package db

import (
	"bytes"
	"encoding/hex"
	"fmt"
	"log"
	"math"
	"os"

	"github.com/lbryio/hub/db/prefixes"
	"github.com/lbryio/lbry.go/v2/extras/util"
	"github.com/linxGnu/grocksdb"
)

type ResolveResult struct {
	Name               string
	NormalizedName     string
	ClaimHash          []byte
	TxNum              int
	Position           int
	TxHash             []byte
	Height             int
	Amount             int
	ShortUrl           string
	IsControlling      bool
	CanonicalUrl       string
	CreationHeight     int
	ActivationHeight   int
	ExpirationHeight   int
	EffectiveAmount    int
	SupportAmount      int
	Reposted           int
	LastTakeoverHeight int
	ClaimsInChannel    int
	ChannelHash        []byte
	RepostedClaimHash  []byte
	SignatureValid     bool
}

type ResolveError struct {
	Error error
}

type OptionalResolveResultOrError interface {
	GetResult() *ResolveResult
	GetError() *ResolveError
}

type optionalResolveResultOrError struct {
	res *ResolveResult
	err *ResolveError
}

func (x *optionalResolveResultOrError) GetResult() *ResolveResult {
	return x.res
}

func (x *optionalResolveResultOrError) GetError() *ResolveError {
	return x.err
}

type ExpandedResolveResult struct {
	Stream          OptionalResolveResultOrError
	Channel         OptionalResolveResultOrError
	Repost          OptionalResolveResultOrError
	RepostedChannel OptionalResolveResultOrError
}

type IterOptions struct {
	FillCache    bool
	Prefix       []byte
	Start        []byte //interface{}
	Stop         []byte //interface{}
	IncludeStart bool
	IncludeStop  bool
	IncludeKey   bool
	IncludeValue bool
	RawKey       bool
	RawValue     bool
	CfHandle     *grocksdb.ColumnFamilyHandle
	It           *grocksdb.Iterator
}

// NewIterateOptions creates a defualt options structure for a db iterator.
func NewIterateOptions() *IterOptions {
	return &IterOptions{
		FillCache:    false,
		Prefix:       []byte{},
		Start:        nil,
		Stop:         nil,
		IncludeStart: true,
		IncludeStop:  false,
		IncludeKey:   true,
		IncludeValue: false,
		RawKey:       false,
		RawValue:     false,
		CfHandle:     nil,
		It:           nil,
	}
}

func (o *IterOptions) WithCfHandle(cfHandle *grocksdb.ColumnFamilyHandle) *IterOptions {
	o.CfHandle = cfHandle
	return o
}

func (o *IterOptions) WithFillCache(fillCache bool) *IterOptions {
	o.FillCache = fillCache
	return o
}

func (o *IterOptions) WithPrefix(prefix []byte) *IterOptions {
	o.Prefix = prefix
	return o
}

func (o *IterOptions) WithStart(start []byte) *IterOptions {
	o.Start = start
	return o
}

func (o *IterOptions) WithStop(stop []byte) *IterOptions {
	o.Stop = stop
	return o
}

func (o *IterOptions) WithIncludeStart(includeStart bool) *IterOptions {
	o.IncludeStart = includeStart
	return o
}

func (o *IterOptions) WithIncludeStop(includeStop bool) *IterOptions {
	o.IncludeStop = includeStop
	return o
}

func (o *IterOptions) WithIncludeKey(includeKey bool) *IterOptions {
	o.IncludeKey = includeKey
	return o
}

func (o *IterOptions) WithIncludeValue(includeValue bool) *IterOptions {
	o.IncludeValue = includeValue
	return o
}

func (o *IterOptions) WithRawKey(rawKey bool) *IterOptions {
	o.RawKey = rawKey
	return o
}

func (o *IterOptions) WithRawValue(rawValue bool) *IterOptions {
	o.RawValue = rawValue
	return o
}

func (o *IterOptions) StopIteration(key []byte) bool {
	if key == nil {
		return false
	}

	maxLen := int(math.Min(float64(len(key)), float64(len(o.Stop))))
	if o.Stop != nil &&
		(bytes.HasPrefix(key, o.Stop) || bytes.Compare(o.Stop, key[:maxLen]) < 0) {
		return true
	} else if o.Start != nil &&
		bytes.Compare(o.Start, key[:len(o.Start)]) > 0 {
		return true
	} else if o.Prefix != nil && !bytes.HasPrefix(key, o.Prefix) {
		return true
	}

	return false
}

type PathSegment struct {
	name        string
	claimId     string
	amountOrder int
}

func (ps *PathSegment) Normalized() string {
	return util.NormalizeName(ps.name)
}

func (ps *PathSegment) IsShortId() bool {
	return ps.claimId != "" && len(ps.claimId) < 40
}

func (ps *PathSegment) IsFullId() bool {
	return len(ps.claimId) == 40
}

func (ps *PathSegment) String() string {
	if ps.claimId != "" {
		return fmt.Sprintf("%s:%s", ps.name, ps.claimId)
	} else if ps.amountOrder != 0 {
		return fmt.Sprintf("%s:%d", ps.name, ps.amountOrder)
	}
	return ps.name
}

type URL struct {
	stream  *PathSegment
	channel *PathSegment
}

func NewURL() *URL {
	return &URL{
		stream:  nil,
		channel: nil,
	}
}

func ParseURL(url string) (parsed *URL, err error) {
	return NewURL(), nil
}

func Resolve(db *grocksdb.DB, url string) *ExpandedResolveResult {
	var res = &ExpandedResolveResult{
		Stream:          nil,
		Channel:         nil,
		Repost:          nil,
		RepostedChannel: nil,
	}

	parsed, err := ParseURL(url)
	if err != nil {
		res.Stream = &optionalResolveResultOrError{
			err: &ResolveError{err},
		}
		return res
	}

	log.Printf("parsed: %+v\n", parsed)
	return res
}

func (opts *IterOptions) ReadRow(ch chan *prefixes.PrefixRowKV, prevKey *[]byte) bool {
	it := opts.It
	key := it.Key()
	keyData := key.Data()
	keyLen := len(keyData)
	value := it.Value()
	valueData := value.Data()
	valueLen := len(valueData)

	var outKey interface{} = nil
	var outValue interface{} = nil
	var err error = nil

	// We need to check the current key is we're not including the stop
	// key.
	if !opts.IncludeStop && opts.StopIteration(keyData) {
		return false
	}

	// We have to copy the key no matter what because we need to check
	// it on the next iterations to see if we're going to stop.
	newKeyData := make([]byte, keyLen)
	copy(newKeyData, keyData)
	if opts.IncludeKey && !opts.RawKey {
		outKey, err = prefixes.UnpackGenericKey(newKeyData)
		if err != nil {
			log.Println(err)
		}
	} else if opts.IncludeKey {
		outKey = newKeyData
	}

	// Value could be quite large, so this setting could be important
	// for performance in some cases.
	if opts.IncludeValue {
		newValueData := make([]byte, valueLen)
		copy(newValueData, valueData)
		if !opts.RawValue {
			outValue, err = prefixes.UnpackGenericValue(newKeyData, newValueData)
			if err != nil {
				log.Println(err)
			}
		} else {
			outValue = newValueData
		}
	}

	key.Free()
	value.Free()

	ch <- &prefixes.PrefixRowKV{
		Key:   outKey,
		Value: outValue,
	}
	*prevKey = newKeyData

	return true
}

func IterCF(db *grocksdb.DB, opts *IterOptions) <-chan *prefixes.PrefixRowKV {
	ch := make(chan *prefixes.PrefixRowKV)

	ro := grocksdb.NewDefaultReadOptions()
	ro.SetFillCache(opts.FillCache)
	it := db.NewIteratorCF(ro, opts.CfHandle)
	// it := db.NewIterator(ro)
	opts.It = it

	it.Seek(opts.Prefix)
	if opts.Start != nil {
		it.Seek(opts.Start)
	}

	go func() {
		defer it.Close()
		defer close(ch)

		var prevKey []byte = nil
		if !opts.IncludeStart {
			it.Next()
		}
		if !it.Valid() && opts.IncludeStop {
			opts.ReadRow(ch, &prevKey)
		}
		for ; !opts.StopIteration(prevKey) && it.Valid(); it.Next() {
			opts.ReadRow(ch, &prevKey)
		}
	}()

	return ch
}

func Iter(db *grocksdb.DB, opts *IterOptions) <-chan *prefixes.PrefixRowKV {
	ch := make(chan *prefixes.PrefixRowKV)

	ro := grocksdb.NewDefaultReadOptions()
	ro.SetFillCache(opts.FillCache)
	it := db.NewIterator(ro)
	opts.It = it

	it.Seek(opts.Prefix)
	if opts.Start != nil {
		it.Seek(opts.Start)
	}

	go func() {
		defer it.Close()
		defer close(ch)

		var prevKey []byte = nil
		if !opts.IncludeStart {
			it.Next()
		}
		if !it.Valid() && opts.IncludeStop {
			opts.ReadRow(ch, &prevKey)
		}
		for ; !opts.StopIteration(prevKey) && it.Valid(); it.Next() {
			opts.ReadRow(ch, &prevKey)
		}
	}()

	return ch
}

func GetWriteDBCF(name string) (*grocksdb.DB, []*grocksdb.ColumnFamilyHandle, error) {
	opts := grocksdb.NewDefaultOptions()
	cfOpt := grocksdb.NewDefaultOptions()
	cfNames, err := grocksdb.ListColumnFamilies(opts, name)
	if err != nil {
		return nil, nil, err
	}
	cfOpts := make([]*grocksdb.Options, len(cfNames))
	for i, _ := range cfNames {
		cfOpts[i] = cfOpt
	}
	db, handles, err := grocksdb.OpenDbColumnFamilies(opts, name, cfNames, cfOpts)
	if err != nil {
		return nil, nil, err
	}

	for i, handle := range handles {
		log.Printf("%d: %s, %+v\n", i, cfNames[i], handle)
	}

	return db, handles, nil
}

func GetDBCF(name string, cf string) (*grocksdb.DB, []*grocksdb.ColumnFamilyHandle, error) {
	opts := grocksdb.NewDefaultOptions()
	cfOpt := grocksdb.NewDefaultOptions()

	cfNames := []string{"default", cf}
	cfOpts := []*grocksdb.Options{cfOpt, cfOpt}

	db, handles, err := grocksdb.OpenDbAsSecondaryColumnFamilies(opts, name, "asdf", cfNames, cfOpts)

	for i, handle := range handles {
		log.Printf("%d: %+v\n", i, handle)
	}
	if err != nil {
		return nil, nil, err
	}

	return db, handles, nil
}

func GetDB(name string) (*grocksdb.DB, error) {
	opts := grocksdb.NewDefaultOptions()
	db, err := grocksdb.OpenDbAsSecondary(opts, name, "asdf")
	if err != nil {
		return nil, err
	}

	return db, nil
}

func ReadPrefixN(db *grocksdb.DB, prefix []byte, n int) []*prefixes.PrefixRowKV {
	ro := grocksdb.NewDefaultReadOptions()
	ro.SetFillCache(false)

	it := db.NewIterator(ro)
	defer it.Close()

	res := make([]*prefixes.PrefixRowKV, n)

	var i = 0
	it.Seek(prefix)
	for ; it.Valid(); it.Next() {
		key := it.Key()
		value := it.Value()

		res[i] = &prefixes.PrefixRowKV{
			Key:   key.Data(),
			Value: value.Data(),
		}

		key.Free()
		value.Free()
		i++
		if i >= n {
			break
		}
	}

	return res
}

func ReadWriteRawNCF(db *grocksdb.DB, options *IterOptions, out string, n int) {

	options.RawKey = true
	options.RawValue = true
	ch := IterCF(db, options)

	file, err := os.Create(out)
	if err != nil {
		log.Println(err)
		return
	}
	defer file.Close()

	var i = 0
	log.Println(options.Prefix)
	file.Write([]byte(fmt.Sprintf("%s,\n", options.Prefix)))
	for kv := range ch {
		log.Println(i)
		if i >= n {
			return
		}
		key := kv.Key.([]byte)
		value := kv.Value.([]byte)
		keyHex := hex.EncodeToString(key)
		valueHex := hex.EncodeToString(value)
		//log.Println(keyHex)
		//log.Println(valueHex)
		file.WriteString(keyHex)
		file.WriteString(",")
		file.WriteString(valueHex)
		file.WriteString("\n")

		i++
	}
}

func ReadWriteRawN(db *grocksdb.DB, options *IterOptions, out string, n int) {

	options.RawKey = true
	options.RawValue = true
	ch := Iter(db, options)

	file, err := os.Create(out)
	if err != nil {
		log.Println(err)
		return
	}
	defer file.Close()

	var i = 0
	for kv := range ch {
		log.Println(i)
		if i >= n {
			return
		}
		key := kv.Key.([]byte)
		value := kv.Value.([]byte)
		keyHex := hex.EncodeToString(key)
		valueHex := hex.EncodeToString(value)
		log.Println(keyHex)
		log.Println(valueHex)
		file.WriteString(keyHex)
		file.WriteString(",")
		file.WriteString(valueHex)
		file.WriteString("\n")

		i++
	}
}

func GenerateTestData(prefix byte, fileName string) {
	dbVal, err := GetDB("/mnt/d/data/wallet/lbry-rocksdb/")
	if err != nil {
		log.Fatalln(err)
	}

	options := NewIterateOptions()
	options.WithRawKey(true).WithRawValue(true).WithIncludeValue(true)
	options.WithPrefix([]byte{prefix})

	ReadWriteRawN(dbVal, options, fileName, 10)
}