package credentials

import (
	"context"
	"errors"
	"fmt"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"
)

func TestMemoryStorePutIsIdempotentForUnchangedScope(t *testing.T) {
	store, err := NewMemoryStore(2)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	value := Value{Username: "alice", Password: "secret-password"}

	first, err := store.Put(context.Background(), "provider-a", value)
	if err != nil {
		t.Fatalf("Put(first): %v", err)
	}
	second, err := store.Put(context.Background(), "provider-a", value)
	if err != nil {
		t.Fatalf("Put(second): %v", err)
	}
	if first != second {
		t.Fatalf("second reference = %#v, want %#v", second, first)
	}
	if first.SecretRef == "" || first.CredentialVersion != "v1" {
		t.Fatalf("first reference = %#v, want opaque ref at v1", first)
	}
	for _, plaintext := range []string{"provider-a", value.Username, value.Password} {
		if strings.Contains(first.SecretRef, plaintext) {
			t.Fatalf("SecretRef %q contains plaintext %q", first.SecretRef, plaintext)
		}
	}

	got, err := store.Resolve(context.Background(), first)
	if err != nil {
		t.Fatalf("Resolve(): %v", err)
	}
	if got != value {
		t.Fatalf("Resolve() = %#v, want %#v", got, value)
	}
}

func TestCredentialFormattingRedactsSensitiveMaterial(t *testing.T) {
	value := Value{Username: "alice", Password: "secret-password"}
	for _, formatted := range []string{
		fmt.Sprintf("%v", value),
		fmt.Sprintf("%+v", value),
		fmt.Sprintf("%#v", value),
		fmt.Sprintf("%s", value),
		fmt.Sprintf("%q", value),
	} {
		if strings.Contains(formatted, value.Password) {
			t.Fatalf("formatted Value exposes password: %s", formatted)
		}
	}

	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	reference, err := store.Put(context.Background(), "provider-secret-scope", value)
	if err != nil {
		t.Fatalf("Put(): %v", err)
	}
	for _, formatted := range []string{
		fmt.Sprintf("%v", store),
		fmt.Sprintf("%+v", store),
		fmt.Sprintf("%#v", store),
		fmt.Sprintf("%s", store),
		fmt.Sprintf("%q", store),
	} {
		for _, secret := range []string{
			"provider-secret-scope",
			value.Username,
			value.Password,
			reference.SecretRef,
		} {
			if strings.Contains(formatted, secret) {
				t.Fatalf("formatted MemoryStore exposes sensitive material: %s", formatted)
			}
		}
	}
}

func TestMemoryStorePutIncrementsVersionAndRejectsStaleReference(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	oldReference, err := store.Put(context.Background(), "provider-a", Value{
		Username: "alice",
		Password: "old-password",
	})
	if err != nil {
		t.Fatalf("Put(old): %v", err)
	}
	want := Value{Username: "alice", Password: "new-password"}
	newReference, err := store.Put(context.Background(), "provider-a", want)
	if err != nil {
		t.Fatalf("Put(new): %v", err)
	}
	if newReference.SecretRef != oldReference.SecretRef {
		t.Fatalf("new SecretRef changed across versions")
	}
	if newReference.CredentialVersion != "v2" {
		t.Fatalf("new CredentialVersion = %q, want v2", newReference.CredentialVersion)
	}
	if _, err := store.Resolve(context.Background(), oldReference); !errors.Is(err, ErrCredentialVersionMismatch) {
		t.Fatalf("Resolve(stale) error = %v, want ErrCredentialVersionMismatch", err)
	}
	got, err := store.Resolve(context.Background(), newReference)
	if err != nil {
		t.Fatalf("Resolve(new): %v", err)
	}
	if got != want {
		t.Fatalf("Resolve(new) returned unexpected credentials")
	}
}

func TestMemoryStoreEnforcesCapacityWithoutChangingExistingCredentials(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	want := Value{Username: "alice", Password: "first-password"}
	reference, err := store.Put(context.Background(), "provider-a", want)
	if err != nil {
		t.Fatalf("Put(first scope): %v", err)
	}
	if _, err := store.Put(context.Background(), "provider-b", Value{
		Username: "bob",
		Password: "second-password",
	}); !errors.Is(err, ErrCapacityExceeded) {
		t.Fatalf("Put(over capacity) error = %v, want ErrCapacityExceeded", err)
	}

	got, err := store.Resolve(context.Background(), reference)
	if err != nil {
		t.Fatalf("Resolve(existing): %v", err)
	}
	if got != want {
		t.Fatalf("Resolve(existing) returned changed credentials")
	}
	if _, err := store.Put(context.Background(), "provider-a", want); err != nil {
		t.Fatalf("Put(idempotent at capacity): %v", err)
	}
}

func TestMemoryStoreStrictlyValidatesCredentialVersion(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	reference, err := store.Put(context.Background(), "provider-a", Value{Password: "password"})
	if err != nil {
		t.Fatalf("Put(): %v", err)
	}
	for _, version := range []string{"", "v0", "v01", "1", "latest", "v-1"} {
		invalid := reference
		invalid.CredentialVersion = version
		if _, err := store.Resolve(context.Background(), invalid); !errors.Is(err, ErrInvalidReference) {
			t.Fatalf("Resolve(version %q) error = %v, want ErrInvalidReference", version, err)
		}
	}
	if _, err := store.Put(context.Background(), " \t\n", Value{}); !errors.Is(err, ErrInvalidScope) {
		t.Fatalf("Put(blank scope) error = %v, want ErrInvalidScope", err)
	}
}

func TestMemoryStoreValidatesCapacityAndHonorsCancellation(t *testing.T) {
	if _, err := NewMemoryStore(0); !errors.Is(err, ErrInvalidCapacity) {
		t.Fatalf("NewMemoryStore(0) error = %v, want ErrInvalidCapacity", err)
	}
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(1): %v", err)
	}
	canceled, cancel := context.WithCancel(context.Background())
	cancel()
	if _, err := store.Put(canceled, "provider-a", Value{}); !errors.Is(err, context.Canceled) {
		t.Fatalf("Put(canceled) error = %v, want context.Canceled", err)
	}
	if _, err := store.Resolve(canceled, Reference{
		SecretRef:         "cred_000000000000000000000000000000000000000000000000",
		CredentialVersion: "v1",
	}); !errors.Is(err, context.Canceled) {
		t.Fatalf("Resolve(canceled) error = %v, want context.Canceled", err)
	}
}

func TestMemoryStoreRejectsNilAndZeroValueStores(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	for _, store := range []*MemoryStore{nil, {}} {
		if _, err := store.Put(ctx, "provider-a", Value{}); !errors.Is(err, ErrInvalidStore) {
			t.Fatalf("Put() error = %v, want ErrInvalidStore", err)
		}
		if _, err := store.Resolve(ctx, Reference{
			SecretRef:         "cred_000000000000000000000000000000000000000000000000",
			CredentialVersion: "v1",
		}); !errors.Is(err, ErrInvalidStore) {
			t.Fatalf("Resolve() error = %v, want ErrInvalidStore", err)
		}
	}
}

func TestMemoryStoreIsConcurrencySafeAndIdempotent(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	want := Value{Username: "alice", Password: "shared-password"}
	const workers = 100
	references := make(chan Reference, workers)
	errorsSeen := make(chan error, workers)
	var wait sync.WaitGroup
	for range workers {
		wait.Add(1)
		go func() {
			defer wait.Done()
			reference, err := store.Put(context.Background(), "provider-a", want)
			if err != nil {
				errorsSeen <- err
				return
			}
			references <- reference
		}()
	}
	wait.Wait()
	close(references)
	close(errorsSeen)
	for err := range errorsSeen {
		t.Errorf("concurrent Put(): %v", err)
	}
	var first Reference
	for reference := range references {
		if first == (Reference{}) {
			first = reference
		}
		if reference != first {
			t.Errorf("concurrent Put() reference differs from first")
		}
	}
	if first.CredentialVersion != "v1" {
		t.Fatalf("concurrent version = %q, want v1", first.CredentialVersion)
	}
	got, err := store.Resolve(context.Background(), first)
	if err != nil {
		t.Fatalf("Resolve(): %v", err)
	}
	if got != want {
		t.Fatalf("Resolve() returned unexpected credentials")
	}
}

func TestMemoryStoreSerializesConcurrentCredentialChanges(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	type result struct {
		value     Value
		reference Reference
		err       error
	}
	const workers = 100
	results := make(chan result, workers)
	var wait sync.WaitGroup
	for index := range workers {
		wait.Add(1)
		go func() {
			defer wait.Done()
			value := Value{Username: "alice", Password: "password-" + strconv.Itoa(index)}
			reference, err := store.Put(context.Background(), "provider-a", value)
			results <- result{value: value, reference: reference, err: err}
		}()
	}
	wait.Wait()
	close(results)

	versions := make(map[string]struct{}, workers)
	var secretRef string
	var latest result
	for current := range results {
		if current.err != nil {
			t.Fatalf("concurrent Put(): %v", current.err)
		}
		if secretRef == "" {
			secretRef = current.reference.SecretRef
		}
		if current.reference.SecretRef != secretRef {
			t.Fatal("SecretRef changed across concurrent updates")
		}
		versions[current.reference.CredentialVersion] = struct{}{}
		if current.reference.CredentialVersion == "v100" {
			latest = current
		}
	}
	if len(versions) != workers {
		t.Fatalf("unique versions = %d, want %d", len(versions), workers)
	}
	if latest.reference == (Reference{}) {
		t.Fatal("highest version v100 was not returned")
	}
	got, err := store.Resolve(context.Background(), latest.reference)
	if err != nil {
		t.Fatalf("Resolve(latest): %v", err)
	}
	if got != latest.value {
		t.Fatal("Resolve(latest) returned a different concurrent write")
	}
}

func TestMemoryStoreErrorsDoNotExposeInputs(t *testing.T) {
	store, err := NewMemoryStore(1)
	if err != nil {
		t.Fatalf("NewMemoryStore(): %v", err)
	}
	value := Value{Username: "sensitive-user", Password: "sensitive-password"}
	reference, err := store.Put(context.Background(), "sensitive-scope", value)
	if err != nil {
		t.Fatalf("Put(): %v", err)
	}
	_, capacityErr := store.Put(context.Background(), "other-sensitive-scope", value)
	unknown := Reference{
		SecretRef:         "sensitive-secret-ref",
		CredentialVersion: "v1",
	}
	_, missingErr := store.Resolve(context.Background(), unknown)
	stale := reference
	stale.CredentialVersion = "v2"
	_, versionErr := store.Resolve(context.Background(), stale)

	for _, operationErr := range []error{capacityErr, missingErr, versionErr} {
		if operationErr == nil {
			t.Fatal("operation unexpectedly succeeded")
		}
		for _, sensitive := range []string{
			"sensitive-scope",
			"other-sensitive-scope",
			value.Username,
			value.Password,
			unknown.SecretRef,
			reference.SecretRef,
		} {
			if strings.Contains(operationErr.Error(), sensitive) {
				t.Fatalf("error exposes sensitive input: %v", operationErr)
			}
		}
	}
}