'use client';

import { memo, useState, useEffect, useMemo } from 'react';
import type { IDockviewPanelProps } from 'dockview-react';
import { IconRefresh, IconExternalLink } from '@tabler/icons-react';
import { Button } from '@kandev/ui/button';
import { Input } from '@kandev/ui/input';
import { PanelRoot, PanelBody, PanelToolbar } from './panel-primitives';
import { useAppStore } from '@/components/state-provider';
import { detectPreviewUrlFromOutput } from '@/lib/preview-url-detector';

export const BrowserPanel = memo(function BrowserPanel(
  props: IDockviewPanelProps<{ url?: string }>
) {
  const initialUrl = props.params.url || '';
  const [userUrl, setUserUrl] = useState(initialUrl);
  const [urlDraft, setUrlDraft] = useState(initialUrl);
  const [refreshKey, setRefreshKey] = useState(0);
  const [showIframe, setShowIframe] = useState(false);

  const activeSessionId = useAppStore((state) => state.tasks.activeSessionId);
  const devProcessId = useAppStore((state) =>
    activeSessionId ? state.processes.devProcessBySessionId[activeSessionId] : undefined
  );
  const devOutput = useAppStore((state) =>
    devProcessId ? state.processes.outputsByProcessId[devProcessId] ?? '' : ''
  );

  // Auto-detect URL from dev server output
  const detectedUrl = detectPreviewUrlFromOutput(devOutput);
  // Use user-set URL if available, otherwise fall back to detected URL
  const effectiveUrl = useMemo(() => userUrl || detectedUrl || '', [userUrl, detectedUrl]);

  // Derive iframe visibility: show after a delay when URL is available
  const showIframeDelayed = effectiveUrl && showIframe;

  // Delay showing iframe after URL is set
  useEffect(() => {
    if (!effectiveUrl) return;
    const showTimer = setTimeout(() => setShowIframe(true), 1500);
    return () => {
      setShowIframe(false);
      clearTimeout(showTimer);
    };
  }, [effectiveUrl, refreshKey]);

  // Sync draft with detected URL when user hasn't typed anything
  const displayDraft = urlDraft || detectedUrl || '';

  const handleUrlSubmit = () => {
    const trimmed = urlDraft.trim();
    if (trimmed) {
      setUserUrl(trimmed);
    }
  };

  const handleOpenInTab = () => {
    if (effectiveUrl) {
      window.open(effectiveUrl, '_blank', 'noopener,noreferrer');
    }
  };

  return (
    <PanelRoot>
      <PanelToolbar>
        <Input
          value={displayDraft}
          onChange={(e) => setUrlDraft(e.target.value)}
          onKeyDown={(e) => {
            if (e.key === 'Enter') {
              e.preventDefault();
              handleUrlSubmit();
            }
          }}
          placeholder={detectedUrl || 'http://localhost:3000'}
          className="h-6 flex-1 min-w-[180px]"
        />
        <Button
          size="sm"
          variant="outline"
          onClick={handleOpenInTab}
          disabled={!effectiveUrl}
          className="cursor-pointer"
          title="Open in browser tab"
        >
          <IconExternalLink className="h-4 w-4" />
        </Button>
        <Button
          size="sm"
          variant="outline"
          onClick={() => setRefreshKey((v) => v + 1)}
          disabled={!effectiveUrl}
          className="cursor-pointer"
          title="Refresh"
        >
          <IconRefresh className="h-4 w-4" />
        </Button>
      </PanelToolbar>

      <PanelBody padding={false} scroll={false}>
        {showIframeDelayed ? (
          <iframe
            key={refreshKey}
            src={effectiveUrl}
            title="Browser Preview"
            className="h-full w-full border-0"
            sandbox="allow-scripts allow-same-origin allow-forms allow-popups allow-modals"
            referrerPolicy="no-referrer"
          />
        ) : effectiveUrl ? (
          <div className="h-full w-full flex flex-col items-center justify-center text-muted-foreground gap-2">
            <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary" />
            <p className="text-sm">Loading preview...</p>
          </div>
        ) : (
          <div className="h-full w-full flex flex-col items-center justify-center text-muted-foreground gap-2">
            <p className="text-sm">Enter a URL above or start the dev server</p>
          </div>
        )}
      </PanelBody>
    </PanelRoot>
  );
});