// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.

package psclient

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"time"

	"github.com/zeebo/errs"
	"go.uber.org/zap"
	"golang.org/x/net/context"

	"storj.io/storj/internal/memory"
	"storj.io/storj/pkg/auth"
	"storj.io/storj/pkg/identity"
	"storj.io/storj/pkg/pb"
	"storj.io/storj/pkg/ranger"
	"storj.io/storj/pkg/storj"
	"storj.io/storj/pkg/transport"
)

var (
	// ClientError is any error returned by the client
	ClientError = errs.Class("piecestore client error")

	// ErrHashDoesNotMatch indicates hash comparison failed
	ErrHashDoesNotMatch = ClientError.New("hash does not match")

	defaultBandwidthMsgSize = 32 * memory.KB
	maxBandwidthMsgSize     = 64 * memory.KB
)

func init() {
	flag.Var(&defaultBandwidthMsgSize,
		"piecestore.rpc.client.default-bandwidth-msg-size",
		"default bandwidth message size in bytes")
	flag.Var(&maxBandwidthMsgSize,
		"piecestore.rpc.client.max-bandwidth-msg-size",
		"max bandwidth message size in bytes")
}

// Client is an interface describing the functions for interacting with piecestore nodes
type Client interface {
	Meta(ctx context.Context, id PieceID) (*pb.PieceSummary, error)
	Put(ctx context.Context, id PieceID, data io.Reader, ttl time.Time, ba *pb.OrderLimit) (*pb.SignedHash, error)
	Get(ctx context.Context, id PieceID, size int64, ba *pb.OrderLimit) (ranger.Ranger, error)
	Delete(ctx context.Context, pieceID PieceID, satelliteID storj.NodeID) error
	io.Closer
}

// PieceStore -- Struct Info needed for protobuf api calls
type PieceStore struct {
	closeFunc        func() error              // function that closes the transport connection
	client           pb.PieceStoreRoutesClient // PieceStore for interacting with Storage Node
	selfID           *identity.FullIdentity    // This client's (an uplink) identity
	bandwidthMsgSize int                       // max bandwidth message size in bytes
	remoteID         storj.NodeID              // Storage node being connected to
}

// NewPSClient initilizes a piecestore client
func NewPSClient(ctx context.Context, tc transport.Client, n *pb.Node, bandwidthMsgSize int) (Client, error) {
	n.Type.DPanicOnInvalid("new ps client")
	conn, err := tc.DialNode(ctx, n)
	if err != nil {
		return nil, err
	}

	if bandwidthMsgSize < 0 || bandwidthMsgSize > maxBandwidthMsgSize.Int() {
		return nil, ClientError.New("invalid Bandwidth Message Size: %v", bandwidthMsgSize)
	}

	if bandwidthMsgSize == 0 {
		bandwidthMsgSize = defaultBandwidthMsgSize.Int()
	}

	return &PieceStore{
		closeFunc:        conn.Close,
		client:           pb.NewPieceStoreRoutesClient(conn),
		bandwidthMsgSize: bandwidthMsgSize,
		selfID:           tc.Identity(),
		remoteID:         n.Id,
	}, nil
}

// NewCustomRoute creates new PieceStore with custom client interface
func NewCustomRoute(client pb.PieceStoreRoutesClient, target *pb.Node, bandwidthMsgSize int, selfID *identity.FullIdentity) (*PieceStore, error) {
	target.Type.DPanicOnInvalid("new custom route")
	if bandwidthMsgSize < 0 || bandwidthMsgSize > maxBandwidthMsgSize.Int() {
		return nil, ClientError.New("invalid Bandwidth Message Size: %v", bandwidthMsgSize)
	}

	if bandwidthMsgSize == 0 {
		bandwidthMsgSize = defaultBandwidthMsgSize.Int()
	}

	return &PieceStore{
		client:           client,
		bandwidthMsgSize: bandwidthMsgSize,
		selfID:           selfID,
		remoteID:         target.Id,
	}, nil
}

// Close closes the connection with piecestore
func (ps *PieceStore) Close() error {
	if ps.closeFunc == nil {
		return nil
	}

	return ps.closeFunc()
}

// Meta requests info about a piece by Id
func (ps *PieceStore) Meta(ctx context.Context, id PieceID) (*pb.PieceSummary, error) {
	return ps.client.Piece(ctx, &pb.PieceId{Id: id.String()})
}

// Put uploads a Piece to a piece store Server
func (ps *PieceStore) Put(ctx context.Context, id PieceID, data io.Reader, ttl time.Time, pba *pb.OrderLimit) (*pb.SignedHash, error) {
	stream, err := ps.client.Store(ctx)
	if err != nil {
		return nil, err
	}

	// Making a clone, otherwise there will be a data race
	// when another goroutine tries to write the cached size
	// of this instance at the same time.
	pbaClone := pba.Clone()

	rba := &pb.Order{
		PayerAllocation: pbaClone,
		StorageNodeId:   ps.remoteID,
	}

	msg := &pb.PieceStore{
		PieceData:           &pb.PieceStore_PieceData{Id: id.String(), ExpirationUnixSec: ttl.Unix()},
		BandwidthAllocation: rba,
	}
	if err = stream.Send(msg); err != nil {
		if _, closeErr := stream.CloseAndRecv(); closeErr != nil {
			zap.S().Errorf("error closing stream %s :: %v.Send() = %v", closeErr, stream, closeErr)
		}

		return nil, fmt.Errorf("%v.Send() = %v", stream, err)
	}

	writer := NewStreamWriter(stream, ps, rba)

	bufw := bufio.NewWriterSize(writer, 32*1024)

	_, err = io.Copy(bufw, data)
	if err != nil {
		return nil, err
	}

	err = bufw.Flush()
	if err != nil {
		return nil, err
	}

	err = writer.Close()
	if err == ErrHashDoesNotMatch {
		return nil, errs.Combine(err, ps.Delete(ctx, id, rba.PayerAllocation.SatelliteId))
	}
	if err != nil && err != io.EOF {
		return nil, ClientError.New("failure during closing writer: %v", err)
	}

	return writer.storagenodeHash, nil
}

// Get begins downloading a Piece from a piece store Server
func (ps *PieceStore) Get(ctx context.Context, id PieceID, size int64, ba *pb.OrderLimit) (ranger.Ranger, error) {
	stream, err := ps.client.Retrieve(ctx)
	if err != nil {
		return nil, err
	}

	return PieceRangerSize(ps, stream, id, size, ba), nil
}

// Delete a Piece from a piece store Server
func (ps *PieceStore) Delete(ctx context.Context, id PieceID, satelliteID storj.NodeID) error {
	reply, err := ps.client.Delete(ctx, &pb.PieceDelete{Id: id.String(), SatelliteId: satelliteID})
	if err != nil {
		return err
	}
	zap.S().Debugf("Delete request route summary: %v", reply)
	return nil
}

// sign a message using the clients private key
func (ps *PieceStore) sign(rba *pb.Order) (err error) {
	return auth.SignMessage(rba, *ps.selfID)
}