package composite

import (
	"crypto/rand"
	"testing"

	"git.smesh.lol/gnarl-hamadryad/crypto/ring"
)

func TestCompositeRingInversion(t *testing.T) {
	p := DefaultParam(); rp := p.Ring
	gs := ring.NewGaussianSamplerFrom(p.Sigma, rand.Reader)
	for trial := 0; trial < 5; trial++ {
		f := gs.SamplePoly(rp)
		fInv := polyInverseModQ(f, rp)
		if fInv == nil { continue }
		prod := ring.Mul(f, fInv)
		if prod.Coeffs[0] != 1 { t.Fatalf("f*f^{-1}[0]=%d, want 1", prod.Coeffs[0]) }
		t.Logf("ring inversion at n=%d q=%d: OK", rp.N, rp.Q)
		return
	}
	t.Skip("all f non-invertible")
}

func TestCompositeH(t *testing.T) {
	p := DefaultParam(); rp := p.Ring
	gs := ring.NewGaussianSamplerFrom(p.Sigma, rand.Reader)
	for trial := 0; trial < 5; trial++ {
		f := gs.SamplePoly(rp); g := gs.SamplePoly(rp)
		fInv := polyInverseModQ(f, rp)
		if fInv == nil { continue }
		h := ring.Mul(g, fInv)
		hf := ring.Mul(h, f)
		if !ring.Equal(hf, g) { t.Fatalf("h*f != g") }
		t.Logf("h = g*f^{-1} at n=%d: OK", rp.N)
		return
	}
	t.Skip("all f non-invertible")
}

func TestCompositeKeyGenH(t *testing.T) {
	p := DefaultParam()
	pk, sk := NTRUKeyGen(p)
	if ring.Norm(pk.H) == 0 { t.Fatal("h is zero") }
	_ = sk
	t.Logf("public key generated: n=%d q=%d, h norm=%d, (F,G) blocked", p.Ring.N, p.Ring.Q, ring.Norm(pk.H))
}

func TestCompositeParams(t *testing.T) {
	p := DefaultParam()
	t.Logf("Composite: n=%d q=%d", p.Ring.N, p.Ring.Q)
	t.Logf("  ring inversion via matrix solve: verified")
	t.Logf("  h = g*f^{-1}: verified")
	t.Logf("  NTRU equation (F,G): blocked")
	t.Logf("  -> requires integer INTT (16x16 matrix with exact rational entries)")
	t.Logf("  -> or ring extended GCD (Euclidean in Z[x]/(x^n+1))")
	t.Logf("")
	t.Logf("Gnarlring: n=27 q=271 — working via LLL at dim 54 (coefficient space)")
	t.Logf("Falcon:    n=512 q=12289 — production target (~128-bit SIS)")
}