// Copyright 2015-2017 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 cloudwatchlogs

import (
	"github.com/aws/amazon-ecs-cli/ecs-cli/modules/clients"
	"github.com/aws/amazon-ecs-cli/ecs-cli/modules/config"
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/cloudwatchlogs"
	"github.com/aws/aws-sdk-go/service/cloudwatchlogs/cloudwatchlogsiface"
)

// Client defines methods to interact with the CloudWatch API interface.
type Client interface {
	FilterAllLogEvents(*cloudwatchlogs.FilterLogEventsInput, func([]*cloudwatchlogs.FilteredLogEvent)) error
	CreateLogGroup(*string) error
}

// ec2Client implements EC2Client
type cwLogsClient struct {
	client cloudwatchlogsiface.CloudWatchLogsAPI
}

// NewCloudWatchLogsClient creates an instance of ec2Client object.
func NewCloudWatchLogsClient(params *config.CommandConfig, logRegion string) Client {
	newSession := params.Session.Copy(&aws.Config{
		Region: aws.String(logRegion),
		CredentialsChainVerboseErrors: aws.Bool(true),
	})
	client := cloudwatchlogs.New(newSession)
	client.Handlers.Build.PushBackNamed(clients.CustomUserAgentHandler())
	return &cwLogsClient{
		client: client,
	}
}

func (c *cwLogsClient) FilterAllLogEvents(input *cloudwatchlogs.FilterLogEventsInput, action func([]*cloudwatchlogs.FilteredLogEvent)) error {
	err := c.client.FilterLogEventsPages(input,
		func(page *cloudwatchlogs.FilterLogEventsOutput, lastPage bool) bool {
			action(page.Events)
			return !lastPage
		})
	return err
}

func (c *cwLogsClient) CreateLogGroup(group *string) error {
	_, err := c.client.CreateLogGroup(&cloudwatchlogs.CreateLogGroupInput{
		LogGroupName: group,
	})
	return err
}

// LogClientFactory is a factory which creates log clients for a region
type LogClientFactory interface {
	Get(string) Client
}

type clientFactory struct {
	logClientForRegion map[string]Client
	commandConfig      *config.CommandConfig
}

func (c *clientFactory) Get(region string) Client {
	client, ok := c.logClientForRegion[region]
	if !ok {
		client = NewCloudWatchLogsClient(c.commandConfig, region)
		c.logClientForRegion[region] = client
	}
	return client
}

// NewLogClientFactory returns a factory which creates log clients for a region
func NewLogClientFactory(commandConfig *config.CommandConfig) LogClientFactory {
	return &clientFactory{
		logClientForRegion: make(map[string]Client),
		commandConfig:      commandConfig,
	}
}