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

package pointerdb

import (
	"context"

	"github.com/golang/protobuf/proto"
	"github.com/golang/protobuf/ptypes"
	"github.com/zeebo/errs"
	"go.uber.org/zap"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	monkit "gopkg.in/spacemonkeygo/monkit.v2"

	"storj.io/storj/pkg/pb"
	"storj.io/storj/pkg/pointerdb/auth"
	"storj.io/storj/pkg/storage/meta"
	"storj.io/storj/storage"
)

var (
	mon          = monkit.Package()
	segmentError = errs.Class("segment error")
)

// Server implements the network state RPC service
type Server struct {
	DB     storage.KeyValueStore
	logger *zap.Logger
	config Config
}

// NewServer creates instance of Server
func NewServer(db storage.KeyValueStore, logger *zap.Logger, c Config) *Server {
	return &Server{
		DB:     db,
		logger: logger,
		config: c,
	}
}

func (s *Server) validateAuth(APIKey []byte) error {
	if !auth.ValidateAPIKey(string(APIKey)) {
		s.logger.Error("unauthorized request: ", zap.Error(status.Errorf(codes.Unauthenticated, "Invalid API credential")))
		return status.Errorf(codes.Unauthenticated, "Invalid API credential")
	}
	return nil
}

func (s *Server) validateSegment(req *pb.PutRequest) error {
	min := s.config.MinInlineSegmentSize
	max := s.config.MaxInlineSegmentSize
	inlineSize := len(req.GetPointer().InlineSegment)
	remote := req.GetPointer().Remote

	if remote != nil && req.GetPointer().GetSize() < min {
		return segmentError.New("inline segment size %d less than minimum allowed %d", inlineSize, min)
	}

	if inlineSize > max {
		return segmentError.New("inline segment size %d greater than maximum allowed %d", inlineSize, max)
	}

	return nil
}

// Put formats and hands off a key/value (path/pointer) to be saved to boltdb
func (s *Server) Put(ctx context.Context, req *pb.PutRequest) (resp *pb.PutResponse, err error) {
	defer mon.Task()(&ctx)(&err)
	s.logger.Debug("entering pointerdb put")

	err = s.validateSegment(req)
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, err.Error())
	}

	if err = s.validateAuth(req.GetAPIKey()); err != nil {
		return nil, err
	}

	// Update the pointer with the creation date
	req.GetPointer().CreationDate = ptypes.TimestampNow()

	pointerBytes, err := proto.Marshal(req.GetPointer())
	if err != nil {
		s.logger.Error("err marshaling pointer", zap.Error(err))
		return nil, status.Errorf(codes.Internal, err.Error())
	}

	// TODO(kaloyan): make sure that we know we are overwriting the pointer!
	// In such case we should delete the pieces of the old segment if it was
	// a remote one.
	if err = s.DB.Put([]byte(req.GetPath()), pointerBytes); err != nil {
		s.logger.Error("err putting pointer", zap.Error(err))
		return nil, status.Errorf(codes.Internal, err.Error())
	}
	s.logger.Debug("put to the db: " + req.GetPath())

	return &pb.PutResponse{}, nil
}

// Get formats and hands off a file path to get from boltdb
func (s *Server) Get(ctx context.Context, req *pb.GetRequest) (resp *pb.GetResponse, err error) {
	defer mon.Task()(&ctx)(&err)
	s.logger.Debug("entering pointerdb get")

	if err = s.validateAuth(req.GetAPIKey()); err != nil {
		return nil, err
	}

	pointerBytes, err := s.DB.Get([]byte(req.GetPath()))
	if err != nil {
		if storage.ErrKeyNotFound.Has(err) {
			return nil, status.Errorf(codes.NotFound, err.Error())
		}
		s.logger.Error("err getting pointer", zap.Error(err))
		return nil, status.Errorf(codes.Internal, err.Error())
	}

	return &pb.GetResponse{
		Pointer: pointerBytes,
	}, nil
}

// List returns all Path keys in the Pointers bucket
func (s *Server) List(ctx context.Context, req *pb.ListRequest) (resp *pb.ListResponse, err error) {
	defer mon.Task()(&ctx)(&err)
	s.logger.Debug("entering pointerdb list")

	if err = s.validateAuth(req.APIKey); err != nil {
		return nil, err
	}

	var prefix storage.Key
	if req.Prefix != "" {
		prefix = storage.Key(req.Prefix)
		if prefix[len(prefix)-1] != storage.Delimiter {
			prefix = append(prefix, storage.Delimiter)
		}
	}

	rawItems, more, err := storage.ListV2(s.DB, storage.ListOptions{
		Prefix:       prefix, //storage.Key(req.Prefix),
		StartAfter:   storage.Key(req.StartAfter),
		EndBefore:    storage.Key(req.EndBefore),
		Recursive:    req.Recursive,
		Limit:        int(req.Limit),
		IncludeValue: req.MetaFlags != meta.None,
	})
	if err != nil {
		return nil, status.Errorf(codes.Internal, "ListV2: %v", err)
	}

	var items []*pb.ListResponse_Item
	for _, rawItem := range rawItems {
		items = append(items, s.createListItem(rawItem, req.MetaFlags))
	}

	return &pb.ListResponse{Items: items, More: more}, nil
}

// createListItem creates a new list item with the given path. It also adds
// the metadata according to the given metaFlags.
func (s *Server) createListItem(rawItem storage.ListItem, metaFlags uint32) *pb.ListResponse_Item {
	item := &pb.ListResponse_Item{
		Path:     rawItem.Key.String(),
		IsPrefix: rawItem.IsPrefix,
	}
	if item.IsPrefix {
		return item
	}

	err := s.setMetadata(item, rawItem.Value, metaFlags)
	if err != nil {
		s.logger.Warn("err retrieving metadata", zap.Error(err))
	}
	return item
}

// getMetadata adds the metadata to the given item pointer according to the
// given metaFlags
func (s *Server) setMetadata(item *pb.ListResponse_Item, data []byte, metaFlags uint32) (err error) {
	if metaFlags == meta.None || len(data) == 0 {
		return nil
	}

	pr := &pb.Pointer{}
	err = proto.Unmarshal(data, pr)
	if err != nil {
		return err
	}

	// Start with an empty pointer to and add only what's requested in
	// metaFlags to safe to transfer payload
	item.Pointer = &pb.Pointer{}
	if metaFlags&meta.Modified != 0 {
		item.Pointer.CreationDate = pr.GetCreationDate()
	}
	if metaFlags&meta.Expiration != 0 {
		item.Pointer.ExpirationDate = pr.GetExpirationDate()
	}
	if metaFlags&meta.Size != 0 {
		item.Pointer.Size = pr.GetSize()
	}
	if metaFlags&meta.UserDefined != 0 {
		item.Pointer.Metadata = pr.GetMetadata()
	}

	return nil
}

// Delete formats and hands off a file path to delete from boltdb
func (s *Server) Delete(ctx context.Context, req *pb.DeleteRequest) (resp *pb.DeleteResponse, err error) {
	defer mon.Task()(&ctx)(&err)
	s.logger.Debug("entering pointerdb delete")

	if err = s.validateAuth(req.GetAPIKey()); err != nil {
		return nil, err
	}

	err = s.DB.Delete([]byte(req.GetPath()))
	if err != nil {
		s.logger.Error("err deleting path and pointer", zap.Error(err))
		return nil, status.Errorf(codes.Internal, err.Error())
	}
	s.logger.Debug("deleted pointer at path: " + req.GetPath())
	return &pb.DeleteResponse{}, nil
}