package access

import (
	"fmt"
	"strconv"
	"strings"

	"github.com/mymmrac/telego"
	th "github.com/mymmrac/telego/telegohandler"

	"git.entityseven.com/rilaxik/pllist/internal/service"
	"git.entityseven.com/rilaxik/pllist/internal/telegram/shared"
)

type Handler struct {
	sender *shared.Sender
	access *service.BotAccessService
}

func New(sender *shared.Sender, access *service.BotAccessService) *Handler {
	return &Handler{sender: sender, access: access}
}

func (h *Handler) Register(router *th.BotHandler) {
	router.HandleMessage(h.allow, th.CommandEqual("allow"))
	router.HandleMessage(h.kick, th.CommandEqual("kick"))
}

func (h *Handler) allow(ctx *th.Context, message telego.Message) error {
	user := shared.UserFrom(ctx)
	if !h.access.IsOwner(user.TelegramID) {
		return h.sender.Send(ctx, message.Chat.ID, ownerOnlyText, nil)
	}

	created, target, err := h.access.Allow(ctx, user.TelegramID, commandArgument(message.Text))
	if err != nil {
		return err
	}
	label := shared.Escape(targetLabel(target))

	var text string
	switch {
	case created && target.Username != "":
		text = fmt.Sprintf(
			"Access granted to %s. It activates when they contact the bot.", label,
		)
	case created:
		text = fmt.Sprintf("Access granted to %s.", label)
	case h.access.IsOwner(target.TelegramID):
		text = "You already have access."
	default:
		text = fmt.Sprintf("%s already has access or a pending grant.", label)
	}
	return h.sender.Send(ctx, message.Chat.ID, text, nil)
}

func (h *Handler) kick(ctx *th.Context, message telego.Message) error {
	user := shared.UserFrom(ctx)
	if !h.access.IsOwner(user.TelegramID) {
		return h.sender.Send(ctx, message.Chat.ID, ownerOnlyText, nil)
	}

	revoked, target, err := h.access.Kick(ctx, user.TelegramID, commandArgument(message.Text))
	if err != nil {
		return err
	}
	label := shared.Escape(targetLabel(target))
	if !revoked {
		return h.sender.Send(ctx, message.Chat.ID,
			fmt.Sprintf("No access grant found for %s.", label), nil)
	}
	return h.sender.Send(ctx, message.Chat.ID,
		fmt.Sprintf("Access revoked for %s.", label), nil)
}

func commandArgument(text string) string {
	fields := strings.Fields(text)
	if len(fields) < 2 {
		return ""
	}
	return strings.Join(fields[1:], " ")
}

func targetLabel(target service.GrantTarget) string {
	if target.Username != "" {
		return "@" + target.Username
	}
	return strconv.FormatInt(target.TelegramID, 10)
}