"use client";

import { useState, useCallback } from "react";
import Image from "next/image";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { toast } from "sonner";
import Logo from "@/public/logo.webp";
import { useLogin, useRegister, useVerifyToken } from "@/lib/hooks/useAuth";
import { useTranslations } from "next-intl";

interface AuthDialogProps {
  isOpen: boolean;
  onClose: () => void;
}

type AuthStep = "phone" | "register" | "verify";

export default function AuthDialog({ isOpen, onClose }: AuthDialogProps) {
  const [phone, setPhone] = useState("+993 ");
  const [name, setName] = useState("");
  const [address, setAddress] = useState("");
  const [otp, setOtp] = useState("");
  const [authStep, setAuthStep] = useState<AuthStep>("phone");
  const [isNewUser, setIsNewUser] = useState(false);
  const t = useTranslations();

  const { mutate: login, isPending: isLoginLoading } = useLogin();
  const { mutate: register, isPending: isRegisterLoading } = useRegister();
  const { mutate: verifyToken, isPending: isVerifyLoading } = useVerifyToken();

  const resetDialog = useCallback(() => {
    setAuthStep("phone");
    setPhone("+993 ");
    setName("");
    setAddress("");
    setOtp("");
    setIsNewUser(false);
    onClose();
  }, [onClose]);

  const formatPhoneForBackend = (phoneNumber: string): string => {
    return phoneNumber.replace(/^\+993\s*/, "").replace(/\s+/g, "");
  };

  const handlePhoneChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const input = e.target.value;
    const prefix = "+993 ";

    if (input.length < prefix.length) {
      setPhone(prefix);
      return;
    }

    const digitsOnly = input.substring(prefix.length).replace(/\D/g, "");
    const limitedDigits = digitsOnly.substring(0, 8);

    let formattedPhone = prefix;
    if (limitedDigits.length > 0) {
      formattedPhone += limitedDigits.substring(0, 2);

      if (limitedDigits.length > 2) {
        formattedPhone += " " + limitedDigits.substring(2);
      }
    }

    setPhone(formattedPhone);
  };

  const isPhoneValid = (): boolean => {
    const phoneDigits = formatPhoneForBackend(phone);
    return phoneDigits.length === 8;
  };

  const handleCheckPhone = useCallback(() => {
    if (!isPhoneValid()) {
      toast.error(t("invalid_phone"));
      return;
    }

    const phoneNumber = formatPhoneForBackend(phone);

    // Try to login first to check if user exists
    login(
      { phone_number: parseInt(phoneNumber, 10) },
      {
        onSuccess: () => {
          toast.success(t("code_sent"));
          setIsNewUser(false);
          setAuthStep("verify");
        },
        onError: (error: any) => {
          // Check if error indicates user not found
          const errorMessage = error?.response?.data?.message || "";
          const lowerMessage = errorMessage.toLowerCase();
          if (
            lowerMessage.includes("tapylmady") ||
            lowerMessage.includes("not found") ||
            lowerMessage.includes("does not exist") ||
            lowerMessage.includes("not exist") ||
            error?.response?.status === 404
          ) {
            // User doesn't exist, show registration form
            setIsNewUser(true);
            setAuthStep("register");
          } else {
            toast.error(errorMessage || t("error_occurred"));
          }
        },
      },
    );
  }, [phone, login, t]);

  const handleRegister = useCallback(() => {
    if (!name.trim()) {
      toast.error(t("name_required") || "Adyňyzy giriziň");
      return;
    }

    if (!address.trim()) {
      toast.error(t("address_required") || "Salgyňyzy giriziň");
      return;
    }

    const phoneNumber = formatPhoneForBackend(phone);

    register(
      {
        phone_number: phoneNumber,
        name: name.trim(),
        address: address.trim(),
      },
      {
        onSuccess: () => {
          toast.success(
            t("registration_success") || "Hasaba alyndy! Kody giriziň",
          );
          setAuthStep("verify");
        },
        onError: (error: any) => {
          toast.error(error?.response?.data?.message || t("error_occurred"));
        },
      },
    );
  }, [phone, name, address, register, t]);

  const handleVerify = useCallback(() => {
    if (otp.length < 4) {
      toast.error(t("invalid_code"));
      return;
    }

    const phoneNumber = formatPhoneForBackend(phone);

    verifyToken(
      {
        phone_number: parseInt(phoneNumber, 10),
        code: parseInt(otp, 10),
      },
      {
        onSuccess: () => {
          toast.success(t("login_success"));
          resetDialog();
          window.location.reload();
        },
        onError: (error: any) => {
          toast.error(error?.response?.data?.message || t("wrong_code"));
        },
      },
    );
  }, [otp, phone, verifyToken, resetDialog, t]);

  const handleKeyPress = useCallback(
    (e: React.KeyboardEvent, action: () => void) => {
      if (e.key === "Enter") {
        action();
      }
    },
    [],
  );

  const getTitle = () => {
    switch (authStep) {
      case "phone":
        return t("common.enterPhone");
      case "register":
        return t("register_title") || "Hasaba alyş";
      case "verify":
        return t("verify_title") || "Kody giriziň";
      default:
        return t("common.enterPhone");
    }
  };

  const getDescription = () => {
    switch (authStep) {
      case "phone":
        return t("common.weWillSendCode");
      case "register":
        return t("register_description") || "Maglumatyňyzy dolduryň";
      case "verify":
        return t("verify_description") || "Telefonyňyza gelen kody giriziň";
      default:
        return t("common.weWillSendCode");
    }
  };

  return (
    <Dialog open={isOpen} onOpenChange={resetDialog}>
      <DialogContent className="sm:max-w-md">
        <DialogHeader>
          <div className="flex items-center justify-center mb-4">
            <div className="relative h-8 w-[180px]">
              <Image src={Logo} alt="Logo" fill className="object-contain" />
            </div>
          </div>
          <DialogTitle className="text-2xl text-center">
            {getTitle()}
          </DialogTitle>
          <p className="text-center text-sm text-gray-600">
            {getDescription()}
          </p>
        </DialogHeader>

        <div className="space-y-4 mt-4">
          {/* Phone Input - Always shown but disabled after first step */}
          <div>
            <Input
              type="tel"
              placeholder="+993 61 097651"
              value={phone}
              onChange={handlePhoneChange}
              className="h-12 rounded-xl"
              onKeyDown={(e) => handleKeyPress(e, handleCheckPhone)}
              disabled={authStep !== "phone" || isLoginLoading}
            />
            <p className="text-xs text-gray-500 mt-1">{t("phone_format")}</p>
          </div>

          {/* Registration Form */}
          {authStep === "register" && (
            <>
              <Input
                type="text"
                placeholder={t("name_placeholder") || "Adyňyz"}
                value={name}
                onChange={(e) => setName(e.target.value)}
                className="h-12 rounded-xl"
                disabled={isRegisterLoading}
                autoFocus
              />
              <Input
                type="text"
                placeholder={
                  t("address_placeholder") || "Salgyňyz (mysal: Tejen)"
                }
                value={address}
                onChange={(e) => setAddress(e.target.value)}
                className="h-12 rounded-xl"
                onKeyDown={(e) => handleKeyPress(e, handleRegister)}
                disabled={isRegisterLoading}
              />
            </>
          )}

          {/* Verification Code Input */}
          {authStep === "verify" && (
            <Input
              type="text"
              placeholder={t("common.code")}
              value={otp}
              onChange={(e) =>
                setOtp(e.target.value.replace(/\D/g, "").substring(0, 6))
              }
              className="h-12 rounded-xl"
              onKeyDown={(e) => handleKeyPress(e, handleVerify)}
              disabled={isVerifyLoading}
              autoFocus
              maxLength={6}
            />
          )}

          {/* Action Button */}
          <Button
            onClick={
              authStep === "phone"
                ? handleCheckPhone
                : authStep === "register"
                  ? handleRegister
                  : handleVerify
            }
            className="w-full cursor-pointer h-12 rounded-xl font-bold text-base bg-[#005bff] hover:bg-[#0041c4]"
            size="lg"
            disabled={
              isLoginLoading ||
              isRegisterLoading ||
              isVerifyLoading ||
              (authStep === "phone" && !isPhoneValid())
            }
          >
            {isLoginLoading
              ? t("checking") || "Barlanýar..."
              : isRegisterLoading
                ? t("registering") || "Hasaba alynýar..."
                : isVerifyLoading
                  ? t("verifying")
                  : authStep === "phone"
                    ? t("common.send")
                    : authStep === "register"
                      ? t("register_button") || "Hasaba al"
                      : t("verify")}
          </Button>

          {/* Back Button for Register and Verify steps */}
          {authStep !== "phone" && (
            <Button
              onClick={() => {
                if (authStep === "register") {
                  setAuthStep("phone");
                  setName("");
                  setAddress("");
                } else if (authStep === "verify") {
                  setAuthStep(isNewUser ? "register" : "phone");
                  setOtp("");
                }
              }}
              variant="ghost"
              className="w-full"
              disabled={isLoginLoading || isRegisterLoading || isVerifyLoading}
            >
              {t("back") || "Yza"}
            </Button>
          )}
        </div>
      </DialogContent>
    </Dialog>
  );
}
