package exported

import (
	"encoding/json"

	ics23 "github.com/confio/ics23/go"

	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"

	"github.com/cosmos/cosmos-sdk/codec"
)

// ClientState defines the required common functions for light clients.
type ClientState interface {
	ClientType() ClientType
	GetLatestHeight() Height
	IsFrozen() bool
	GetFrozenHeight() Height
	Validate() error
	GetProofSpecs() []*ics23.ProofSpec

	// Update and Misbehaviour functions

	CheckHeaderAndUpdateState(sdk.Context, codec.BinaryMarshaler, sdk.KVStore, Header) (ClientState, ConsensusState, error)
	CheckMisbehaviourAndUpdateState(sdk.Context, codec.BinaryMarshaler, sdk.KVStore, Misbehaviour) (ClientState, error)
	CheckProposedHeaderAndUpdateState(sdk.Context, codec.BinaryMarshaler, sdk.KVStore, Header) (ClientState, ConsensusState, error)

	// State verification functions

	VerifyClientState(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		root Root,
		height Height,
		prefix Prefix,
		counterpartyClientIdentifier string,
		proof []byte,
		clientState ClientState,
	) error
	VerifyClientConsensusState(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		root Root,
		height Height,
		counterpartyClientIdentifier string,
		consensusHeight Height,
		prefix Prefix,
		proof []byte,
		consensusState ConsensusState,
	) error
	VerifyConnectionState(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		connectionID string,
		connectionEnd ConnectionI,
	) error
	VerifyChannelState(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		portID,
		channelID string,
		channel ChannelI,
	) error
	VerifyPacketCommitment(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		portID,
		channelID string,
		sequence uint64,
		commitmentBytes []byte,
	) error
	VerifyPacketAcknowledgement(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		portID,
		channelID string,
		sequence uint64,
		acknowledgement []byte,
	) error
	VerifyPacketAcknowledgementAbsence(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		portID,
		channelID string,
		sequence uint64,
	) error
	VerifyNextSequenceRecv(
		store sdk.KVStore,
		cdc codec.BinaryMarshaler,
		height Height,
		prefix Prefix,
		proof []byte,
		portID,
		channelID string,
		nextSequenceRecv uint64,
	) error
}

// ConsensusState is the state of the consensus process
type ConsensusState interface {
	ClientType() ClientType // Consensus kind

	// GetRoot returns the commitment root of the consensus state,
	// which is used for key-value pair verification.
	GetRoot() Root

	// GetTimestamp returns the timestamp (in nanoseconds) of the consensus state
	GetTimestamp() uint64

	ValidateBasic() error
}

// TypeClientMisbehaviour is the shared evidence misbehaviour type
const TypeClientMisbehaviour string = "client_misbehaviour"

// Misbehaviour defines counterparty misbehaviour for a specific consensus type
type Misbehaviour interface {
	ClientType() ClientType
	GetClientID() string
	String() string
	ValidateBasic() error

	// Height at which the infraction occurred
	GetHeight() Height
}

// Header is the consensus state update information
type Header interface {
	ClientType() ClientType
	GetHeight() Height
	ValidateBasic() error
}

// Height is a wrapper interface over clienttypes.Height
// all clients must use the concrete implementation in types
type Height interface {
	IsZero() bool
	LT(Height) bool
	LTE(Height) bool
	EQ(Height) bool
	GT(Height) bool
	GTE(Height) bool
	GetEpochNumber() uint64
	GetEpochHeight() uint64
	Decrement() (Height, bool)
	String() string
}

// ClientType defines the type of the consensus algorithm
type ClientType byte

// available client types
const (
	SoloMachine ClientType = 6
	Tendermint  ClientType = 7
	Localhost   ClientType = 9
)

// string representation of the client types
const (
	ClientTypeSoloMachine string = "solomachine"
	ClientTypeTendermint  string = "tendermint"
	ClientTypeLocalHost   string = "localhost"
)

func (ct ClientType) String() string {
	switch ct {
	case SoloMachine:
		return ClientTypeSoloMachine
	case Tendermint:
		return ClientTypeTendermint
	case Localhost:
		return ClientTypeLocalHost
	default:
		return ""
	}
}

// MarshalJSON marshal to JSON using string.
func (ct ClientType) MarshalJSON() ([]byte, error) {
	return json.Marshal(ct.String())
}

// UnmarshalJSON decodes from JSON.
func (ct *ClientType) UnmarshalJSON(data []byte) error {
	var s string
	err := json.Unmarshal(data, &s)
	if err != nil {
		return err
	}

	clientType := ClientTypeFromString(s)
	if clientType == 0 {
		return sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "invalid client type '%s'", s)
	}

	*ct = clientType
	return nil
}

// ClientTypeFromString returns a byte that corresponds to the registered client
// type. It returns 0 if the type is not found/registered.
func ClientTypeFromString(clientType string) ClientType {
	switch clientType {
	case ClientTypeSoloMachine:
		return SoloMachine
	case ClientTypeTendermint:
		return Tendermint
	case ClientTypeLocalHost:
		return Localhost
	default:
		return 0
	}
}