# This file is a part of JuliaFEM.
# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md

using Test
using JuliaFEM
using Tensors

@testset "State Variables" begin
    @testset "AbstractStateVariable" begin
        # Test that state variable types are defined
        @test PlasticStrain <: AbstractStateVariable
        @test Backstress <: AbstractStateVariable
        @test EquivalentPlasticStrain <: AbstractStateVariable
        @test DamageVariable <: AbstractStateVariable
    end

    @testset "state_variable_type trait" begin
        # Test that state_variable_type returns correct concrete types
        @test state_variable_type(PlasticStrain) === SymmetricTensor{2,3,Float64,6}
        @test state_variable_type(Backstress) === SymmetricTensor{2,3,Float64,6}
        @test state_variable_type(EquivalentPlasticStrain) === Float64
        @test state_variable_type(DamageVariable) === Float64
    end

    @testset "default_symbol trait" begin
        # Test that default_symbol returns correct symbols
        @test default_symbol(PlasticStrain) === :ε_p
        @test default_symbol(Backstress) === :α
        @test default_symbol(EquivalentPlasticStrain) === :κ
        @test default_symbol(DamageVariable) === :d
    end

    @testset "Concrete type instantiation" begin
        # Test that we can create instances of the concrete types
        ε_p_type = state_variable_type(PlasticStrain)
        ε_p = zero(ε_p_type)
        @test ε_p isa SymmetricTensor{2,3,Float64,6}
        @test ε_p == zero(SymmetricTensor{2,3})

        α_type = state_variable_type(Backstress)
        α = zero(α_type)
        @test α isa SymmetricTensor{2,3,Float64,6}
        @test α == zero(SymmetricTensor{2,3})

        κ_type = state_variable_type(EquivalentPlasticStrain)
        κ = zero(κ_type)
        @test κ isa Float64
        @test κ == 0.0

        d_type = state_variable_type(DamageVariable)
        d = zero(d_type)
        @test d isa Float64
        @test d == 0.0
    end

    @testset "Symbol usage" begin
        # Test that symbols can be used in NamedTuples
        ε_p_sym = default_symbol(PlasticStrain)
        α_sym = default_symbol(Backstress)
        κ_sym = default_symbol(EquivalentPlasticStrain)

        state = NamedTuple{(ε_p_sym, α_sym, κ_sym)}((
            zero(SymmetricTensor{2,3}),
            zero(SymmetricTensor{2,3}),
            0.0
        ))

        @test haskey(state, :ε_p)
        @test haskey(state, :α)
        @test haskey(state, :κ)
        @test state.ε_p isa SymmetricTensor{2,3}
        @test state.α isa SymmetricTensor{2,3}
        @test state.κ isa Float64
    end

    @testset "Trait consistency" begin
        # Verify that all state variables have both traits defined
        state_vars = [PlasticStrain, Backstress, EquivalentPlasticStrain, DamageVariable]

        for var in state_vars
            # Should not throw
            @test state_variable_type(var) !== nothing
            @test default_symbol(var) !== nothing

            # Symbol should be a Symbol
            @test default_symbol(var) isa Symbol

            # Type should be a concrete type
            T = state_variable_type(var)
            @test isconcretetype(T)
        end
    end
end