import React, { useState, useRef, useEffect } from 'react';
import { Download, LogOut, Undo2, CloudUpload, Loader2, ChevronDown, RotateCcw } from 'lucide-react';
import { cn } from '../lib/utils';

interface TopBarProps {
  stats: any;
  onExport: () => void;
  hasData: boolean;
  hasUnsavedChanges: boolean;
  userEmail?: string;
  onSignOut?: () => void;
  canUndo: boolean;
  onUndo: () => void;
  undoMessage?: string;
  undoSteps: number;
  pendingCount: number;
  pendingChanges: Record<string, { articleName: string }>;
  onSaveAll: () => Promise<void>;
  onRevertRow: (articleNo: string) => void;
  isSavingAll: boolean;
}

export function TopBar({ stats, onExport, hasData, hasUnsavedChanges, userEmail, onSignOut, canUndo, onUndo, undoMessage, undoSteps, pendingCount, pendingChanges, onSaveAll, onRevertRow, isSavingAll }: TopBarProps) {
  const [showPending, setShowPending] = useState(false);
  const dropdownRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    if (!showPending) return;
    const handler = (e: MouseEvent) => {
      if (dropdownRef.current && !dropdownRef.current.contains(e.target as Node)) {
        setShowPending(false);
      }
    };
    document.addEventListener('mousedown', handler);
    return () => document.removeEventListener('mousedown', handler);
  }, [showPending]);

  // Close dropdown when all changes are saved/reverted
  useEffect(() => {
    if (pendingCount === 0) setShowPending(false);
  }, [pendingCount]);

  return (
    <header className="bg-[#020812] border-b border-slate-700/30 h-32 flex items-center justify-between px-10 shrink-0 z-10 shadow-2xl">
      <div className="flex items-center -ml-4">
        <img
          src="/logo.png"
          alt="Craze Scan"
          className="h-24 w-auto object-contain filter brightness-110 contrast-125 hover:scale-105 transition-transform duration-300"
        />
      </div>

      {stats && (
        <div className="flex items-center gap-4 text-xs font-medium">
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Total</span>
            <span className="bg-slate-700 text-white px-2 py-0.5 rounded mt-1">{stats.total}</span>
          </div>
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Missing DE Long</span>
            <span className="bg-red-500/20 text-red-400 px-2 py-0.5 rounded border border-red-500/30 mt-1">{stats.missingDeLong}</span>
          </div>
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Missing EN Long</span>
            <span className="bg-orange-500/20 text-orange-400 px-2 py-0.5 rounded border border-orange-500/30 mt-1">{stats.missingEnLong}</span>
          </div>
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Missing DE Short</span>
            <span className="bg-orange-500/20 text-orange-400 px-2 py-0.5 rounded border border-orange-500/30 mt-1">{stats.missingDeShort}</span>
          </div>
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Missing EN Short</span>
            <span className="bg-orange-500/20 text-orange-400 px-2 py-0.5 rounded border border-orange-500/30 mt-1">{stats.missingEnShort}</span>
          </div>
          <div className="flex flex-col items-center">
            <span className="text-slate-400">Fully Complete</span>
            <span className="bg-green-500/20 text-green-400 px-2 py-0.5 rounded border border-green-500/30 mt-1">{stats.fullyComplete}</span>
          </div>
        </div>
      )}

      <div className="flex items-center gap-3">
        <div className="relative" ref={dropdownRef}>
          {/* Split button: Save All + dropdown toggle */}
          <div className={cn(
            "flex items-center rounded-md overflow-hidden shadow-lg transition-all",
            pendingCount > 0 ? "shadow-green-900/30" : "shadow-none opacity-40"
          )}>
            <button
              onClick={onSaveAll}
              disabled={isSavingAll || pendingCount === 0}
              className={cn(
                "flex items-center gap-2 px-4 py-2 text-sm font-bold transition-all text-white",
                pendingCount > 0
                  ? "bg-green-600 hover:bg-green-500 disabled:opacity-60"
                  : "bg-slate-700 cursor-not-allowed"
              )}
            >
              {isSavingAll ? <Loader2 className="w-4 h-4 animate-spin" /> : <CloudUpload className="w-4 h-4" />}
              {isSavingAll
                ? 'Saving...'
                : pendingCount > 0
                  ? `Save ${pendingCount} change${pendingCount > 1 ? 's' : ''}`
                  : 'No pending changes'}
            </button>
            <button
              onClick={() => pendingCount > 0 && setShowPending(v => !v)}
              disabled={isSavingAll || pendingCount === 0}
              className={cn(
                "flex items-center px-2 py-2 text-white border-l transition-all",
                pendingCount > 0
                  ? "bg-green-700 hover:bg-green-600 border-green-500/40"
                  : "bg-slate-700 cursor-not-allowed border-slate-600"
              )}
              title="View pending changes"
            >
              <ChevronDown className={cn("w-4 h-4 transition-transform", showPending && "rotate-180")} />
            </button>
          </div>

          {/* Dropdown: list of pending changes */}
          {showPending && pendingCount > 0 && (
            <div className="absolute right-0 top-full mt-2 w-80 bg-slate-800 border border-slate-700 rounded-lg shadow-2xl z-50 overflow-hidden">
              <div className="px-3 py-2 border-b border-slate-700 flex items-center justify-between">
                <span className="text-xs font-bold text-slate-400 uppercase tracking-wider">Pending changes</span>
                <span className="text-xs text-slate-500">{pendingCount} unsaved</span>
              </div>
              <div className="max-h-64 overflow-y-auto">
                {Object.entries(pendingChanges).map(([articleNo, { articleName }]) => (
                  <div
                    key={articleNo}
                    className="flex items-center gap-2 px-3 py-2.5 hover:bg-slate-700/50 border-b border-slate-700/50 last:border-0"
                  >
                    <div className="w-2 h-2 rounded-full bg-yellow-400 shrink-0" />
                    <div className="flex-1 min-w-0">
                      <p className="text-xs font-mono text-slate-400">{articleNo}</p>
                      <p className="text-sm text-white truncate">{articleName}</p>
                    </div>
                    <button
                      onClick={() => onRevertRow(articleNo)}
                      title="Discard this change"
                      className="shrink-0 flex items-center gap-1 px-2 py-1 text-xs text-red-400 hover:text-white hover:bg-red-600 rounded transition-colors"
                    >
                      <RotateCcw className="w-3 h-3" />
                      Revert
                    </button>
                  </div>
                ))}
              </div>
            </div>
          )}
        </div>

        {hasData && (
          <button
            onClick={onExport}
            className={`flex items-center gap-2 px-4 py-2 rounded-md text-sm font-medium transition-colors ${
              hasUnsavedChanges
                ? 'bg-blue-600 hover:bg-blue-700 text-white'
                : 'bg-slate-700 hover:bg-slate-600 text-slate-200'
            }`}
          >
            <Download className="w-4 h-4" />
            Export Updated Excel
            {hasUnsavedChanges && <span className="w-2 h-2 rounded-full bg-red-500 ml-1 animate-pulse" />}
          </button>
        )}

        <button
          onClick={onUndo}
          disabled={!canUndo}
          title={canUndo ? `Undo: ${undoMessage}` : 'No changes to undo'}
          className={cn(
            "flex items-center gap-2 px-4 py-2 rounded-md text-sm font-bold transition-all shadow-lg relative group",
            canUndo
              ? "bg-amber-600 hover:bg-amber-700 text-white shadow-amber-900/40 cursor-pointer"
              : "bg-slate-800 text-slate-600 shadow-none cursor-not-allowed opacity-50"
          )}
        >
          <Undo2 className="w-4 h-4" />
          BACK / UNDO
          {canUndo && undoSteps > 1 && (
            <span className="absolute -top-1 -right-1 bg-white text-amber-700 text-[10px] w-4 h-4 rounded-full flex items-center justify-center shadow-md font-bold">
              {undoSteps}
            </span>
          )}
        </button>

        {userEmail && (
          <div className="flex items-center gap-2 border-l border-slate-700 pl-3">
            <span className="text-xs text-slate-400">{userEmail}</span>
            <button
              onClick={onSignOut}
              title="Sign out"
              className="p-1.5 text-slate-400 hover:text-white hover:bg-slate-700 rounded-md transition-colors"
            >
              <LogOut className="w-4 h-4" />
            </button>
          </div>
        )}
      </div>
    </header>
  );
}
