package s3

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

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/dop251/goja"
	"github.com/nspcc-dev/xk6-neofs/internal/stats"
	"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 goja.ArrayBuffer) PutResponse {
	rdr := bytes.NewReader(payload.Bytes())
	sz := rdr.Size()

	stats.Report(c.vu, objPutTotal, 1)

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

func (c *Client) Delete(bucket, key string) DeleteResponse {
	stats.Report(c.vu, objDeleteTotal, 1)
	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, objDeleteDuration, metrics.D(time.Since(start)))
	return DeleteResponse{Success: true}
}

func (c *Client) Get(bucket, key string) GetResponse {
	stats.Report(c.vu, objGetTotal, 1)
	start := time.Now()

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

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: true, Error: "hash mismatch"}
	}

	return VerifyHashResponse{Success: true}
}

func (c *Client) CreateBucket(bucket string, params map[string]string) CreateBucketResponse {
	stats.Report(c.vu, createBucketTotal, 1)

	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()}
	}

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