import { useEffect, useState, type ReactNode } from 'react';

import { DashboardLayout } from '../../components/dashboard/DashboardLayout';
import { getDevDiagnostics, runDevStorageCheck } from '../../lib/api';
import type { DevDiagnostics, DevStorageCheck } from '../../types/dev';

interface UploadErrorLog {
  at: string;
  filename: string;
  message: string;
}

export default function DevPage() {
  const [diagnostics, setDiagnostics] = useState<DevDiagnostics | null>(null);
  const [storageCheck, setStorageCheck] = useState<DevStorageCheck | null>(null);
  const [uploadError, setUploadError] = useState<UploadErrorLog | null>(null);
  const [loading, setLoading] = useState(true);
  const [checking, setChecking] = useState(false);
  const [error, setError] = useState('');

  async function refresh() {
    setLoading(true);
    setError('');
    try {
      setDiagnostics(await getDevDiagnostics());
    } catch (reason) {
      setError(reason instanceof Error ? reason.message : 'Could not load diagnostics.');
    } finally {
      setLoading(false);
    }
  }

  useEffect(() => {
    void refresh();
    try {
      const raw = window.localStorage.getItem('studio:last-upload-error');
      if (raw) setUploadError(JSON.parse(raw) as UploadErrorLog);
    } catch {
      setUploadError(null);
    }
  }, []);

  async function checkStorage() {
    setChecking(true);
    try {
      setStorageCheck(await runDevStorageCheck());
    } catch (reason) {
      setStorageCheck({
        ok: false,
        step: 'api',
        error: reason instanceof Error ? reason.message : 'Storage check failed.',
      });
    } finally {
      setChecking(false);
      void refresh();
    }
  }

  const browser = {
    origin: window.location.origin,
    online: navigator.onLine,
    xhr: typeof XMLHttpRequest !== 'undefined',
    fileApi: typeof File !== 'undefined' && typeof FileReader !== 'undefined',
    secureContext: window.isSecureContext,
  };

  return (
    <DashboardLayout>
      <div className="studio-page dev-page">
        <header className="studio-page__header studio-page__header--compact">
          <div>
            <p className="studio-kicker">Workspace / diagnostics</p>
            <h1 className="studio-display">Dev Console</h1>
            <p className="studio-page__lede">Local runtime diagnostics and storage checks.</p>
          </div>
          <div className="dev-page__actions">
            <button
              className="editor-button editor-button--quiet"
              type="button"
              onClick={() => void refresh()}
              disabled={loading}
            >
              Refresh
            </button>
            <button
              className="editor-button editor-button--accent"
              type="button"
              onClick={() => void checkStorage()}
              disabled={checking}
            >
              {checking ? 'Checking...' : 'Test storage'}
            </button>
          </div>
        </header>
        {error && <p className="studio-alert studio-alert--error">{error}</p>}
        <div className="dev-grid">
          <DevPanel title="Runtime" eyebrow="01 / API">
            {loading || !diagnostics ? (
              <DevLoading />
            ) : (
              <>
                <DevRow label="Environment" value={diagnostics.environment} />
                <DevRow label="API time" value={diagnostics.now} />
                <DevRow label="Account" value={diagnostics.user.email} />
                <DevRow
                  label="Session cookie"
                  value={diagnostics.http.cookieSecure ? 'Secure' : 'Local / insecure'}
                />
              </>
            )}
          </DevPanel>
          <DevPanel title="Database" eyebrow="02 / Persistence">
            {loading || !diagnostics ? (
              <DevLoading />
            ) : (
              <>
                <DevStatus
                  label={diagnostics.database.driver}
                  ok={diagnostics.database.connected}
                />
                <DevRow
                  label="Connection"
                  value={
                    diagnostics.database.connected
                      ? 'Reachable'
                      : diagnostics.database.error || 'Unavailable'
                  }
                />
              </>
            )}
          </DevPanel>
          <DevPanel title="Object storage" eyebrow="03 / MinIO">
            {loading || !diagnostics ? (
              <DevLoading />
            ) : (
              <>
                <DevStatus
                  label={diagnostics.storage.provider}
                  ok={diagnostics.storage.reachable}
                />
                <DevRow label="Endpoint" value={diagnostics.storage.endpoint} />
                <DevRow label="Bucket" value={diagnostics.storage.bucket} />
                <DevRow label="Protocol" value={diagnostics.storage.secure ? 'HTTPS' : 'HTTP'} />
                {diagnostics.storage.error && (
                  <p className="dev-panel__error">{diagnostics.storage.error}</p>
                )}
              </>
            )}
          </DevPanel>
          <DevPanel title="Browser" eyebrow="04 / Client">
            <DevRow label="Origin" value={browser.origin} />
            <DevRow label="Network" value={browser.online ? 'Online' : 'Offline'} />
            <DevRow label="XMLHttpRequest" value={browser.xhr ? 'Available' : 'Unavailable'} />
            <DevRow label="File API" value={browser.fileApi ? 'Available' : 'Unavailable'} />
            <DevRow
              label="Secure context"
              value={browser.secureContext ? 'Yes' : 'No (normal for local HTTP)'}
            />
          </DevPanel>
        </div>
        <section className="dev-panel dev-panel--wide">
          <div className="dev-panel__heading">
            <p className="studio-kicker">05 / Upload path</p>
            <h2>What happens when you choose a file.</h2>
          </div>
          <div className="dev-flow">
            <span>
              01 <strong>API URL</strong>
              <small>Creates media metadata</small>
            </span>
            <i>&#8594;</i>
            <span>
              02 <strong>Presigned PUT</strong>
              <small>Browser to MinIO</small>
            </span>
            <i>&#8594;</i>
            <span>
              03 <strong>Complete</strong>
              <small>Stat object and queue processing</small>
            </span>
            <i>&#8594;</i>
            <span>
              04 <strong>Ready</strong>
              <small>Preview becomes visible</small>
            </span>
          </div>
          <p className="dev-hint">
            If an upload stops at 0%, the failure is usually the browser reaching the presigned
            MinIO origin. Check that the browser origin below is listed in the MinIO bucket CORS
            rule.
          </p>
          {diagnostics && (
            <div className="dev-cors">
              <span>Effective browser origins</span>
              {diagnostics.http.corsOrigins.map((origin) => (
                <code key={origin}>{origin}</code>
              ))}
            </div>
          )}
        </section>
        <section className="dev-panel dev-panel--wide">
          <div className="dev-panel__heading">
            <p className="studio-kicker">06 / Last client failure</p>
            <h2>Recent upload signal.</h2>
          </div>
          {uploadError ? (
            <div className="dev-last-error">
              <span className="dev-last-error__mark">!</span>
              <div>
                <strong>{uploadError.filename}</strong>
                <p>{uploadError.message}</p>
                <small>{new Date(uploadError.at).toLocaleString()}</small>
              </div>
              <button
                type="button"
                onClick={() => {
                  window.localStorage.removeItem('studio:last-upload-error');
                  setUploadError(null);
                }}
              >
                Clear
              </button>
            </div>
          ) : (
            <p className="dev-empty">
              No client-side upload failures have been recorded in this browser.
            </p>
          )}
          {storageCheck && (
            <div className={`dev-check-result ${storageCheck.ok ? 'is-ok' : 'is-failed'}`}>
              <strong>{storageCheck.ok ? 'Storage check passed' : 'Storage check failed'}</strong>
              <span>
                {storageCheck.ok
                  ? `${storageCheck.bytes} bytes / ${storageCheck.contentType}`
                  : `${storageCheck.step}: ${storageCheck.error}`}
              </span>
            </div>
          )}
        </section>
        <details className="dev-raw">
          <summary>Show raw diagnostics JSON</summary>
          <pre>{diagnostics ? JSON.stringify(diagnostics, null, 2) : 'No response yet.'}</pre>
        </details>
      </div>
    </DashboardLayout>
  );
}

function DevPanel({
  title,
  eyebrow,
  children,
}: {
  title: string;
  eyebrow: string;
  children: ReactNode;
}) {
  return (
    <section className="dev-panel">
      <div className="dev-panel__heading">
        <p className="studio-kicker">{eyebrow}</p>
        <h2>{title}</h2>
      </div>
      {children}
    </section>
  );
}

function DevRow({ label, value }: { label: string; value: string }) {
  return (
    <div className="dev-row">
      <span>{label}</span>
      <strong>{value}</strong>
    </div>
  );
}

function DevStatus({ label, ok }: { label: string; ok: boolean }) {
  return (
    <div className={`dev-status ${ok ? 'is-ok' : 'is-failed'}`}>
      <i /> <strong>{label}</strong>
      <span>{ok ? 'reachable' : 'unavailable'}</span>
    </div>
  );
}

function DevLoading() {
  return (
    <div className="dev-loading">
      <span />
      <span />
      <span />
    </div>
  );
}