package main

import (
	"context"
	"flag"
	"io"
	"net/http"
	"net/url"
	"os"
	"reflect"
	"strconv"
	"time"
	"unsafe"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
	"github.com/pkg/errors"

	_ "unsafe"
)

type obsS3Options struct {
	Endpoint string
	Region   string
	Secure   bool // S3 secure
}

const maxURLExpiry = time.Duration(int64(^uint64(0) / 2))

var defaultObsS3Opts = obsS3Options{}

func (opts *obsS3Options) Bind(fs *flag.FlagSet) (err error) {
	fs.StringVar(&opts.Endpoint, "obs-endpoint", os.Getenv("OBS_ENDPOINT"), "OBS S3 Host")
	fs.StringVar(&opts.Region, "obs-region", os.Getenv("OBS_REGION"), "OBS S3 Region")

	var vObsSecure = opts.Secure
	if sObsSecure := os.Getenv("OBS_SECURE"); sObsSecure != "" {
		var obsSecure bool
		if obsSecure, err = strconv.ParseBool(sObsSecure); err != nil {
			err = errors.Wrap(err, "obs secure")
			return
		}
		vObsSecure = obsSecure
	}
	fs.BoolVar(&opts.Secure, "obs-secure", vObsSecure, "OBS S3 secure transport")

	return
}

func newObsS3Client(opts obsS3Options) (*minio.Client, error) {
	client, err := minio.New(opts.Endpoint, &minio.Options{
		Creds:        credentials.NewEnvAWS(),
		BucketLookup: minio.BucketLookupAuto, // vhost / path
		Region:       opts.Region,
		Secure:       opts.Secure,
	})
	if err != nil {
		return nil, err
	}
	setOverrideSignerType(client, credentials.SignatureV2)
	return client, nil
}

var (
	offsetCredsProvider      uintptr
	offsetOverrideSignerType uintptr
)

func init() {
	vt := reflect.TypeOf(minio.Client{})
	if field, ok := vt.FieldByName("credsProvider"); ok {
		offsetCredsProvider = field.Offset
	} else {
		panic("cannot find credsProvider field")
	}

	if field, ok := vt.FieldByName("overrideSignerType"); ok {
		offsetOverrideSignerType = field.Offset
	} else {
		panic("cannot find overrideSignerType field")
	}
}

func getCredsProvider(client *minio.Client) *credentials.Credentials {
	return *(**credentials.Credentials)(unsafe.Add(unsafe.Pointer(client), offsetCredsProvider))
}

func setOverrideSignerType(client *minio.Client, signerType credentials.SignatureType) {
	ptr := (*credentials.SignatureType)(unsafe.Add(unsafe.Pointer(client), offsetOverrideSignerType))
	*ptr = signerType
}

//go:linkname isVirtualHostStyleRequest github.com/minio/minio-go/v7.(*Client).isVirtualHostStyleRequest
func isVirtualHostStyleRequest(client *minio.Client, url url.URL, bucketName string) bool

//go:linkname makeTargetURL github.com/minio/minio-go/v7.(*Client).makeTargetURL
func makeTargetURL(client *minio.Client, bucketName, objectName, bucketLocation string, isVirtualHostStyle bool, queryValues url.Values) (*url.URL, error)

// requestMetadata - is container for all the values to make a request.
type requestMetadata struct {
	// If set newRequest presigns the URL.
	presignURL bool

	// User supplied.
	bucketName         string
	objectName         string
	queryValues        url.Values
	customHeader       http.Header
	extraPresignHeader http.Header
	expires            int64

	// Generated by our internal code.
	bucketLocation   string
	contentBody      io.Reader
	contentLength    int64
	contentMD5Base64 string // carries base64 encoded md5sum
	contentSHA256Hex string // carries hex encoded sha256sum
	streamSha256     bool
	addCrc           bool
	trailer          http.Header // (http.Request).Trailer. Requires v4 signature.
}

//go:linkname newRequest github.com/minio/minio-go/v7.(*Client).newRequest
func newRequest(client *minio.Client, ctx context.Context, method string, metadata requestMetadata) (req *http.Request, err error)