/*
 * MinIO Go Library for Amazon S3 Compatible Cloud Storage
 * Copyright 2017 MinIO, Inc.
 *
 * 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 minio

import (
	"bytes"
	"context"
	"encoding/base64"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"sort"
	"strings"

	"github.com/google/uuid"
	"github.com/minio/minio-go/v7/pkg/s3utils"
)

// putObjectMultipartStream - upload a large object using
// multipart upload and streaming signature for signing payload.
// Comprehensive put object operation involving multipart uploads.
//
// Following code handles these types of readers.
//
//  - *minio.Object
//  - Any reader which has a method 'ReadAt()'
//
func (c *Client) putObjectMultipartStream(ctx context.Context, bucketName, objectName string,
	reader io.Reader, size int64, opts PutObjectOptions,
) (info UploadInfo, err error) {
	if !isObject(reader) && isReadAt(reader) && !opts.SendContentMd5 {
		// Verify if the reader implements ReadAt and it is not a *minio.Object then we will use parallel uploader.
		info, err = c.putObjectMultipartStreamFromReadAt(ctx, bucketName, objectName, reader.(io.ReaderAt), size, opts)
	} else {
		info, err = c.putObjectMultipartStreamOptionalChecksum(ctx, bucketName, objectName, reader, size, opts)
	}
	if err != nil {
		errResp := ToErrorResponse(err)
		// Verify if multipart functionality is not available, if not
		// fall back to single PutObject operation.
		if errResp.Code == "AccessDenied" && strings.Contains(errResp.Message, "Access Denied") {
			// Verify if size of reader is greater than '5GiB'.
			if size > maxSinglePutObjectSize {
				return UploadInfo{}, errEntityTooLarge(size, maxSinglePutObjectSize, bucketName, objectName)
			}
			// Fall back to uploading as single PutObject operation.
			return c.putObject(ctx, bucketName, objectName, reader, size, opts)
		}
	}
	return info, err
}

// uploadedPartRes - the response received from a part upload.
type uploadedPartRes struct {
	Error   error // Any error encountered while uploading the part.
	PartNum int   // Number of the part uploaded.
	Size    int64 // Size of the part uploaded.
	Part    ObjectPart
}

type uploadPartReq struct {
	PartNum int        // Number of the part uploaded.
	Part    ObjectPart // Size of the part uploaded.
}

// putObjectMultipartFromReadAt - Uploads files bigger than 128MiB.
// Supports all readers which implements io.ReaderAt interface
// (ReadAt method).
//
// NOTE: This function is meant to be used for all readers which
// implement io.ReaderAt which allows us for resuming multipart
// uploads but reading at an offset, which would avoid re-read the
// data which was already uploaded. Internally this function uses
// temporary files for staging all the data, these temporary files are
// cleaned automatically when the caller i.e http client closes the
// stream after uploading all the contents successfully.
func (c *Client) putObjectMultipartStreamFromReadAt(ctx context.Context, bucketName, objectName string,
	reader io.ReaderAt, size int64, opts PutObjectOptions,
) (info UploadInfo, err error) {
	// Input validation.
	if err = s3utils.CheckValidBucketName(bucketName); err != nil {
		return UploadInfo{}, err
	}
	if err = s3utils.CheckValidObjectName(objectName); err != nil {
		return UploadInfo{}, err
	}

	// Calculate the optimal parts info for a given size.
	totalPartsCount, partSize, lastPartSize, err := OptimalPartInfo(size, opts.PartSize)
	if err != nil {
		return UploadInfo{}, err
	}

	// Initiate a new multipart upload.
	uploadID, err := c.newUploadID(ctx, bucketName, objectName, opts)
	if err != nil {
		return UploadInfo{}, err
	}

	// Aborts the multipart upload in progress, if the
	// function returns any error, since we do not resume
	// we should purge the parts which have been uploaded
	// to relinquish storage space.
	defer func() {
		if err != nil {
			c.abortMultipartUpload(ctx, bucketName, objectName, uploadID)
		}
	}()

	// Total data read and written to server. should be equal to 'size' at the end of the call.
	var totalUploadedSize int64

	// Complete multipart upload.
	var complMultipartUpload completeMultipartUpload

	// Declare a channel that sends the next part number to be uploaded.
	uploadPartsCh := make(chan uploadPartReq)

	// Declare a channel that sends back the response of a part upload.
	uploadedPartsCh := make(chan uploadedPartRes)

	// Used for readability, lastPartNumber is always totalPartsCount.
	lastPartNumber := totalPartsCount

	partitionCtx, partitionCancel := context.WithCancel(ctx)
	defer partitionCancel()
	// Send each part number to the channel to be processed.
	go func() {
		defer close(uploadPartsCh)

		for p := 1; p <= totalPartsCount; p++ {
			select {
			case <-partitionCtx.Done():
				return
			case uploadPartsCh <- uploadPartReq{PartNum: p}:
			}
		}
	}()

	// Receive each part number from the channel allowing three parallel uploads.
	for w := 1; w <= opts.getNumThreads(); w++ {
		go func(partSize int64) {
			for {
				var uploadReq uploadPartReq
				var ok bool
				select {
				case <-ctx.Done():
					return
				case uploadReq, ok = <-uploadPartsCh:
					if !ok {
						return
					}
					// Each worker will draw from the part channel and upload in parallel.
				}

				// If partNumber was not uploaded we calculate the missing
				// part offset and size. For all other part numbers we
				// calculate offset based on multiples of partSize.
				readOffset := int64(uploadReq.PartNum-1) * partSize

				// As a special case if partNumber is lastPartNumber, we
				// calculate the offset based on the last part size.
				if uploadReq.PartNum == lastPartNumber {
					readOffset = (size - lastPartSize)
					partSize = lastPartSize
				}

				sectionReader := newHook(io.NewSectionReader(reader, readOffset, partSize), opts.Progress)

				// Proceed to upload the part.
				objPart, err := c.uploadPart(ctx, bucketName, objectName,
					uploadID, sectionReader, uploadReq.PartNum,
					"", "", partSize,
					opts.ServerSideEncryption,
					!opts.DisableContentSha256,
				)
				if err != nil {
					uploadedPartsCh <- uploadedPartRes{
						Error: err,
					}
					// Exit the goroutine.
					return
				}

				// Save successfully uploaded part metadata.
				uploadReq.Part = objPart

				// Send successful part info through the channel.
				uploadedPartsCh <- uploadedPartRes{
					Size:    objPart.Size,
					PartNum: uploadReq.PartNum,
					Part:    uploadReq.Part,
				}
			}
		}(partSize)
	}

	// Gather the responses as they occur and update any
	// progress bar.
	for u := 1; u <= totalPartsCount; u++ {
		select {
		case <-ctx.Done():
			return UploadInfo{}, ctx.Err()
		case uploadRes := <-uploadedPartsCh:
			if uploadRes.Error != nil {

				return UploadInfo{}, uploadRes.Error
			}

			// Update the totalUploadedSize.
			totalUploadedSize += uploadRes.Size
			complMultipartUpload.Parts = append(complMultipartUpload.Parts, CompletePart{
				ETag:       uploadRes.Part.ETag,
				PartNumber: uploadRes.Part.PartNumber,
			})
		}
	}

	// Verify if we uploaded all the data.
	if totalUploadedSize != size {
		return UploadInfo{}, errUnexpectedEOF(totalUploadedSize, size, bucketName, objectName)
	}

	// Sort all completed parts.
	sort.Sort(completedParts(complMultipartUpload.Parts))

	uploadInfo, err := c.completeMultipartUpload(ctx, bucketName, objectName, uploadID, complMultipartUpload, PutObjectOptions{})
	if err != nil {
		return UploadInfo{}, err
	}

	uploadInfo.Size = totalUploadedSize
	return uploadInfo, nil
}

func (c *Client) putObjectMultipartStreamOptionalChecksum(ctx context.Context, bucketName, objectName string,
	reader io.Reader, size int64, opts PutObjectOptions,
) (info UploadInfo, err error) {
	// Input validation.
	if err = s3utils.CheckValidBucketName(bucketName); err != nil {
		return UploadInfo{}, err
	}
	if err = s3utils.CheckValidObjectName(objectName); err != nil {
		return UploadInfo{}, err
	}

	// Calculate the optimal parts info for a given size.
	totalPartsCount, partSize, lastPartSize, err := OptimalPartInfo(size, opts.PartSize)
	if err != nil {
		return UploadInfo{}, err
	}
	// Initiates a new multipart request
	uploadID, err := c.newUploadID(ctx, bucketName, objectName, opts)
	if err != nil {
		return UploadInfo{}, err
	}

	// Aborts the multipart upload if the function returns
	// any error, since we do not resume we should purge
	// the parts which have been uploaded to relinquish
	// storage space.
	defer func() {
		if err != nil {
			c.abortMultipartUpload(ctx, bucketName, objectName, uploadID)
		}
	}()

	// Total data read and written to server. should be equal to 'size' at the end of the call.
	var totalUploadedSize int64

	// Initialize parts uploaded map.
	partsInfo := make(map[int]ObjectPart)

	// Create a buffer.
	buf := make([]byte, partSize)

	// Avoid declaring variables in the for loop
	var md5Base64 string
	var hookReader io.Reader

	// Part number always starts with '1'.
	var partNumber int
	for partNumber = 1; partNumber <= totalPartsCount; partNumber++ {

		// Proceed to upload the part.
		if partNumber == totalPartsCount {
			partSize = lastPartSize
		}

		if opts.SendContentMd5 {
			length, rerr := readFull(reader, buf)
			if rerr == io.EOF && partNumber > 1 {
				break
			}

			if rerr != nil && rerr != io.ErrUnexpectedEOF && err != io.EOF {
				return UploadInfo{}, rerr
			}

			// Calculate md5sum.
			hash := c.md5Hasher()
			hash.Write(buf[:length])
			md5Base64 = base64.StdEncoding.EncodeToString(hash.Sum(nil))
			hash.Close()

			// Update progress reader appropriately to the latest offset
			// as we read from the source.
			hookReader = newHook(bytes.NewReader(buf[:length]), opts.Progress)
		} else {
			// Update progress reader appropriately to the latest offset
			// as we read from the source.
			hookReader = newHook(reader, opts.Progress)
		}

		objPart, uerr := c.uploadPart(ctx, bucketName, objectName, uploadID,
			io.LimitReader(hookReader, partSize),
			partNumber, md5Base64, "", partSize,
			opts.ServerSideEncryption,
			!opts.DisableContentSha256,
		)
		if uerr != nil {
			return UploadInfo{}, uerr
		}

		// Save successfully uploaded part metadata.
		partsInfo[partNumber] = objPart

		// Save successfully uploaded size.
		totalUploadedSize += partSize
	}

	// Verify if we uploaded all the data.
	if size > 0 {
		if totalUploadedSize != size {
			return UploadInfo{}, errUnexpectedEOF(totalUploadedSize, size, bucketName, objectName)
		}
	}

	// Complete multipart upload.
	var complMultipartUpload completeMultipartUpload

	// Loop over total uploaded parts to save them in
	// Parts array before completing the multipart request.
	for i := 1; i < partNumber; i++ {
		part, ok := partsInfo[i]
		if !ok {
			return UploadInfo{}, errInvalidArgument(fmt.Sprintf("Missing part number %d", i))
		}
		complMultipartUpload.Parts = append(complMultipartUpload.Parts, CompletePart{
			ETag:       part.ETag,
			PartNumber: part.PartNumber,
		})
	}

	// Sort all completed parts.
	sort.Sort(completedParts(complMultipartUpload.Parts))

	uploadInfo, err := c.completeMultipartUpload(ctx, bucketName, objectName, uploadID, complMultipartUpload, PutObjectOptions{})
	if err != nil {
		return UploadInfo{}, err
	}

	uploadInfo.Size = totalUploadedSize
	return uploadInfo, nil
}

// putObject special function used Google Cloud Storage. This special function
// is used for Google Cloud Storage since Google's multipart API is not S3 compatible.
func (c *Client) putObject(ctx context.Context, bucketName, objectName string, reader io.Reader, size int64, opts PutObjectOptions) (info UploadInfo, err error) {
	// Input validation.
	if err := s3utils.CheckValidBucketName(bucketName); err != nil {
		return UploadInfo{}, err
	}
	if err := s3utils.CheckValidObjectName(objectName); err != nil {
		return UploadInfo{}, err
	}

	// Size -1 is only supported on Google Cloud Storage, we error
	// out in all other situations.
	if size < 0 && !s3utils.IsGoogleEndpoint(*c.endpointURL) {
		return UploadInfo{}, errEntityTooSmall(size, bucketName, objectName)
	}

	if opts.SendContentMd5 && s3utils.IsGoogleEndpoint(*c.endpointURL) && size < 0 {
		return UploadInfo{}, errInvalidArgument("MD5Sum cannot be calculated with size '-1'")
	}

	if size > 0 {
		if isReadAt(reader) && !isObject(reader) {
			seeker, ok := reader.(io.Seeker)
			if ok {
				offset, err := seeker.Seek(0, io.SeekCurrent)
				if err != nil {
					return UploadInfo{}, errInvalidArgument(err.Error())
				}
				reader = io.NewSectionReader(reader.(io.ReaderAt), offset, size)
			}
		}
	}

	var md5Base64 string
	if opts.SendContentMd5 {
		// Create a buffer.
		buf := make([]byte, size)

		length, rErr := readFull(reader, buf)
		if rErr != nil && rErr != io.ErrUnexpectedEOF && rErr != io.EOF {
			return UploadInfo{}, rErr
		}

		// Calculate md5sum.
		hash := c.md5Hasher()
		hash.Write(buf[:length])
		md5Base64 = base64.StdEncoding.EncodeToString(hash.Sum(nil))
		reader = bytes.NewReader(buf[:length])
		hash.Close()
	}

	// Update progress reader appropriately to the latest offset as we
	// read from the source.
	readSeeker := newHook(reader, opts.Progress)

	// This function does not calculate sha256 and md5sum for payload.
	// Execute put object.
	return c.putObjectDo(ctx, bucketName, objectName, readSeeker, md5Base64, "", size, opts)
}

// putObjectDo - executes the put object http operation.
// NOTE: You must have WRITE permissions on a bucket to add an object to it.
func (c *Client) putObjectDo(ctx context.Context, bucketName, objectName string, reader io.Reader, md5Base64, sha256Hex string, size int64, opts PutObjectOptions) (UploadInfo, error) {
	// Input validation.
	if err := s3utils.CheckValidBucketName(bucketName); err != nil {
		return UploadInfo{}, err
	}
	if err := s3utils.CheckValidObjectName(objectName); err != nil {
		return UploadInfo{}, err
	}
	// Set headers.
	customHeader := opts.Header()

	// Populate request metadata.
	reqMetadata := requestMetadata{
		bucketName:       bucketName,
		objectName:       objectName,
		customHeader:     customHeader,
		contentBody:      reader,
		contentLength:    size,
		contentMD5Base64: md5Base64,
		contentSHA256Hex: sha256Hex,
		streamSha256:     !opts.DisableContentSha256,
	}
	if opts.Internal.SourceVersionID != "" {
		if opts.Internal.SourceVersionID != nullVersionID {
			if _, err := uuid.Parse(opts.Internal.SourceVersionID); err != nil {
				return UploadInfo{}, errInvalidArgument(err.Error())
			}
		}
		urlValues := make(url.Values)
		urlValues.Set("versionId", opts.Internal.SourceVersionID)
		reqMetadata.queryValues = urlValues
	}

	// Execute PUT an objectName.
	resp, err := c.executeMethod(ctx, http.MethodPut, reqMetadata)
	defer closeResponse(resp)
	if err != nil {
		return UploadInfo{}, err
	}
	if resp != nil {
		if resp.StatusCode != http.StatusOK {
			return UploadInfo{}, httpRespToErrorResponse(resp, bucketName, objectName)
		}
	}

	// extract lifecycle expiry date and rule ID
	expTime, ruleID := amzExpirationToExpiryDateRuleID(resp.Header.Get(amzExpiration))

	return UploadInfo{
		Bucket:           bucketName,
		Key:              objectName,
		ETag:             trimEtag(resp.Header.Get("ETag")),
		VersionID:        resp.Header.Get(amzVersionID),
		Size:             size,
		Expiration:       expTime,
		ExpirationRuleID: ruleID,
	}, nil
}