package remote

import (
	"sync"
	"testing"

	"github.com/google/go-cmp/cmp"
	"github.com/zclconf/go-cty/cty"

	"github.com/hashicorp/terraform/states"
	"github.com/hashicorp/terraform/states/statemgr"
	"github.com/hashicorp/terraform/version"
)

func TestState_impl(t *testing.T) {
	var _ statemgr.Reader = new(State)
	var _ statemgr.Writer = new(State)
	var _ statemgr.Persister = new(State)
	var _ statemgr.Refresher = new(State)
	var _ statemgr.Locker = new(State)
}

func TestStateRace(t *testing.T) {
	s := &State{
		Client: nilClient{},
	}

	current := states.NewState()

	var wg sync.WaitGroup

	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			s.WriteState(current)
			s.PersistState()
			s.RefreshState()
		}()
	}
	wg.Wait()
}

func TestStatePersist(t *testing.T) {
	mgr := &State{
		Client: &mockClient{
			// Initial state just to give us a fixed starting point for our
			// test assertions below, or else we'd need to deal with
			// random lineage.
			current: []byte(`
				{
					"version": 4,
					"lineage": "mock-lineage",
					"serial": 1,
					"terraform_version":"0.0.0",
					"outputs": {},
					"resources": []
				}
			`),
		},
	}

	// In normal use (during a Terraform operation) we always refresh and read
	// before any writes would happen, so we'll mimic that here for realism.
	if err := mgr.RefreshState(); err != nil {
		t.Fatalf("failed to RefreshState: %s", err)
	}
	s := mgr.State()

	s.RootModule().SetOutputValue("foo", cty.StringVal("bar"), false)
	if err := mgr.WriteState(s); err != nil {
		t.Fatalf("failed to WriteState: %s", err)
	}
	if err := mgr.PersistState(); err != nil {
		t.Fatalf("failed to PersistState: %s", err)
	}

	// Persisting the same state again should be a no-op: it doesn't fail,
	// but it ought not to appear in the client's log either.
	if err := mgr.WriteState(s); err != nil {
		t.Fatalf("failed to WriteState: %s", err)
	}
	if err := mgr.PersistState(); err != nil {
		t.Fatalf("failed to PersistState: %s", err)
	}

	// ...but if we _do_ change something in the state then we should see
	// it re-persist.
	s.RootModule().SetOutputValue("foo", cty.StringVal("baz"), false)
	if err := mgr.WriteState(s); err != nil {
		t.Fatalf("failed to WriteState: %s", err)
	}
	if err := mgr.PersistState(); err != nil {
		t.Fatalf("failed to PersistState: %s", err)
	}

	got := mgr.Client.(*mockClient).log
	want := []mockClientRequest{
		// The initial fetch from mgr.RefreshState above.
		{
			Method: "Get",
			Content: map[string]interface{}{
				"version":           4.0, // encoding/json decodes this as float64 by default
				"lineage":           "mock-lineage",
				"serial":            1.0, // encoding/json decodes this as float64 by default
				"terraform_version": "0.0.0",
				"outputs":           map[string]interface{}{},
				"resources":         []interface{}{},
			},
		},

		// First call to PersistState, with output "foo" set to "bar".
		{
			Method: "Put",
			Content: map[string]interface{}{
				"version":           4.0,
				"lineage":           "mock-lineage",
				"serial":            2.0, // serial increases because the outputs changed
				"terraform_version": version.Version,
				"outputs": map[string]interface{}{
					"foo": map[string]interface{}{
						"type":  "string",
						"value": "bar",
					},
				},
				"resources": []interface{}{},
			},
		},

		// Second call to PersistState generates no client requests, because
		// nothing changed in the state itself.

		// Third call to PersistState, with the "foo" output value updated
		// to "baz".
		{
			Method: "Put",
			Content: map[string]interface{}{
				"version":           4.0,
				"lineage":           "mock-lineage",
				"serial":            3.0, // serial increases because the outputs changed
				"terraform_version": version.Version,
				"outputs": map[string]interface{}{
					"foo": map[string]interface{}{
						"type":  "string",
						"value": "baz",
					},
				},
				"resources": []interface{}{},
			},
		},
	}
	if diff := cmp.Diff(want, got); len(diff) > 0 {
		t.Errorf("incorrect client requests\n%s", diff)
	}
}