package keyset

import (
	"bytes"
	"git.xdrm.io/logauth/schastsp/context"
	"git.xdrm.io/logauth/schastsp/internal/scha"
	"testing"
)

func TestGenerationDepthBoundaries(t *testing.T) {

	var min, max uint16 = 0x0f0, 0xfff
	var rangeMin = min + (max-min)/2
	var rangeMax = max
	var created *T

	ctx, err := context.Create(2.5, min, 0, max)
	if err != nil {
		t.Errorf("Do not expected an error: %s", err)
		return
	}

	created, err = Create(ctx)

	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	if created.depth < min || created.depth > max {
		t.Errorf("Expected 'depth' to be in the range [%d, %d], got '%d'", rangeMin, rangeMax, created.depth)
	}

}

func TestSchaDecrementingProperty(t *testing.T) {
	ctx, err := context.Create(2.5)
	if err != nil {
		t.Errorf("Do not expected an error")
		return
	}

	var h1, h2, hcheck []byte
	var created *T

	created, err = Create(ctx)

	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (1) Get current hash */
	h1, err = created.CurrentHash()
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (2) Decrement */
	created.Decrement()

	/* (3) Get new hash */
	h2, err = created.CurrentHash()
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (4) Try to guess h1 from h2 */
	hcheck, err = scha.Hash(h2, 1)
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (5) Fail if property is not fulfilled */
	for k, v := range h1 {

		if v != hcheck[k] {
			t.Errorf("Expected h(h[x-1]) to equal h[x]; expected '%x' ; got '%x'", h1, hcheck)
			return
		}

	}

}

func TestDecrementMinimum(t *testing.T) {
	ctx, err := context.Create(2.5)
	if err != nil {
		t.Errorf("Do not expected an error")
		return
	}

	var h1, h2, hcheck []byte
	var created *T

	created, err = Create(ctx)

	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (1) Get current hash */
	h1, err = created.CurrentHash()
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (2) Decrement */
	created.Decrement()

	/* (3) Get new hash */
	h2, err = created.CurrentHash()
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (4) Try to guess h1 from h2 */
	hcheck, err = scha.Hash(h2, 1)
	if err != nil {
		t.Errorf("Do not expected an error, got: %s", err)
	}

	/* (5) Fail if property is not fulfilled */
	for k, v := range h1 {

		if v != hcheck[k] {
			t.Errorf("Expected h(h[x-1]) to equal h[x]; expected '%x' ; got '%x'", h1, hcheck)
			return
		}

	}

}

func TestRestore(t *testing.T) {

	var buffer, srcData bytes.Buffer
	var src, dst *T
	var ctx *context.T
	var err error

	/* (1) Create a context */
	ctx, err = context.Create(2.2)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	/* (2) Create our source */
	src, err = Create(ctx)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	/* (3) Store it to buffer (+to another buffer to check after) */
	buffer.Reset()
	srcData.Reset()
	err = src.Store(&buffer)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}
	err = src.Store(&srcData)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	/* (4) Create our target */
	dst, err = Create(ctx)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	/* (5) Restore from buffer */
	err = dst.Fetch(&buffer)
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	/* (6) Get both data */
	dst.Store(&buffer) // dst data is in buffer
	if err != nil {
		t.Fatalf("[Unexpected error] %s", err)
	}

	if len(buffer.Bytes()) != len(srcData.Bytes()) || buffer.String() != srcData.String() {
		t.Fatalf("Expected restored keyset to be equal to original ;\n  - expected %x\n  - got      %x", srcData.String(), buffer.String())
	}

}