package chat

import (
	"context"
	"errors"
	"strings"

	"github.com/ethereum/go-ethereum/log"

	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/status-im/status-go/eth-node/crypto"
	"github.com/status-im/status-go/eth-node/types"
	"github.com/status-im/status-go/images"
	"github.com/status-im/status-go/protocol"
	"github.com/status-im/status-go/protocol/common"
	"github.com/status-im/status-go/protocol/communities"
	"github.com/status-im/status-go/protocol/protobuf"
	"github.com/status-im/status-go/protocol/requests"
	v1protocol "github.com/status-im/status-go/protocol/v1"
)

var (
	ErrChatNotFound            = errors.New("can't find chat")
	ErrCommunityNotFound       = errors.New("can't find community")
	ErrCommunitiesNotSupported = errors.New("communities are not supported")
	ErrChatTypeNotSupported    = errors.New("chat type not supported")
)

type ChannelGroupType string

const Personal ChannelGroupType = "personal"
const Community ChannelGroupType = "community"

type PinnedMessages struct {
	Cursor         string
	PinnedMessages []*common.PinnedMessage
}

type Member struct {
	// Community Role
	Role protobuf.CommunityMember_Roles `json:"role,omitempty"`
	// Joined indicates if the member has joined the group chat
	Joined bool `json:"joined"`
}

type Chat struct {
	ID                       string                             `json:"id"`
	Name                     string                             `json:"name"`
	Description              string                             `json:"description"`
	Color                    string                             `json:"color"`
	Emoji                    string                             `json:"emoji"`
	Active                   bool                               `json:"active"`
	ChatType                 protocol.ChatType                  `json:"chatType"`
	Timestamp                int64                              `json:"timestamp"`
	LastClockValue           uint64                             `json:"lastClockValue"`
	DeletedAtClockValue      uint64                             `json:"deletedAtClockValue"`
	ReadMessagesAtClockValue uint64                             `json:"readMessagesAtClockValue"`
	UnviewedMessagesCount    uint                               `json:"unviewedMessagesCount"`
	UnviewedMentionsCount    uint                               `json:"unviewedMentionsCount"`
	LastMessage              *common.Message                    `json:"lastMessage"`
	Members                  map[string]Member                  `json:"members,omitempty"`
	MembershipUpdates        []v1protocol.MembershipUpdateEvent `json:"membershipUpdateEvents"`
	Alias                    string                             `json:"alias,omitempty"`
	Identicon                string                             `json:"identicon"`
	Muted                    bool                               `json:"muted"`
	InvitationAdmin          string                             `json:"invitationAdmin,omitempty"`
	ReceivedInvitationAdmin  string                             `json:"receivedInvitationAdmin,omitempty"`
	Profile                  string                             `json:"profile,omitempty"`
	CommunityID              string                             `json:"communityId"`
	CategoryID               string                             `json:"categoryId"`
	Position                 int32                              `json:"position,omitempty"`
	Permissions              *protobuf.CommunityPermissions     `json:"permissions,omitempty"`
	Joined                   int64                              `json:"joined,omitempty"`
	SyncedTo                 uint32                             `json:"syncedTo,omitempty"`
	SyncedFrom               uint32                             `json:"syncedFrom,omitempty"`
	FirstMessageTimestamp    uint32                             `json:"firstMessageTimestamp,omitempty"`
	Highlight                bool                               `json:"highlight,omitempty"`
	PinnedMessages           *PinnedMessages                    `json:"pinnedMessages,omitempty"`
	CanPost                  bool                               `json:"canPost"`
	Base64Image              string                             `json:"image,omitempty"`
}

type ChannelGroup struct {
	Type                            ChannelGroupType                                        `json:"channelGroupType"`
	Name                            string                                                  `json:"name"`
	Images                          map[string]images.IdentityImage                         `json:"images"`
	Color                           string                                                  `json:"color"`
	Chats                           map[string]*Chat                                        `json:"chats"`
	Categories                      map[string]communities.CommunityCategory                `json:"categories"`
	EnsName                         string                                                  `json:"ensName"`
	MemberRole                      protobuf.CommunityMember_Roles                          `json:"memberRole"`
	Verified                        bool                                                    `json:"verified"`
	Description                     string                                                  `json:"description"`
	IntroMessage                    string                                                  `json:"introMessage"`
	OutroMessage                    string                                                  `json:"outroMessage"`
	Tags                            []communities.CommunityTag                              `json:"tags"`
	Permissions                     *protobuf.CommunityPermissions                          `json:"permissions"`
	Members                         map[string]*protobuf.CommunityMember                    `json:"members"`
	CanManageUsers                  bool                                                    `json:"canManageUsers"`
	Muted                           bool                                                    `json:"muted"`
	BanList                         []string                                                `json:"banList"`
	Encrypted                       bool                                                    `json:"encrypted"`
	CommunityTokensMetadata         []*protobuf.CommunityTokenMetadata                      `json:"communityTokensMetadata"`
	UnviewedMessagesCount           int                                                     `json:"unviewedMessagesCount"`
	UnviewedMentionsCount           int                                                     `json:"unviewedMentionsCount"`
	CheckChannelPermissionResponses map[string]*communities.CheckChannelPermissionsResponse `json:"checkChannelPermissionResponses"`
	PubsubTopic                     string                                                  `json:"pubsubTopic"`
	PubsubTopicKey                  string                                                  `json:"pubsubTopicKey"`
	Shard                           *common.Shard                                           `json:"shard"`
}

func NewAPI(service *Service) *API {
	return &API{
		s:   service,
		log: log.New("package", "status-go/services/chat.API"),
	}
}

type API struct {
	s   *Service
	log log.Logger
}

func unique(communities []*communities.Community) (result []*communities.Community) {
	inResult := make(map[string]bool)
	for _, community := range communities {
		if _, ok := inResult[community.IDString()]; !ok {
			inResult[community.IDString()] = true
			result = append(result, community)
		}
	}
	return result
}

func (api *API) getChannelGroups(ctx context.Context, channelGroupID string) (map[string]ChannelGroup, error) {
	joinedCommunities, err := api.s.messenger.JoinedCommunities()
	if err != nil {
		return nil, err
	}
	spectatedCommunities, err := api.s.messenger.SpectatedCommunities()
	if err != nil {
		return nil, err
	}

	pubKey := types.EncodeHex(crypto.FromECDSAPub(api.s.messenger.IdentityPublicKey()))

	result := make(map[string]ChannelGroup)

	// Get chats from cache to get unviewed	messages counts
	channels := api.s.messenger.Chats()
	totalUnviewedMessageCount := 0
	totalUnviewedMentionsCount := 0

	if channelGroupID == "" || channelGroupID == pubKey {
		chats := make(map[string]*Chat)
		for _, chat := range channels {
			if !chat.IsActivePersonalChat() {
				continue
			}
			if !chat.Muted || chat.UnviewedMentionsCount > 0 {
				totalUnviewedMessageCount += int(chat.UnviewedMessagesCount)
			}
			totalUnviewedMentionsCount += int(chat.UnviewedMentionsCount)

			c, err := api.toAPIChat(chat, nil, pubKey, true)
			if err != nil {
				return nil, err
			}
			chats[chat.ID] = c
		}

		result[pubKey] = ChannelGroup{
			Type:                            Personal,
			Name:                            "",
			Images:                          make(map[string]images.IdentityImage),
			Color:                           "",
			Chats:                           chats,
			Categories:                      make(map[string]communities.CommunityCategory),
			EnsName:                         "", // Not implemented yet in communities
			MemberRole:                      protobuf.CommunityMember_ROLE_OWNER,
			Verified:                        true,
			Description:                     "",
			IntroMessage:                    "",
			OutroMessage:                    "",
			Tags:                            []communities.CommunityTag{},
			Permissions:                     &protobuf.CommunityPermissions{},
			Muted:                           false,
			CommunityTokensMetadata:         []*protobuf.CommunityTokenMetadata{},
			UnviewedMessagesCount:           totalUnviewedMessageCount,
			UnviewedMentionsCount:           totalUnviewedMentionsCount,
			CheckChannelPermissionResponses: make(map[string]*communities.CheckChannelPermissionsResponse),
		}
	}

	if channelGroupID == pubKey {
		// They asked for the personal channel group only, so we return now
		return result, nil
	}

	for _, community := range unique(append(joinedCommunities, spectatedCommunities...)) {
		if channelGroupID != "" && channelGroupID != community.IDString() {
			continue
		}
		totalUnviewedMessageCount = 0
		totalUnviewedMentionsCount = 0

		for _, chat := range channels {
			if chat.CommunityID != community.IDString() || !chat.Active {
				continue
			}
			if !chat.Muted || chat.UnviewedMentionsCount > 0 {
				totalUnviewedMessageCount += int(chat.UnviewedMessagesCount)
			}
			totalUnviewedMentionsCount += int(chat.UnviewedMentionsCount)
		}

		chGrp := ChannelGroup{
			Type:                            Community,
			Name:                            community.Name(),
			Color:                           community.Color(),
			Images:                          make(map[string]images.IdentityImage),
			Chats:                           make(map[string]*Chat),
			Categories:                      make(map[string]communities.CommunityCategory),
			MemberRole:                      community.MemberRole(community.MemberIdentity()),
			Verified:                        community.Verified(),
			Description:                     community.DescriptionText(),
			IntroMessage:                    community.IntroMessage(),
			OutroMessage:                    community.OutroMessage(),
			Tags:                            community.Tags(),
			Permissions:                     community.Description().Permissions,
			Members:                         community.Description().Members,
			CanManageUsers:                  community.CanManageUsers(community.MemberIdentity()),
			Muted:                           community.Muted(),
			BanList:                         community.Description().BanList,
			Encrypted:                       community.Encrypted(),
			CommunityTokensMetadata:         community.Description().CommunityTokensMetadata,
			UnviewedMessagesCount:           totalUnviewedMessageCount,
			UnviewedMentionsCount:           totalUnviewedMentionsCount,
			CheckChannelPermissionResponses: make(map[string]*communities.CheckChannelPermissionsResponse),
			PubsubTopic:                     community.PubsubTopic(),
			PubsubTopicKey:                  community.PubsubTopicKey(),
			Shard:                           community.Shard(),
		}

		for t, i := range community.Images() {
			chGrp.Images[t] = images.IdentityImage{Name: t, Payload: i.Payload}
		}

		for _, cat := range community.Categories() {
			chGrp.Categories[cat.CategoryId] = communities.CommunityCategory{
				ID:       cat.CategoryId,
				Name:     cat.Name,
				Position: int(cat.Position),
			}
		}

		for _, chat := range channels {
			if chat.CommunityID == community.IDString() && chat.Active {
				_, exists := community.Chats()[chat.CommunityChatID()]
				if !exists {
					api.log.Warn("Chat not found in the community", "chat.ID", chat.ID)
					continue
				}

				c, err := api.toAPIChat(chat, community, pubKey, true)
				if err != nil {
					return nil, err
				}

				chGrp.Chats[c.ID] = c
			}
		}

		response, err := api.s.messenger.GetCommunityCheckChannelPermissionResponses(community.ID())
		if err != nil {
			return nil, err
		}
		chGrp.CheckChannelPermissionResponses = response.Channels

		result[community.IDString()] = chGrp

		if channelGroupID == community.IDString() {
			// We asked for this particular community, so we return now
			return result, nil
		}
	}

	return result, nil
}

func (api *API) GetChannelGroups(ctx context.Context) (map[string]ChannelGroup, error) {
	return api.getChannelGroups(ctx, "")
}

func (api *API) GetChannelGroupByID(ctx context.Context, channelGroupID string) (map[string]ChannelGroup, error) {
	return api.getChannelGroups(ctx, channelGroupID)
}

func (api *API) GetChat(ctx context.Context, communityID types.HexBytes, chatID string) (*Chat, error) {
	pubKey := types.EncodeHex(crypto.FromECDSAPub(api.s.messenger.IdentityPublicKey()))
	messengerChat, community, err := api.getChatAndCommunity(pubKey, communityID, chatID)
	if err != nil {
		return nil, err
	}

	if messengerChat == nil {
		return nil, ErrChatNotFound
	}

	result, err := api.toAPIChat(messengerChat, community, pubKey, false)
	if err != nil {
		return nil, err
	}

	return result, nil
}

func (api *API) GetMembers(ctx context.Context, communityID types.HexBytes, chatID string) (map[string]Member, error) {
	pubKey := types.EncodeHex(crypto.FromECDSAPub(api.s.messenger.IdentityPublicKey()))
	messengerChat, community, err := api.getChatAndCommunity(pubKey, communityID, chatID)
	if err != nil {
		return nil, err
	}

	return getChatMembers(messengerChat, community, pubKey)
}

func (api *API) JoinChat(ctx context.Context, communityID types.HexBytes, chatID string) (*Chat, error) {
	if len(communityID) != 0 {
		return nil, ErrCommunitiesNotSupported
	}

	response, err := api.s.messenger.CreatePublicChat(&requests.CreatePublicChat{ID: chatID})
	if err != nil {
		return nil, err
	}

	pubKey := types.EncodeHex(crypto.FromECDSAPub(api.s.messenger.IdentityPublicKey()))

	return api.toAPIChat(response.Chats()[0], nil, pubKey, false)
}

func (api *API) toAPIChat(protocolChat *protocol.Chat, community *communities.Community, pubKey string, skipPinnedMessages bool) (*Chat, error) {
	chat := &Chat{
		ID:                       strings.TrimPrefix(protocolChat.ID, protocolChat.CommunityID),
		Name:                     protocolChat.Name,
		Description:              protocolChat.Description,
		Color:                    protocolChat.Color,
		Emoji:                    protocolChat.Emoji,
		Active:                   protocolChat.Active,
		ChatType:                 protocolChat.ChatType,
		Timestamp:                protocolChat.Timestamp,
		LastClockValue:           protocolChat.LastClockValue,
		DeletedAtClockValue:      protocolChat.DeletedAtClockValue,
		ReadMessagesAtClockValue: protocolChat.ReadMessagesAtClockValue,
		UnviewedMessagesCount:    protocolChat.UnviewedMessagesCount,
		UnviewedMentionsCount:    protocolChat.UnviewedMentionsCount,
		LastMessage:              protocolChat.LastMessage,
		MembershipUpdates:        protocolChat.MembershipUpdates,
		Alias:                    protocolChat.Alias,
		Identicon:                protocolChat.Identicon,
		Muted:                    protocolChat.Muted,
		InvitationAdmin:          protocolChat.InvitationAdmin,
		ReceivedInvitationAdmin:  protocolChat.ReceivedInvitationAdmin,
		Profile:                  protocolChat.Profile,
		CommunityID:              protocolChat.CommunityID,
		CategoryID:               protocolChat.CategoryID,
		Joined:                   protocolChat.Joined,
		SyncedTo:                 protocolChat.SyncedTo,
		SyncedFrom:               protocolChat.SyncedFrom,
		FirstMessageTimestamp:    protocolChat.FirstMessageTimestamp,
		Highlight:                protocolChat.Highlight,
		Base64Image:              protocolChat.Base64Image,
	}

	if protocolChat.OneToOne() {
		chat.Name = "" // Emptying since it contains non useful data
	}

	if !skipPinnedMessages {
		pinnedMessages, cursor, err := api.s.messenger.PinnedMessageByChatID(protocolChat.ID, "", -1)
		if err != nil {
			return nil, err
		}

		if len(pinnedMessages) != 0 {
			chat.PinnedMessages = &PinnedMessages{
				Cursor:         cursor,
				PinnedMessages: pinnedMessages,
			}
		}
	}

	err := chat.populateCommunityFields(community)
	if err != nil {
		return nil, err
	}

	chatMembers, err := getChatMembers(protocolChat, community, pubKey)
	if err != nil {
		return nil, err
	}
	chat.Members = chatMembers

	return chat, nil
}

func getChatMembers(sourceChat *protocol.Chat, community *communities.Community, userPubKey string) (map[string]Member, error) {
	result := make(map[string]Member)
	if sourceChat != nil {
		if sourceChat.ChatType == protocol.ChatTypePrivateGroupChat && len(sourceChat.Members) > 0 {
			for _, m := range sourceChat.Members {
				result[m.ID] = Member{
					Role: func() protobuf.CommunityMember_Roles {
						if m.Admin {
							return protobuf.CommunityMember_ROLE_OWNER
						}
						return protobuf.CommunityMember_ROLE_NONE
					}(),
					Joined: true,
				}
			}
			return result, nil
		}

		if sourceChat.ChatType == protocol.ChatTypeOneToOne {
			result[sourceChat.ID] = Member{
				Joined: true,
			}
			result[userPubKey] = Member{
				Joined: true,
			}
			return result, nil
		}
	}

	if community != nil {
		channel, exists := community.Chats()[sourceChat.CommunityChatID()]
		if !exists {
			// Skip unknown community chats. They might be channels that were deleted. We shouldn't get here
			return result, nil
		}
		for member := range channel.Members {
			pubKey, err := common.HexToPubkey(member)
			if err != nil {
				return nil, err
			}
			result[member] = Member{
				Role:   community.MemberRole(pubKey),
				Joined: community.Joined(),
			}
		}
		return result, nil
	}

	return nil, nil
}

func (api *API) getCommunityByID(id string) (*communities.Community, error) {
	communityID, err := hexutil.Decode(id)
	if err != nil {
		return nil, err
	}

	community, err := api.s.messenger.GetCommunityByID(communityID)
	if community == nil && err == nil {
		return nil, ErrCommunityNotFound
	}

	return community, err
}

func (chat *Chat) populateCommunityFields(community *communities.Community) error {
	if community == nil {
		return nil
	}

	commChat, exists := community.Chats()[chat.ID]
	if !exists {
		// Skip unknown community chats. They might be channels that were deleted
		return nil
	}

	canPost, err := community.CanMemberIdentityPost(chat.ID)
	if err != nil {
		return err
	}

	chat.CategoryID = commChat.CategoryId
	chat.Position = commChat.Position
	chat.Permissions = commChat.Permissions
	chat.Emoji = commChat.Identity.Emoji
	chat.Name = commChat.Identity.DisplayName
	chat.Description = commChat.Identity.Description
	chat.CanPost = canPost

	return nil
}

func (api *API) getChatAndCommunity(pubKey string, communityID types.HexBytes, chatID string) (*protocol.Chat, *communities.Community, error) {
	fullChatID := chatID

	if string(communityID.Bytes()) == pubKey { // Obtaining chats from personal
		communityID = []byte{}
	}

	if len(communityID) != 0 {
		id := string(communityID.Bytes())

		if chatID == "" {
			community, err := api.getCommunityByID(id)
			return nil, community, err
		}

		fullChatID = id + chatID
	}

	messengerChat := api.s.messenger.Chat(fullChatID)
	if messengerChat == nil {
		return nil, nil, ErrChatNotFound
	}

	var community *communities.Community
	if messengerChat.CommunityID != "" {
		var err error
		community, err = api.getCommunityByID(messengerChat.CommunityID)

		if err != nil {
			return nil, nil, err
		}
	}

	return messengerChat, community, nil
}

func (api *API) EditChat(ctx context.Context, communityID types.HexBytes, chatID string, name string, color string, image images.CroppedImage) (*Chat, error) {
	if len(communityID) != 0 {
		return nil, ErrCommunitiesNotSupported
	}

	chatToEdit := api.s.messenger.Chat(chatID)
	if chatToEdit == nil {
		return nil, ErrChatNotFound
	}

	if chatToEdit.ChatType != protocol.ChatTypePrivateGroupChat {
		return nil, ErrChatTypeNotSupported
	}

	response, err := api.s.messenger.EditGroupChat(ctx, chatID, name, color, image)
	if err != nil {
		return nil, err
	}

	pubKey := types.EncodeHex(crypto.FromECDSAPub(api.s.messenger.IdentityPublicKey()))
	return api.toAPIChat(response.Chats()[0], nil, pubKey, false)
}