/*
Copyright 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.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License 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 dth

import (
	"encoding/json"
	"fmt"
	"log"
	"net/url"
	"strconv"
	"strings"
)

var (
	// KB is 1024 Bytes
	KB int = 1 << 10

	// MB is 1024 KB
	MB int = 1 << 20
)

// Global variables which are updated automatically every 02:00 a.m.
// When calling a S3 API, the credentials of the client will be updated according to these two variables
var (
	SRC_CRED *S3Credentials
	DST_CRED *S3Credentials
)

// Source is an interface represents a type of cloud storage services
// type Source interface {
// 	GetEndpointURL()
// }

// Object represents an object to be replicated.
type Object struct {
	Key       string `json:"key"`
	Size      int64  `json:"size"`
	Sequencer string `json:"sequencer,omitempty"`
}

// S3Event represents a basic structure of a S3 Event Message
// See https://docs.aws.amazon.com/AmazonS3/latest/userguide/notification-content-structure.html for more details
type S3Event struct {
	Records []struct {
		EventSource, AwsRegion, EventTime, EventName string
		S3                                           struct {
			Object `json:"object"`
		}
	}
}

// Part represents a part for multipart upload
type Part struct {
	partNumber int
	etag       *string
}

// Metadata info of object
type Metadata struct {
	// ContentType
	ContentType *string

	// ContentLanguage
	ContentLanguage *string

	// ContentEncoding
	ContentEncoding *string

	// CacheControl
	CacheControl *string

	// Custom metadata to store with the object in S3.
	// Map keys will be normalized to lower-case.
	Metadata map[string]string
}

// Helper function to convert Object into Json string
func (o *Object) toString() *string {
	// log.Printf("Convert %v to string", o)

	obj, err := json.Marshal(*o)

	if err != nil {
		log.Printf("Unable to convert object to json string - %s", err)
		return nil
	}

	str := string(obj)
	// msgStr := fmt.Sprintf(`{"key":"%s","size":%d,"version":"%s"}`, m.Key, m.Size, m.Version)
	return &str
}

// Helper function to create Object base on Json string
func newObject(str *string) (o *Object) {

	o = new(Object)
	err := json.Unmarshal([]byte(*str), o)

	if err != nil {
		log.Printf("Unable to convert string to object - %s", err.Error())
		return nil
	}
	// log.Printf("Key: %s, Size: %d\n", m.Key, m.Size)
	return
}

// Helper function to create S3Event base on Json string
func newS3Event(str *string) (e *S3Event) {

	e = new(S3Event)
	err := json.Unmarshal([]byte(*str), e)

	if err != nil {
		log.Printf("Unable to convert string to S3 Event - %s", err.Error())
		return nil
	}
	// log.Printf("Key: %s, Size: %d\n", m.Key, m.Size)
	return
}

func getHex(str *string) int64 {
	i64, _ := strconv.ParseInt(*str, 16, 64)
	return i64
}

func unescape(str *string) string {
	output, _ := url.QueryUnescape(*str)
	return output
}

func escape(str *string) string {
	return url.QueryEscape(*str)
}

func removePrefix(key, prefix *string) *string {
	if prefix == nil || *prefix == "" || *prefix == "/" {
		return key
	}
	delimiter := ""
	if !strings.HasSuffix(*prefix, "/") {
		delimiter = "/"
	}
	newkey := strings.Replace(*key, *prefix+delimiter, "", 1)
	return &newkey
}

func appendPrefix(key, prefix *string) *string {
	if prefix == nil || *prefix == "" || *prefix == "/" {
		return key
	}
	delimiter := ""
	if !strings.HasSuffix(*prefix, "/") {
		delimiter = "/"
	}
	newkey := fmt.Sprintf("%s%s%s", *prefix, delimiter, *key)
	return &newkey
}