package awsinv

import (
	"context"
	"errors"
	"testing"

	"github.com/aws/aws-sdk-go-v2/aws"
	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
	"github.com/aws/aws-sdk-go-v2/service/ec2"
	"github.com/aws/aws-sdk-go-v2/service/ec2/types"
	"github.com/aws/smithy-go/middleware"
)

type exactEC2 struct {
	out    *ec2.DescribeInstancesOutput
	err    error
	in     *ec2.DescribeInstancesInput
	region string
}

func (f *exactEC2) DescribeInstances(_ context.Context, in *ec2.DescribeInstancesInput, options ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
	f.in = in
	var opts ec2.Options
	for _, option := range options {
		option(&opts)
	}
	f.region = opts.Region
	return f.out, f.err
}

func exactOutput(owner, id string, state types.InstanceStateName) *ec2.DescribeInstancesOutput {
	out := &ec2.DescribeInstancesOutput{Reservations: []types.Reservation{{
		OwnerId:   aws.String(owner),
		Instances: []types.Instance{{InstanceId: aws.String(id), State: &types.InstanceState{Name: state}}},
	}}}
	awsmiddleware.SetRequestIDMetadata(&out.ResultMetadata, "aws-request-123")
	return out
}

func TestVerifyExactStoppedInstanceAcceptsOnlyStoppedOrTerminated(t *testing.T) {
	for _, state := range []types.InstanceStateName{types.InstanceStateNameStopped, types.InstanceStateNameTerminated} {
		t.Run(string(state), func(t *testing.T) {
			api := &exactEC2{out: exactOutput("123456789012", "i-123", state)}
			got, err := VerifyExactStoppedInstance(t.Context(), api, "123456789012", "eu-west-1", "i-123")
			if err != nil {
				t.Fatal(err)
			}
			if got.Account != "123456789012" || got.Region != "eu-west-1" || got.InstanceID != "i-123" || got.State != string(state) || got.RequestID != "aws-request-123" {
				t.Fatalf("observation = %+v", got)
			}
			if len(api.in.InstanceIds) != 1 || api.in.InstanceIds[0] != "i-123" {
				t.Fatalf("DescribeInstances input = %+v", api.in)
			}
			if api.region != "eu-west-1" {
				t.Fatalf("DescribeInstances region = %q", api.region)
			}
		})
	}
}

func TestVerifyExactStoppedInstanceRefusesEveryIncompleteOrLiveAnswer(t *testing.T) {
	notFound := errors.New("InvalidInstanceID.NotFound")
	cases := map[string]*exactEC2{
		"missing-request-id": {out: func() *ec2.DescribeInstancesOutput {
			o := exactOutput("123456789012", "i-123", types.InstanceStateNameStopped)
			o.ResultMetadata = middleware.Metadata{}
			return o
		}()},
		"empty-request-id": {out: func() *ec2.DescribeInstancesOutput {
			o := exactOutput("123456789012", "i-123", types.InstanceStateNameStopped)
			awsmiddleware.SetRequestIDMetadata(&o.ResultMetadata, "")
			return o
		}()},
		"blank-request-id": {out: func() *ec2.DescribeInstancesOutput {
			o := exactOutput("123456789012", "i-123", types.InstanceStateNameStopped)
			awsmiddleware.SetRequestIDMetadata(&o.ResultMetadata, " ")
			return o
		}()},
		"not-found":      {err: notFound},
		"nil":            {},
		"no-reservation": {out: &ec2.DescribeInstancesOutput{}},
		"partial-page": {out: func() *ec2.DescribeInstancesOutput {
			o := exactOutput("123456789012", "i-123", types.InstanceStateNameStopped)
			o.NextToken = aws.String("more")
			return o
		}()},
		"wrong-owner":      {out: exactOutput("999999999999", "i-123", types.InstanceStateNameStopped)},
		"missing-owner":    {out: exactOutput("", "i-123", types.InstanceStateNameStopped)},
		"wrong-instance":   {out: exactOutput("123456789012", "i-other", types.InstanceStateNameStopped)},
		"running":          {out: exactOutput("123456789012", "i-123", types.InstanceStateNameRunning)},
		"missing-state":    {out: &ec2.DescribeInstancesOutput{Reservations: []types.Reservation{{OwnerId: aws.String("123456789012"), Instances: []types.Instance{{InstanceId: aws.String("i-123")}}}}}},
		"two-reservations": {out: &ec2.DescribeInstancesOutput{Reservations: []types.Reservation{{OwnerId: aws.String("123456789012")}, {OwnerId: aws.String("123456789012")}}}},
		"two-instances":    {out: &ec2.DescribeInstancesOutput{Reservations: []types.Reservation{{OwnerId: aws.String("123456789012"), Instances: []types.Instance{{InstanceId: aws.String("i-123")}, {InstanceId: aws.String("i-123")}}}}}},
	}
	for name, api := range cases {
		t.Run(name, func(t *testing.T) {
			if _, err := VerifyExactStoppedInstance(t.Context(), api, "123456789012", "eu-west-1", "i-123"); !errors.Is(err, ErrExactInstance) {
				t.Fatalf("error = %v, want ErrExactInstance", err)
			}
		})
	}
}