package channeldb

import (
	"crypto/sha256"
	"reflect"
	"testing"
)

// TestWitnessCacheRetrieval tests that we're able to add and lookup new
// witnesses to the witness cache.
func TestWitnessCacheRetrieval(t *testing.T) {
	t.Parallel()

	cdb, cleanUp, err := makeTestDB()
	if err != nil {
		t.Fatalf("unable to make test database: %v", err)
	}
	defer cleanUp()

	wCache := cdb.NewWitnessCache()

	// We'll be attempting to add then lookup two simple hash witnesses
	// within this test.
	witness1 := rev[:]
	witness1Key := sha256.Sum256(witness1)

	witness2 := key[:]
	witness2Key := sha256.Sum256(witness2)

	witnesses := [][]byte{witness1, witness2}
	keys := [][]byte{witness1Key[:], witness2Key[:]}

	// First, we'll attempt to add the witnesses to the database.
	err = wCache.AddWitnesses(Sha256HashWitness, witnesses...)
	if err != nil {
		t.Fatalf("unable to add witness: %v", err)
	}

	// With the witnesses stored, we'll now attempt to look them up.
	for i, key := range keys {
		witness := witnesses[i]

		// We should get back the *exact* same witness as we originally
		// stored.
		dbWitness, err := wCache.LookupWitness(Sha256HashWitness, key)
		if err != nil {
			t.Fatalf("unable to look up witness: %v", err)
		}

		if !reflect.DeepEqual(witness, dbWitness[:]) {
			t.Fatalf("witnesses don't match: expected %x, got %x",
				witness[:], dbWitness[:])
		}
	}
}

// TestWitnessCacheDeletion tests that we're able to delete a single witness,
// and also a class of witnesses from the cache.
func TestWitnessCacheDeletion(t *testing.T) {
	t.Parallel()

	cdb, cleanUp, err := makeTestDB()
	if err != nil {
		t.Fatalf("unable to make test database: %v", err)
	}
	defer cleanUp()

	wCache := cdb.NewWitnessCache()

	// We'll start by adding two witnesses to the cache.
	witness1 := rev[:]
	witness1Key := sha256.Sum256(witness1)

	if err := wCache.AddWitnesses(Sha256HashWitness, witness1); err != nil {
		t.Fatalf("unable to add witness: %v", err)
	}

	witness2 := key[:]
	witness2Key := sha256.Sum256(witness2)

	if err := wCache.AddWitnesses(Sha256HashWitness, witness2); err != nil {
		t.Fatalf("unable to add witness: %v", err)
	}

	// We'll now delete the first witness. If we attempt to look it up, we
	// should get ErrNoWitnesses.
	err = wCache.DeleteWitness(Sha256HashWitness, witness1Key[:])
	if err != nil {
		t.Fatalf("unable to delete witness: %v", err)
	}
	_, err = wCache.LookupWitness(Sha256HashWitness, witness1Key[:])
	if err != ErrNoWitnesses {
		t.Fatalf("expected ErrNoWitnesses instead got: %v", err)
	}

	// Next, we'll attempt to delete the entire witness class itself. When
	// we try to lookup the second witness, we should again get
	// ErrNoWitnesses.
	if err := wCache.DeleteWitnessClass(Sha256HashWitness); err != nil {
		t.Fatalf("unable to delete witness class: %v", err)
	}
	_, err = wCache.LookupWitness(Sha256HashWitness, witness2Key[:])
	if err != ErrNoWitnesses {
		t.Fatalf("expected ErrNoWitnesses instead got: %v", err)
	}
}

// TestWitnessCacheUnknownWitness tests that we get an error if we attempt to
// query/add/delete an unknown witness.
func TestWitnessCacheUnknownWitness(t *testing.T) {
	t.Parallel()

	cdb, cleanUp, err := makeTestDB()
	if err != nil {
		t.Fatalf("unable to make test database: %v", err)
	}
	defer cleanUp()

	wCache := cdb.NewWitnessCache()

	// We'll attempt to add a new, undefined witness type to the database.
	// We should get an error.
	err = wCache.AddWitnesses(234, key[:])
	if err != ErrUnknownWitnessType {
		t.Fatalf("expected ErrUnknownWitnessType, got %v", err)
	}
}