package local

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"

	"github.com/mitchellh/cli"
	"github.com/zclconf/go-cty/cty"

	"github.com/hashicorp/terraform/backend"
	"github.com/hashicorp/terraform/configs/configschema"
	"github.com/hashicorp/terraform/internal/initwd"
	"github.com/hashicorp/terraform/providers"
	"github.com/hashicorp/terraform/states"
	"github.com/hashicorp/terraform/states/statemgr"
	"github.com/hashicorp/terraform/terraform"
	"github.com/hashicorp/terraform/tfdiags"
)

func TestLocal_applyBasic(t *testing.T) {
	b, cleanup := TestLocal(t)
	defer cleanup()

	p := TestLocalProvider(t, b, "test", applyFixtureSchema())
	p.ApplyResourceChangeResponse = providers.ApplyResourceChangeResponse{NewState: cty.ObjectVal(map[string]cty.Value{
		"id":  cty.StringVal("yes"),
		"ami": cty.StringVal("bar"),
	})}

	op, configCleanup := testOperationApply(t, "./testdata/apply")
	defer configCleanup()

	run, err := b.Operation(context.Background(), op)
	if err != nil {
		t.Fatalf("bad: %s", err)
	}
	<-run.Done()
	if run.Result != backend.OperationSuccess {
		t.Fatal("operation failed")
	}

	if p.ReadResourceCalled {
		t.Fatal("ReadResource should not be called")
	}

	if !p.PlanResourceChangeCalled {
		t.Fatal("diff should be called")
	}

	if !p.ApplyResourceChangeCalled {
		t.Fatal("apply should be called")
	}

	checkState(t, b.StateOutPath, `
test_instance.foo:
  ID = yes
  provider = provider["registry.terraform.io/hashicorp/test"]
  ami = bar
`)

}

func TestLocal_applyEmptyDir(t *testing.T) {
	b, cleanup := TestLocal(t)
	defer cleanup()

	p := TestLocalProvider(t, b, "test", &terraform.ProviderSchema{})
	p.ApplyResourceChangeResponse = providers.ApplyResourceChangeResponse{NewState: cty.ObjectVal(map[string]cty.Value{"id": cty.StringVal("yes")})}

	op, configCleanup := testOperationApply(t, "./testdata/empty")
	defer configCleanup()

	run, err := b.Operation(context.Background(), op)
	if err != nil {
		t.Fatalf("bad: %s", err)
	}
	<-run.Done()
	if run.Result == backend.OperationSuccess {
		t.Fatal("operation succeeded; want error")
	}

	if p.ApplyResourceChangeCalled {
		t.Fatal("apply should not be called")
	}

	if _, err := os.Stat(b.StateOutPath); err == nil {
		t.Fatal("should not exist")
	}

	// the backend should be unlocked after a run
	assertBackendStateUnlocked(t, b)
}

func TestLocal_applyEmptyDirDestroy(t *testing.T) {
	b, cleanup := TestLocal(t)
	defer cleanup()

	p := TestLocalProvider(t, b, "test", &terraform.ProviderSchema{})
	p.ApplyResourceChangeResponse = providers.ApplyResourceChangeResponse{}

	op, configCleanup := testOperationApply(t, "./testdata/empty")
	defer configCleanup()
	op.Destroy = true

	run, err := b.Operation(context.Background(), op)
	if err != nil {
		t.Fatalf("bad: %s", err)
	}
	<-run.Done()
	if run.Result != backend.OperationSuccess {
		t.Fatalf("apply operation failed")
	}

	if p.ApplyResourceChangeCalled {
		t.Fatal("apply should not be called")
	}

	checkState(t, b.StateOutPath, `<no state>`)
}

func TestLocal_applyError(t *testing.T) {
	b, cleanup := TestLocal(t)
	defer cleanup()

	schema := &terraform.ProviderSchema{
		ResourceTypes: map[string]*configschema.Block{
			"test_instance": {
				Attributes: map[string]*configschema.Attribute{
					"ami": {Type: cty.String, Optional: true},
					"id":  {Type: cty.String, Computed: true},
				},
			},
		},
	}
	p := TestLocalProvider(t, b, "test", schema)

	var lock sync.Mutex
	errored := false
	p.ApplyResourceChangeFn = func(
		r providers.ApplyResourceChangeRequest) providers.ApplyResourceChangeResponse {

		lock.Lock()
		defer lock.Unlock()
		var diags tfdiags.Diagnostics

		ami := r.Config.GetAttr("ami").AsString()
		if !errored && ami == "error" {
			errored = true
			diags = diags.Append(errors.New("error"))
			return providers.ApplyResourceChangeResponse{
				Diagnostics: diags,
			}
		}
		return providers.ApplyResourceChangeResponse{
			Diagnostics: diags,
			NewState: cty.ObjectVal(map[string]cty.Value{
				"id":  cty.StringVal("foo"),
				"ami": cty.StringVal("bar"),
			}),
		}
	}

	op, configCleanup := testOperationApply(t, "./testdata/apply-error")
	defer configCleanup()

	run, err := b.Operation(context.Background(), op)
	if err != nil {
		t.Fatalf("bad: %s", err)
	}
	<-run.Done()
	if run.Result == backend.OperationSuccess {
		t.Fatal("operation succeeded; want failure")
	}

	checkState(t, b.StateOutPath, `
test_instance.foo:
  ID = foo
  provider = provider["registry.terraform.io/hashicorp/test"]
  ami = bar
	`)

	// the backend should be unlocked after a run
	assertBackendStateUnlocked(t, b)
}

func TestLocal_applyBackendFail(t *testing.T) {
	b, cleanup := TestLocal(t)
	defer cleanup()

	p := TestLocalProvider(t, b, "test", applyFixtureSchema())
	p.ApplyResourceChangeResponse = providers.ApplyResourceChangeResponse{NewState: cty.ObjectVal(map[string]cty.Value{
		"id":  cty.StringVal("yes"),
		"ami": cty.StringVal("bar"),
	})}

	wd, err := os.Getwd()
	if err != nil {
		t.Fatalf("failed to get current working directory")
	}
	err = os.Chdir(filepath.Dir(b.StatePath))
	if err != nil {
		t.Fatalf("failed to set temporary working directory")
	}
	defer os.Chdir(wd)

	op, configCleanup := testOperationApply(t, wd+"/testdata/apply")
	defer configCleanup()

	b.Backend = &backendWithFailingState{}
	b.CLI = new(cli.MockUi)

	run, err := b.Operation(context.Background(), op)
	if err != nil {
		t.Fatalf("bad: %s", err)
	}
	<-run.Done()
	if run.Result == backend.OperationSuccess {
		t.Fatalf("apply succeeded; want error")
	}

	msgStr := b.CLI.(*cli.MockUi).ErrorWriter.String()
	if !strings.Contains(msgStr, "Failed to save state: fake failure") {
		t.Fatalf("missing \"fake failure\" message in output:\n%s", msgStr)
	}

	// The fallback behavior should've created a file errored.tfstate in the
	// current working directory.
	checkState(t, "errored.tfstate", `
test_instance.foo:
  ID = yes
  provider = provider["registry.terraform.io/hashicorp/test"]
  ami = bar
	`)

	// the backend should be unlocked after a run
	assertBackendStateUnlocked(t, b)
}

type backendWithFailingState struct {
	Local
}

func (b *backendWithFailingState) StateMgr(name string) (statemgr.Full, error) {
	return &failingState{
		statemgr.NewFilesystem("failing-state.tfstate"),
	}, nil
}

type failingState struct {
	*statemgr.Filesystem
}

func (s failingState) WriteState(state *states.State) error {
	return errors.New("fake failure")
}

func testOperationApply(t *testing.T, configDir string) (*backend.Operation, func()) {
	t.Helper()

	_, configLoader, configCleanup := initwd.MustLoadConfigForTests(t, configDir)

	return &backend.Operation{
		Type:         backend.OperationTypeApply,
		ConfigDir:    configDir,
		ConfigLoader: configLoader,
	}, configCleanup
}

// applyFixtureSchema returns a schema suitable for processing the
// configuration in testdata/apply . This schema should be
// assigned to a mock provider named "test".
func applyFixtureSchema() *terraform.ProviderSchema {
	return &terraform.ProviderSchema{
		ResourceTypes: map[string]*configschema.Block{
			"test_instance": {
				Attributes: map[string]*configschema.Attribute{
					"ami": {Type: cty.String, Optional: true},
					"id":  {Type: cty.String, Computed: true},
				},
			},
		},
	}
}