using StatsBase
using Plots
using ProfileView

const Iterations = 100000
const vec_len = 4


#black_sq = eye(Int64, NumColumns, NumColumns)


#=
black_sq = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]=#

black_sq = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
            1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1;
            1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1;
            1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1;
            1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1;
            1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1;
            1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1;
            1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1;
            1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 1 1 1 1 1 1;
            1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1;
            1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1;
            1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1;
            1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1;
            1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1;
            1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1;
            0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]

const NumColumns = size(black_sq)[1] #Int64((stop - start) / step + 1)
const col_max = NumColumns - vec_len

# Bresenham's line algorithm
function b_line(x1::Int, y1::Int, x2::Int, y2::Int)
    coords = Array{CartesianIndex{2}}(0)
    @fastmath dx = Int(abs(x2-x1))
    @fastmath dy = Int(abs(y2-y1))

    sx::Int = x1<x2 ? 1 : -1
    sy::Int = y1<y2 ? 1 : -1;

    err = (dx>dy ? dx : -dy)/2

    @fastmath while true
        push!(coords, CartesianIndex(x1, y1))

        if (x1==x2 && y1==y2);
            return coords
        end

        err2 = err;
        if err2 > -dx
            err -= dy
            x1 += sx
        end

        if err2 < dy
            err += dx
            y1 += sy
        end
    end
end

function gen_heatmap(black_map::Array{Int}, col::Int, iter::Int)
    counters = zeros(Int, col, col)

    for i in 1:iter
        #rand_line = b_line(rand(1:col), rand(1:col), rand(1:col), rand(1:col))
        @fastmath x1, y1 = rand(vec_len:col_max), rand(vec_len:col_max)
        @fastmath rand_line = b_line(x1, y1, rand((x1-vec_len+1):(x1+vec_len)), rand((y1-vec_len+1):(y1+vec_len)))
        @fastmath if countnz(black_map[rand_line]) == 0
            @inbounds counters[rand_line] += 1
        end
    end
    return counters
end

gen_heatmap(black_sq, NumColumns, Iterations)
Profile.clear()
@profile @time  gen_heatmap(black_sq, NumColumns, Iterations)
ProfileView.view()

#heatmap(gen_heatmap(black_sq, NumColumns, Iterations))