package cmd

import (
	"context"
	"fmt"
	"io"
	"math"
	"math/rand"
	"time"

	"github.com/samber/lo"

	"gitlink.org.cn/cloudream/common/pkgs/distlock"
	"gitlink.org.cn/cloudream/common/pkgs/logger"
	cdssdk "gitlink.org.cn/cloudream/common/sdks/storage"
	"gitlink.org.cn/cloudream/common/utils/sort2"

	stgglb "gitlink.org.cn/cloudream/storage/common/globals"
	"gitlink.org.cn/cloudream/storage/common/pkgs/connectivity"
	"gitlink.org.cn/cloudream/storage/common/pkgs/distlock/reqbuilder"
	"gitlink.org.cn/cloudream/storage/common/pkgs/ioswitch/plans"
	"gitlink.org.cn/cloudream/storage/common/pkgs/iterator"
	agtmq "gitlink.org.cn/cloudream/storage/common/pkgs/mq/agent"
	coormq "gitlink.org.cn/cloudream/storage/common/pkgs/mq/coordinator"
)

type UploadObjects struct {
	userID       cdssdk.UserID
	packageID    cdssdk.PackageID
	objectIter   iterator.UploadingObjectIterator
	nodeAffinity *cdssdk.NodeID
}

type UploadObjectsResult struct {
	Objects []ObjectUploadResult
}

type ObjectUploadResult struct {
	Info   *iterator.IterUploadingObject
	Error  error
	Object cdssdk.Object
}

type UploadNodeInfo struct {
	Node           cdssdk.Node
	Delay          time.Duration
	IsSameLocation bool
}

type UploadObjectsContext struct {
	Distlock     *distlock.Service
	Connectivity *connectivity.Collector
}

func NewUploadObjects(userID cdssdk.UserID, packageID cdssdk.PackageID, objIter iterator.UploadingObjectIterator, nodeAffinity *cdssdk.NodeID) *UploadObjects {
	return &UploadObjects{
		userID:       userID,
		packageID:    packageID,
		objectIter:   objIter,
		nodeAffinity: nodeAffinity,
	}
}

func (t *UploadObjects) Execute(ctx *UploadObjectsContext) (*UploadObjectsResult, error) {
	defer t.objectIter.Close()

	coorCli, err := stgglb.CoordinatorMQPool.Acquire()
	if err != nil {
		return nil, fmt.Errorf("new coordinator client: %w", err)
	}

	getUserNodesResp, err := coorCli.GetUserNodes(coormq.NewGetUserNodes(t.userID))
	if err != nil {
		return nil, fmt.Errorf("getting user nodes: %w", err)
	}

	cons := ctx.Connectivity.GetAll()
	userNodes := lo.Map(getUserNodesResp.Nodes, func(node cdssdk.Node, index int) UploadNodeInfo {
		delay := time.Duration(math.MaxInt64)

		con, ok := cons[node.NodeID]
		if ok && con.Delay != nil {
			delay = *con.Delay
		}

		return UploadNodeInfo{
			Node:           node,
			Delay:          delay,
			IsSameLocation: node.LocationID == stgglb.Local.LocationID,
		}
	})
	if len(userNodes) == 0 {
		return nil, fmt.Errorf("user no available nodes")
	}

	// 给上传节点的IPFS加锁
	ipfsReqBlder := reqbuilder.NewBuilder()
	// 如果本地的IPFS也是存储系统的一个节点，那么从本地上传时，需要加锁
	if stgglb.Local.NodeID != nil {
		ipfsReqBlder.IPFS().Buzy(*stgglb.Local.NodeID)
	}
	for _, node := range userNodes {
		if stgglb.Local.NodeID != nil && node.Node.NodeID == *stgglb.Local.NodeID {
			continue
		}

		ipfsReqBlder.IPFS().Buzy(node.Node.NodeID)
	}
	// TODO 考虑加Object的Create锁
	// 防止上传的副本被清除
	ipfsMutex, err := ipfsReqBlder.MutexLock(ctx.Distlock)
	if err != nil {
		return nil, fmt.Errorf("acquire locks failed, err: %w", err)
	}
	defer ipfsMutex.Unlock()

	rets, err := uploadAndUpdatePackage(t.packageID, t.objectIter, userNodes, t.nodeAffinity)
	if err != nil {
		return nil, err
	}

	return &UploadObjectsResult{
		Objects: rets,
	}, nil
}

// chooseUploadNode 选择一个上传文件的节点
// 1. 选择设置了亲和性的节点
// 2. 从与当前客户端相同地域的节点中随机选一个
// 3. 没有的话从所有节点选择延迟最低的节点
func chooseUploadNode(nodes []UploadNodeInfo, nodeAffinity *cdssdk.NodeID) UploadNodeInfo {
	if nodeAffinity != nil {
		aff, ok := lo.Find(nodes, func(node UploadNodeInfo) bool { return node.Node.NodeID == *nodeAffinity })
		if ok {
			return aff
		}
	}

	sameLocationNodes := lo.Filter(nodes, func(e UploadNodeInfo, i int) bool { return e.IsSameLocation })
	if len(sameLocationNodes) > 0 {
		return sameLocationNodes[rand.Intn(len(sameLocationNodes))]
	}

	// 选择延迟最低的节点
	nodes = sort2.Sort(nodes, func(e1, e2 UploadNodeInfo) int { return sort2.Cmp(e1.Delay, e2.Delay) })

	return nodes[0]
}

func uploadAndUpdatePackage(packageID cdssdk.PackageID, objectIter iterator.UploadingObjectIterator, userNodes []UploadNodeInfo, nodeAffinity *cdssdk.NodeID) ([]ObjectUploadResult, error) {
	coorCli, err := stgglb.CoordinatorMQPool.Acquire()
	if err != nil {
		return nil, fmt.Errorf("new coordinator client: %w", err)
	}
	defer stgglb.CoordinatorMQPool.Release(coorCli)

	// 为所有文件选择相同的上传节点
	uploadNode := chooseUploadNode(userNodes, nodeAffinity)

	var uploadRets []ObjectUploadResult
	//上传文件夹
	var adds []coormq.AddObjectEntry
	for {
		objInfo, err := objectIter.MoveNext()
		if err == iterator.ErrNoMoreItem {
			break
		}
		if err != nil {
			return nil, fmt.Errorf("reading object: %w", err)
		}
		err = func() error {
			defer objInfo.File.Close()

			uploadTime := time.Now()
			fileHash, err := uploadFile(objInfo.File, uploadNode)
			if err != nil {
				return fmt.Errorf("uploading file: %w", err)
			}

			uploadRets = append(uploadRets, ObjectUploadResult{
				Info:  objInfo,
				Error: err,
			})

			adds = append(adds, coormq.NewAddObjectEntry(objInfo.Path, objInfo.Size, fileHash, uploadTime, uploadNode.Node.NodeID))
			return nil
		}()
		if err != nil {
			return nil, err
		}
	}

	updateResp, err := coorCli.UpdatePackage(coormq.NewUpdatePackage(packageID, adds, nil))
	if err != nil {
		return nil, fmt.Errorf("updating package: %w", err)
	}

	updatedObjs := make(map[string]*cdssdk.Object)
	for _, obj := range updateResp.Added {
		o := obj
		updatedObjs[obj.Path] = &o
	}

	for i := range uploadRets {
		obj := updatedObjs[uploadRets[i].Info.Path]
		if obj == nil {
			uploadRets[i].Error = fmt.Errorf("object %s not found in package", uploadRets[i].Info.Path)
			continue
		}
		uploadRets[i].Object = *obj
	}

	return uploadRets, nil
}

func uploadFile(file io.Reader, uploadNode UploadNodeInfo) (string, error) {
	// 本地有IPFS，则直接从本地IPFS上传
	if stgglb.IPFSPool != nil {
		logger.Debug("try to use local IPFS to upload file")

		// 只有本地IPFS不是存储系统中的一个节点，才需要Pin文件
		fileHash, err := uploadToLocalIPFS(file, uploadNode.Node.NodeID, stgglb.Local.NodeID == nil)
		if err == nil {
			return fileHash, nil

		} else {
			logger.Warnf("upload to local IPFS failed, so try to upload to node %d, err: %s", uploadNode.Node.NodeID, err.Error())
		}
	}

	// 否则发送到agent上传
	fileHash, err := uploadToNode(file, uploadNode.Node)
	if err != nil {
		return "", fmt.Errorf("uploading to node %v: %w", uploadNode.Node.NodeID, err)
	}

	return fileHash, nil
}

func uploadToNode(file io.Reader, node cdssdk.Node) (string, error) {
	ft := plans.NewFromTo()
	fromExec, hd := plans.NewFromExecutor(-1)
	ft.AddFrom(fromExec).AddTo(plans.NewToNode(node, -1, "fileHash"))

	parser := plans.NewParser(cdssdk.DefaultECRedundancy)
	plans := plans.NewPlanBuilder()
	err := parser.Parse(ft, plans)
	if err != nil {
		return "", fmt.Errorf("parsing plan: %w", err)
	}

	exec := plans.Execute()
	exec.BeginWrite(io.NopCloser(file), hd)
	ret, err := exec.Wait(context.TODO())
	if err != nil {
		return "", err
	}

	return ret["fileHash"].(string), nil
}

func uploadToLocalIPFS(file io.Reader, nodeID cdssdk.NodeID, shouldPin bool) (string, error) {
	ipfsCli, err := stgglb.IPFSPool.Acquire()
	if err != nil {
		return "", fmt.Errorf("new ipfs client: %w", err)
	}
	defer ipfsCli.Close()

	// 从本地IPFS上传文件
	fileHash, err := ipfsCli.CreateFile(file)
	if err != nil {
		return "", fmt.Errorf("creating ipfs file: %w", err)
	}

	if !shouldPin {
		return fileHash, nil
	}

	err = pinIPFSFile(nodeID, fileHash)
	if err != nil {
		return "", err
	}

	return fileHash, nil
}

func pinIPFSFile(nodeID cdssdk.NodeID, fileHash string) error {
	agtCli, err := stgglb.AgentMQPool.Acquire(nodeID)
	if err != nil {
		return fmt.Errorf("new agent client: %w", err)
	}
	defer stgglb.AgentMQPool.Release(agtCli)

	// 然后让最近节点pin本地上传的文件
	_, err = agtCli.PinObject(agtmq.ReqPinObject([]string{fileHash}, false))
	if err != nil {
		return fmt.Errorf("start pinning object: %w", err)
	}

	return nil
}