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

# test SimpleSolver

using FactCheck
using JuliaFEM: DirichletProblem, Seg2, PlaneHeatProblem, Quad4, SimpleSolver, get_element, get_basis

""" Define Problem 1:

- Field function: Laplace equation Δu=0 in Ω={u∈R²|(x,y)∈[0,1]×[0,1]}
- Neumann boundary on Γ₁={0<=x<=1, y=0}, ∂u/∂n=600 on Γ₁
"""
function get_heatproblem()
    el1 = Quad4([1, 2, 3, 4])
    # these might look like normal values but believe me, they
    # are fields with temporal and spatial dimension
    el1["geometry"] = Vector[[0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0]]
    el1["temperature thermal conductivity"] = 6.0
    el1["density"] = 36.0

    el2 = Seg2([1, 2])
    el2["geometry"] = Vector[[0.0, 0.0], [1.0, 0.0]]
    # Boundary load, linear ramp 0 -> 600 at time 0 -> 1
    # yet another simplification, if field is given as a tuple,
    # multiple fields are created. there is 1 second time step between
    # each field. So the following is basically same as
    # fieldset = FieldSet("temperature flux")
    # field1 = Field(0.0, 0.0)
    # field2 = Field(1.0, 600.0)
    # push!(fieldset, field1)
    # push!(fieldset, field2)
    # element["temperature flux"] = fieldset
    el2["temperature flux"] = (0.0, 600.0)

    problem1 = PlaneHeatProblem()
    push!(problem1, el1)
    push!(problem1, el2)
    return problem1
end

""" Define Problem 2:
 - Dirichlet boundary Γ₂={0<=x<=1, y=1}, u=0 on Γ₂
"""
function get_boundaryproblem()
    el3 = Seg2([3, 4])
    el3["geometry"] = Vector[[1.0, 1.0], [0.0, 1.0]]
    problem2 = DirichletProblem(1)
    push!(problem2, el3)
    return problem2
end

facts("test simplesolver") do
    problem1 = get_heatproblem()
    problem2 = get_boundaryproblem()
    # Create a solver for a set of problems
    solver = SimpleSolver()
    push!(solver, problem1)
    push!(solver, problem2)
    # Solve problem at time t=1.0 and update fields
    call(solver, 1.0)
    # Postprocess.
    # Interpolate temperature field along boundary of Γ₁ at time t=1.0
    xi = [0.0, -1.0]
    el2 = get_element(problem1.equations[2])
    basis = get_basis(el2)
    X = basis("geometry", xi, 1.0)
    T = basis("temperature", xi, 1.0)
    Logging.info("Temperature at point X = $X is T = $T")
    @fact T --> roughly(100.0)
end