// Copyright (C) 2015  The GoHBase Authors.  All rights reserved.
// This file is part of GoHBase.
// Use of this source code is governed by the Apache License 2.0
// that can be found in the COPYING file.

package hrpc

import (
	"context"
	"encoding/binary"
	"errors"
	"time"

	"github.com/golang/protobuf/proto"
	"github.com/tsuna/gohbase/pb"
)

var (
	// ErrNotAStruct is returned by any of the *Ref functions when something
	// other than a struct is passed in to their data argument
	ErrNotAStruct = errors.New("data must be a struct")

	// ErrUnsupportedUints is returned when this message is serialized and uints
	// are unsupported on your platform (this will probably never happen)
	ErrUnsupportedUints = errors.New("uints are unsupported on your platform")

	// ErrUnsupportedInts is returned when this message is serialized and ints
	// are unsupported on your platform (this will probably never happen)
	ErrUnsupportedInts = errors.New("ints are unsupported on your platform")

	attributeNameTTL = "_ttl"
)

// DurabilityType is used to set durability for Durability option
type DurabilityType int32

const (
	// UseDefault is USER_DEFAULT
	UseDefault DurabilityType = iota
	// SkipWal is SKIP_WAL
	SkipWal
	// AsyncWal is ASYNC_WAL
	AsyncWal
	// SyncWal is SYNC_WAL
	SyncWal
	// FsyncWal is FSYNC_WAL
	FsyncWal
)

// Mutate represents a mutation on HBase.
type Mutate struct {
	base

	mutationType pb.MutationProto_MutationType //*int32

	// values is a map of column families to a map of column qualifiers to bytes
	values map[string]map[string][]byte

	ttl              []byte
	timestamp        uint64
	durability       DurabilityType
	deleteOneVersion bool
	skipbatch        bool
}

// TTL sets a time-to-live for mutation queries.
// The value will be in millisecond resolution.
func TTL(t time.Duration) func(Call) error {
	return func(o Call) error {
		m, ok := o.(*Mutate)
		if !ok {
			return errors.New("'TTL' option can only be used with mutation queries")
		}

		buf := make([]byte, 8)
		binary.BigEndian.PutUint64(buf, uint64(t.Nanoseconds()/1e6))
		m.ttl = buf

		return nil
	}
}

// Timestamp sets timestamp for mutation queries.
// The time object passed will be rounded to a millisecond resolution, as by default,
// if no timestamp is provided, HBase sets it to current time in milliseconds.
// In order to have custom time precision, use TimestampUint64 call option for
// mutation requests and corresponding TimeRangeUint64 for retrieval requests.
func Timestamp(ts time.Time) func(Call) error {
	return func(o Call) error {
		m, ok := o.(*Mutate)
		if !ok {
			return errors.New("'Timestamp' option can only be used with mutation queries")
		}
		m.timestamp = uint64(ts.UnixNano() / 1e6)
		return nil
	}
}

// TimestampUint64 sets timestamp for mutation queries.
func TimestampUint64(ts uint64) func(Call) error {
	return func(o Call) error {
		m, ok := o.(*Mutate)
		if !ok {
			return errors.New("'TimestampUint64' option can only be used with mutation queries")
		}
		m.timestamp = ts
		return nil
	}
}

// Durability sets durability for mutation queries.
func Durability(d DurabilityType) func(Call) error {
	return func(o Call) error {
		m, ok := o.(*Mutate)
		if !ok {
			return errors.New("'Durability' option can only be used with mutation queries")
		}
		if d < UseDefault || d > FsyncWal {
			return errors.New("invalid durability value")
		}
		m.durability = d
		return nil
	}
}

// DeleteOneVersion is a delete option that can be passed in order to delete only
// one latest version of the specified qualifiers. Without timestamp specified,
// it will have no effect for delete specific column families request.
// If a Timestamp option is passed along, only the version at that timestamp will be removed
// for delete specific column families and/or qualifier request.
// This option cannot be used for delete entire row request.
func DeleteOneVersion() func(Call) error {
	return func(o Call) error {
		m, ok := o.(*Mutate)
		if !ok {
			return errors.New("'DeleteOneVersion' option can only be used with mutation queries")
		}
		m.deleteOneVersion = true
		return nil
	}
}

// baseMutate returns a Mutate struct without the mutationType filled in.
func baseMutate(ctx context.Context, table, key []byte, values map[string]map[string][]byte,
	options ...func(Call) error) (*Mutate, error) {
	m := &Mutate{
		base: base{
			table:    table,
			key:      key,
			ctx:      ctx,
			resultch: make(chan RPCResult, 1),
		},
		values:    values,
		timestamp: MaxTimestamp,
	}
	err := applyOptions(m, options...)
	if err != nil {
		return nil, err
	}
	return m, nil
}

// NewPut creates a new Mutation request to insert the given
// family-column-values in the given row key of the given table.
func NewPut(ctx context.Context, table, key []byte,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	m, err := baseMutate(ctx, table, key, values, options...)
	if err != nil {
		return nil, err
	}
	m.mutationType = pb.MutationProto_PUT
	return m, nil
}

// NewPutStr is just like NewPut but takes table and key as strings.
func NewPutStr(ctx context.Context, table, key string,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	return NewPut(ctx, []byte(table), []byte(key), values, options...)
}

// NewDel is used to perform Delete operations on a single row.
// To delete entire row, values should be nil.
//
// To delete specific families, qualifiers map should be nil:
//  map[string]map[string][]byte{
//		"cf1": nil,
//		"cf2": nil,
//  }
//
// To delete specific qualifiers:
//  map[string]map[string][]byte{
//      "cf": map[string][]byte{
//			"q1": nil,
//			"q2": nil,
//		},
//  }
//
// To delete all versions before and at a timestamp, pass hrpc.Timestamp() option.
// By default all versions will be removed.
//
// To delete only a specific version at a timestamp, pass hrpc.DeleteOneVersion() option
// along with a timestamp. For delete specific qualifiers request, if timestamp is not
// passed, only the latest version will be removed. For delete specific families request,
// the timestamp should be passed or it will have no effect as it's an expensive
// operation to perform.
func NewDel(ctx context.Context, table, key []byte,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	m, err := baseMutate(ctx, table, key, values, options...)
	if err != nil {
		return nil, err
	}

	if len(m.values) == 0 && m.deleteOneVersion {
		return nil, errors.New(
			"'DeleteOneVersion' option cannot be specified for delete entire row request")
	}

	m.mutationType = pb.MutationProto_DELETE
	return m, nil
}

// NewDelStr is just like NewDel but takes table and key as strings.
func NewDelStr(ctx context.Context, table, key string,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	return NewDel(ctx, []byte(table), []byte(key), values, options...)
}

// NewApp creates a new Mutation request to append the given
// family-column-values into the existing cells in HBase (or create them if
// needed), in given row key of the given table.
func NewApp(ctx context.Context, table, key []byte,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	m, err := baseMutate(ctx, table, key, values, options...)
	if err != nil {
		return nil, err
	}
	m.mutationType = pb.MutationProto_APPEND
	return m, nil
}

// NewAppStr is just like NewApp but takes table and key as strings.
func NewAppStr(ctx context.Context, table, key string,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	return NewApp(ctx, []byte(table), []byte(key), values, options...)
}

// NewIncSingle creates a new Mutation request that will increment the given value
// by amount in HBase under the given table, key, family and qualifier.
func NewIncSingle(ctx context.Context, table, key []byte, family, qualifier string,
	amount int64, options ...func(Call) error) (*Mutate, error) {
	buf := make([]byte, 8)
	binary.BigEndian.PutUint64(buf, uint64(amount))
	value := map[string]map[string][]byte{family: map[string][]byte{qualifier: buf}}
	return NewInc(ctx, table, key, value, options...)
}

// NewIncStrSingle is just like NewIncSingle but takes table and key as strings.
func NewIncStrSingle(ctx context.Context, table, key, family, qualifier string,
	amount int64, options ...func(Call) error) (*Mutate, error) {
	return NewIncSingle(ctx, []byte(table), []byte(key), family, qualifier, amount, options...)
}

// NewInc creates a new Mutation request that will increment the given values
// in HBase under the given table and key.
func NewInc(ctx context.Context, table, key []byte,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	m, err := baseMutate(ctx, table, key, values, options...)
	if err != nil {
		return nil, err
	}
	m.mutationType = pb.MutationProto_INCREMENT
	return m, nil
}

// NewIncStr is just like NewInc but takes table and key as strings.
func NewIncStr(ctx context.Context, table, key string,
	values map[string]map[string][]byte, options ...func(Call) error) (*Mutate, error) {
	return NewInc(ctx, []byte(table), []byte(key), values, options...)
}

// Name returns the name of this RPC call.
func (m *Mutate) Name() string {
	return "Mutate"
}

// SkipBatch returns true if the Mutate request shouldn't be batched,
// but should be sent to Region Server right away.
func (m *Mutate) SkipBatch() bool {
	return m.skipbatch
}

func (m *Mutate) setSkipBatch(v bool) {
	m.skipbatch = v
}

func (m *Mutate) toProto() *pb.MutateRequest {
	var ts *uint64
	if m.timestamp != MaxTimestamp {
		ts = &m.timestamp
	}

	// We need to convert everything in the values field
	// to a protobuf ColumnValue
	cvs := make([]*pb.MutationProto_ColumnValue, len(m.values))
	i := 0
	for k, v := range m.values {
		// And likewise, each item in each column needs to be converted to a
		// protobuf QualifierValue

		// if it's a delete, figure out the type
		var dt *pb.MutationProto_DeleteType
		if m.mutationType == pb.MutationProto_DELETE {
			if len(v) == 0 {
				// delete the whole column family
				if m.deleteOneVersion {
					dt = pb.MutationProto_DELETE_FAMILY_VERSION.Enum()
				} else {
					dt = pb.MutationProto_DELETE_FAMILY.Enum()
				}
				// add empty qualifier
				if v == nil {
					v = make(map[string][]byte)
				}
				v[""] = nil
			} else {
				// delete specific qualifiers
				if m.deleteOneVersion {
					dt = pb.MutationProto_DELETE_ONE_VERSION.Enum()
				} else {
					dt = pb.MutationProto_DELETE_MULTIPLE_VERSIONS.Enum()
				}
			}
		}

		qvs := make([]*pb.MutationProto_ColumnValue_QualifierValue, len(v))
		j := 0
		for k1, v1 := range v {
			qvs[j] = &pb.MutationProto_ColumnValue_QualifierValue{
				Qualifier:  []byte(k1),
				Value:      v1,
				Timestamp:  ts,
				DeleteType: dt,
			}
			j++
		}
		cvs[i] = &pb.MutationProto_ColumnValue{
			Family:         []byte(k),
			QualifierValue: qvs,
		}
		i++
	}

	mProto := &pb.MutationProto{
		Row:         m.key,
		MutateType:  &m.mutationType,
		ColumnValue: cvs,
		Durability:  pb.MutationProto_Durability(m.durability).Enum(),
		Timestamp:   ts,
	}

	if len(m.ttl) > 0 {
		mProto.Attribute = append(mProto.Attribute, &pb.NameBytesPair{
			Name:  &attributeNameTTL,
			Value: m.ttl,
		})
	}

	return &pb.MutateRequest{
		Region:   m.regionSpecifier(),
		Mutation: mProto,
	}
}

// ToProto converts this mutate RPC into a protobuf message
func (m *Mutate) ToProto() proto.Message {
	return m.toProto()
}

// NewResponse creates an empty protobuf message to read the response of this RPC.
func (m *Mutate) NewResponse() proto.Message {
	return &pb.MutateResponse{}
}

// DeserializeCellBlocks deserializes mutate result from cell blocks
func (m *Mutate) DeserializeCellBlocks(pm proto.Message, b []byte) (uint32, error) {
	resp := pm.(*pb.MutateResponse)
	if resp.Result == nil {
		// TODO: is this possible?
		return 0, nil
	}
	cells, read, err := deserializeCellBlocks(b, uint32(resp.Result.GetAssociatedCellCount()))
	if err != nil {
		return 0, err
	}
	resp.Result.Cell = append(resp.Result.Cell, cells...)
	return read, nil
}