import { useRef, useEffect } from 'react';
import { useShallow } from 'zustand/react/shallow';
import { useMachineStore } from '../stores/useMachineStore';
import { useUIStore } from '../stores/useUIStore';
import { WorkflowStepper } from './WorkflowStepper';
import { ErrorPopover } from './ErrorPopover';
import { getStateVisualInfo } from '../utils/machineStateHelpers';
import {
  CheckCircleIcon,
  BoltIcon,
  PauseCircleIcon,
  ExclamationTriangleIcon,
  ArrowPathIcon,
  XMarkIcon,
} from '@heroicons/react/24/solid';

export function AppHeader() {
  const {
    isConnected,
    machineInfo,
    machineStatus,
    machineStatusName,
    machineError,
    error: machineErrorMessage,
    isPairingError,
    isCommunicating: isPolling,
    disconnect,
  } = useMachineStore(
    useShallow((state) => ({
      isConnected: state.isConnected,
      machineInfo: state.machineInfo,
      machineStatus: state.machineStatus,
      machineStatusName: state.machineStatusName,
      machineError: state.machineError,
      error: state.error,
      isPairingError: state.isPairingError,
      isCommunicating: state.isCommunicating,
      disconnect: state.disconnect,
    }))
  );

  const {
    pyodideError,
    showErrorPopover,
    setErrorPopover,
  } = useUIStore(
    useShallow((state) => ({
      pyodideError: state.pyodideError,
      showErrorPopover: state.showErrorPopover,
      setErrorPopover: state.setErrorPopover,
    }))
  );

  const errorPopoverRef = useRef<HTMLDivElement>(null);
  const errorButtonRef = useRef<HTMLButtonElement>(null);

  // Get state visual info for header status badge
  const stateVisual = getStateVisualInfo(machineStatus);
  const stateIcons = {
    ready: CheckCircleIcon,
    active: BoltIcon,
    waiting: PauseCircleIcon,
    complete: CheckCircleIcon,
    interrupted: PauseCircleIcon,
    error: ExclamationTriangleIcon,
  };
  const StatusIcon = stateIcons[stateVisual.iconName];

  // Close error popover when clicking outside
  useEffect(() => {
    const handleClickOutside = (event: MouseEvent) => {
      if (
        errorPopoverRef.current &&
        !errorPopoverRef.current.contains(event.target as Node) &&
        errorButtonRef.current &&
        !errorButtonRef.current.contains(event.target as Node)
      ) {
        setErrorPopover(false);
      }
    };

    if (showErrorPopover) {
      document.addEventListener('mousedown', handleClickOutside);
      return () => document.removeEventListener('mousedown', handleClickOutside);
    }
  }, [showErrorPopover, setErrorPopover]);

  return (
    <header className="bg-gradient-to-r from-blue-600 via-blue-700 to-blue-800 dark:from-blue-700 dark:via-blue-800 dark:to-blue-900 px-4 sm:px-6 lg:px-8 py-3 shadow-lg border-b-2 border-blue-900/20 dark:border-blue-800/30 flex-shrink-0">
      <div className="grid grid-cols-1 lg:grid-cols-[280px_1fr] gap-4 lg:gap-8 items-center">
        {/* Machine Connection Status - Responsive width column */}
        <div className="flex items-center gap-3 w-full lg:w-[280px]">
          <div className="w-2.5 h-2.5 bg-green-400 rounded-full animate-pulse shadow-lg shadow-green-400/50" style={{ visibility: isConnected ? 'visible' : 'hidden' }}></div>
          <div className="w-2.5 h-2.5 bg-gray-400 rounded-full -ml-2.5" style={{ visibility: !isConnected ? 'visible' : 'hidden' }}></div>
          <div className="flex-1 min-w-0">
            <div className="flex items-center gap-2">
              <h1 className="text-lg lg:text-xl font-bold text-white leading-tight">Respira</h1>
              {isConnected && machineInfo?.serialNumber && (
                <span
                  className="text-xs text-blue-200 cursor-help"
                  title={`Serial: ${machineInfo.serialNumber}${
                    machineInfo.macAddress
                      ? `\nMAC: ${machineInfo.macAddress}`
                      : ''
                  }${
                    machineInfo.totalCount !== undefined
                      ? `\nTotal stitches: ${machineInfo.totalCount.toLocaleString()}`
                      : ''
                  }${
                    machineInfo.serviceCount !== undefined
                      ? `\nStitches since service: ${machineInfo.serviceCount.toLocaleString()}`
                      : ''
                  }`}
                >
                  • {machineInfo.serialNumber}
                </span>
              )}
              {isPolling && (
                <ArrowPathIcon className="w-3.5 h-3.5 text-blue-200 animate-spin" title="Auto-refreshing status" />
              )}
            </div>
            <div className="flex items-center gap-2 mt-1 min-h-[32px]">
              {isConnected ? (
                <>
                  <button
                    onClick={disconnect}
                    className="inline-flex items-center gap-1.5 px-2.5 py-1.5 sm:py-1 rounded text-sm font-medium bg-white/10 hover:bg-red-600 text-blue-100 hover:text-white border border-white/20 hover:border-red-600 cursor-pointer transition-all flex-shrink-0"
                    title="Disconnect from machine"
                    aria-label="Disconnect from machine"
                  >
                    <XMarkIcon className="w-3 h-3" />
                    Disconnect
                  </button>
                  <span className="inline-flex items-center gap-1.5 px-2.5 py-1.5 sm:py-1 rounded text-sm font-semibold bg-white/20 text-white border border-white/30 flex-shrink-0">
                    <StatusIcon className="w-3 h-3" />
                    {machineStatusName}
                  </span>
                </>
              ) : (
                <p className="text-xs text-blue-200">Not Connected</p>
              )}

              {/* Error indicator - always render to prevent layout shift */}
              <div className="relative">
                <button
                  ref={errorButtonRef}
                  onClick={() => setErrorPopover(!showErrorPopover)}
                  className={`inline-flex items-center gap-1.5 px-2.5 py-1.5 sm:py-1 rounded text-sm font-medium bg-red-500/90 hover:bg-red-600 text-white border border-red-400 transition-all flex-shrink-0 ${
                    (machineErrorMessage || pyodideError)
                      ? 'cursor-pointer animate-pulse hover:animate-none'
                      : 'invisible pointer-events-none'
                  }`}
                  title="Click to view error details"
                  aria-label="View error details"
                  disabled={!(machineErrorMessage || pyodideError)}
                >
                  <ExclamationTriangleIcon className="w-3.5 h-3.5 flex-shrink-0" />
                  <span>
                    {(() => {
                      if (pyodideError) return 'Python Error';
                      if (isPairingError) return 'Pairing Required';

                      const errorMsg = machineErrorMessage || '';

                      // Categorize by error message content
                      if (errorMsg.toLowerCase().includes('bluetooth') || errorMsg.toLowerCase().includes('connection')) {
                        return 'Connection Error';
                      }
                      if (errorMsg.toLowerCase().includes('upload')) {
                        return 'Upload Error';
                      }
                      if (errorMsg.toLowerCase().includes('pattern')) {
                        return 'Pattern Error';
                      }
                      if (machineError !== undefined) {
                        return `Machine Error`;
                      }

                      // Default fallback
                      return 'Error';
                    })()}
                  </span>
                </button>

                {/* Error popover */}
                {showErrorPopover && (machineErrorMessage || pyodideError) && (
                  <ErrorPopover
                    ref={errorPopoverRef}
                    machineError={machineError}
                    isPairingError={isPairingError}
                    errorMessage={machineErrorMessage}
                    pyodideError={pyodideError}
                  />
                )}
              </div>
            </div>
          </div>
        </div>

        {/* Workflow Stepper - Flexible width column */}
        <div>
          <WorkflowStepper />
        </div>
      </div>
    </header>
  );
}