package main

import (
	"context"
	"log/slog"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"syscall"
	"time"

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

	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"))

	var h *bot.Handler

	dispatch := func(ctx context.Context, b *tgbot.Bot, update *models.Update) {
		if update.Message != nil {
			h.HandleMessage(ctx, update.Message)
		}
		if update.CallbackQuery != nil {
			h.HandleCallback(ctx, update.CallbackQuery)
		}
	}

	b, err := tgbot.New(token, tgbot.WithDefaultHandler(dispatch))
	if err != nil {
		slog.Error("failed to create bot", "error", err)
		os.Exit(1)
	}

	h = bot.NewHandler(b, dbStore, allowedUsers)

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer cancel()

	if url := os.Getenv("BOT_WEBHOOK_URL"); url != "" {
		startWebhook(ctx, b, h, url)
	} else {
		b.DeleteWebhook(ctx, &tgbot.DeleteWebhookParams{})
		go dailyReportScheduler(ctx, h, dbStore)
		slog.Info("bot started",
			"allowed_users", len(allowedUsers),
			"mode", "polling",
		)
		b.Start(ctx)
	}

	dbStore.Close()
}

// dailyReportScheduler runs a periodic ticker that triggers daily report checks every 30 seconds.
func dailyReportScheduler(ctx context.Context, h *bot.Handler, store *db.Store) {
	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

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

// checkDailyReports iterates all users and sends a daily report to those whose report time has arrived.
func checkDailyReports(ctx context.Context, 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(ctx, u.ID, u.ChatID)
	}
}

// parseAllowedUsers parses a comma-separated list of Telegram user IDs into a set.
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
}

// getEnvDefault returns the environment variable value or a default if unset or empty.
func getEnvDefault(key, defaultValue string) string {
	if val := os.Getenv(key); val != "" {
		return val
	}
	return defaultValue
}