// Copyright (C) 2018 Storj Labs, Inc.
// See LICENSE for copying information.

package pdbclient

import (
	"context"

	"github.com/golang/protobuf/proto"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	monkit "gopkg.in/spacemonkeygo/monkit.v2"

	p "storj.io/storj/pkg/paths"
	pb "storj.io/storj/protos/pointerdb"
	"storj.io/storj/storage"
)

var (
	mon = monkit.Package()
)

// PointerDB creates a grpcClient
type PointerDB struct {
	grpcClient pb.PointerDBClient
	APIKey     []byte
}

// a compiler trick to make sure *Overlay implements Client
var _ Client = (*PointerDB)(nil)

// ListItem is a single item in a listing
type ListItem struct {
	Path    p.Path
	Pointer *pb.Pointer
}

// Client services offerred for the interface
type Client interface {
	Put(ctx context.Context, path p.Path, pointer *pb.Pointer) error
	Get(ctx context.Context, path p.Path) (*pb.Pointer, error)
	List(ctx context.Context, prefix, startAfter, endBefore p.Path,
		recursive bool, limit int, metaFlags uint32) (
		items []ListItem, more bool, err error)
	Delete(ctx context.Context, path p.Path) error
}

// NewClient initializes a new pointerdb client
func NewClient(address string, APIKey []byte) (*PointerDB, error) {
	c, err := clientConnection(address, grpc.WithInsecure())

	if err != nil {
		return nil, err
	}
	return &PointerDB{
		grpcClient: c,
		APIKey:     APIKey,
	}, nil
}

// a compiler trick to make sure *PointerDB implements Client
var _ Client = (*PointerDB)(nil)

// ClientConnection makes a server connection
func clientConnection(serverAddr string, opts ...grpc.DialOption) (pb.PointerDBClient, error) {
	conn, err := grpc.Dial(serverAddr, opts...)

	if err != nil {
		return nil, err
	}
	return pb.NewPointerDBClient(conn), nil
}

// Put is the interface to make a PUT request, needs Pointer and APIKey
func (pdb *PointerDB) Put(ctx context.Context, path p.Path, pointer *pb.Pointer) (err error) {
	defer mon.Task()(&ctx)(&err)

	_, err = pdb.grpcClient.Put(ctx, &pb.PutRequest{Path: path.String(), Pointer: pointer, APIKey: pdb.APIKey})

	return err
}

// Get is the interface to make a GET request, needs PATH and APIKey
func (pdb *PointerDB) Get(ctx context.Context, path p.Path) (pointer *pb.Pointer, err error) {
	defer mon.Task()(&ctx)(&err)

	res, err := pdb.grpcClient.Get(ctx, &pb.GetRequest{Path: path.String(), APIKey: pdb.APIKey})
	if err != nil {
		if status.Code(err) == codes.NotFound {
			return nil, storage.ErrKeyNotFound.Wrap(err)
		}
		return nil, Error.Wrap(err)
	}

	pointer = &pb.Pointer{}
	err = proto.Unmarshal(res.GetPointer(), pointer)
	if err != nil {
		return nil, err
	}

	return pointer, nil
}

// List is the interface to make a LIST request, needs StartingPathKey, Limit, and APIKey
func (pdb *PointerDB) List(ctx context.Context, prefix, startAfter, endBefore p.Path,
	recursive bool, limit int, metaFlags uint32) (
	items []ListItem, more bool, err error) {
	defer mon.Task()(&ctx)(&err)

	res, err := pdb.grpcClient.List(ctx, &pb.ListRequest{
		Prefix:     prefix.String(),
		StartAfter: startAfter.String(),
		EndBefore:  endBefore.String(),
		Recursive:  recursive,
		Limit:      int32(limit),
		MetaFlags:  metaFlags,
		APIKey:     pdb.APIKey,
	})
	if err != nil {
		return nil, false, err
	}

	list := res.GetItems()
	items = make([]ListItem, len(list))
	for i, itm := range list {
		items[i] = ListItem{
			Path:    p.New(itm.GetPath()),
			Pointer: itm.GetPointer(),
		}
	}

	return items, res.GetMore(), nil
}

// Delete is the interface to make a Delete request, needs Path and APIKey
func (pdb *PointerDB) Delete(ctx context.Context, path p.Path) (err error) {
	defer mon.Task()(&ctx)(&err)

	_, err = pdb.grpcClient.Delete(ctx, &pb.DeleteRequest{Path: path.String(), APIKey: pdb.APIKey})

	return err
}