// Copyright 2016-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License"). You may
// not use this file except in compliance with the License. A copy of the
// License is located at
//
//     http://aws.amazon.com/apache2.0/
//
// or in the "license" file accompanying this file. This file is distributed
// on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
// express or implied. See the License for the specific language governing
// permissions and limitations under the License.

package event

import (
	"context"
	"testing"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/sqs"
	"github.com/aws/amazon-ecs-cluster-state-service/handler/mocks"
	"github.com/golang/mock/gomock"
	"github.com/pkg/errors"
)

const (
	queueUrl       = "url://test"
	receiptHandle  = "receiptHandle"
	receiptHandle2 = "receiptHandle2"
	messageBody    = "messageBody"
	messageBody2   = "messageBody2"
	queueName      = "event_stream"
)

type consumerMockContext struct {
	mockCtrl             *gomock.Controller
	sqsClient            *mocks.MockSQSAPI
	processor            *mocks.MockProcessor
	getQueueUrlInput     *sqs.GetQueueUrlInput
	getQueueUrlOutput    *sqs.GetQueueUrlOutput
	receiveMessageInput  *sqs.ReceiveMessageInput
	receiveMessageOutput *sqs.ReceiveMessageOutput
	sqsMessage           *sqs.Message
	sqsMessage2          *sqs.Message
	deleteMessageInput   *sqs.DeleteMessageInput
	deleteMessageInput2  *sqs.DeleteMessageInput
}

func NewConsumerMockContext(t *testing.T) *consumerMockContext {
	context := consumerMockContext{}
	context.mockCtrl = gomock.NewController(t)
	context.sqsClient = mocks.NewMockSQSAPI(context.mockCtrl)
	context.processor = mocks.NewMockProcessor(context.mockCtrl)

	context.sqsMessage = &sqs.Message{
		Body:          aws.String(messageBody),
		ReceiptHandle: aws.String(receiptHandle),
	}

	context.sqsMessage2 = &sqs.Message{
		Body:          aws.String(messageBody2),
		ReceiptHandle: aws.String(receiptHandle2),
	}

	context.getQueueUrlInput = &sqs.GetQueueUrlInput{
		QueueName: aws.String(queueName),
	}

	context.getQueueUrlOutput = &sqs.GetQueueUrlOutput{
		QueueUrl: aws.String(queueUrl),
	}

	context.receiveMessageInput = &sqs.ReceiveMessageInput{
		QueueUrl:          aws.String(queueUrl),
		VisibilityTimeout: aws.Int64(sqsVisibilityTimeout),
		WaitTimeSeconds:   aws.Int64(sqsWaitTimeSeconds),
	}

	context.receiveMessageOutput = &sqs.ReceiveMessageOutput{
		Messages: []*sqs.Message{context.sqsMessage, context.sqsMessage2},
	}

	context.deleteMessageInput = &sqs.DeleteMessageInput{
		ReceiptHandle: aws.String(receiptHandle),
		QueueUrl:      aws.String(queueUrl),
	}

	context.deleteMessageInput2 = &sqs.DeleteMessageInput{
		ReceiptHandle: aws.String(receiptHandle2),
		QueueUrl:      aws.String(queueUrl),
	}

	return &context
}

func TestNewConsumerNilSQS(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	_, err := NewSQSConsumer(nil, context.processor, queueName)
	if err == nil {
		t.Error("Expected an error when sqs is nil")
	}
}

func TestNewConsumerNilProcessor(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	_, err := NewSQSConsumer(context.sqsClient, nil, queueName)
	if err == nil {
		t.Error("Expected an error when processor is nil")
	}
}

func TestNewConsumerEmptyQueueName(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	_, err := NewSQSConsumer(context.sqsClient, context.processor, "")
	if err == nil {
		t.Error("Expected an error when queueue name is empty")
	}
}

func TestNewConsumerGetQueueUrlFails(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	context.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(context.getQueueUrlInput)).Return(nil, errors.New(""))

	_, err := NewSQSConsumer(context.sqsClient, context.processor, queueName)

	if err == nil {
		t.Error("Expected an error when getQueueUrl fails")
	}
}

func TestNewConsumerGetQueueUrlIsEmpty(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	context.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(context.getQueueUrlInput)).Return(&sqs.GetQueueUrlOutput{}, nil)

	_, err := NewSQSConsumer(context.sqsClient, context.processor, queueName)

	if err == nil {
		t.Error("Expected an error when getQueueUrl output is empty")
	}
}

func TestNewConsumer(t *testing.T) {
	context := NewConsumerMockContext(t)
	defer context.mockCtrl.Finish()

	context.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(context.getQueueUrlInput)).Return(context.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(context.sqsClient, context.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	if c == nil {
		t.Error("Consumer should not be nil")
	}
}

func TestPollForEventsReceiveMessageFails(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).
		Return(nil, errors.New("Receive message fails")).Do(func(x interface{}) {
		pollCount++
		if pollCount == 1 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}

func TestPollForEventsReceiveMessageOutputNil(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).Return(nil, nil).Do(func(x interface{}) {
		pollCount++
		if pollCount == 1 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}

func TestPollForEventsReceiveMessageOutputMessagesNil(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	receiveMessageOutput := &sqs.ReceiveMessageOutput{}
	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).
		Return(receiveMessageOutput, nil).Do(func(x interface{}) {
		pollCount++
		if pollCount == 1 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}

func TestPollForEventsFirstProcessEventFails(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).Return(mockContext.receiveMessageOutput, nil)
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[0].Body).Return(errors.New("Process event failed"))
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[1].Body).Return(nil)
	mockContext.sqsClient.EXPECT().DeleteMessage(mockContext.deleteMessageInput2).Return(nil, nil).Do(func(x interface{}) {
		pollCount++
		if pollCount == 1 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}

func TestPollForEventsFirstDeleteEventFails(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).Return(mockContext.receiveMessageOutput, nil)
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[0].Body).Return(nil)
	mockContext.sqsClient.EXPECT().DeleteMessage(mockContext.deleteMessageInput).Return(nil, errors.New("Delete event failed"))
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[1].Body).Return(nil)
	mockContext.sqsClient.EXPECT().DeleteMessage(mockContext.deleteMessageInput2).Return(nil, nil).Do(func(x interface{}) {
		pollCount++
		if pollCount == 1 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}

func TestPollForEventsReceiveTwoMessages(t *testing.T) {
	mockContext := NewConsumerMockContext(t)
	defer mockContext.mockCtrl.Finish()

	mockContext.sqsClient.EXPECT().GetQueueUrl(gomock.Eq(mockContext.getQueueUrlInput)).Return(mockContext.getQueueUrlOutput, nil)

	c, err := NewSQSConsumer(mockContext.sqsClient, mockContext.processor, queueName)

	if err != nil {
		t.Errorf("Unexpected error when calling NewConsumer: %+v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	pollCount := 0

	mockContext.sqsClient.EXPECT().ReceiveMessage(mockContext.receiveMessageInput).Return(mockContext.receiveMessageOutput, nil).Times(2)
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[0].Body).Return(nil).Times(2)
	mockContext.sqsClient.EXPECT().DeleteMessage(mockContext.deleteMessageInput).Return(nil, nil).Times(2)
	mockContext.processor.EXPECT().ProcessEvent(*mockContext.receiveMessageOutput.Messages[1].Body).Return(nil).Times(2)
	mockContext.sqsClient.EXPECT().DeleteMessage(mockContext.deleteMessageInput2).Return(nil, nil).Times(2).Do(func(x interface{}) {
		pollCount++
		if pollCount == 2 {
			cancel()
		}
	})

	c.PollForEvents(ctx)
}