"use client";

import { useState, useEffect, useRef, useCallback, useMemo } from "react";
import { useTranslations } from "next-intl";
import Modal from "./Modal";
import Button from "./Button";
import Input from "./Input";
import { useCopyToClipboard } from "@/shared/hooks/useCopyToClipboard";

const GOOGLE_OAUTH_PROVIDERS = new Set(["antigravity", "agy", "gemini-cli"]);

/** Providers that use a local callback server on a random port (PKCE browser flow). */
const PKCE_CALLBACK_SERVER_PROVIDERS = new Set(["codex"]);

/**
 * Phase 1 hotfix (2026-05-29): windsurf & devin-cli only support import-token.
 * Their PKCE flow targeting app.devin.ai/editor/signin returned 404 post-rebrand.
 * Phase 2 will reintroduce browser login via Firebase OAuth + RegisterUser.
 * Spec: docs/superpowers/specs/2026-05-29-windsurf-login-fix-design.md.
 */
const IMPORT_TOKEN_ONLY_PROVIDERS = new Set(["windsurf", "devin-cli"]);

type OAuthModalProps = {
  isOpen: boolean;
  provider?: string;
  providerInfo?: { name?: string } | null;
  onSuccess?: () => void;
  onClose: () => void;
  idcConfig?: unknown;
  reauthConnection?: null | { id?: string };
};

/**
 * OAuth Modal Component
 * - Localhost: Auto callback via popup message
 * - Remote: Manual paste callback URL
 */
export default function OAuthModal({
  isOpen,
  provider,
  providerInfo,
  onSuccess,
  onClose,
  idcConfig,
  reauthConnection,
}: OAuthModalProps) {
  const t = useTranslations("oauthModal");
  const [step, setStep] = useState("waiting"); // waiting | input | success | error
  const [authData, setAuthData] = useState(null);
  const [callbackUrl, setCallbackUrl] = useState("");
  const [error, setError] = useState(null);
  const [isDeviceCode, setIsDeviceCode] = useState(false);
  const [deviceData, setDeviceData] = useState(null);
  const [polling, setPolling] = useState(false);
  // API-key paste mode: for providers that accept a token directly (windsurf, devin-cli)
  const [showPasteToken, setShowPasteToken] = useState(
    provider === "windsurf" || provider === "devin-cli"
  );
  const [pasteToken, setPasteToken] = useState("");
  const [savingToken, setSavingToken] = useState(false);

  const supportsTokenPaste = provider === "windsurf" || provider === "devin-cli";
  // Phase 1 hotfix (2026-05-29): windsurf/devin-cli are import-token-only.
  // Hide the "Browser Login" tab — Phase 2 will restore it via Firebase OAuth.
  const importTokenOnly = IMPORT_TOKEN_ONLY_PROVIDERS.has(provider);
  const popupRef = useRef(null);
  const { copied, copy } = useCopyToClipboard();
  const deviceVerificationUrl =
    deviceData?.verification_uri_complete || deviceData?.verification_uri || "";

  // Client-only runtime values
  const runtimeLocation = useMemo(() => {
    if (typeof window === "undefined") {
      return {
        isLocalhost: false,
        isTrueLocalhost: false,
        placeholderUrl: "/callback?code=...",
      };
    }

    const hostname = window.location.hostname;
    const isLocal =
      hostname === "localhost" ||
      hostname === "127.0.0.1" ||
      hostname.startsWith("192.168.") ||
      hostname.startsWith("10.") ||
      /^172\.(1[6-9]|2\d|3[01])\./.test(hostname);
    const isTrulyLocal = hostname === "localhost" || hostname === "127.0.0.1";

    return {
      isLocalhost: isLocal,
      isTrueLocalhost: isTrulyLocal,
      placeholderUrl: `${window.location.origin}/callback?code=...`,
    };
  }, []);

  const { isLocalhost, isTrueLocalhost, placeholderUrl } = runtimeLocation;
  const callbackProcessedRef = useRef(false);
  const flowStartedRef = useRef(false);

  // Define all useCallback hooks BEFORE the useEffects that reference them

  // Exchange tokens
  const exchangeTokens = useCallback(
    async (code, state) => {
      if (!authData) return;
      try {
        if (!authData.redirectUri || !authData.codeVerifier) {
          throw new Error(
            "OAuth session is incomplete (missing redirect URI or code verifier). Restart the connection and try again."
          );
        }

        const normalizedState = typeof state === "string" && state.length > 0 ? state : undefined;

        const res = await fetch(`/api/oauth/${provider}/exchange`, {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({
            code,
            redirectUri: authData.redirectUri,
            connectionId: reauthConnection?.id,
            codeVerifier: authData.codeVerifier,
            ...(normalizedState ? { state: normalizedState } : {}),
          }),
        });

        const data = await res.json();
        if (!res.ok) {
          const errorObject =
            typeof data.error === "object" && data.error !== null
              ? (data.error as Record<string, unknown>)
              : null;
          const errMsg = errorObject
            ? (errorObject.message as string) || JSON.stringify(errorObject)
            : data.error || "Exchange failed";
          const details = Array.isArray(errorObject?.details)
            ? (errorObject.details as Array<{ field?: string; message?: string }>)
                .map((detail) => {
                  if (!detail?.message) return null;
                  return detail.field ? `${detail.field}: ${detail.message}` : detail.message;
                })
                .filter(Boolean)
                .join("; ")
            : "";
          throw new Error(details ? `${errMsg} (${details})` : errMsg);
        }

        setStep("success");
        onSuccess?.();
      } catch (err) {
        // Provide actionable guidance for redirect_uri_mismatch on Google OAuth providers
        if (
          err.message?.toLowerCase().includes("redirect_uri_mismatch") &&
          GOOGLE_OAUTH_PROVIDERS.has(provider)
        ) {
          setError(
            "redirect_uri_mismatch: The default Google OAuth credentials only work on localhost. " +
              "For remote use, configure your own OAuth credentials via environment variables: " +
              (provider === "antigravity"
                ? "ANTIGRAVITY_OAUTH_CLIENT_ID and ANTIGRAVITY_OAUTH_CLIENT_SECRET"
                : "GEMINI_CLI_OAUTH_CLIENT_ID and GEMINI_CLI_OAUTH_CLIENT_SECRET") +
              ". See the README section 'OAuth on a Remote Server'."
          );
        } else {
          setError(err.message);
        }
        setStep("error");
      }
    },
    [authData, provider, onSuccess, reauthConnection]
  );

  // Save a raw API token directly (windsurf / devin-cli import-token path)
  const handleSaveToken = useCallback(async () => {
    const token = pasteToken.trim();
    if (!token || !provider) return;
    setSavingToken(true);
    setError(null);
    try {
      // POST to /exchange with a synthetic "import_token" payload.
      // The windsurf provider's mapTokens() handles a bare accessToken/apiKey field.
      const res = await fetch(`/api/oauth/${provider}/import-token`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          token,
          connectionId: reauthConnection?.id,
        }),
      });
      const data = await res.json();
      if (!res.ok) {
        const errMsg =
          typeof data.error === "object" && data.error !== null
            ? ((data.error as Record<string, unknown>).message as string) ||
              JSON.stringify(data.error)
            : data.error || "Save failed";
        throw new Error(errMsg);
      }
      setStep("success");
      onSuccess?.();
    } catch (err) {
      // Show error inline inside the paste-token form (don't flip to error step)
      setError(err.message);
    } finally {
      setSavingToken(false);
    }
  }, [pasteToken, provider, onSuccess, reauthConnection]);

  // Poll for device code token
  const startPolling = useCallback(
    async (deviceCode, codeVerifier, interval, extraData) => {
      setPolling(true);
      const maxAttempts = 60;

      for (let i = 0; i < maxAttempts; i++) {
        await new Promise((r) => setTimeout(r, interval * 1000));

        try {
          const res = await fetch(`/api/oauth/${provider}/poll`, {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({
              deviceCode,
              connectionId: reauthConnection?.id,
              codeVerifier,
              extraData,
            }),
          });

          const data = await res.json();

          if (data.success) {
            setStep("success");
            setPolling(false);
            onSuccess?.();
            return;
          }

          if (data.error === "expired_token" || data.error === "access_denied") {
            throw new Error(data.errorDescription || data.error);
          }

          if (data.error === "slow_down") {
            interval = Math.min(interval + 5, 30);
          }
        } catch (err) {
          setError(err.message);
          setStep("error");
          setPolling(false);
          return;
        }
      }

      setError("Authorization timeout");
      setStep("error");
      setPolling(false);
    },
    [provider, onSuccess, reauthConnection]
  );

  // Start OAuth flow
  const startOAuthFlow = useCallback(async () => {
    if (!provider) return;
    try {
      setError(null);

      // Device code flow (GitHub, Qwen, Kiro, Kimi Coding, KiloCode)
      if (
        provider === "github" ||
        provider === "qwen" ||
        provider === "kiro" ||
        provider === "amazon-q" ||
        provider === "kimi-coding" ||
        provider === "kilocode"
      ) {
        setIsDeviceCode(true);
        setStep("waiting");

        const deviceCodeUrl = new URL(`/api/oauth/${provider}/device-code`, window.location.origin);
        if (
          (provider === "kiro" || provider === "amazon-q") &&
          idcConfig &&
          typeof idcConfig === "object"
        ) {
          const idc = idcConfig as { startUrl?: string; region?: string };
          if (typeof idc.startUrl === "string" && idc.startUrl.trim()) {
            deviceCodeUrl.searchParams.set("startUrl", idc.startUrl.trim());
          }
          if (typeof idc.region === "string" && idc.region.trim()) {
            deviceCodeUrl.searchParams.set("region", idc.region.trim());
          }
        }

        const res = await fetch(deviceCodeUrl.toString());
        const data = await res.json();
        if (!res.ok) {
          const errMsg =
            typeof data.error === "object" && data.error !== null
              ? ((data.error as Record<string, unknown>).message as string) ||
                JSON.stringify(data.error)
              : data.error || "Request failed";
          throw new Error(errMsg);
        }

        setDeviceData(data);

        // Open verification URL
        const verifyUrl = data.verification_uri_complete || data.verification_uri;
        if (verifyUrl) window.open(verifyUrl, "oauth_verify");

        // Start polling - pass extraData for Kiro (contains _clientId, _clientSecret)
        const extraData =
          provider === "kiro" || provider === "amazon-q"
            ? {
                _clientId: data._clientId,
                _clientSecret: data._clientSecret,
                _region: data._region,
              }
            : null;
        startPolling(data.device_code, data.codeVerifier, data.interval || 5, extraData);
        return;
      }

      let forceManual = false;

      // Claude Code and Cline OAuth flows can finish on provider-hosted pages that
      // show an auth code instead of redirecting back to OmniRoute.
      // Start directly in manual mode so users always have an input to paste code/url.
      if (provider === "claude" || provider === "cline") {
        forceManual = true;
      }

      // PKCE callback server providers (Codex, Windsurf, Devin CLI):
      // On localhost, spin up a local callback server and poll for the result.
      // Codex uses a fixed port 1455; Windsurf/Devin CLI use a random OS-assigned port.
      // On remote the server is unreachable — fall through to standard manual flow.
      if (PKCE_CALLBACK_SERVER_PROVIDERS.has(provider)) {
        if (isTrueLocalhost) {
          try {
            const serverRes = await fetch(`/api/oauth/${provider}/start-callback-server`);
            const serverData = await serverRes.json();
            if (!serverRes.ok) throw new Error(serverData.error);

            setAuthData({ ...serverData, redirectUri: serverData.redirectUri });
            setStep("waiting");
            popupRef.current = window.open(serverData.authUrl, "oauth_auth");

            // If browser blocked the popup, switch to manual input step immediately
            if (!popupRef.current) {
              setStep("input");
            }

            setPolling(true);
            const maxAttempts = 150;
            for (let i = 0; i < maxAttempts; i++) {
              await new Promise((r) => setTimeout(r, 2000));

              const pollRes = await fetch(`/api/oauth/${provider}/poll-callback`, {
                method: "POST",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify({ connectionId: reauthConnection?.id }),
              });
              const pollData = await pollRes.json();

              if (pollData.success) {
                setStep("success");
                setPolling(false);
                onSuccess?.();
                return;
              }

              if (pollData.error && !pollData.pending) {
                throw new Error(pollData.errorDescription || pollData.error);
              }
            }

            setPolling(false);
            throw new Error("Authorization timeout");
          } catch (pkceErr) {
            console.warn(
              `${provider} callback server failed, falling back to manual flow`,
              pkceErr
            );
            setPolling(false);
            forceManual = true;
          }
        }
        // Remote: fall through to standard auth code flow below
      }

      // Authorization code flow
      // Redirect URI strategy:
      // - Codex/OpenAI: always port 1455 (registered in OAuth app)
      // - Windsurf/Devin CLI (remote fallback): use localhost with OmniRoute port + /auth/callback
      //   (on true localhost the callback server handles it; this is only reached on remote)
      // - Google OAuth providers (antigravity, gemini-cli): default to loopback so the
      //   bundled native/desktop credentials keep working. Prefer 127.0.0.1 over
      //   localhost for the Google native-app handoff; Google documents that localhost
      //   can run into local firewall/name-resolution edge cases. The authorize route
      //   upgrades this to the public callback when custom Google web credentials plus
      //   NEXT_PUBLIC_BASE_URL or OMNIROUTE_PUBLIC_BASE_URL are configured.
      // - Other providers on remote: use actual origin (supports PUBLIC_URL env var)
      // - Localhost: use localhost:port
      let redirectUri: string;
      if (provider === "codex" || provider === "openai") {
        redirectUri = "http://localhost:1455/auth/callback";
      } else if (provider === "windsurf" || provider === "devin-cli") {
        // Remote fallback: use OmniRoute's port with the /auth/callback path Windsurf expects.
        // On true localhost this code is never reached (callback server handles the flow above).
        const port = window.location.port || "20128";
        redirectUri = `http://localhost:${port}/auth/callback`;
      } else if (GOOGLE_OAUTH_PROVIDERS.has(provider)) {
        // Google OAuth built-in credentials only accept loopback redirect URIs.
        // Even in remote deployments we use loopback — user copies the callback URL manually.
        const port = window.location.port || "20128";
        redirectUri = `http://127.0.0.1:${port}/callback`;
      } else if (!isLocalhost) {
        // Behind reverse proxy: use actual origin (e.g., https://omniroute.example.com/callback)
        // Supports PUBLIC_URL env var override, or falls back to window.location.origin.
        const publicUrl = process.env.NEXT_PUBLIC_BASE_URL;
        const origin =
          publicUrl && publicUrl !== "http://localhost:20128"
            ? publicUrl.replace(/\/$/, "")
            : window.location.origin;
        redirectUri = `${origin}/callback`;
      } else {
        const port = window.location.port || (window.location.protocol === "https:" ? "443" : "80");
        redirectUri = `http://localhost:${port}/callback`;
      }

      const res = await fetch(
        `/api/oauth/${provider}/authorize?redirect_uri=${encodeURIComponent(redirectUri)}`
      );
      const data = await res.json();
      if (!res.ok) {
        const errMsg =
          typeof data.error === "object" && data.error !== null
            ? ((data.error as Record<string, unknown>).message as string) ||
              JSON.stringify(data.error)
            : data.error || "Authorization failed";
        throw new Error(errMsg);
      }

      if (!data.authUrl) {
        throw new Error(
          data.error ||
            "Browser OAuth is unavailable for this provider in the current environment. Use the supported auth method instead."
        );
      }

      setAuthData({ ...data, redirectUri: data.redirectUri || redirectUri });

      // For non-true-localhost (LAN IPs, remote) or manual fallback: use manual input mode (user pastes callback URL)
      if (!isTrueLocalhost || forceManual) {
        setStep("input");
        window.open(data.authUrl, "oauth_auth");
      } else {
        // Localhost: Open popup and wait for message
        setStep("waiting");
        popupRef.current = window.open(data.authUrl, "oauth_popup", "width=600,height=700");

        // Check if popup was blocked
        if (!popupRef.current) {
          setStep("input");
        }
      }
    } catch (err) {
      setError(err.message);
      setStep("error");
    }
  }, [
    provider,
    isLocalhost,
    isTrueLocalhost,
    startPolling,
    onSuccess,
    reauthConnection,
    idcConfig,
  ]);

  // Reset guard when modal closes
  useEffect(() => {
    if (!isOpen) {
      flowStartedRef.current = false;
    }
  }, [isOpen]);

  // Reset state and start OAuth when modal opens
  useEffect(() => {
    if (isOpen && provider) {
      if (flowStartedRef.current) return; // Already started, prevent duplicate
      flowStartedRef.current = true;
      setAuthData(null);
      setCallbackUrl("");
      setError(null);
      setIsDeviceCode(false);
      setDeviceData(null);
      setPolling(false);
      // Auto start OAuth
      startOAuthFlow();
    }
  }, [isOpen, provider, startOAuthFlow]);

  // Listen for OAuth callback via multiple methods
  useEffect(() => {
    if (!authData) return;
    callbackProcessedRef.current = false; // Reset when authData changes

    // Handler for callback data - only process once
    const handleCallback = async (data) => {
      if (callbackProcessedRef.current) return; // Already processed

      const { code, state, error: callbackError, errorDescription } = data;

      if (authData?.state && state && state !== authData.state) {
        callbackProcessedRef.current = true;
        setError("OAuth state mismatch. Restart the connection and try again.");
        setStep("error");
        return;
      }

      if (callbackError) {
        callbackProcessedRef.current = true;
        setError(errorDescription || callbackError);
        setStep("error");
        return;
      }

      if (code) {
        callbackProcessedRef.current = true;
        await exchangeTokens(code, state);
      }
    };

    // Method 1: postMessage from popup
    const handleMessage = (event) => {
      // Accept same-origin OR localhost with same port (remote access scenario:
      // dashboard at 192.168.x:port, callback redirects to localhost:port)
      const currentPort = window.location.port;
      let isLoopbackOrigin = false;
      let isLocalhostSamePort = false;
      try {
        const eventUrl = new URL(event.origin);
        isLoopbackOrigin = /^(localhost|127\.0\.0\.1|\[::1\]|::1)$/i.test(eventUrl.hostname);
        isLocalhostSamePort = isLoopbackOrigin && eventUrl.port === currentPort;
      } catch {
        // Ignore malformed origins.
      }

      const payload = event.data?.data;
      const hasMatchingState = !!authData?.state && payload?.state === authData.state;
      const isGoogleLoopbackRelay =
        GOOGLE_OAUTH_PROVIDERS.has(provider) && isLoopbackOrigin && hasMatchingState;

      if (event.origin !== window.location.origin && !isLocalhostSamePort && !isGoogleLoopbackRelay) {
        return;
      }
      if (event.data?.type === "oauth_callback") {
        handleCallback(payload);
      }
    };
    window.addEventListener("message", handleMessage);

    // Method 2: BroadcastChannel
    let channel;
    try {
      channel = new BroadcastChannel("oauth_callback");
      channel.onmessage = (event) => handleCallback(event.data);
    } catch (e) {
      console.log("BroadcastChannel not supported");
    }

    // Method 3: localStorage event
    const handleStorage = (event) => {
      if (event.key === "oauth_callback" && event.newValue) {
        try {
          const data = JSON.parse(event.newValue);
          handleCallback(data);
          localStorage.removeItem("oauth_callback");
        } catch (e) {
          console.log("Failed to parse localStorage data");
        }
      }
    };
    window.addEventListener("storage", handleStorage);

    // Also check localStorage on mount (in case callback already happened)
    try {
      const stored = localStorage.getItem("oauth_callback");
      if (stored) {
        const data = JSON.parse(stored);
        // Only use if recent (within 30 seconds)
        if (data.timestamp && Date.now() - data.timestamp < 30000) {
          handleCallback(data);
          localStorage.removeItem("oauth_callback");
        }
      }
    } catch {
      // localStorage may be unavailable or data may be malformed - ignore silently
    }

    return () => {
      window.removeEventListener("message", handleMessage);
      window.removeEventListener("storage", handleStorage);
      if (channel) channel.close();
    };
  }, [authData, exchangeTokens, provider]);

  // Fix #344: Detect when OAuth popup is closed without completing authorization
  // Some providers (like Qoder) redirect to their own chat UI instead of sending a callback,
  // leaving the modal stuck at "Waiting for Authorization" forever.
  useEffect(() => {
    if (step !== "waiting" || isDeviceCode || !popupRef.current) return;

    let closed = false;
    const popupClosedInterval = setInterval(() => {
      if (callbackProcessedRef.current) {
        clearInterval(popupClosedInterval);
        return;
      }
      try {
        if (popupRef.current?.closed) {
          closed = true;
          clearInterval(popupClosedInterval);
          // Popup was closed without completing OAuth — switch to manual input mode
          // so user can paste the callback URL from their browser address bar
          if (step === "waiting") {
            setStep("input");
          }
        }
      } catch {
        // Cross-origin access may throw — ignore
      }
    }, 1000);

    // Safety timeout: 5 minutes
    const safetyTimeout = setTimeout(
      () => {
        if (!callbackProcessedRef.current && step === "waiting") {
          clearInterval(popupClosedInterval);
          setStep("input");
        }
      },
      5 * 60 * 1000
    );

    return () => {
      clearInterval(popupClosedInterval);
      clearTimeout(safetyTimeout);
    };
  }, [step, isDeviceCode]);

  // Handle manual URL input
  const handleManualSubmit = async () => {
    try {
      setError(null);

      if (!authData) {
        throw new Error(
          "OAuth session not initialized. Restart the connection flow and try again."
        );
      }

      const input = callbackUrl.trim();
      let code = null;
      let state = authData?.state || null;
      let errorParam = null;
      let errorDescription = null;

      try {
        const url = new URL(input);
        code = url.searchParams.get("code");
        state = url.searchParams.get("state") || url.hash.replace(/^#/, "") || state;
        errorParam = url.searchParams.get("error");
        errorDescription = url.searchParams.get("error_description");
      } catch {
        // Claude Code remote auth may provide a raw "Authentication Code" like code#state.
        const [rawCode, rawState] = input.split("#", 2);
        code = rawCode || null;
        state = rawState || state;
      }

      if (errorParam) {
        throw new Error(errorDescription || errorParam);
      }

      if (!code) {
        throw new Error(
          "No authorization code found. Paste the callback URL or the Authentication Code."
        );
      }

      await exchangeTokens(code, state);
    } catch (err) {
      setError(err.message);
      setStep("error");
    }
  };

  if (!provider || !providerInfo) return null;

  return (
    <Modal
      isOpen={isOpen}
      title={t("title", { providerName: providerInfo.name })}
      onClose={onClose}
      size="lg"
    >
      <div className="flex flex-col gap-4">
        {/* Paste-token tab toggle (Windsurf / Devin CLI only).
            Phase 1 hotfix: when importTokenOnly is true, hide the entire toggle —
            there is no "Browser Login" tab to switch to until Phase 2 ships. */}
        {supportsTokenPaste && !importTokenOnly && step !== "success" && (
          <div className="flex gap-2 border-b border-border pb-3">
            <button
              className={`text-sm px-3 py-1 rounded-t ${!showPasteToken ? "font-semibold border-b-2 border-primary text-primary" : "text-text-muted"}`}
              onClick={() => setShowPasteToken(false)}
            >
              Browser Login
            </button>
            <button
              className={`text-sm px-3 py-1 rounded-t ${showPasteToken ? "font-semibold border-b-2 border-primary text-primary" : "text-text-muted"}`}
              onClick={() => setShowPasteToken(true)}
            >
              Paste API Key
            </button>
          </div>
        )}

        {/* Paste-token form (Windsurf / Devin CLI) */}
        {supportsTokenPaste && showPasteToken && step !== "success" && (
          <div className="flex flex-col gap-3">
            <p className="text-sm text-text-muted">
              {provider === "windsurf"
                ? "Visit windsurf.com/show-auth-token, copy your Windsurf API key, and paste it below."
                : "Provide your WINDSURF_API_KEY (obtained via `devin auth login` or windsurf.com/show-auth-token)."}
            </p>
            <Input
              value={pasteToken}
              onChange={(e) => setPasteToken(e.target.value)}
              placeholder="ws-..."
              type="password"
              label="API Key / Token"
            />
            {error && <p className="text-sm text-red-500">{error}</p>}
            <div className="flex gap-2">
              <Button
                onClick={handleSaveToken}
                fullWidth
                disabled={!pasteToken.trim() || savingToken}
              >
                {savingToken ? "Saving…" : "Save Connection"}
              </Button>
              <Button onClick={onClose} variant="ghost" fullWidth>
                Cancel
              </Button>
            </div>
          </div>
        )}

        {/* OAuth flow steps — hidden when paste-token mode is active */}
        {(!supportsTokenPaste || !showPasteToken) && (
          <>
            {/* Waiting Step (Localhost - popup mode) */}
            {step === "waiting" && !isDeviceCode && (
              <div className="text-center py-6">
                <div className="size-16 mx-auto mb-4 rounded-full bg-primary/10 flex items-center justify-center">
                  <span className="material-symbols-outlined text-3xl text-primary animate-spin">
                    progress_activity
                  </span>
                </div>
                <h3 className="text-lg font-semibold mb-2">{t("waiting")}</h3>
                <p className="text-sm text-text-muted mb-2">{t("completeAuthInPopup")}</p>
                <p className="text-xs text-text-muted mb-4 opacity-70">{t("popupClosedHint")}</p>
                <Button variant="ghost" onClick={() => setStep("input")}>
                  {t("popupBlocked")}
                </Button>
              </div>
            )}

            {/* Device Code Flow - Waiting */}
            {step === "waiting" && isDeviceCode && deviceData && (
              <>
                <div className="text-center py-4">
                  <p className="text-sm text-text-muted mb-4">{t("deviceCodeVisitUrl")}</p>
                  <div className="bg-sidebar p-4 rounded-lg mb-4">
                    <p className="text-xs text-text-muted mb-1">{t("deviceCodeVerificationUrl")}</p>
                    <div className="flex items-center gap-2">
                      <code className="flex-1 text-sm break-all">{deviceVerificationUrl}</code>
                      <Button
                        size="sm"
                        variant="ghost"
                        icon={copied === "verify_url" ? "check" : "content_copy"}
                        onClick={() => copy(deviceVerificationUrl, "verify_url")}
                      />
                    </div>
                  </div>
                  <div className="bg-primary/10 p-4 rounded-lg">
                    <p className="text-xs text-text-muted mb-1">{t("deviceCodeYourCode")}</p>
                    <div className="flex items-center justify-center gap-2">
                      <p className="text-2xl font-mono font-bold text-primary">
                        {deviceData.user_code}
                      </p>
                      <Button
                        size="sm"
                        variant="ghost"
                        icon={copied === "user_code" ? "check" : "content_copy"}
                        onClick={() => copy(deviceData.user_code, "user_code")}
                      />
                    </div>
                  </div>
                </div>
                {polling && (
                  <div className="flex items-center justify-center gap-2 text-sm text-text-muted">
                    <span className="material-symbols-outlined animate-spin">
                      progress_activity
                    </span>
                    {t("deviceCodeWaiting")}
                  </div>
                )}
              </>
            )}

            {/* Manual Input Step */}
            {step === "input" && !isDeviceCode && (
              <>
                <div className="space-y-4">
                  {/* Remote/LAN server info for Google OAuth providers */}
                  {!isTrueLocalhost && GOOGLE_OAUTH_PROVIDERS.has(provider) && (
                    <div className="rounded-lg border border-amber-500/30 bg-amber-500/10 p-3 text-xs text-amber-200">
                      <span className="material-symbols-outlined text-sm align-middle mr-1">
                        warning
                      </span>
                      <strong>
                        {t.rich("googleOAuthWarning", {
                          code: (c) => <code className="font-mono">{c}</code>,
                          a: (c) => (
                            <a
                              href="https://github.com/diegosouzapw/OmniRoute#oauth-on-a-remote-server"
                              target="_blank"
                              rel="noreferrer"
                              className="underline"
                            >
                              {c}
                            </a>
                          ),
                        })}
                      </strong>
                    </div>
                  )}
                  {/* Generic remote info for other providers */}
                  {!isTrueLocalhost && !GOOGLE_OAUTH_PROVIDERS.has(provider) && (
                    <div className="rounded-lg border border-blue-500/30 bg-blue-500/10 p-3 text-xs text-blue-200">
                      <span className="material-symbols-outlined text-sm align-middle mr-1">
                        info
                      </span>
                      {t("remoteAccessInfo")}
                    </div>
                  )}
                  <div>
                    <p className="text-sm font-medium mb-2">{t("step1OpenUrl")}</p>
                    <div className="flex gap-2">
                      <Input
                        value={authData?.authUrl || ""}
                        readOnly
                        className="flex-1 font-mono text-xs"
                      />
                      <Button
                        variant="secondary"
                        icon={copied === "auth_url" ? "check" : "content_copy"}
                        onClick={() => copy(authData?.authUrl, "auth_url")}
                      >
                        {t("copy")}
                      </Button>
                    </div>
                  </div>

                  <div>
                    <p className="text-sm font-medium mb-2">{t("step2PasteCallback")}</p>
                    <p className="text-xs text-text-muted mb-2">
                      {t.rich("step2Hint", {
                        code: (c) => <code className="font-mono">{c}</code>,
                      })}
                    </p>
                    <Input
                      value={callbackUrl}
                      onChange={(e) => setCallbackUrl(e.target.value)}
                      placeholder={
                        provider === "claude" || provider === "cline"
                          ? "code#state or /callback?code=..."
                          : placeholderUrl
                      }
                      className="font-mono text-xs"
                    />
                  </div>
                </div>

                <div className="flex gap-2">
                  <Button
                    onClick={handleManualSubmit}
                    fullWidth
                    disabled={!callbackUrl || !authData}
                  >
                    {t("connect")}
                  </Button>
                  <Button onClick={onClose} variant="ghost" fullWidth>
                    {t("cancel")}
                  </Button>
                </div>
              </>
            )}
          </>
        )}

        {/* Success Step — shown for both OAuth and paste-token flows */}
        {step === "success" && (
          <div className="text-center py-6">
            <div className="size-16 mx-auto mb-4 rounded-full bg-green-100 dark:bg-green-900/30 flex items-center justify-center">
              <span className="material-symbols-outlined text-3xl text-green-600">
                check_circle
              </span>
            </div>
            <h3 className="text-lg font-semibold mb-2">{t("success")}</h3>
            <p className="text-sm text-text-muted mb-4">
              {t("successMessage", { providerName: providerInfo.name })}
            </p>
            <Button onClick={onClose} fullWidth>
              {t("done")}
            </Button>
          </div>
        )}

        {/* Error Step — OAuth errors only; paste-token errors shown inline */}
        {step === "error" && !showPasteToken && (
          <div className="text-center py-6">
            <div className="size-16 mx-auto mb-4 rounded-full bg-red-100 dark:bg-red-900/30 flex items-center justify-center">
              <span className="material-symbols-outlined text-3xl text-red-600">error</span>
            </div>
            <h3 className="text-lg font-semibold mb-2">{t("error")}</h3>
            <p className="text-sm text-red-600 mb-4">{error}</p>
            <div className="flex gap-2">
              <Button onClick={startOAuthFlow} variant="secondary" fullWidth>
                {t("tryAgain")}
              </Button>
              <Button onClick={onClose} variant="ghost" fullWidth>
                {t("cancel")}
              </Button>
            </div>
          </div>
        )}
      </div>
    </Modal>
  );
}