package main

import (
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"sync"
	"syscall"
	"time"

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

	"worktimeBot/internal/bot"
	"worktimeBot/internal/db"
)

func main() {
	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
		AddSource: true,
		Level:     slog.LevelInfo,
	})))
	godotenv.Load()

	token := os.Getenv("BOT_TOKEN")
	dbPath := getEnvDefault("DB_PATH", "db.sqlite3")

	httpClient := http.DefaultClient

	botAPI, err := tgbotapi.NewBotAPIWithClient(token, tgbotapi.APIEndpoint, httpClient)
	if err != nil {
		slog.Error("failed to create bot API", "error", err)
		os.Exit(1)
	}

	dbStore, err := db.NewStore(dbPath)
	if err != nil {
		slog.Error("failed to open database", "path", dbPath, "error", err)
		os.Exit(1)
	}

	allowedUsers := parseAllowedUsers(os.Getenv("BOT_ALLOWED_USERS"))
	handler := bot.NewHandler(botAPI, dbStore, allowedUsers)

	stop := make(chan struct{})
	var wg sync.WaitGroup

	if url := os.Getenv("BOT_WEBHOOK_URL"); url != "" {
		wg.Add(1)
		go func() {
			defer wg.Done()
			startWebhook(botAPI, handler, url)
		}()
	} else {
		if _, err := botAPI.Request(tgbotapi.DeleteWebhookConfig{}); err != nil {
			slog.Error("delete webhook", "error", err)
		}

		wg.Add(1)
		go func() {
			defer wg.Done()
			dailyReportScheduler(handler, dbStore, stop)
		}()

		wg.Add(1)
		go func() {
			defer wg.Done()
			startPolling(botAPI, handler, stop)
		}()
	}

	slog.Info("bot started",
		"bot_user", botAPI.Self.UserName,
		"allowed_users", len(allowedUsers),
		"mode", map[bool]string{true: "webhook", false: "polling"}[os.Getenv("BOT_WEBHOOK_URL") != ""],
	)

	sig := make(chan os.Signal, 1)
	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
	s := <-sig
	slog.Info("shutting down", "signal", s.String())
	close(stop)
	wg.Wait()
	dbStore.Close()
}

func startPolling(botAPI *tgbotapi.BotAPI, handler *bot.Handler, stop chan struct{}) {
	u := tgbotapi.NewUpdate(0)
	u.Timeout = 30
	updates := botAPI.GetUpdatesChan(u)
	for {
		select {
		case <-stop:
			return
		case update, ok := <-updates:
			if !ok {
				return
			}
			if update.Message != nil {
				handler.HandleMessage(update)
			}
			if update.CallbackQuery != nil {
				handler.HandleCallback(update)
			}
		}
	}
}

func parseAllowedUsers(raw string) map[int64]bool {
	m := make(map[int64]bool)
	for _, s := range strings.Split(raw, ",") {
		s = strings.TrimSpace(s)
		if s == "" {
			continue
		}
		id, err := strconv.ParseInt(s, 10, 64)
		if err == nil {
			m[id] = true
		} else {
			slog.Warn("invalid user ID in BOT_ALLOWED_USERS", "value", s)
		}
	}
	return m
}

func dailyReportScheduler(h *bot.Handler, store *db.Store, stop chan struct{}) {
	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-stop:
			return
		case <-ticker.C:
			checkDailyReports(h, store)
		}
	}
}

func checkDailyReports(h *bot.Handler, store *db.Store) {
	users, err := store.GetAllUsers()
	if err != nil {
		slog.Error("report scheduler: get users", "error", err)
		return
	}

	now := time.Now().UTC()

	for _, u := range users {
		if !u.ReportEnabled || !u.IsActive {
			continue
		}

		loc, err := time.LoadLocation(u.Timezone)
		if err != nil {
			continue
		}
		localNow := now.In(loc)
		today := localNow.Format("2006-01-02")
		currentHHMM := localNow.Format("15:04")

		if currentHHMM != u.ReportTime {
			continue
		}

		if u.LastReportDate != nil && *u.LastReportDate == today {
			continue
		}

		slog.Info("sending daily report",
			"user_id", u.ID, "chat_id", u.ChatID, "timezone", u.Timezone,
		)
		h.SendDailyReport(u.ID, u.ChatID)
	}
}

func getEnvDefault(key, defaultValue string) string {
	if val := os.Getenv(key); val != "" {
		return val
	}
	return defaultValue
}