package handler

import (
	"context"
	"errors"
	"strings"

	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/internal/data"
	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/tree"
)

type nodeMeta struct {
	key   string
	value []byte
}

func (m nodeMeta) GetKey() string {
	return m.key
}

func (m nodeMeta) GetValue() []byte {
	return m.value
}

type nodeResponse struct {
	meta      []nodeMeta
	nodeID    uint64
	parentID  uint64
	timestamp uint64
}

func (n nodeResponse) GetNodeID() []uint64 {
	return []uint64{n.nodeID}
}

func (n nodeResponse) GetParentID() []uint64 {
	return []uint64{n.parentID}
}

func (n nodeResponse) GetTimestamp() []uint64 {
	return []uint64{n.timestamp}
}

func (n nodeResponse) GetMeta() []tree.Meta {
	res := make([]tree.Meta, len(n.meta))
	for i, value := range n.meta {
		res[i] = value
	}
	return res
}

type containerInfo struct {
	trees map[string]map[string]nodeResponse
}

type treeServiceClientMock struct {
	containers map[string]containerInfo
}

func newTreeServiceClientMock() *treeServiceClientMock {
	return &treeServiceClientMock{
		containers: make(map[string]containerInfo),
	}
}

func (t *treeServiceClientMock) GetNodes(_ context.Context, p *tree.GetNodesParams) ([]tree.NodeResponse, error) {
	cnr, ok := t.containers[p.CnrID.EncodeToString()]
	if !ok {
		return nil, tree.ErrNodeNotFound
	}

	tr, ok := cnr.trees[p.TreeID]
	if !ok {
		return nil, tree.ErrNodeNotFound
	}

	node, ok := tr[strings.Join(p.Path, "/")]
	if !ok {
		return nil, tree.ErrNodeNotFound
	}

	return []tree.NodeResponse{node}, nil
}

func (t *treeServiceClientMock) GetSubTree(_ context.Context, bktInfo *data.BucketInfo, treeID string, rootID []uint64, depth uint32, _ bool) ([]tree.NodeResponse, error) {
	cnr, ok := t.containers[bktInfo.CID.EncodeToString()]
	if !ok {
		return nil, tree.ErrNodeNotFound
	}

	tr, ok := cnr.trees[treeID]
	if !ok {
		return nil, tree.ErrNodeNotFound
	}

	if len(rootID) != 1 {
		return nil, errors.New("invalid rootID")
	}

	var root *nodeResponse
	for _, v := range tr {
		if v.nodeID == rootID[0] {
			root = &v
			break
		}
	}

	if root == nil {
		return nil, tree.ErrNodeNotFound
	}

	var res []nodeResponse
	if depth == 0 {
		for _, v := range tr {
			res = append(res, v)
		}
	} else {
		res = append(res, *root)
		depthIndex := 0
		for i := uint32(0); i < depth-1; i++ {
			childrenCount := 0
			for _, v := range tr {
				for j := range res[depthIndex:] {
					if v.parentID == res[j].nodeID {
						res = append(res, v)
						childrenCount++
						break
					}
				}
			}
			depthIndex = len(res) - childrenCount
		}
	}

	res2 := make([]tree.NodeResponse, len(res))
	for i := range res {
		res2[i] = res[i]
	}

	return res2, nil
}