package match

import (
	"strings"

	"github.com/go-telegram/bot/models"
)

type MessageMF func(update *models.Update) bool

/*
All match functions should not check whether `update` and
its subfields (such as `Message`, `CallbackQuery`) are nil.

this step should be handled internally,
calling match functions manually may trigger a panic.
*/

// SlashCommand will match `command` in `/command`.
func SlashCommand(command string) MessageMF {
	return func(update *models.Update) bool {
		for _, e := range update.Message.Entities {
			if e.Offset == 0 && e.Type == models.MessageEntityTypeBotCommand {
				return update.Message.Text[1:e.Length] == command
			}
		}

		return false
	}
}

// SlashCommandMaybeUsername will match `command` in `/command` and `/command@username`.
func SlashCommandMaybeUsername(cmd, username string) MessageMF {
	return func(update *models.Update) bool {
		for _, e := range update.Message.Entities {
			if e.Offset == 0 && e.Type == models.MessageEntityTypeBotCommand {
				return update.Message.Text[1:e.Length] == cmd || update.Message.Text[1:e.Length] == cmd+"@"+username
			}
		}

		return false
	}
}

// TextContains will match `text` in `sometextor...`.
func TextContains(text string) MessageMF {
	return func(update *models.Update) bool {
		return strings.Contains(update.Message.Text, text)
	}
}