package glist

import (
	"encoding/json"
	"fmt"
	"sync"
)

type Entry struct {
	Text    string `json:"text"`
	Checked bool   `json:"checked"`
}

type GList struct {
	AllMsgCounter int        `json:"-"`
	Mutex         sync.Mutex `json:"-"`
	ChatID        int        `json:"chat_id"`
	MessageID     *int       `json:"message_id"`
	Items         []Entry    `json:"items"`
}

func NewGList(chatID int, items ...string) *GList {
	g := GList{ChatID: chatID}
	for _, text := range items {
		g.Items = append(g.Items, Entry{text, false})
	}
	return &g
}

func (g *GList) Add(text string) error {
	for _, item := range g.Items {
		if item.Text == text {
			return fmt.Errorf("dupe:%s", text)
		}
	}
	g.Items = append(g.Items, Entry{text, false})
	return nil
}

func (g *GList) Toggle(text string) error {
	for i, item := range g.Items {
		if item.Text == text {
			g.Items[i].Checked = !g.Items[i].Checked
			return nil
		}
	}
	return fmt.Errorf("not found:%s", text)
}

func (g *GList) ClearChecked() {
	var remaining []Entry
	for _, item := range g.Items {
		if !item.Checked {
			remaining = append(remaining, item)
		}
	}
	g.Items = remaining
}

type button struct {
	Text         string `json:"text"`
	CallbackData string `json:"callback_data"`
}

type newListReq struct {
	ChatID      int    `json:"chat_id"`
	MessageID   *int   `json:"message_id,omitempty"`
	Text        string `json:"text"`
	ReplyMarkup struct {
		InlineKeyboard [][]button `json:"inline_keyboard"`
	} `json:"reply_markup"`
}

func makeButton(e Entry) button {
	b := button{Text: e.Text, CallbackData: e.Text}
	if e.Checked {
		b.Text = fmt.Sprintf("✓ %s", e.Text)
	}
	return b
}

func makeButtons(items []Entry) [][]button {
	var buttons [][]button
	var current []button
	for _, item := range items {
		current = append(current, makeButton(item))
		if len(current) == 2 {
			buttons = append(buttons, current)
			current = []button{}
		}
	}
	if len(current) != 0 {
		buttons = append(buttons, current)
	}
	return buttons
}

func (g *GList) GenSendListReq() ([]byte, error) {
	req := newListReq{ChatID: g.ChatID, MessageID: g.MessageID, Text: "List:"}
	itemButtons := makeButtons(g.Items)
	controlButtons := []button{{"clear checked", "clear"}}
	req.ReplyMarkup.InlineKeyboard = append(itemButtons, controlButtons)
	data, err := json.Marshal(req)
	return data, err
}