package s3

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"strconv"
	"time"

	"git.frostfs.info/TrueCloudLab/xk6-frostfs/internal/datagen"
	"git.frostfs.info/TrueCloudLab/xk6-frostfs/internal/stats"
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"go.k6.io/k6/js/modules"
	"go.k6.io/k6/metrics"
)

type (
	Client struct {
		vu  modules.VU
		cli *s3.Client
	}

	PutResponse struct {
		Success bool
		Error   string
	}

	DeleteResponse struct {
		Success bool
		Error   string
	}

	GetResponse struct {
		Success bool
		Error   string
	}

	CreateBucketResponse struct {
		Success bool
		Error   string
	}

	VerifyHashResponse struct {
		Success bool
		Error   string
	}
)

func (c *Client) Put(bucket, key string, payload datagen.Payload) PutResponse {
	rdr := payload.Reader()
	sz := payload.Size()

	start := time.Now()
	_, err := c.cli.PutObject(c.vu.Context(), &s3.PutObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		Body:   rdr,
	})
	if err != nil {
		stats.Report(c.vu, objPutFails, 1)
		return PutResponse{Success: false, Error: err.Error()}
	}

	stats.Report(c.vu, objPutSuccess, 1)
	stats.ReportDataSent(c.vu, float64(sz))
	stats.Report(c.vu, objPutDuration, metrics.D(time.Since(start)))
	stats.Report(c.vu, objPutData, float64(sz))
	return PutResponse{Success: true}
}

const multipartUploadMinPartSize = 5 * 1024 * 1024 // 5MB

func (c *Client) Multipart(bucket, key string, objPartSize, concurrency int, payload datagen.Payload) PutResponse {
	if objPartSize < multipartUploadMinPartSize {
		stats.Report(c.vu, objPutFails, 1)
		return PutResponse{Success: false, Error: fmt.Sprintf("part size '%d' must be greater than '%d'(5 MB)", objPartSize, multipartUploadMinPartSize)}
	}

	start := time.Now()
	uploader := manager.NewUploader(c.cli, func(u *manager.Uploader) {
		u.PartSize = int64(objPartSize)
		u.Concurrency = concurrency
	})

	payloadReader := payload.Reader()
	sz := payload.Size()

	_, err := uploader.Upload(c.vu.Context(), &s3.PutObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		Body:   payloadReader,
	})
	if err != nil {
		stats.Report(c.vu, objPutFails, 1)
		return PutResponse{Success: false, Error: err.Error()}
	}

	stats.Report(c.vu, objPutSuccess, 1)
	stats.ReportDataSent(c.vu, float64(sz))
	stats.Report(c.vu, objPutDuration, metrics.D(time.Since(start)))
	stats.Report(c.vu, objPutData, float64(sz))
	return PutResponse{Success: true}
}

func (c *Client) Delete(bucket, key string) DeleteResponse {
	start := time.Now()

	_, err := c.cli.DeleteObject(c.vu.Context(), &s3.DeleteObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	})
	if err != nil {
		stats.Report(c.vu, objDeleteFails, 1)
		return DeleteResponse{Success: false, Error: err.Error()}
	}

	stats.Report(c.vu, objDeleteSuccess, 1)
	stats.Report(c.vu, objDeleteDuration, metrics.D(time.Since(start)))
	return DeleteResponse{Success: true}
}

func (c *Client) Get(bucket, key string) GetResponse {
	start := time.Now()

	objSize := 0
	err := get(c.cli, bucket, key, func(chunk []byte) {
		objSize += len(chunk)
	})
	if err != nil {
		stats.Report(c.vu, objGetFails, 1)
		return GetResponse{Success: false, Error: err.Error()}
	}

	stats.Report(c.vu, objGetSuccess, 1)
	stats.Report(c.vu, objGetDuration, metrics.D(time.Since(start)))
	stats.ReportDataReceived(c.vu, float64(objSize))
	stats.Report(c.vu, objGetData, float64(objSize))
	return GetResponse{Success: true}
}

// DeleteObjectVersion deletes object version with specified versionID.
// If version argument is empty, deletes all versions and delete-markers of specified object.
func (c *Client) DeleteObjectVersion(bucket, key, version string) DeleteResponse {
	var toDelete []types.ObjectIdentifier

	if version != "" {
		toDelete = append(toDelete, types.ObjectIdentifier{
			Key:       aws.String(key),
			VersionId: aws.String(version),
		})
	} else {
		versions, err := c.cli.ListObjectVersions(c.vu.Context(), &s3.ListObjectVersionsInput{
			Bucket: aws.String(bucket),
			Prefix: aws.String(key),
		})
		if err != nil {
			stats.Report(c.vu, objDeleteFails, 1)
			return DeleteResponse{Success: false, Error: err.Error()}
		}
		toDelete = filterObjectVersions(versions, key)
	}
	if len(toDelete) == 0 {
		return c.Delete(bucket, key)
	} else {
		_, err := c.cli.DeleteObjects(c.vu.Context(), &s3.DeleteObjectsInput{
			Bucket: aws.String(bucket),
			Delete: &types.Delete{
				Objects: toDelete,
				Quiet:   true,
			},
		})
		if err != nil {
			stats.Report(c.vu, objDeleteFails, 1)
			return DeleteResponse{Success: false, Error: err.Error()}
		}
	}

	return DeleteResponse{Success: true}
}

func filterObjectVersions(versions *s3.ListObjectVersionsOutput, key string) []types.ObjectIdentifier {
	var result []types.ObjectIdentifier

	for _, v := range versions.Versions {
		if *v.Key == key {
			result = append(result, types.ObjectIdentifier{
				Key:       v.Key,
				VersionId: v.VersionId,
			})
		}
	}

	for _, marker := range versions.DeleteMarkers {
		if *marker.Key == key {
			result = append(result, types.ObjectIdentifier{
				Key:       marker.Key,
				VersionId: marker.VersionId,
			})
		}
	}

	return result
}

func get(
	c *s3.Client,
	bucket string,
	key string,
	onDataChunk func(chunk []byte),
) error {
	var buf = make([]byte, 4*1024)

	obj, err := c.GetObject(context.Background(), &s3.GetObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	})
	if err != nil {
		return err
	}

	for {
		n, err := obj.Body.Read(buf)
		if n > 0 {
			onDataChunk(buf[:n])
		}
		if err != nil {
			break
		}
	}
	return nil
}

func (c *Client) VerifyHash(bucket, key, expectedHash string) VerifyHashResponse {
	hasher := sha256.New()
	err := get(c.cli, bucket, key, func(data []byte) {
		hasher.Write(data)
	})
	if err != nil {
		return VerifyHashResponse{Success: false, Error: err.Error()}
	}
	actualHash := hex.EncodeToString(hasher.Sum(nil))
	if actualHash != expectedHash {
		return VerifyHashResponse{Success: false, Error: "hash mismatch"}
	}

	return VerifyHashResponse{Success: true}
}

func (c *Client) CreateBucket(bucket string, params map[string]string) CreateBucketResponse {
	var err error
	var lockEnabled bool
	if lockEnabledStr, ok := params["lock_enabled"]; ok {
		if lockEnabled, err = strconv.ParseBool(lockEnabledStr); err != nil {
			stats.Report(c.vu, createBucketFails, 1)
			return CreateBucketResponse{Success: false, Error: "invalid lock_enabled params"}
		}
	}

	var bucketConfiguration *types.CreateBucketConfiguration
	if locationConstraint, ok := params["location_constraint"]; ok {
		bucketConfiguration = &types.CreateBucketConfiguration{
			LocationConstraint: types.BucketLocationConstraint(locationConstraint),
		}
	}

	start := time.Now()
	_, err = c.cli.CreateBucket(c.vu.Context(), &s3.CreateBucketInput{
		Bucket:                     aws.String(bucket),
		ACL:                        types.BucketCannedACL(params["acl"]),
		CreateBucketConfiguration:  bucketConfiguration,
		ObjectLockEnabledForBucket: lockEnabled,
	})
	if err != nil {
		stats.Report(c.vu, createBucketFails, 1)
		return CreateBucketResponse{Success: false, Error: err.Error()}
	}

	var versioning bool
	if strVersioned, ok := params["versioning"]; ok {
		if versioning, err = strconv.ParseBool(strVersioned); err != nil {
			stats.Report(c.vu, createBucketFails, 1)
			return CreateBucketResponse{Success: false, Error: err.Error()}
		}
	}
	if versioning {
		_, err = c.cli.PutBucketVersioning(context.TODO(), &s3.PutBucketVersioningInput{
			Bucket: aws.String(bucket),
			VersioningConfiguration: &types.VersioningConfiguration{
				Status: types.BucketVersioningStatusEnabled,
			},
		})
		if err != nil {
			stats.Report(c.vu, createBucketFails, 1)
			return CreateBucketResponse{Success: false, Error: err.Error()}
		}
	}

	stats.Report(c.vu, createBucketSuccess, 1)
	stats.Report(c.vu, createBucketDuration, metrics.D(time.Since(start)))
	return CreateBucketResponse{Success: true}
}