package bot

import (
	"context"
	"fmt"

	"github.com/NicoNex/echotron/v3"
	"github.com/rs/zerolog/log"
)

func (b *Bot) forwardSystemEvent(u *echotron.Update) {
	ctx := context.Background()

	switch {
	case u.ChatJoinRequest != nil:
		req := u.ChatJoinRequest
		if !isChannelChat(req.Chat.Type) {
			return
		}

		inviteLink := ""
		if req.InviteLink != nil {
			inviteLink = req.InviteLink.InviteLink
		}
		if inviteLink == "" {
			log.Debug().Msg("No invite link in chat join request")
			return
		}

		userID := req.From.ID
		username := stringPtr(req.From.Username)
		firstName := stringPtr(req.From.FirstName)
		lastName := stringPtr(req.From.LastName)
		if userID == 0 && req.UserChatID != 0 {
			userID = req.UserChatID
		}
		if userID == 0 {
			log.Error().Msg("No user id in chat join request")
			return
		}

		payload := map[string]any{
			"type":             "subscription",
			"user_telegram_id": userID,
			"invite_link":      inviteLink,
			"username":         username,
			"first_name":       firstName,
			"last_name":        lastName,
		}
		if err := b.Backend.SendEvent(ctx, payload); err != nil {
			log.Error().Err(err).Msg("Failed to send subscription event")
		}

	case u.ChatMember != nil:
		event := u.ChatMember
		if !isChannelChat(event.Chat.Type) {
			return
		}

		memberUser := event.NewChatMember.User
		if memberUser == nil {
			log.Error().Msg("No user in chat member update")
			return
		}

		oldStatus := event.OldChatMember.Status
		newStatus := event.NewChatMember.Status

		wasNotMember := oldStatus == "left" || oldStatus == "kicked"
		isNowMember := newStatus == "member" || newStatus == "administrator" || newStatus == "creator"
		userJoined := wasNotMember && isNowMember

		wasMember := oldStatus == "member" || oldStatus == "administrator" || oldStatus == "creator" || oldStatus == "restricted"
		isNowNotMember := newStatus == "left" || newStatus == "kicked"
		userLeft := wasMember && isNowNotMember

		if userJoined {
			inviteLink := ""
			if event.InviteLink != nil {
				inviteLink = event.InviteLink.InviteLink
			}
			if inviteLink == "" {
				log.Debug().Msg("No invite link in chat member update")
				return
			}

			username := stringPtr(memberUser.Username)
			firstName := stringPtr(memberUser.FirstName)
			lastName := stringPtr(memberUser.LastName)
			payload := map[string]any{
				"type":             "subscription",
				"user_telegram_id": memberUser.ID,
				"invite_link":      inviteLink,
				"username":         username,
				"first_name":       firstName,
				"last_name":        lastName,
			}
			if err := b.Backend.SendEvent(ctx, payload); err != nil {
				log.Error().Err(err).Msg("Failed to send subscription event")
			}
			return
		}

		if userLeft {
			payload := map[string]any{
				"type":                "unsubscription",
				"user_telegram_id":    memberUser.ID,
				"channel_telegram_id": event.Chat.ID,
			}
			if err := b.Backend.SendEvent(ctx, payload); err != nil {
				log.Error().Err(err).Msg("Failed to send unsubscription event")
			}
		}

	case u.MyChatMember != nil:
		event := u.MyChatMember
		if !isChannelChat(event.Chat.Type) {
			return
		}

		actorID := event.From.ID
		if actorID == 0 {
			log.Error().Msg("No user in my chat member update")
			return
		}

		oldStatus := event.OldChatMember.Status
		newStatus := event.NewChatMember.Status

		wasMember := oldStatus == "administrator" || oldStatus == "member"
		isNowNotMember := newStatus == "left" || newStatus == "kicked"
		botRemoved := wasMember && isNowNotMember

		permissionsChanged := oldStatus == "administrator" && newStatus == "administrator"

		if botRemoved {
			payload := map[string]any{
				"type":             "bot_removed",
				"telegram_id":      event.Chat.ID,
				"user_telegram_id": actorID,
			}
			if err := b.Backend.SendEvent(ctx, payload); err != nil {
				log.Error().Err(err).Msg("Failed to send bot removed event")
			}
			return
		}

		if permissionsChanged {
			title := event.Chat.Title
			if title == "" {
				title = fmt.Sprintf("Channel %d", event.Chat.ID)
			}
			payload := map[string]any{
				"type":             "bot_permissions",
				"telegram_id":      event.Chat.ID,
				"chat_title":       title,
				"user_telegram_id": actorID,
				"permissions": map[string]any{
					"is_admin":             newStatus == "administrator",
					"can_invite_users":     event.NewChatMember.CanInviteUsers,
					"can_restrict_members": event.NewChatMember.CanRestrictMembers,
				},
			}
			if err := b.Backend.SendEvent(ctx, payload); err != nil {
				log.Error().Err(err).Msg("Failed to send bot permissions event")
			}
			return
		}

		wasNotMember := oldStatus == "left" || oldStatus == "kicked"
		isNowMember := newStatus == "administrator" || newStatus == "member"
		botAdded := wasNotMember && isNowMember

		if botAdded {
			title := event.Chat.Title
			if title == "" {
				title = fmt.Sprintf("Channel %d", event.Chat.ID)
			}
			payload := map[string]any{
				"type":             "bot_added",
				"telegram_id":      event.Chat.ID,
				"title":            title,
				"username":         stringPtr(event.Chat.Username),
				"user_telegram_id": actorID,
				"bot_permissions": map[string]any{
					"is_admin":             newStatus == "administrator",
					"can_invite_users":     event.NewChatMember.CanInviteUsers,
					"can_restrict_members": event.NewChatMember.CanRestrictMembers,
				},
			}
			if err := b.Backend.SendEvent(ctx, payload); err != nil {
				log.Error().Err(err).Msg("Failed to send bot added event")
			}
		}
	}
}