using NPZ
using Distributions
using LinearAlgebra

#irit

"""
    generate_gaussian_data(N::Int64, D::Int64, K::Int64,MixtureVar::Number)

Generate `N` observations, generated from `K` `D` dimensions Gaussians, with the Gaussian means sampled from a `Normal` distribution with mean `0` and `MixtureVar` variance.

Returns `(Samples, Labels, Clusters_means, Clusters_cov)`

# Example
```julia
julia> x,y,clusters = generate_gaussian_data(10000,2,6,100.0)
[3644, 2880, 119, 154, 33, 3170]
...
```
"""
function generate_gaussian_data(N::Int64, D::Int64, K::Int64,MixtureVar::Number)
	x = randn(Float32,D,N)
	tpi = rand(Dirichlet(ones(K)))
	tzn = rand(Multinomial(N,tpi))
	tz = zeros(Float32,N)

	tmean = zeros(Float32,D,K)
	tcov = zeros(Float32,D,D,K)

	ind = 1
	println(tzn)
	for i=1:length(tzn)
		indices = ind:ind+tzn[i]-1
		tz[indices] .= i
		tmean[:,i] .= rand(MvNormal(zeros(Float32,D), MixtureVar*Matrix{Float32}(I, D, D)))
		tcov[:,:,i] .= rand(InverseWishart(D+2, Matrix{Float32}(I, D, D)))
		#println(minimum(eigvals(tcov[:,:,i]))>0)
		d = MvNormal(tmean[:,i], tcov[:,:,i])
		for j=indices
			x[:,j] = rand(d)
		end
		ind += tzn[i]
	end
	return x, tz, tmean, tcov
end



"""
     generate_mnmm_data(N::Int64, D::Int64, K::Int64, trials::Int64)

Generate `N` observations, generated from `K` `D` features Multinomial vectors, with `trials` draws from each vector.

Returns `(Samples, Labels, Vectors)`

# Example
```julia
julia> generate_mnmm_data(10000, 10, 5, 100)
...
```
"""
function generate_mnmm_data(N::Int64, D::Int64, K::Int64, trials::Int64)
	clusters = zeros(Float64,D,K)
	x = zeros(Float32,D,N)
	labels = rand(1:K,(N,))
	for i=1:K
		alphas = rand(1:20,(D,))
		alphas[i] = rand(30:100)
		clusters[:,i] = rand(Dirichlet(alphas))
	end
	for i=1:N
		x[:,i] = rand(Multinomial(trials,clusters[:,labels[i]]))
	end
	return x, labels, clusters
end
