using ArrayFire

import Plots: frame, gif, mp4
include("SimpleAnimation.jl")
using SimpleAnimation

import Colors: Gray

const MB = UInt64(1024*1024);

gpu32(a) = AFArray([Float32(a)])

# generate Laplacian with free edge
# 1D usage: Δ*u
# 2D usage: Δ*u + u*Δ
function genLaplacian(N::Int)
    Δ = AFArray(Array(Float32.(SymTridiagonal(-2*ones(N), ones(N-1)))))
    Δ[1, 1] = Δ[end, end] = -1.
    return Δ 
end

du_react(u, v) = a - b*u + u*u/(1+c*u*u)/v
dv_react(u, v) = u*u - v

a, b, c = 0.f0, 1.2f0, 0.4f0
Du, Dv = 4.f0, 80.f0
;

N = 256
u = rand(AFArray{Float32}, N, N)
v = rand(AFArray{Float32}, N, N)
Δ = genLaplacian(N)
dt = 0.001f0

@time for count in 1:10
    u, v = (
        u + dt * du_react.(u, v) + dt * Du * (Δ*u + u*Δ),
        v + dt * dv_react.(u, v) + dt * Dv * (Δ*v + v*Δ)
    )
    
    afgc(3200MB)
end

N = 256
#u = rand(AFArray{Float32}, N, N)
#v = rand(AFArray{Float32}, N, N)
u = AFArray(repmat(Float32.(1-cospi.((1:N)/N*20)), 1, N))
v = AFArray(Float32.(0.5*ones(N, N)))

Δ = genLaplacian(N)
dt = 0.001f0

anim = SimpleAnim()

@time for count in 1:1000
    
    u, v = (
        u + dt * du_react.(u, v) + dt * Du * (Δ*u + u*Δ),
        v + dt * dv_react.(u, v) + dt * Dv * (Δ*v + v*Δ)
    )
    
    if mod(count, 10) == 0
        #frame(anim, Gray.(clamp.(Array(sync(u)), 0, 1)))
        
        gc(false)
        afgc(3200MB)
    end
end

#@time gif(anim, "zebra.gif")
Gray.(clamp.(Array(sync(u)), 0, 1))

u[51:200, 51:200] = rand(AFArray{Float32}, 150, 150)
v[51:200, 51:200] = rand(AFArray{Float32}, 150, 150)
Gray.(clamp.(Array(sync(u)), 0, 1))

@time for count in 1:60000
    
    u, v = (
        u + dt * du_react.(u, v) + dt * Du * (Δ*u + u*Δ),
        v + dt * dv_react.(u, v) + dt * Dv * (Δ*v + v*Δ)
    )
    
    if mod(count, 2000) == 0
        frame(anim, Gray.(clamp.(Array(sync(u)), 0, 1)))
        
        gc(false)
        afgc(3200MB)
    end

end

@time mp4(anim, "zebra.mp4")

@time gif(anim, "zebra.gif")

fn = "zebra.gif"
run(`ffmpeg -v 0 -framerate 10 -loop 0 -i $(anim.dir)/%06d.bmp -i "$(anim.dir)/palette.bmp" -lavfi "paletteuse=dither=sierra2_4a" -y $fn`)

Gray.(clamp.(Array(sync(u)), 0, 1))