linear elastic analysis
//! - `cantilever_beam`: Classical beam bending problem
//! - Advanced examples with nonlinear materials and contact

pub mod analysis;
pub mod assembly;
pub mod boundary;
pub mod elements;
pub mod error;
pub mod kernels;
pub mod materials;
pub mod mesh;
pub mod mor;
pub mod solvers;
pub mod utils;

// Re-export commonly used types for convenience
pub use error::{FeaError, FeaResult};

/// Common prelude for RTX-FEA.
///
/// This module re-exports the most commonly used types and traits
/// to make it easier to get started with the library.
pub mod prelude {
    pub use crate::analysis::{Analysis, DynamicAnalysis, StaticLinearAnalysis};
    pub use crate::assembly::{AssemblyOptions, GlobalAssembler, SparseMatrix};
    pub use crate::boundary::{BoundaryCondition, DirichletBC, NeumannBC};
    pub use crate::elements::{
        ElementFactory, FiniteElement, NaturalCoords, PhysicalCoords, QuadratureRule,
        ShapeFunctionEval,
    };
    pub use crate::error::{FeaError, FeaResult};
    pub use crate::materials::{LinearElastic, Material, MaterialProperties};
    pub use crate::mesh::{
        Element, ElementId, ElementType, MaterialId, Mesh, Node, NodeId,
        geometry::{Box3D, Circle, Rectangle, Sphere},
    };
    pub use crate::solvers::{CholeskyDirect, ConjugateGradient, LinearSolver, SolverOptions};
}

/// Library information and version.
pub mod info {
    /// Get the library version.
    pub fn version() -> &'static str {
        env!("CARGO_PKG_VERSION")
    }

    /// Get the library name.
    pub fn name() -> &'static str {
        env!("CARGO_PKG_NAME")
    }

    /// Get the library description.
    pub fn description() -> &'static str {
        env!("CARGO_PKG_DESCRIPTION")
    }

    /// Check if CUDA support is available.
    pub fn has_cuda_support() -> bool {
        cfg!(feature = "cuda")
    }

    /// Get supported element types.
    pub fn supported_elements() -> Vec<crate::mesh::ElementType> {
        crate::mesh::ElementType::all()
    }

    /// Library build information.
    pub fn build_info() -> BuildInfo {
        BuildInfo {
            version: version().to_string(),
            cuda_support: has_cuda_support(),
            element_types: supported_elements(),
            build_date: std::env::var("VERGEN_BUILD_DATE")
                .unwrap_or_else(|_| "unknown".to_string()),
            git_sha: std::env::var("VERGEN_GIT_SHA").unwrap_or_else(|_| "unknown".to_string()),
        }
    }

    /// Detailed build information.
    #[derive(Debug, Clone)]
    pub struct BuildInfo {
        /// Library version
        pub version: String,
        /// CUDA support enabled
        pub cuda_support: bool,
        /// Supported element types
        pub element_types: Vec<crate::mesh::ElementType>,
        /// Build date
        pub build_date: String,
        /// Git commit SHA
        pub git_sha: String,
    }

    impl std::fmt::Display for BuildInfo {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            writeln!(f, "RTX-FEA Build Information:")?;
            writeln!(f, "  Version: {}", self.version)?;
            writeln!(
                f,
                "  CUDA Support: {}",
                if self.cuda_support { "Yes" } else { "No" }
            )?;
            writeln!(f, "  Element Types: {} supported", self.element_types.len())?;
            writeln!(f, "  Build Date: {}", self.build_date)?;
            writeln!(f, "  Git SHA: {}", &self.git_sha[..8])?;
            Ok(())
        }
    }
}

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

    #[test]
    fn test_library_info() {
        assert!(!info::version().is_empty());
        assert_eq!(info::name(), "rtx-fea");
        assert!(!info::description().is_empty());

        let build_info = info::build_info();
        assert!(!build_info.version.is_empty());
        assert!(!build_info.element_types.is_empty());
    }

    #[test]
    fn test_supported_elements() {
        let elements = info::supported_elements();
        assert!(elements.contains(&mesh::ElementType::Tri3));
        assert!(elements.contains(&mesh::ElementType::Quad4));
        assert!(elements.contains(&mesh::ElementType::Tet4));
        assert!(elements.contains(&mesh::ElementType::Hex8));
    }

    #[test]
    fn test_prelude_imports() -> FeaResult<()> {
        use prelude::*;

        // Test that we can create basic types from prelude
        let _mesh = Mesh::new(2)?;
        let _coords = NaturalCoords::new_2d(0.0, 0.0);
        let _material = LinearElastic::new(200e9, 0.3);

        // Test error types
        let _result: FeaResult<()> = Ok(());

        Ok(())
    }

    // Fixture correction on re-enable (2026-08-19): the factory deliberately
    // refuses Point/Line2/Line3, which have no finite element implementation
    // — requiring every ElementType to construct asserted a capability the
    // crate does not claim. Implemented types must construct with the right
    // node count; unimplemented ones must refuse explicitly, not stub.
    #[test]
    fn test_element_factory() {
        use elements::ElementFactory;
        use mesh::ElementType;

        for element_type in ElementType::all() {
            let element = ElementFactory::create(element_type);
            match element_type {
                ElementType::Point | ElementType::Line2 | ElementType::Line3 => {
                    assert!(element.is_err(), "{element_type:?} has no implementation");
                }
                _ => {
                    let element = element
                        .unwrap_or_else(|e| panic!("failed to create {element_type:?}: {e}"));
                    assert_eq!(element.num_nodes(), element_type.num_nodes());
                }
            }
        }
    }

    #[test]
    fn test_mesh_creation() {
        let mesh = mesh::Mesh::generate_rectangle(1.0, 1.0, 3, 3);
        assert!(mesh.is_ok());

        let mesh = mesh.unwrap();
        assert_eq!(mesh.num_nodes(), 9); // 3x3 grid
        assert_eq!(mesh.num_elements(), 4); // 2x2 quads
        assert!(mesh.validate().is_ok());
    }

    #[test]
    fn test_basic_workflow() {
        use materials::LinearElastic;

        // Create mesh
        let mesh = mesh::Mesh::generate_rectangle(1.0, 1.0, 3, 3).unwrap();

        // Create material
        let material = LinearElastic::new(200e9, 0.3);

        // Validate mesh
        assert!(mesh.validate().is_ok());
        assert_eq!(mesh.spatial_dimension, 2);
        assert!(mesh.num_elements() > 0);
        assert!(mesh.num_nodes() > 0);

        // Check material properties
        assert!((material.elastic_modulus() - 200e9).abs() < 1e-6);
        assert!((material.poisson_ratio() - 0.3).abs() < 1e-6);
    }
}