using Plots
using XCALibre
using Krylov
using KernelAbstractions
using CUDA

# backwardFacingStep_2mm, backwardFacingStep_10mm
mesh_file = "unv_sample_meshes/backwardFacingStep_10mm.unv"
mesh = UNV2D_mesh(mesh_file, scale=0.001)

mesh_dev = adapt(CUDABackend(), mesh)
mesh_dev = mesh

velocity = [0.5, 0.0, 0.0]
nu = 1e-3
Re = velocity[1]*0.1/nu

model = Physics(
    time = Transient(),
    fluid = Fluid{Incompressible}(nu = nu),
    turbulence = RANS{Laminar}(),
    energy = Energy{Isothermal}(),
    domain = mesh_dev
    )

@assign! model momentum U (
    Dirichlet(:inlet, velocity),
    Neumann(:outlet, 0.0),
    Wall(:wall, [0.0, 0.0, 0.0]),
    Dirichlet(:top, [0.0, 0.0, 0.0])
)

 @assign! model momentum p (
    Neumann(:inlet, 0.0),
    Dirichlet(:outlet, 0.0),
    Neumann(:wall, 0.0),
    Neumann(:top, 0.0)
)

schemes = (
    U = set_schemes(time=Euler),
    p = set_schemes()
)


solvers = (
    U = set_solver(
        model.momentum.U;
        solver      = BicgstabSolver, # BicgstabSolver, GmresSolver
        preconditioner = Jacobi(),
        convergence = 1e-7,
        relax       = 1.0,
    ),
    p = set_solver(
        model.momentum.p;
        solver      = CgSolver, # BicgstabSolver, GmresSolver
        preconditioner = Jacobi(),
        convergence = 1e-7,
        relax       = 1.0,
    )
)

runtime = set_runtime(
    iterations=1000, time_step=0.005, write_interval=10)

hardware = set_hardware(backend=CUDABackend(), workgroup=32)
# hardware = set_hardware(backend=CPU(), workgroup=4)

config = Configuration(
    solvers=solvers, schemes=schemes, runtime=runtime, hardware=hardware)

GC.gc()

initialise!(model.momentum.U, velocity)
initialise!(model.momentum.p, 0.0)

# backend = CUDABackend()
backend = CPU()

residuals = run!(model, config) # 9.39k allocs

# plot(; xlims=(0,184))
# plot!(1:length(Rx), Rx, yscale=:log10, label="Ux")
# plot!(1:length(Ry), Ry, yscale=:log10, label="Uy")
# plot!(1:length(Rp), Rp, yscale=:log10, label="p")

# # PROFILING CODE

# using Profile, PProf

# GC.gc()
# initialise!(U, velocity)
# initialise!(p, 0.0)

# Profile.Allocs.clear()
# Profile.Allocs.@profile sample_rate=1 begin Rx, Ry, Rp = isimple!(
#     mesh, nu, U, p,
#     # setup_U, setup_p, iterations, pref=0.0)
#     setup_U, setup_p, iterations)
# end

# PProf.Allocs.pprof()