import { useEffect, useRef, useState } from 'react';
import { io, Socket } from 'socket.io-client';

interface GitStatusData {
  status: string;
  details: string;
}

interface GitBranchData {
  current_branch: string;
}

function isDataEnvelope(payload: unknown): payload is { data: unknown } {
  return (
    typeof payload === 'object' &&
    payload !== null &&
    !Array.isArray(payload) &&
    'data' in payload
  );
}

function isGitStatusData(data: unknown): data is GitStatusData {
  const d = data as GitStatusData;
  return (
    !!d &&
    typeof d === 'object' &&
    !Array.isArray(d) &&
    typeof d.status === 'string' &&
    typeof d.details === 'string'
  );
}

function isGitBranchData(data: unknown): data is GitBranchData {
    const d = data as GitBranchData;
    return (
      !!d &&
      typeof d === 'object' &&
      !Array.isArray(d) &&
      typeof d.current_branch === 'string'
    );
}

interface User {
  email: string;
  name?: string;
}

export default function App() {
  const [user, setUser] = useState<User | null>(null);
  const [statusData, setStatusData] = useState<GitStatusData | null>(null);
  const [branchData, setBranchData] = useState<GitBranchData | null>(null);
  const [statusLoading, setStatusLoading] = useState<boolean>(false);
  const [branchLoading, setBranchLoading] = useState<boolean>(false);
  const [statusError, setStatusError] = useState<string | null>(null);
  const [branchError, setBranchError] = useState<string | null>(null);

  const socketRef = useRef<Socket | null>(null);

  useEffect(() => {
    fetch('/auth/me', { credentials: 'include' })
      .then((r) => (r.ok ? r.json() : null))
      .then(setUser);
  }, []);

  useEffect(() => {
    if (!user) return;

    const socket = io('/');
    socketRef.current = socket;

    const onStatusResult = (payload: unknown) => {
      setStatusLoading(false);
      if (isDataEnvelope(payload) && isGitStatusData(payload.data)) {
        setStatusData({ status: payload.data.status, details: payload.data.details });
      } else {
        setStatusData(null);
        setStatusError('Ugyldig svar for Git-status.');
      }
    };

    const onStatusError = () => {
      setStatusData(null);
      setStatusLoading(false);
      setStatusError('Kunne ikke hente Git-status.');
    };

    const onBranchResult = (payload: unknown) => {
      setBranchLoading(false);
      if (isDataEnvelope(payload) && isGitBranchData(payload.data)) {
        setBranchData({ current_branch: payload.data.current_branch });
      } else {
        setBranchData(null);
        setBranchError('Ugyldig svar for aktiv branch.');
      }
    };

    const onBranchError = () => {
      setBranchData(null);
      setBranchLoading(false);
      setBranchError('Kunne ikke hente aktiv branch.');
    };

    socket.on('git:status:result', onStatusResult);
    socket.on('git:status:error', onStatusError);
    socket.on('git:branch:result', onBranchResult);
    socket.on('git:branch:error', onBranchError);

    return () => {
      socket.off('git:status:result', onStatusResult);
      socket.off('git:status:error', onStatusError);
      socket.off('git:branch:result', onBranchResult);
      socket.off('git:branch:error', onBranchError);
      socket.close();
      socketRef.current = null;
    };
  }, [user]);

  const handleGetStatus = () => {
    if (!socketRef.current) {
      setStatusData(null);
      setStatusLoading(false);
      setStatusError('Kunne ikke hente Git-status.');
      return;
    }
    setStatusError(null);
    setStatusData(null);
    setStatusLoading(true);
    socketRef.current.emit('git:getStatus');
  };

  const handleGetBranch = () => {
    if (!socketRef.current) {
      setBranchData(null);
      setBranchLoading(false);
      setBranchError('Kunne ikke hente aktiv branch.');
      return;
    }
    setBranchError(null);
    setBranchData(null);
    setBranchLoading(true);
    socketRef.current.emit('git:getBranch');
  };

  if (!user) {
    return (
      <main className="login">
        <h1>OPAX</h1>
        <a href="/auth/google">Continue with Google</a>
      </main>
    );
  }

  return (
    <main>
      <header>
        <b>OPAX / Web TUI</b>
        <span>{user.email}</span>
      </header>
      <section>
        <div>
          <h2>Git Status</h2>
          <button onClick={handleGetStatus} disabled={statusLoading}>
            {statusLoading ? 'Laster...' : 'Hent Git-status'}
          </button>
          {statusError && <p className="error">{statusError}</p>}
          {statusData && (
            <pre>
              <strong>Status:</strong> {statusData.status}\n\n
              <strong>Detaljer:</strong>\n{statusData.details || '(ingen endringer)'}
            </pre>
          )}
        </div>
        <div>
          <h2>Aktiv Branch</h2>
          <button onClick={handleGetBranch} disabled={branchLoading}>
            {branchLoading ? 'Laster...' : 'Hent aktiv branch'}
          </button>
          {branchError && <p className="error">{branchError}</p>}
          {branchData && (
            <p>
              <strong>Nåværende branch:</strong> {branchData.current_branch}
            </p>
          )}
        </div>
      </section>
    </main>
  );
}