Stirling-PDF/frontend/src/components/shared/TopControls.tsx

import React, { useState, useCallback } from "react";
import { SegmentedControl, Loader } from "@mantine/core";
import { useRainbowThemeContext } from "./RainbowThemeProvider";
import rainbowStyles from '../../styles/rainbow.module.css';
import VisibilityIcon from "@mui/icons-material/Visibility";
import EditNoteIcon from "@mui/icons-material/EditNote";
import FolderIcon from "@mui/icons-material/Folder";
import { WorkbenchType, isValidWorkbench } from '../../types/workbench';


const viewOptionStyle = {
  display: 'inline-flex',
  flexDirection: 'row',
  alignItems: 'center',
  gap: 6,
  whiteSpace: 'nowrap',
  paddingTop: '0.3rem',
};


// Build view options showing text always
const createViewOptions = (currentView: WorkbenchType, switchingTo: WorkbenchType | null) => {
  const viewerOption = {
    label: (
      <div style={viewOptionStyle as React.CSSProperties}>
        {switchingTo === "viewer" ? (
          <Loader size="xs" />
        ) : (
          <VisibilityIcon fontSize="small" />
        )}
        <span>Viewer</span>
      </div>
    ),
    value: "viewer",
  };

  const pageEditorOption = {
    label: (
      <div style={viewOptionStyle as React.CSSProperties}>
        {currentView === "pageEditor" ? (
          <>
            {switchingTo === "pageEditor" ? <Loader size="xs" /> : <EditNoteIcon fontSize="small" />}
            <span>Page Editor</span>
          </>
        ) : (
          <>
            {switchingTo === "pageEditor" ? <Loader size="xs" /> : <EditNoteIcon fontSize="small" />}
            <span>Page Editor</span>
          </>
        )}
      </div>
    ),
    value: "pageEditor",
  };

  const fileEditorOption = {
    label: (
      <div style={viewOptionStyle as React.CSSProperties}>
        {currentView === "fileEditor" ? (
          <>
            {switchingTo === "fileEditor" ? <Loader size="xs" /> : <FolderIcon fontSize="small" />}
            <span>Active Files</span>
          </>
        ) : (
          <>
            {switchingTo === "fileEditor" ? <Loader size="xs" /> : <FolderIcon fontSize="small" />}
            <span>Active Files</span>
          </>
        )}
      </div>
    ),
    value: "fileEditor",
  };

  // Build options array conditionally
  return [
    viewerOption,
    pageEditorOption,
    fileEditorOption,
  ];
};

interface TopControlsProps {
  currentView: WorkbenchType;
  setCurrentView: (view: WorkbenchType) => void;
}

const TopControls = ({
  currentView,
  setCurrentView,
  }: TopControlsProps) => {
  const { isRainbowMode } = useRainbowThemeContext();
  const [switchingTo, setSwitchingTo] = useState<WorkbenchType | null>(null);

  const handleViewChange = useCallback((view: string) => {
    if (!isValidWorkbench(view)) {
      return;
    }

    const workbench = view;

    // Show immediate feedback
    setSwitchingTo(workbench);

    // Defer the heavy view change to next frame so spinner can render
    requestAnimationFrame(() => {
      // Give the spinner one more frame to show
      requestAnimationFrame(() => {
        setCurrentView(workbench);

        // Clear the loading state after view change completes
        setTimeout(() => setSwitchingTo(null), 300);
      });
    });
  }, [setCurrentView]);

  return (
    <div className="absolute left-0 w-full top-0 z-[100] pointer-events-none">
      <div className="flex justify-center mt-[0.5rem]">
        <SegmentedControl
          data={createViewOptions(currentView, switchingTo)}
          value={currentView}
          onChange={handleViewChange}
          color="blue"
          fullWidth
          className={isRainbowMode ? rainbowStyles.rainbowSegmentedControl : ''}
          style={{
            transition: 'all 0.2s ease',
            opacity: switchingTo ? 0.8 : 1,
            pointerEvents: 'auto'
          }}
          styles={{
            root: {
              borderRadius: 9999,
              maxHeight: '2.6rem',
            },
            control: {
              borderRadius: 9999,
            },
            indicator: {
              borderRadius: 9999,
              maxHeight: '2rem',
            },
            label: {
              paddingTop: '0rem',
            }
          }}
        />
      </div>
    </div>
  );
};

export default TopControls;