package communities

import (
	"bytes"
	"crypto/ecdsa"
	"encoding/json"
	"errors"
	"sort"

	"github.com/golang/protobuf/proto"

	"github.com/status-im/status-go/eth-node/crypto"
	"github.com/status-im/status-go/protocol/protobuf"
)

type CommunityEvent struct {
	CommunityEventClock    uint64                                      `json:"communityEventClock"`
	Type                   protobuf.CommunityEvent_EventType           `json:"type"`
	CommunityConfig        *protobuf.CommunityConfig                   `json:"communityConfig,omitempty"`
	TokenPermission        *protobuf.CommunityTokenPermission          `json:"tokenPermissions,omitempty"`
	CategoryData           *protobuf.CategoryData                      `json:"categoryData,omitempty"`
	ChannelData            *protobuf.ChannelData                       `json:"channelData,omitempty"`
	MemberToAction         string                                      `json:"memberToAction,omitempty"`
	MembersAdded           map[string]*protobuf.CommunityMember        `json:"membersAdded,omitempty"`
	RejectedRequestsToJoin map[string]*protobuf.CommunityRequestToJoin `json:"rejectedRequestsToJoin,omitempty"`
	AcceptedRequestsToJoin map[string]*protobuf.CommunityRequestToJoin `json:"acceptedRequestsToJoin,omitempty"`
	TokenMetadata          *protobuf.CommunityTokenMetadata            `json:"tokenMetadata,omitempty"`
	Payload                []byte                                      `json:"payload"`
	Signature              []byte                                      `json:"signature"`
}

func (e *CommunityEvent) ToProtobuf() *protobuf.CommunityEvent {
	return &protobuf.CommunityEvent{
		CommunityEventClock:    e.CommunityEventClock,
		Type:                   e.Type,
		CommunityConfig:        e.CommunityConfig,
		TokenPermission:        e.TokenPermission,
		CategoryData:           e.CategoryData,
		ChannelData:            e.ChannelData,
		MemberToAction:         e.MemberToAction,
		MembersAdded:           e.MembersAdded,
		RejectedRequestsToJoin: e.RejectedRequestsToJoin,
		AcceptedRequestsToJoin: e.AcceptedRequestsToJoin,
		TokenMetadata:          e.TokenMetadata,
	}
}

func communityEventFromProtobuf(msg *protobuf.SignedCommunityEvent) (*CommunityEvent, error) {
	decodedEvent := protobuf.CommunityEvent{}
	err := proto.Unmarshal(msg.Payload, &decodedEvent)
	if err != nil {
		return nil, err
	}

	return &CommunityEvent{
		CommunityEventClock:    decodedEvent.CommunityEventClock,
		Type:                   decodedEvent.Type,
		CommunityConfig:        decodedEvent.CommunityConfig,
		TokenPermission:        decodedEvent.TokenPermission,
		CategoryData:           decodedEvent.CategoryData,
		ChannelData:            decodedEvent.ChannelData,
		MemberToAction:         decodedEvent.MemberToAction,
		MembersAdded:           decodedEvent.MembersAdded,
		RejectedRequestsToJoin: decodedEvent.RejectedRequestsToJoin,
		AcceptedRequestsToJoin: decodedEvent.AcceptedRequestsToJoin,
		TokenMetadata:          decodedEvent.TokenMetadata,
		Payload:                msg.Payload,
		Signature:              msg.Signature,
	}, nil
}

func (e *CommunityEvent) RecoverSigner() (*ecdsa.PublicKey, error) {
	if e.Signature == nil || len(e.Signature) == 0 {
		return nil, errors.New("missing signature")
	}

	signer, err := crypto.SigToPub(
		crypto.Keccak256(e.Payload),
		e.Signature,
	)
	if err != nil {
		return nil, errors.New("failed to recover signer")
	}

	return signer, nil
}

func (e *CommunityEvent) Sign(pk *ecdsa.PrivateKey) error {
	sig, err := crypto.Sign(crypto.Keccak256(e.Payload), pk)
	if err != nil {
		return err
	}

	e.Signature = sig
	return nil
}

type CommunityEventsMessage struct {
	CommunityID                    []byte           `json:"communityId"`
	EventsBaseCommunityDescription []byte           `json:"eventsBaseCommunityDescription"`
	Events                         []CommunityEvent `json:"events,omitempty"`
}

func (m *CommunityEventsMessage) ToProtobuf() *protobuf.CommunityEventsMessage {
	result := protobuf.CommunityEventsMessage{
		CommunityId:                    m.CommunityID,
		EventsBaseCommunityDescription: m.EventsBaseCommunityDescription,
		SignedEvents:                   []*protobuf.SignedCommunityEvent{},
	}

	for _, event := range m.Events {
		signedEvent := &protobuf.SignedCommunityEvent{
			Signature: event.Signature,
			Payload:   event.Payload,
		}
		result.SignedEvents = append(result.SignedEvents, signedEvent)
	}

	return &result
}

func CommunityEventsMessageFromProtobuf(msg *protobuf.CommunityEventsMessage) (*CommunityEventsMessage, error) {
	result := &CommunityEventsMessage{
		CommunityID:                    msg.CommunityId,
		EventsBaseCommunityDescription: msg.EventsBaseCommunityDescription,
		Events:                         []CommunityEvent{},
	}

	for _, signedEvent := range msg.SignedEvents {
		event, err := communityEventFromProtobuf(signedEvent)
		if err != nil {
			return nil, err
		}
		result.Events = append(result.Events, *event)
	}

	return result, nil
}

func (m *CommunityEventsMessage) Marshal() ([]byte, error) {
	pb := m.ToProtobuf()
	return proto.Marshal(pb)
}

func (c *Community) mergeCommunityEvents(communityEventMessage *CommunityEventsMessage) {
	if c.config.EventsData == nil {
		c.config.EventsData = &EventsData{
			EventsBaseCommunityDescription: communityEventMessage.EventsBaseCommunityDescription,
			Events:                         communityEventMessage.Events,
		}
		return
	}

	for _, update := range communityEventMessage.Events {
		var exists bool
		for _, existing := range c.config.EventsData.Events {
			if isCommunityEventsEqual(update, existing) {
				exists = true
				break
			}
		}
		if !exists {
			c.config.EventsData.Events = append(c.config.EventsData.Events, update)
		}
	}

	c.sortCommunityEvents()
}

func (c *Community) sortCommunityEvents() {
	sort.Slice(c.config.EventsData.Events, func(i, j int) bool {
		return c.config.EventsData.Events[i].CommunityEventClock < c.config.EventsData.Events[j].CommunityEventClock
	})
}

func validateCommunityEvent(communityEvent *CommunityEvent) error {
	switch communityEvent.Type {
	case protobuf.CommunityEvent_COMMUNITY_EDIT:
		if communityEvent.CommunityConfig == nil || communityEvent.CommunityConfig.Identity == nil ||
			communityEvent.CommunityConfig.Permissions == nil || communityEvent.CommunityConfig.AdminSettings == nil {
			return errors.New("invalid config change admin event")
		}

	case protobuf.CommunityEvent_COMMUNITY_MEMBER_TOKEN_PERMISSION_CHANGE:
		if communityEvent.TokenPermission == nil || len(communityEvent.TokenPermission.Id) == 0 {
			return errors.New("invalid token permission change event")
		}

	case protobuf.CommunityEvent_COMMUNITY_MEMBER_TOKEN_PERMISSION_DELETE:
		if communityEvent.TokenPermission == nil || len(communityEvent.TokenPermission.Id) == 0 {
			return errors.New("invalid token permission delete event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CATEGORY_CREATE:
		if communityEvent.CategoryData == nil || len(communityEvent.CategoryData.CategoryId) == 0 {
			return errors.New("invalid community category create event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CATEGORY_DELETE:
		if communityEvent.CategoryData == nil || len(communityEvent.CategoryData.CategoryId) == 0 {
			return errors.New("invalid community category delete event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CATEGORY_EDIT:
		if communityEvent.CategoryData == nil || len(communityEvent.CategoryData.CategoryId) == 0 {
			return errors.New("invalid community category edit event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CHANNEL_CREATE:
		if communityEvent.ChannelData == nil || len(communityEvent.ChannelData.ChannelId) == 0 ||
			communityEvent.ChannelData.Channel == nil {
			return errors.New("invalid community channel create event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CHANNEL_DELETE:
		if communityEvent.ChannelData == nil || len(communityEvent.ChannelData.ChannelId) == 0 {
			return errors.New("invalid community channel delete event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CHANNEL_EDIT:
		if communityEvent.ChannelData == nil || len(communityEvent.ChannelData.ChannelId) == 0 ||
			communityEvent.ChannelData.Channel == nil {
			return errors.New("invalid community channel edit event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CHANNEL_REORDER:
		if communityEvent.ChannelData == nil || len(communityEvent.ChannelData.ChannelId) == 0 {
			return errors.New("invalid community channel reorder event")
		}

	case protobuf.CommunityEvent_COMMUNITY_CATEGORY_REORDER:
		if communityEvent.CategoryData == nil || len(communityEvent.CategoryData.CategoryId) == 0 {
			return errors.New("invalid community category reorder event")
		}

	case protobuf.CommunityEvent_COMMUNITY_REQUEST_TO_JOIN_ACCEPT:
		if communityEvent.AcceptedRequestsToJoin == nil {
			return errors.New("invalid community request to join accepted event")
		}

	case protobuf.CommunityEvent_COMMUNITY_REQUEST_TO_JOIN_REJECT:
		if communityEvent.RejectedRequestsToJoin == nil {
			return errors.New("invalid community request to join reject event")
		}

	case protobuf.CommunityEvent_COMMUNITY_MEMBER_KICK:
		if len(communityEvent.MemberToAction) == 0 {
			return errors.New("invalid community member kick event")
		}

	case protobuf.CommunityEvent_COMMUNITY_MEMBER_BAN:
		if len(communityEvent.MemberToAction) == 0 {
			return errors.New("invalid community member ban event")
		}

	case protobuf.CommunityEvent_COMMUNITY_MEMBER_UNBAN:
		if len(communityEvent.MemberToAction) == 0 {
			return errors.New("invalid community member unban event")
		}

	case protobuf.CommunityEvent_COMMUNITY_TOKEN_ADD:
		if communityEvent.TokenMetadata == nil || len(communityEvent.TokenMetadata.ContractAddresses) == 0 {
			return errors.New("invalid add community token event")
		}
	}
	return nil
}

func isCommunityEventsEqual(left CommunityEvent, right CommunityEvent) bool {
	return bytes.Equal(left.Payload, right.Payload)
}

func communityEventsToJSONEncodedBytes(communityEvents []CommunityEvent) ([]byte, error) {
	return json.Marshal(communityEvents)
}

func communityEventsFromJSONEncodedBytes(jsonEncodedRawEvents []byte) ([]CommunityEvent, error) {
	var events []CommunityEvent
	err := json.Unmarshal(jsonEncodedRawEvents, &events)
	if err != nil {
		return nil, err
	}

	return events, nil
}