import { useState, useEffect } from 'react';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import api from '../api/client';

interface SsoStatus {
  microsoft: boolean;
}

interface SsoConfigResponse {
  configured: boolean;
  config: {
    tenantId: string;
    clientId: string;
    redirectUri: string;
    clientSecretMasked: string;
  } | null;
}

const cardStyle: React.CSSProperties = {
  background: 'var(--color-bg-card)',
  borderRadius: 'var(--radius-md)',
  boxShadow: 'var(--shadow-sm)',
  border: '1px solid var(--color-border)',
  padding: '1.5rem',
  marginBottom: '1.5rem',
};

const inlineCodeStyle: React.CSSProperties = {
  background: 'var(--color-bg)',
  padding: '0.125rem 0.375rem',
  borderRadius: 'var(--radius-sm)',
  fontSize: '0.8125rem',
  fontFamily: "'JetBrains Mono', 'Fira Code', 'Consolas', monospace",
  color: '#1e40af',
};

const stepStyle: React.CSSProperties = {
  display: 'flex',
  gap: '1rem',
  marginBottom: '1.5rem',
};

const stepNumberStyle: React.CSSProperties = {
  display: 'flex',
  alignItems: 'center',
  justifyContent: 'center',
  width: 32,
  height: 32,
  borderRadius: '50%',
  background: 'var(--color-primary)',
  color: 'white',
  fontSize: '0.875rem',
  fontWeight: 700,
  flexShrink: 0,
};

const stepContentStyle: React.CSSProperties = {
  flex: 1,
  paddingTop: '0.25rem',
};

const h3Style: React.CSSProperties = {
  fontSize: '1rem',
  fontWeight: 600,
  color: 'var(--color-text)',
  marginBottom: '0.5rem',
};

const pStyle: React.CSSProperties = {
  fontSize: '0.875rem',
  color: 'var(--color-text-secondary)',
  lineHeight: 1.6,
  marginBottom: '0.5rem',
};

const tableStyle: React.CSSProperties = {
  width: '100%',
  borderCollapse: 'collapse',
  marginTop: '0.75rem',
};

const thStyle: React.CSSProperties = {
  padding: '0.625rem 0.75rem',
  textAlign: 'left',
  fontSize: '0.75rem',
  textTransform: 'uppercase',
  color: 'var(--color-text-muted)',
  borderBottom: '1px solid var(--color-border)',
  background: 'var(--color-bg)',
};

const tdStyle: React.CSSProperties = {
  padding: '0.625rem 0.75rem',
  fontSize: '0.8125rem',
  borderBottom: '1px solid var(--color-border)',
  verticalAlign: 'top',
};

const inputStyle: React.CSSProperties = {
  width: '100%',
  padding: '0.625rem 0.75rem',
  fontSize: '0.875rem',
  border: '1px solid var(--color-border)',
  borderRadius: 'var(--radius-sm)',
  background: 'var(--color-bg-card)',
  color: 'var(--color-text)',
  fontFamily: "'JetBrains Mono', 'Fira Code', 'Consolas', monospace",
  outline: 'none',
  boxSizing: 'border-box' as const,
};

const labelStyle: React.CSSProperties = {
  display: 'block',
  fontSize: '0.8125rem',
  fontWeight: 600,
  color: 'var(--color-text)',
  marginBottom: '0.375rem',
};

const hintStyle: React.CSSProperties = {
  fontSize: '0.75rem',
  color: 'var(--color-text-muted)',
  marginTop: '0.25rem',
};

export function AdminSsoPage() {
  const queryClient = useQueryClient();

  const { data: ssoStatus, isLoading: statusLoading } = useQuery<SsoStatus>({
    queryKey: ['sso', 'status'],
    queryFn: async () => {
      const res = await api.get<SsoStatus>('/auth/sso/status');
      return res.data;
    },
  });

  const { data: ssoConfig, isLoading: configLoading } =
    useQuery<SsoConfigResponse>({
      queryKey: ['sso', 'config'],
      queryFn: async () => {
        const res = await api.get<SsoConfigResponse>('/auth/sso/config');
        return res.data;
      },
    });

  // Formular-State
  const [tenantId, setTenantId] = useState('');
  const [clientId, setClientId] = useState('');
  const [clientSecret, setClientSecret] = useState('');
  const [redirectUri, setRedirectUri] = useState('');
  const [saveSuccess, setSaveSuccess] = useState(false);

  // Default Redirect-URI
  const defaultRedirectUri = `${window.location.origin}/api/v1/auth/sso/microsoft/callback`;

  // Formular mit bestehenden Werten befuellen
  useEffect(() => {
    if (ssoConfig?.config) {
      setTenantId(ssoConfig.config.tenantId);
      setClientId(ssoConfig.config.clientId);
      setRedirectUri(ssoConfig.config.redirectUri);
      // Secret bleibt leer — wird nur bei Aenderung gesendet
    } else {
      // Default Redirect-URI setzen wenn noch keine Config da
      setRedirectUri(defaultRedirectUri);
    }
  }, [ssoConfig, defaultRedirectUri]);

  const saveMutation = useMutation({
    mutationFn: async (data: {
      tenantId: string;
      clientId: string;
      clientSecret?: string;
      redirectUri: string;
    }) => {
      const res = await api.post('/auth/sso/config', data);
      return res.data;
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['sso', 'status'] });
      queryClient.invalidateQueries({ queryKey: ['sso', 'config'] });
      setClientSecret(''); // Secret-Feld leeren
      setSaveSuccess(true);
      setTimeout(() => setSaveSuccess(false), 4000);
    },
  });

  const handleSave = () => {
    const data: {
      tenantId: string;
      clientId: string;
      clientSecret?: string;
      redirectUri: string;
    } = {
      tenantId,
      clientId,
      redirectUri,
    };

    // Secret nur mitsenden wenn es geaendert wurde
    if (clientSecret) {
      data.clientSecret = clientSecret;
    }

    saveMutation.mutate(data);
  };

  const isLoading = statusLoading || configLoading;
  const hasExistingConfig = !!ssoConfig?.config;
  const canSave =
    tenantId.trim() &&
    clientId.trim() &&
    redirectUri.trim() &&
    (clientSecret.trim() || hasExistingConfig); // Secret nur noetig bei Erstconfig

  return (
    <div>
      <div
        style={{
          display: 'flex',
          justifyContent: 'space-between',
          alignItems: 'center',
          marginBottom: '1.5rem',
        }}
      >
        <h1 style={{ fontSize: '1.5rem', fontWeight: 600 }}>
          SSO-Konfiguration
        </h1>
      </div>

      {/* Status-Anzeige */}
      <div style={cardStyle}>
        <div
          style={{
            display: 'flex',
            alignItems: 'center',
            gap: '0.75rem',
            marginBottom: '0.5rem',
          }}
        >
          <svg
            width="24"
            height="24"
            viewBox="0 0 21 21"
            xmlns="http://www.w3.org/2000/svg"
          >
            <rect x="1" y="1" width="9" height="9" fill="#f25022" />
            <rect x="11" y="1" width="9" height="9" fill="#7fba00" />
            <rect x="1" y="11" width="9" height="9" fill="#00a4ef" />
            <rect x="11" y="11" width="9" height="9" fill="#ffb900" />
          </svg>
          <h2 style={{ fontSize: '1.125rem', fontWeight: 600 }}>
            Microsoft Entra ID (Azure AD)
          </h2>
        </div>

        <div
          style={{
            display: 'flex',
            alignItems: 'center',
            gap: '0.5rem',
            padding: '0.75rem 1rem',
            borderRadius: 'var(--radius-sm)',
            background: ssoStatus?.microsoft ? '#f0fdf4' : '#fef2f2',
            border: `1px solid ${ssoStatus?.microsoft ? '#bbf7d0' : '#fecaca'}`,
            marginTop: '0.75rem',
          }}
        >
          <span
            style={{
              display: 'inline-block',
              width: 10,
              height: 10,
              borderRadius: '50%',
              background: ssoStatus?.microsoft
                ? 'var(--color-success)'
                : 'var(--color-error)',
            }}
          />
          <span
            style={{
              fontSize: '0.875rem',
              fontWeight: 500,
              color: ssoStatus?.microsoft ? '#166534' : '#991b1b',
            }}
          >
            {isLoading
              ? 'Status wird geladen...'
              : ssoStatus?.microsoft
                ? 'SSO ist aktiv — Benutzer können sich mit Microsoft anmelden'
                : 'SSO ist nicht konfiguriert — folge der Anleitung unten'}
          </span>
        </div>
      </div>

      {/* Einrichtungs-Anleitung */}
      <div style={cardStyle}>
        <h2
          style={{
            fontSize: '1.125rem',
            fontWeight: 600,
            marginBottom: '1.25rem',
          }}
        >
          Einrichtungsanleitung
        </h2>

        {/* Schritt 1 */}
        <div style={stepStyle}>
          <div style={stepNumberStyle}>1</div>
          <div style={stepContentStyle}>
            <h3 style={h3Style}>App Registration im Azure Portal anlegen</h3>
            <p style={pStyle}>
              Gehe zum{' '}
              <a
                href="https://portal.azure.com/#view/Microsoft_AAD_RegisteredApps/ApplicationsListBlade"
                target="_blank"
                rel="noopener noreferrer"
                style={{
                  color: 'var(--color-primary)',
                  textDecoration: 'underline',
                }}
              >
                Azure Portal &rarr; App registrations
              </a>{' '}
              und klicke auf <strong>New registration</strong>.
            </p>
            <table style={tableStyle}>
              <thead>
                <tr>
                  <th style={thStyle}>Feld</th>
                  <th style={thStyle}>Wert</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style={tdStyle}>
                    <strong>Name</strong>
                  </td>
                  <td style={tdStyle}>INSIGHT Platform</td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <strong>Supported account types</strong>
                  </td>
                  <td style={tdStyle}>
                    Accounts in this organizational directory only
                    <br />
                    <span
                      style={{
                        fontSize: '0.75rem',
                        color: 'var(--color-text-muted)',
                      }}
                    >
                      (Single tenant — nur euer Azure AD)
                    </span>
                  </td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <strong>Redirect URI</strong>
                  </td>
                  <td style={tdStyle}>
                    Platform: <strong>Web</strong>
                    <br />
                    URI:{' '}
                    <code style={inlineCodeStyle}>{defaultRedirectUri}</code>
                  </td>
                </tr>
              </tbody>
            </table>
          </div>
        </div>

        {/* Schritt 2 */}
        <div style={stepStyle}>
          <div style={stepNumberStyle}>2</div>
          <div style={stepContentStyle}>
            <h3 style={h3Style}>Client Secret erstellen</h3>
            <p style={pStyle}>
              In der App Registration &rarr;{' '}
              <strong>Certificates &amp; secrets</strong> &rarr;{' '}
              <strong>New client secret</strong>.
            </p>
            <table style={tableStyle}>
              <thead>
                <tr>
                  <th style={thStyle}>Feld</th>
                  <th style={thStyle}>Wert</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style={tdStyle}>
                    <strong>Description</strong>
                  </td>
                  <td style={tdStyle}>INSIGHT Platform SSO</td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <strong>Expires</strong>
                  </td>
                  <td style={tdStyle}>
                    24 months (empfohlen)
                    <br />
                    <span
                      style={{
                        fontSize: '0.75rem',
                        color: 'var(--color-text-muted)',
                      }}
                    >
                      Danach muss das Secret erneuert werden
                    </span>
                  </td>
                </tr>
              </tbody>
            </table>
            <div
              style={{
                marginTop: '0.75rem',
                padding: '0.625rem 0.75rem',
                background: '#fffbeb',
                border: '1px solid #fde68a',
                borderRadius: 'var(--radius-sm)',
                fontSize: '0.8125rem',
                color: '#92400e',
              }}
            >
              <strong>Wichtig:</strong> Den <strong>Value</strong> des Secrets
              sofort kopieren — er wird nur einmalig angezeigt!
            </div>
          </div>
        </div>

        {/* Schritt 3 */}
        <div style={stepStyle}>
          <div style={stepNumberStyle}>3</div>
          <div style={stepContentStyle}>
            <h3 style={h3Style}>API Permissions konfigurieren</h3>
            <p style={pStyle}>
              In der App Registration &rarr;{' '}
              <strong>API permissions</strong> &rarr;{' '}
              <strong>Add a permission</strong> &rarr;{' '}
              <strong>Microsoft Graph</strong> &rarr;{' '}
              <strong>Delegated permissions</strong>.
            </p>
            <p style={pStyle}>Folgende Berechtigungen hinzufügen:</p>
            <table style={tableStyle}>
              <thead>
                <tr>
                  <th style={thStyle}>Permission</th>
                  <th style={thStyle}>Typ</th>
                  <th style={thStyle}>Beschreibung</th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style={tdStyle}>
                    <code style={inlineCodeStyle}>openid</code>
                  </td>
                  <td style={tdStyle}>Delegated</td>
                  <td style={tdStyle}>Sign users in</td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <code style={inlineCodeStyle}>profile</code>
                  </td>
                  <td style={tdStyle}>Delegated</td>
                  <td style={tdStyle}>View users' basic profile</td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <code style={inlineCodeStyle}>email</code>
                  </td>
                  <td style={tdStyle}>Delegated</td>
                  <td style={tdStyle}>View users' email address</td>
                </tr>
                <tr>
                  <td style={tdStyle}>
                    <code style={inlineCodeStyle}>User.Read</code>
                  </td>
                  <td style={tdStyle}>Delegated</td>
                  <td style={tdStyle}>Sign in and read user profile</td>
                </tr>
              </tbody>
            </table>
            <p style={{ ...pStyle, marginTop: '0.5rem' }}>
              Dann <strong>Grant admin consent</strong> klicken, um die
              Berechtigungen für alle Benutzer freizugeben.
            </p>
          </div>
        </div>

        {/* Schritt 4 — Konfiguration eingeben und speichern */}
        <div style={stepStyle}>
          <div style={stepNumberStyle}>4</div>
          <div style={stepContentStyle}>
            <h3 style={h3Style}>
              Werte aus Azure Portal hier eintragen und speichern
            </h3>
            <p style={pStyle}>
              Kopiere die Werte aus der App Registration &rarr;{' '}
              <strong>Overview</strong> und trage sie in die Felder ein. Beim
              Speichern wird die SSO-Verbindung automatisch aktiviert.
            </p>

            <div
              style={{
                display: 'flex',
                flexDirection: 'column',
                gap: '1rem',
                marginTop: '1rem',
              }}
            >
              {/* Tenant ID */}
              <div>
                <label style={labelStyle}>
                  Directory (Tenant) ID{' '}
                  <span style={{ color: 'var(--color-error)' }}>*</span>
                </label>
                <input
                  type="text"
                  value={tenantId}
                  onChange={(e) => setTenantId(e.target.value)}
                  placeholder="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
                  style={inputStyle}
                />
                <div style={hintStyle}>
                  Azure Portal &rarr; App Registration &rarr; Overview &rarr;
                  Directory (tenant) ID
                </div>
              </div>

              {/* Client ID */}
              <div>
                <label style={labelStyle}>
                  Application (Client) ID{' '}
                  <span style={{ color: 'var(--color-error)' }}>*</span>
                </label>
                <input
                  type="text"
                  value={clientId}
                  onChange={(e) => setClientId(e.target.value)}
                  placeholder="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
                  style={inputStyle}
                />
                <div style={hintStyle}>
                  Azure Portal &rarr; App Registration &rarr; Overview &rarr;
                  Application (client) ID
                </div>
              </div>

              {/* Client Secret */}
              <div>
                <label style={labelStyle}>
                  Client Secret{' '}
                  {!hasExistingConfig && (
                    <span style={{ color: 'var(--color-error)' }}>*</span>
                  )}
                </label>
                <input
                  type="password"
                  value={clientSecret}
                  onChange={(e) => setClientSecret(e.target.value)}
                  placeholder={
                    hasExistingConfig
                      ? `Gespeichert (${ssoConfig?.config?.clientSecretMasked}) — leer lassen um beizubehalten`
                      : 'Client Secret Value eingeben'
                  }
                  style={inputStyle}
                />
                <div style={hintStyle}>
                  Azure Portal &rarr; App Registration &rarr; Certificates &amp;
                  secrets &rarr; Client secret Value
                  {hasExistingConfig && (
                    <span style={{ color: 'var(--color-text-secondary)' }}>
                      {' '}
                      — Leer lassen, um das bestehende Secret zu behalten
                    </span>
                  )}
                </div>
              </div>

              {/* Redirect URI */}
              <div>
                <label style={labelStyle}>
                  Redirect URI{' '}
                  <span style={{ color: 'var(--color-error)' }}>*</span>
                </label>
                <input
                  type="text"
                  value={redirectUri}
                  onChange={(e) => setRedirectUri(e.target.value)}
                  placeholder={defaultRedirectUri}
                  style={inputStyle}
                />
                <div style={hintStyle}>
                  Muss exakt mit der Redirect URI in der Azure App Registration
                  übereinstimmen
                </div>
              </div>

              {/* Speichern-Button + Status */}
              <div
                style={{
                  display: 'flex',
                  alignItems: 'center',
                  gap: '1rem',
                  marginTop: '0.5rem',
                }}
              >
                <button
                  onClick={handleSave}
                  disabled={!canSave || saveMutation.isPending}
                  style={{
                    padding: '0.625rem 1.5rem',
                    background: canSave ? 'var(--color-primary)' : '#94a3b8',
                    color: 'white',
                    border: 'none',
                    borderRadius: 'var(--radius-sm)',
                    fontSize: '0.875rem',
                    fontWeight: 600,
                    cursor: canSave ? 'pointer' : 'not-allowed',
                    opacity: saveMutation.isPending ? 0.7 : 1,
                  }}
                >
                  {saveMutation.isPending
                    ? 'Wird gespeichert...'
                    : 'Speichern und aktivieren'}
                </button>

                {saveSuccess && (
                  <span
                    style={{
                      fontSize: '0.875rem',
                      color: '#166534',
                      fontWeight: 500,
                    }}
                  >
                    SSO-Konfiguration gespeichert und aktiviert!
                  </span>
                )}

                {saveMutation.isError && (
                  <span
                    style={{
                      fontSize: '0.875rem',
                      color: 'var(--color-error)',
                      fontWeight: 500,
                    }}
                  >
                    Fehler:{' '}
                    {(saveMutation.error as Error)?.message ||
                      'Konfiguration konnte nicht gespeichert werden'}
                  </span>
                )}
              </div>
            </div>
          </div>
        </div>
      </div>

      {/* Funktionsweise */}
      <div style={cardStyle}>
        <h2
          style={{
            fontSize: '1.125rem',
            fontWeight: 600,
            marginBottom: '1rem',
          }}
        >
          Funktionsweise
        </h2>
        <div
          style={{
            display: 'grid',
            gridTemplateColumns: '1fr 1fr',
            gap: '1rem',
          }}
        >
          <div
            style={{
              padding: '1rem',
              background: 'var(--color-bg)',
              borderRadius: 'var(--radius-sm)',
            }}
          >
            <h3 style={{ ...h3Style, fontSize: '0.875rem' }}>Erstanmeldung</h3>
            <p
              style={{ ...pStyle, fontSize: '0.8125rem', marginBottom: 0 }}
            >
              Wenn ein Benutzer sich zum ersten Mal mit Microsoft anmeldet,
              wird automatisch ein Konto angelegt (Rolle: Benutzer). Existiert
              bereits ein Konto mit derselben E-Mail-Adresse, wird das
              Microsoft-Konto automatisch verknüpft.
            </p>
          </div>
          <div
            style={{
              padding: '1rem',
              background: 'var(--color-bg)',
              borderRadius: 'var(--radius-sm)',
            }}
          >
            <h3 style={{ ...h3Style, fontSize: '0.875rem' }}>Sicherheit</h3>
            <p
              style={{ ...pStyle, fontSize: '0.8125rem', marginBottom: 0 }}
            >
              Der SSO-Flow nutzt den OAuth2 Authorization Code Flow. Das Client
              Secret verlässt nie den Server. CSRF-Schutz via State-Parameter.
              Die Multi-Faktor-Authentifizierung (MFA) von Microsoft wird
              unterstützt.
            </p>
          </div>
        </div>
      </div>

      {/* Technische Details */}
      <div style={cardStyle}>
        <h2
          style={{
            fontSize: '1.125rem',
            fontWeight: 600,
            marginBottom: '1rem',
          }}
        >
          Technische Referenz
        </h2>
        <table style={tableStyle}>
          <thead>
            <tr>
              <th style={thStyle}>Endpoint</th>
              <th style={thStyle}>Beschreibung</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td style={tdStyle}>
                <code style={inlineCodeStyle}>
                  GET /api/v1/auth/sso/microsoft
                </code>
              </td>
              <td style={tdStyle}>
                Startet den SSO-Flow (Redirect zu Microsoft)
              </td>
            </tr>
            <tr>
              <td style={tdStyle}>
                <code style={inlineCodeStyle}>
                  GET /api/v1/auth/sso/microsoft/callback
                </code>
              </td>
              <td style={tdStyle}>
                Callback von Microsoft (Token-Exchange + User-Provisioning)
              </td>
            </tr>
            <tr>
              <td style={tdStyle}>
                <code style={inlineCodeStyle}>
                  GET /api/v1/auth/sso/status
                </code>
              </td>
              <td style={tdStyle}>
                Prüft ob SSO konfiguriert ist (für Login-Seite)
              </td>
            </tr>
          </tbody>
        </table>

        <h3
          style={{ ...h3Style, marginTop: '1.25rem', fontSize: '0.9375rem' }}
        >
          Redirect URI
        </h3>
        <p style={pStyle}>
          Diese URI muss exakt so in der Azure App Registration eingetragen
          sein:
        </p>
        <div
          style={{
            background: '#1e293b',
            color: '#e2e8f0',
            borderRadius: 'var(--radius-sm)',
            padding: '1rem 1.25rem',
            fontSize: '0.8125rem',
            fontFamily:
              "'JetBrains Mono', 'Fira Code', 'Consolas', monospace",
            lineHeight: 1.7,
            overflowX: 'auto',
            display: 'flex',
            alignItems: 'center',
            justifyContent: 'space-between',
            gap: '1rem',
            marginTop: '0.75rem',
          }}
        >
          <span>{defaultRedirectUri}</span>
          <button
            onClick={() => navigator.clipboard.writeText(defaultRedirectUri)}
            style={{
              padding: '0.25rem 0.5rem',
              background: '#334155',
              color: '#e2e8f0',
              border: '1px solid #475569',
              borderRadius: 'var(--radius-sm)',
              fontSize: '0.75rem',
              cursor: 'pointer',
              whiteSpace: 'nowrap',
            }}
          >
            Kopieren
          </button>
        </div>
      </div>
    </div>
  );
}