package bot

import (
	"context"
	"fmt"
	"log"
	"time"

	"telegramvpn/internal/db"
	"telegramvpn/internal/remnawave"

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

func (h *Handler) handleUserConfig(chatID, telegramID int64) {
	ctx, cancel := context.WithTimeout(context.Background(), 45*time.Second)
	defer cancel()

	days := h.cfg.TrialUserDays
	if days <= 0 {
		days = 1
	}

	existing, err := h.database.GetVPNByTelegramID(ctx, telegramID)
	if err != nil {
		h.sendText(chatID, "Ошибка базы данных. Попробуйте позже.")
		return
	}
	if existing != nil && existing.ExpireAt != nil && existing.ExpireAt.After(time.Now()) {
		link := h.resolveSubscriptionLink(ctx, existing.RemnawaveUsername, telegramID)
		h.sendConfigMessage(chatID, telegramID, days, existing.RemnawaveUsername, *existing.ExpireAt, link)
		return
	}

	panelUser, err := h.panel.GetUserByTelegramID(ctx, telegramID)
	if err == nil && panelUser != nil && panelUser.ExpireAt.After(time.Now()) {
		link := panelUser.SubscriptionURL
		if link == "" {
			link = h.subscriptionLink(panelUser.ShortUUID)
		}
		_ = h.saveVPNFromPanel(ctx, telegramID, panelUser)
		h.sendConfigMessage(chatID, telegramID, days, panelUser.Username, panelUser.ExpireAt, link)
		return
	}

	username := fmt.Sprintf("u%d", telegramID)
	var extPtr *string
	if h.cfg.DefaultExternalSquadUUID != "" {
		e := h.cfg.DefaultExternalSquadUUID
		extPtr = &e
	}
	ints := h.cfg.DefaultInternalSquadUUIDs
	tgID := telegramID

	u, err := h.panel.CreateUser(ctx, remnawave.CreateUserInput{
		Username:             username,
		ExpireAt:             db.DefaultExpireAt(days),
		TelegramID:           &tgID,
		ExternalSquadUUID:    extPtr,
		ActiveInternalSquads: ints,
		Description:          fmt.Sprintf("trial %d day via tgvpn bot", days),
	})
	if err != nil {
		h.sendText(chatID, "Не удалось создать доступ: "+err.Error()+"\n\nПопробуйте позже или напишите администратору.")
		return
	}

	if err := h.saveVPNFromPanel(ctx, telegramID, u); err != nil {
		log.Printf("save vpn user: %v", err)
	}

	link := u.SubscriptionURL
	if link == "" {
		link = h.subscriptionLink(u.ShortUUID)
	}
	h.sendConfigMessage(chatID, telegramID, days, u.Username, u.ExpireAt, link)
}

func (h *Handler) saveVPNFromPanel(ctx context.Context, telegramID int64, u *remnawave.PanelUser) error {
	if u == nil {
		return nil
	}
	var ext *string
	if h.cfg.DefaultExternalSquadUUID != "" {
		e := h.cfg.DefaultExternalSquadUUID
		ext = &e
	}
	return h.database.SaveVPNUser(ctx, db.VPNUser{
		TelegramID:          &telegramID,
		RemnawaveUUID:       u.UUID,
		RemnawaveUsername:   u.Username,
		ExternalSquadUUID:   ext,
		InternalSquadUUIDs:  h.cfg.DefaultInternalSquadUUIDs,
		ExpireAt:            &u.ExpireAt,
	})
}

func (h *Handler) resolveSubscriptionLink(ctx context.Context, username string, telegramID int64) string {
	if u, err := h.panel.GetUserByUsername(ctx, username); err == nil && u != nil {
		if u.SubscriptionURL != "" {
			return u.SubscriptionURL
		}
		return h.subscriptionLink(u.ShortUUID)
	}
	if u, err := h.panel.GetUserByTelegramID(ctx, telegramID); err == nil && u != nil {
		if u.SubscriptionURL != "" {
			return u.SubscriptionURL
		}
		return h.subscriptionLink(u.ShortUUID)
	}
	return ""
}

func (h *Handler) subscriptionLink(shortUUID string) string {
	if shortUUID != "" && h.cfg.RemnawaveSubscription != "" {
		return h.cfg.RemnawaveSubscription + "/" + shortUUID
	}
	return ""
}

func (h *Handler) sendConfigMessage(chatID, telegramID int64, days int, username string, expireAt time.Time, link string) {
	text := fmt.Sprintf(
		"✅ VPN готов\n\n"+
			"⏱ Срок: %d дн. (до %s)\n"+
			"👤 Логин: %s\n",
		days,
		expireAt.Local().Format("02.01.2006 15:04"),
		username,
	)
	if link != "" {
		text += "\n🔗 Ссылка подписки — кнопка ниже или:\n" + link
	} else {
		text += "\n\n⚠️ Ссылка не настроена — REMNAWAVE_SUBSCRIPTION_URL в .env"
	}
	msg := tgbotapi.NewMessage(chatID, text)
	msg.ReplyMarkup = configResultKeyboard(h.cfg, telegramID, h.admin, link)
	h.send(msg)
}