package main

import (
	"bytes"
	"context"

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	"bdchain/api/grpc/common"
	"bdchain/api/grpc/txledger"

	"github.com/golang/protobuf/proto"
	"github.com/golang/protobuf/ptypes/empty"
)

/////////////////////////////////////////////////////////////////////////////
// server
type server struct{}

/////////////////////////////////////////////////////////////////////////////
// grpcServer
type grpcServer server

func (s *grpcServer) ClientVersion(
	c context.Context,
	r *empty.Empty,
) (res *common.ClientVersionResponse, err error) {
	switch {
	case s == nil:
		err = toStatusError(ErrInvalidServer)
	case r == nil:
		err = toStatusError(ErrInvalidRequest)
	default:
		res = &common.ClientVersionResponse{
			Version: "TxLedgerGo/v0.0.1alpha/darwin/go1.11",
		}
	}
	return
}

func (s *grpcServer) CreateLedger(
	c context.Context,
	r *txledger.CreateLedgerRequest,
) (res *txledger.CreateLedgerResponse, err error) {
	switch {
	case s == nil:
		err = toStatusError(ErrInvalidServer)
	case r == nil:
		err = toStatusError(ErrInvalidRequest)
	case r.Name == "":
		err = toStatusError(ErrEmptyName)
	case r.Name == "test":
		res = &txledger.CreateLedgerResponse{
			Ok: true,
		}
	default:
		err = toStatusError(ErrTestNotImplemented)
	}
	return
}

func (s *grpcServer) GetLedgers(
	c context.Context,
	r *empty.Empty,
) (res *txledger.GetLedgersResponse, err error) {
	switch {
	case s == nil:
		err = toStatusError(ErrInvalidServer)
	case r == nil:
		err = toStatusError(ErrInvalidRequest)
	default:
		res = &txledger.GetLedgersResponse{
			Ledgers: []string{
				"first",
				"second",
				"third",
			},
		}
	}
	return
}

func (s *grpcServer) SendTransaction(
	c context.Context,
	r *txledger.SendTransactionRequest,
) (res *txledger.SendTransactionResponse, err error) {
	switch {
	case s == nil:
		err = toStatusError(ErrInvalidServer)
	case r == nil:
		fallthrough
	case r.Transaction == nil:
		err = toStatusError(ErrInvalidRequest)
	case r.Ledger != "test":
		err = toStatusError(ErrTestNotImplemented)
	default:
		type Input struct {
			Type common.TransactionType
			From []byte
			To   []byte
			Data []byte
		}
		type Output struct {
			Hash  []byte
			Error error
		}
		type Case struct {
			I Input
			O Output
		}

		Merge := func(
			p *status.Status,
			cs ...*status.Status,
		) *status.Status {
			msg := []proto.Message{}
			for _, c := range cs {
				msg = append(msg, c.Proto())
			}
			r, err := p.WithDetails(msg...)
			if err != nil {
				panic(err)
			}
			return r
		}

		tx := r.Transaction
		for _, c := range [...]Case{
			{
				I: Input{
					Type: common.TransactionType_MESSAGE,
					From: []byte{
						0xf0, 0x0d, 0xca, 0xfe, 0xf0, 0x0d, 0xca, 0xfe,
						0xf0, 0x0d, 0xca, 0xfe, 0xf0, 0x0d, 0xca, 0xfe,
						0xf0, 0x0d, 0xca, 0xfe,
					},
					To: []byte{
						0xfe, 0xed, 0xba, 0xbe, 0xfe, 0xed, 0xba, 0xbe,
						0xfe, 0xed, 0xba, 0xbe, 0xfe, 0xed, 0xba, 0xbe,
						0xfe, 0xed, 0xba, 0xbe,
					},
					Data: []byte{
						0xde, 0xad, 0xbe, 0xef,
					},
				},
				O: Output{
					Hash: []byte{
						0xd1, 0x5e, 0xa5, 0xed, 0xd1, 0x5e, 0xa5, 0xed,
						0xd1, 0x5e, 0xa5, 0xed, 0xd1, 0x5e, 0xa5, 0xed,
						0xd1, 0x5e, 0xa5, 0xed, 0xd1, 0x5e, 0xa5, 0xed,
						0xd1, 0x5e, 0xa5, 0xed, 0xd1, 0x5e, 0xa5, 0xed,
					},
					Error: nil,
				},
			},
			{
				I: Input{
					Type: common.TransactionType_MESSAGE,
					From: nil,
					To: []byte{
						0x50, 0xba, 0xda, 0x55,
					},
					Data: nil,
				},
				O: Output{
					Hash: nil,
					Error: Merge(
						status.New(codes.InvalidArgument, ErrMultiple.Error()),
						status.New(codes.InvalidArgument, ErrEmptyFrom.Error()),
						status.New(codes.InvalidArgument, ErrInvalidTo.Error()),
					).Err(),
				},
			},
		} {
			if c.I.Type == tx.Type &&
				bytes.Equal(c.I.From, tx.From) &&
				bytes.Equal(c.I.To, tx.To) &&
				bytes.Equal(c.I.Data, tx.Data) {
				if c.O.Error != nil {
					err = c.O.Error
				} else {
					res = &txledger.SendTransactionResponse{Hash: c.O.Hash}
				}
				return
			}
		}
		err = toStatusError(ErrTestNotImplemented)
	}
	return
}