/*
 * Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015, 2016 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"
	"crypto/md5"
	"crypto/sha256"
	"hash"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"reflect"
	"runtime"
	"strings"
)

// toInt - converts go value to its integer representation based
// on the value kind if it is an integer.
func toInt(value reflect.Value) (size int64) {
	size = -1
	if value.IsValid() {
		switch value.Kind() {
		case reflect.Int:
			fallthrough
		case reflect.Int8:
			fallthrough
		case reflect.Int16:
			fallthrough
		case reflect.Int32:
			fallthrough
		case reflect.Int64:
			size = value.Int()
		}
	}
	return size
}

// getReaderSize - Determine the size of Reader if available.
func getReaderSize(reader io.Reader) (size int64, err error) {
	size = -1
	if reader == nil {
		return -1, nil
	}
	// Verify if there is a method by name 'Size'.
	sizeFn := reflect.ValueOf(reader).MethodByName("Size")
	// Verify if there is a method by name 'Len'.
	lenFn := reflect.ValueOf(reader).MethodByName("Len")
	if sizeFn.IsValid() {
		if sizeFn.Kind() == reflect.Func {
			// Call the 'Size' function and save its return value.
			result := sizeFn.Call([]reflect.Value{})
			if len(result) == 1 {
				size = toInt(result[0])
			}
		}
	} else if lenFn.IsValid() {
		if lenFn.Kind() == reflect.Func {
			// Call the 'Len' function and save its return value.
			result := lenFn.Call([]reflect.Value{})
			if len(result) == 1 {
				size = toInt(result[0])
			}
		}
	} else {
		// Fallback to Stat() method, two possible Stat() structs exist.
		switch v := reader.(type) {
		case *os.File:
			var st os.FileInfo
			st, err = v.Stat()
			if err != nil {
				// Handle this case specially for "windows",
				// certain files for example 'Stdin', 'Stdout' and
				// 'Stderr' it is not allowed to fetch file information.
				if runtime.GOOS == "windows" {
					if strings.Contains(err.Error(), "GetFileInformationByHandle") {
						return -1, nil
					}
				}
				return
			}
			// Ignore if input is a directory, throw an error.
			if st.Mode().IsDir() {
				return -1, ErrInvalidArgument("Input file cannot be a directory.")
			}
			// Ignore 'Stdin', 'Stdout' and 'Stderr', since they
			// represent *os.File type but internally do not
			// implement Seekable calls. Ignore them and treat
			// them like a stream with unknown length.
			switch st.Name() {
			case "stdin", "stdout", "stderr":
				return
			// Ignore read/write stream of os.Pipe() which have unknown length too.
			case "|0", "|1":
				return
			}
			size = st.Size()
		case *Object:
			var st ObjectInfo
			st, err = v.Stat()
			if err != nil {
				return
			}
			size = st.Size
		}
	}
	// Returns the size here.
	return size, err
}

// completedParts is a collection of parts sortable by their part numbers.
// used for sorting the uploaded parts before completing the multipart request.
type completedParts []CompletePart

func (a completedParts) Len() int           { return len(a) }
func (a completedParts) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
func (a completedParts) Less(i, j int) bool { return a[i].PartNumber < a[j].PartNumber }

// PutObject creates an object in a bucket.
//
// You must have WRITE permissions on a bucket to create an object.
//
//  - For size smaller than 5MiB PutObject automatically does a single atomic Put operation.
//  - For size larger than 5MiB PutObject automatically does a resumable multipart Put operation.
//  - For size input as -1 PutObject does a multipart Put operation until input stream reaches EOF.
//    Maximum object size that can be uploaded through this operation will be 5TiB.
//
// NOTE: Google Cloud Storage does not implement Amazon S3 Compatible multipart PUT.
// So we fall back to single PUT operation with the maximum limit of 5GiB.
//
func (c Client) PutObject(bucketName, objectName string, reader io.Reader, contentType string) (n int64, err error) {
	return c.PutObjectWithProgress(bucketName, objectName, reader, contentType, nil)
}

// putObjectNoChecksum 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) putObjectNoChecksum(bucketName, objectName string, reader io.Reader, size int64, metaData map[string][]string, progress io.Reader) (n int64, err error) {
	// Input validation.
	if err := isValidBucketName(bucketName); err != nil {
		return 0, err
	}
	if err := isValidObjectName(objectName); err != nil {
		return 0, err
	}
	if size > maxSinglePutObjectSize {
		return 0, ErrEntityTooLarge(size, maxSinglePutObjectSize, bucketName, objectName)
	}

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

	// This function does not calculate sha256 and md5sum for payload.
	// Execute put object.
	st, err := c.putObjectDo(bucketName, objectName, readSeeker, nil, nil, size, metaData)
	if err != nil {
		return 0, err
	}
	if st.Size != size {
		return 0, ErrUnexpectedEOF(st.Size, size, bucketName, objectName)
	}
	return size, nil
}

// putObjectSingle is a special function for uploading single put object request.
// This special function is used as a fallback when multipart upload fails.
func (c Client) putObjectSingle(bucketName, objectName string, reader io.Reader, size int64, metaData map[string][]string, progress io.Reader) (n int64, err error) {
	// Input validation.
	if err := isValidBucketName(bucketName); err != nil {
		return 0, err
	}
	if err := isValidObjectName(objectName); err != nil {
		return 0, err
	}
	if size > maxSinglePutObjectSize {
		return 0, ErrEntityTooLarge(size, maxSinglePutObjectSize, bucketName, objectName)
	}
	// If size is a stream, upload up to 5GiB.
	if size <= -1 {
		size = maxSinglePutObjectSize
	}

	// Add the appropriate hash algorithms that need to be calculated by hashCopyN
	// In case of non-v4 signature request or HTTPS connection, sha256 is not needed.
	hashAlgos := make(map[string]hash.Hash)
	hashSums := make(map[string][]byte)
	hashAlgos["md5"] = md5.New()
	if c.signature.isV4() && !c.secure {
		hashAlgos["sha256"] = sha256.New()
	}

	if size <= minPartSize {
		// Initialize a new temporary buffer.
		tmpBuffer := new(bytes.Buffer)
		size, err = hashCopyN(hashAlgos, hashSums, tmpBuffer, reader, size)
		reader = bytes.NewReader(tmpBuffer.Bytes())
		tmpBuffer.Reset()
	} else {
		// Initialize a new temporary file.
		var tmpFile *tempFile
		tmpFile, err = newTempFile("single$-putobject-single")
		if err != nil {
			return 0, err
		}
		defer tmpFile.Close()
		size, err = hashCopyN(hashAlgos, hashSums, tmpFile, reader, size)
		if err != nil {
			return 0, err
		}
		// Seek back to beginning of the temporary file.
		if _, err = tmpFile.Seek(0, 0); err != nil {
			return 0, err
		}
		reader = tmpFile
	}
	// Return error if its not io.EOF.
	if err != nil && err != io.EOF {
		return 0, err
	}
	// Execute put object.
	st, err := c.putObjectDo(bucketName, objectName, reader, hashSums["md5"], hashSums["sha256"], size, metaData)
	if err != nil {
		return 0, err
	}
	if st.Size != size {
		return 0, ErrUnexpectedEOF(st.Size, size, bucketName, objectName)
	}
	// Progress the reader to the size if putObjectDo is successful.
	if progress != nil {
		if _, err = io.CopyN(ioutil.Discard, progress, size); err != nil {
			return size, err
		}
	}
	return size, nil
}

// 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(bucketName, objectName string, reader io.Reader, md5Sum []byte, sha256Sum []byte, size int64, metaData map[string][]string) (ObjectInfo, error) {
	// Input validation.
	if err := isValidBucketName(bucketName); err != nil {
		return ObjectInfo{}, err
	}
	if err := isValidObjectName(objectName); err != nil {
		return ObjectInfo{}, err
	}

	if size <= -1 {
		return ObjectInfo{}, ErrEntityTooSmall(size, bucketName, objectName)
	}

	if size > maxSinglePutObjectSize {
		return ObjectInfo{}, ErrEntityTooLarge(size, maxSinglePutObjectSize, bucketName, objectName)
	}

	// Set headers.
	customHeader := make(http.Header)

	// Set metadata to headers
	for k, v := range metaData {
		if len(v) > 0 {
			customHeader.Set(k, v[0])
		}
	}

	// If Content-Type is not provided, set the default application/octet-stream one
	if v, ok := metaData["Content-Type"]; !ok || len(v) == 0 {
		customHeader.Set("Content-Type", "application/octet-stream")
	}

	// Populate request metadata.
	reqMetadata := requestMetadata{
		bucketName:         bucketName,
		objectName:         objectName,
		customHeader:       customHeader,
		contentBody:        reader,
		contentLength:      size,
		contentMD5Bytes:    md5Sum,
		contentSHA256Bytes: sha256Sum,
	}

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

	var objInfo ObjectInfo
	// Trim off the odd double quotes from ETag in the beginning and end.
	objInfo.ETag = strings.TrimPrefix(resp.Header.Get("ETag"), "\"")
	objInfo.ETag = strings.TrimSuffix(objInfo.ETag, "\"")
	// A success here means data was written to server successfully.
	objInfo.Size = size

	// Return here.
	return objInfo, nil
}