package bot

import (
	"database/sql"
	"errors"
	"fmt"
	"log/slog"
	"strconv"
	"time"

	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"

	"worktimeBot/internal/db"
)

type Handler struct {
	Bot          *tgbotapi.BotAPI
	DB           *db.Store
	AllowedUsers map[int64]bool
}

func NewHandler(bot *tgbotapi.BotAPI, store *db.Store, allowed map[int64]bool) *Handler {
	return &Handler{Bot: bot, DB: store, AllowedUsers: allowed}
}

type actionFunc func(int64) (string, error)

func (h *Handler) handleActionMsg(msg *tgbotapi.Message, fn actionFunc) {
	text, err := fn(msg.Chat.ID)
	if err != nil {
		h.sendText(msg.Chat.ID, err.Error())
	} else {
		h.sendSuccessWithMenu(msg.Chat.ID, text)
	}
}

func (h *Handler) handleActionCallback(chatID int64, msgID int, callbackID string, fn actionFunc) {
	defer h.Bot.Request(tgbotapi.NewCallback(callbackID, ""))
	text, err := fn(chatID)
	if err != nil {
		text = err.Error()
	}
	edit := tgbotapi.NewEditMessageText(chatID, msgID, text)
	kb := backKeyboard()
	edit.ReplyMarkup = &kb
	h.Bot.Send(edit)
}

func (h *Handler) HandleMessage(update tgbotapi.Update) {
	msg := update.Message
	if len(h.AllowedUsers) > 0 && !h.AllowedUsers[msg.Chat.ID] {
		return
	}
	slog.Info("message", "chat_id", msg.Chat.ID, "text", msg.Text)
	switch msg.Text {
	case "/start":
		h.handleStart(msg)
	case "/clockin", "Clock In":
		h.handleActionMsg(msg, h.clockIn)
	case "/clockout", "Clock Out":
		h.handleActionMsg(msg, h.clockOut)
	case "/worktype":
		h.handleWorkTypeMsg(msg)
	case "/report":
		h.handleActionMsg(msg, h.report)
	case "/export":
		h.handleExport(msg)
	case "/dayoff":
		h.handleActionMsg(msg, h.dayOff)
	case "/reporttoggle":
		h.handleActionMsg(msg, h.toggleReport)
	case "/setreporttime":
		h.handleSetReportTime(msg)
	default:
		h.sendText(msg.Chat.ID, "Unknown command")
	}
}

func (h *Handler) HandleCallback(update tgbotapi.Update) {
	cb := update.CallbackQuery
	if len(h.AllowedUsers) > 0 && !h.AllowedUsers[cb.Message.Chat.ID] {
		h.Bot.Request(tgbotapi.NewCallback(cb.ID, "Unauthorized"))
		return
	}
	slog.Info("callback", "chat_id", cb.Message.Chat.ID, "data", cb.Data)
	chatID := cb.Message.Chat.ID
	msgID := cb.Message.MessageID

	switch cb.Data {
	case "clockin":
		h.handleActionCallback(chatID, msgID, cb.ID, h.clockIn)
	case "clockout":
		h.handleActionCallback(chatID, msgID, cb.ID, h.clockOut)
	case "worktype":
		h.workTypeCallback(chatID, msgID, cb.ID)
	case "report":
		h.handleActionCallback(chatID, msgID, cb.ID, h.report)
	case "export":
		h.exportCallback(chatID, msgID, cb.ID)
	case "dayoff":
		h.handleActionCallback(chatID, msgID, cb.ID, h.dayOff)
	case "back_menu":
		h.backToMenu(chatID, msgID, cb.ID)
	default:
		if len(cb.Data) > 9 && cb.Data[:9] == "worktype_" {
			h.selectWorkType(chatID, msgID, cb.ID, cb.Data[9:])
		}
	}
}

func (h *Handler) getOrCreateUser(chatID int64) (*db.User, error) {
	return h.DB.GetOrCreateUser(chatID)
}

func (h *Handler) getUserToday(chatID int64) (*db.User, *db.Day, error) {
	user, err := h.getOrCreateUser(chatID)
	if err != nil {
		return nil, nil, err
	}
	loc, err := time.LoadLocation(user.Timezone)
	if err != nil {
		loc = time.UTC
	}
	today := time.Now().In(loc).Format("2006-01-02")
	day, err := h.DB.GetOrCreateDay(user.ID, today)
	if err != nil {
		return nil, nil, err
	}
	return user, day, nil
}

func (h *Handler) clockIn(chatID int64) (string, error) {
	user, day, err := h.getUserToday(chatID)
	if err != nil {
		return "", err
	}
	if day.IsDayOff {
		return "", errors.New("Today is a day off. Use /dayoff to remove it first.")
	}
	last, err := h.DB.GetLastEvent(user.ID)
	if err != nil && err != sql.ErrNoRows {
		return "", err
	}
	if last != nil && last.EventType == "in" {
		return "", errors.New("Already clocked in")
	}
	loc, _ := time.LoadLocation(user.Timezone)
	now := time.Now().In(loc)
	wt := day.CurrentWorkTypeID
	if err := h.DB.CreateEvent(user.ID, day.ID, "in", &wt, now.Unix(), ""); err != nil {
		return "", err
	}
	return fmt.Sprintf("Clocked in at %s", now.Format("15:04")), nil
}

func (h *Handler) clockOut(chatID int64) (string, error) {
	user, day, err := h.getUserToday(chatID)
	if err != nil {
		return "", err
	}
	if day.IsDayOff {
		return "", errors.New("Today is a day off. Use /dayoff to remove it first.")
	}
	last, err := h.DB.GetLastEvent(user.ID)
	if err != nil {
		return "", err
	}
	if last == nil {
		return "", errors.New("No clock-in found. Start with /clockin first")
	}
	if last.EventType == "out" {
		return "", errors.New("Already clocked out")
	}
	loc, _ := time.LoadLocation(user.Timezone)
	now := time.Now().In(loc)
	if err := h.DB.CreateEvent(user.ID, day.ID, "out", nil, now.Unix(), ""); err != nil {
		return "", err
	}
	return fmt.Sprintf("Clocked out at %s", now.Format("15:04")), nil
}

func (h *Handler) dayOff(chatID int64) (string, error) {
	user, day, err := h.getUserToday(chatID)
	if err != nil {
		return "", err
	}
	if day.IsDayOff {
		if err := h.DB.RemoveDayOff(user.ID, day.Date); err != nil {
			return "", err
		}
		return "Day off removed", nil
	}
	if err := h.DB.SetDayOff(user.ID, day.Date, ""); err != nil {
		return "", err
	}
	return "Today marked as day off", nil
}

func (h *Handler) report(chatID int64) (string, error) {
	user, day, err := h.getUserToday(chatID)
	if err != nil {
		return "", err
	}
	events, err := h.DB.EventsForDayByDayID(day.ID)
	if err != nil {
		return "", err
	}
	return h.buildDailyReport(user, day, events), nil
}

func (h *Handler) toggleReport(chatID int64) (string, error) {
	user, err := h.getOrCreateUser(chatID)
	if err != nil {
		return "", err
	}
	user.ReportEnabled = !user.ReportEnabled
	if err := h.DB.UpdateUser(user); err != nil {
		return "", err
	}
	if user.ReportEnabled {
		return "Daily report enabled", nil
	}
	return "Daily report disabled", nil
}

func (h *Handler) handleSetReportTime(msg *tgbotapi.Message) {
	arg := msg.CommandArguments()
	if arg == "" {
		user, err := h.getOrCreateUser(msg.Chat.ID)
		if err != nil {
			h.sendText(msg.Chat.ID, "Error loading profile")
			return
		}
		h.sendText(msg.Chat.ID, fmt.Sprintf("Current report time: %s\nUsage: /setreporttime HH:MM (24-hour)", user.ReportTime))
		return
	}
	if len(arg) != 5 || arg[2] != ':' {
		h.sendText(msg.Chat.ID, "Invalid format. Usage: /setreporttime HH:MM (24-hour)")
		return
	}
	hours, err1 := strconv.Atoi(arg[:2])
	mins, err2 := strconv.Atoi(arg[3:])
	if err1 != nil || err2 != nil || hours < 0 || hours > 23 || mins < 0 || mins > 59 {
		h.sendText(msg.Chat.ID, "Invalid time. Usage: /setreporttime HH:MM (24-hour)")
		return
	}
	user, err := h.getOrCreateUser(msg.Chat.ID)
	if err != nil {
		h.sendText(msg.Chat.ID, "Error updating report time")
		return
	}
	user.ReportTime = arg
	if err := h.DB.UpdateUser(user); err != nil {
		h.sendText(msg.Chat.ID, "Error updating report time")
		return
	}
	h.sendText(msg.Chat.ID, fmt.Sprintf("Report time set to %s", arg))
}

func (h *Handler) handleStart(msg *tgbotapi.Message) {
	user, err := h.getOrCreateUser(msg.Chat.ID)
	if err != nil {
		slog.Error("start: create user", "error", err)
		h.sendText(msg.Chat.ID, "Error setting up your profile")
		return
	}
	slog.Info("start", "user_id", user.ID, "chat_id", msg.Chat.ID)
	reply := tgbotapi.NewMessage(msg.Chat.ID, "We hope you have a happy day working.")
	reply.ReplyMarkup = quickKeyboard()
	h.Bot.Send(reply)
	menu := tgbotapi.NewMessage(msg.Chat.ID, "Welcome. Choose an action:")
	menu.ReplyMarkup = mainKeyboard()
	h.Bot.Send(menu)
}

func (h *Handler) handleWorkTypeMsg(msg *tgbotapi.Message) {
	user, day, err := h.getUserToday(msg.Chat.ID)
	if err != nil {
		h.sendText(msg.Chat.ID, "Error loading work types")
		return
	}
	text, kb := h.buildWorkTypeKeyboard(user, day)
	reply := tgbotapi.NewMessage(msg.Chat.ID, text)
	reply.ReplyMarkup = &kb
	h.Bot.Send(reply)
}

func (h *Handler) workTypeCallback(chatID int64, msgID int, callbackID string) {
	defer h.Bot.Request(tgbotapi.NewCallback(callbackID, ""))
	user, day, err := h.getUserToday(chatID)
	if err != nil {
		edit := tgbotapi.NewEditMessageText(chatID, msgID, "Error loading work types")
		kb := backKeyboard()
		edit.ReplyMarkup = &kb
		h.Bot.Send(edit)
		return
	}
	text, kb := h.buildWorkTypeKeyboard(user, day)
	edit := tgbotapi.NewEditMessageText(chatID, msgID, text)
	edit.ReplyMarkup = &kb
	h.Bot.Send(edit)
}

func (h *Handler) buildWorkTypeKeyboard(user *db.User, day *db.Day) (string, tgbotapi.InlineKeyboardMarkup) {
	wts, err := h.DB.GetWorkTypes()
	if err != nil || len(wts) == 0 {
		return "No work types available.", backKeyboard()
	}
	text := "Select work type:"
	var rows [][]tgbotapi.InlineKeyboardButton
	for _, wt := range wts {
		label := wt.Name
		if wt.ID == day.CurrentWorkTypeID {
			label = "> " + wt.Name
		}
		callbackData := fmt.Sprintf("worktype_%d", wt.ID)
		row := tgbotapi.NewInlineKeyboardRow(
			tgbotapi.NewInlineKeyboardButtonData(label, callbackData),
		)
		rows = append(rows, row)
	}
	rows = append(rows, tgbotapi.NewInlineKeyboardRow(
		tgbotapi.NewInlineKeyboardButtonData("Back to Menu", "back_menu"),
	))
	kb := tgbotapi.NewInlineKeyboardMarkup(rows...)
	return text, kb
}

func (h *Handler) selectWorkType(chatID int64, msgID int, callbackID, idStr string) {
	defer h.Bot.Request(tgbotapi.NewCallback(callbackID, ""))
	_, day, err := h.getUserToday(chatID)
	if err != nil {
		return
	}
	var wtID int64
	if _, err := fmt.Sscanf(idStr, "%d", &wtID); err != nil {
		return
	}
	wt, err := h.DB.GetWorkType(wtID)
	if err != nil {
		return
	}
	day.CurrentWorkTypeID = wtID
	if err := h.DB.UpdateDay(day); err != nil {
		return
	}
	text := fmt.Sprintf("Work type set to: %s", wt.Name)
	edit := tgbotapi.NewEditMessageText(chatID, msgID, text)
	kb := backKeyboard()
	edit.ReplyMarkup = &kb
	h.Bot.Send(edit)
}

func (h *Handler) handleExport(msg *tgbotapi.Message) {
	user, err := h.getOrCreateUser(msg.Chat.ID)
	if err != nil {
		h.sendText(msg.Chat.ID, "Error loading profile")
		return
	}
	now := time.Now()
	slog.Info("export", "user_id", user.ID, "year", now.Year(), "month", now.Month())
	data, err := GenerateMonthlyReport(h.DB, user.ID, user.Timezone, user.ExportAccent, now.Year(), now.Month())
	if err != nil {
		slog.Error("generate report", "error", err)
		h.sendText(msg.Chat.ID, "Error generating report")
		return
	}
	doc := tgbotapi.NewDocument(msg.Chat.ID, tgbotapi.FileBytes{
		Name:  fmt.Sprintf("worktime_%s.xlsx", now.Format("2006_01")),
		Bytes: data,
	})
	if _, err := h.Bot.Send(doc); err != nil {
		slog.Error("send document", "error", err)
		h.sendText(msg.Chat.ID, "Error sending file")
	}
}

func (h *Handler) exportCallback(chatID int64, msgID int, callbackID string) {
	defer h.Bot.Request(tgbotapi.NewCallback(callbackID, ""))
	user, err := h.getOrCreateUser(chatID)
	if err != nil {
		edit := tgbotapi.NewEditMessageText(chatID, msgID, "Error loading profile")
		kb := backKeyboard()
		edit.ReplyMarkup = &kb
		h.Bot.Send(edit)
		return
	}
	now := time.Now()
	slog.Info("export", "user_id", user.ID, "year", now.Year(), "month", now.Month())
	data, err := GenerateMonthlyReport(h.DB, user.ID, user.Timezone, user.ExportAccent, now.Year(), now.Month())
	if err != nil {
		slog.Error("generate report", "error", err)
		edit := tgbotapi.NewEditMessageText(chatID, msgID, "Error generating report")
		kb := backKeyboard()
		edit.ReplyMarkup = &kb
		h.Bot.Send(edit)
		return
	}
	slog.Info("report generated", "bytes", len(data))
	edit := tgbotapi.NewEditMessageText(chatID, msgID, "Report ready:")
	kb := backKeyboard()
	edit.ReplyMarkup = &kb
	h.Bot.Send(edit)
	doc := tgbotapi.NewDocument(chatID, tgbotapi.FileBytes{
		Name:  fmt.Sprintf("worktime_%s.xlsx", now.Format("2006_01")),
		Bytes: data,
	})
	if _, err := h.Bot.Send(doc); err != nil {
		slog.Error("send document", "error", err)
	}
}

func (h *Handler) backToMenu(chatID int64, msgID int, callbackID string) {
	defer h.Bot.Request(tgbotapi.NewCallback(callbackID, ""))
	edit := tgbotapi.NewEditMessageText(chatID, msgID, "Welcome. Choose an action:")
	kb := mainKeyboard()
	edit.ReplyMarkup = &kb
	h.Bot.Send(edit)
}

func (h *Handler) buildDailyReport(user *db.User, day *db.Day, events []db.Event) string {
	loc, err := time.LoadLocation(user.Timezone)
	if err != nil {
		loc = time.UTC
	}

	if len(events) == 0 {
		if day.IsDayOff {
			return fmt.Sprintf("%s - Day Off", day.Date)
		}
		return fmt.Sprintf("%s - No events recorded.", day.Date)
	}

	totals := ComputeDailyTotals(events, day.MinBreakThreshold)
	lines := fmt.Sprintf("Report for %s", day.Date)
	if day.IsDayOff {
		lines += "\nDay Off: Yes"
	}
	lines += "\n\n"

	for _, e := range events {
		t := time.Unix(e.OccurredAt, 0).In(loc).Format("15:04")
		label := "IN"
		if e.EventType == "out" {
			label = "OUT"
		}
		wt := ""
		if e.WorkTypeID != nil {
			if wtObj, err := h.DB.GetWorkType(*e.WorkTypeID); err == nil {
				wt = " [" + wtObj.Name + "]"
			}
		}
		lines += fmt.Sprintf("%s %s%s\n", label, t, wt)
	}

	workStr := formatDuration(totals.TotalSeconds)
	breakStr := formatDuration(totals.BreakSeconds)
	lines += fmt.Sprintf("\nSummary:\n  Work: %s\n  Break: %s\n", workStr, breakStr)

	return lines
}

func (h *Handler) SendDailyReport(userID int64, chatID int64) {
	user, err := h.DB.GetUserByChatID(chatID)
	if err != nil {
		slog.Error("daily report: user not found", "user_id", userID)
		return
	}
	loc, err := time.LoadLocation(user.Timezone)
	if err != nil {
		loc = time.UTC
	}
	now := time.Now().In(loc)
	today := now.Format("2006-01-02")

	day, err := h.DB.GetOrCreateDay(user.ID, today)
	if err != nil {
		slog.Error("daily report: get day", "error", err)
		return
	}
	events, err := h.DB.EventsForDayByDayID(day.ID)
	if err != nil {
		slog.Error("daily report: get events", "error", err)
		return
	}
	text := h.buildDailyReport(user, day, events)
	reply := tgbotapi.NewMessage(chatID, text)
	reply.ReplyMarkup = quickKeyboard()
	h.Bot.Send(reply)
	h.DB.MarkReportSent(user.ID, today)
}

func quickKeyboard() tgbotapi.ReplyKeyboardMarkup {
	return tgbotapi.NewReplyKeyboard(
		tgbotapi.NewKeyboardButtonRow(
			tgbotapi.NewKeyboardButton("Clock In"),
			tgbotapi.NewKeyboardButton("Clock Out"),
		),
	)
}

func mainKeyboard() tgbotapi.InlineKeyboardMarkup {
	return tgbotapi.NewInlineKeyboardMarkup(
		tgbotapi.NewInlineKeyboardRow(
			tgbotapi.NewInlineKeyboardButtonData("Clock In", "clockin"),
			tgbotapi.NewInlineKeyboardButtonData("Clock Out", "clockout"),
		),
		tgbotapi.NewInlineKeyboardRow(
			tgbotapi.NewInlineKeyboardButtonData("Work Type", "worktype"),
			tgbotapi.NewInlineKeyboardButtonData("Day Off", "dayoff"),
		),
		tgbotapi.NewInlineKeyboardRow(
			tgbotapi.NewInlineKeyboardButtonData("Report", "report"),
			tgbotapi.NewInlineKeyboardButtonData("Export", "export"),
		),
	)
}

func backKeyboard() tgbotapi.InlineKeyboardMarkup {
	return tgbotapi.NewInlineKeyboardMarkup(
		tgbotapi.NewInlineKeyboardRow(
			tgbotapi.NewInlineKeyboardButtonData("Back to Menu", "back_menu"),
		),
	)
}

func formatDuration(seconds int64) string {
	hours := seconds / 3600
	mins := (seconds % 3600) / 60
	if hours > 0 {
		return fmt.Sprintf("%dh %dm", hours, mins)
	}
	return fmt.Sprintf("%dm", mins)
}

func (h *Handler) sendText(chatID int64, text string) {
	reply := tgbotapi.NewMessage(chatID, text)
	reply.ReplyMarkup = quickKeyboard()
	h.Bot.Send(reply)
}

func (h *Handler) sendSuccessWithMenu(chatID int64, text string) {
	reply := tgbotapi.NewMessage(chatID, text)
	reply.ReplyMarkup = mainKeyboard()
	h.Bot.Send(reply)
}