import React, { useState, useRef, useEffect } from "react";
import { Check, ChevronsUpDown, Search, X } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Avatar, AvatarFallback } from "@/components/ui/avatar";
import { cn } from "@/lib/utils";
import { Employee } from "@/types";

interface EmployeeSelectorProps {
  employees: Employee[];
  selectedEmployeeId: string;
  onSelect: (employeeId: string) => void;
  placeholder?: string;
  disabled?: boolean;
  className?: string;
}

const EmployeeSelector = ({
  employees,
  selectedEmployeeId,
  onSelect,
  placeholder = "Select an employee",
  disabled = false,
  className
}: EmployeeSelectorProps) => {
  const [isOpen, setIsOpen] = useState(false);
  const [searchQuery, setSearchQuery] = useState("");
  const dropdownRef = useRef<HTMLDivElement>(null);
  
  // Find the currently selected employee
  const selected = employees.find(employee => employee.id.toString() === selectedEmployeeId);
  
  // Get full name of employee
  const getFullName = (employee: Employee): string => {
    return [employee.firstName, employee.middleName, employee.lastName]
      .filter(Boolean)
      .join(" ");
  };
  
  // Get initials for avatar
  const getInitials = (employee: Employee): string => {
    return `${employee.firstName.charAt(0)}${employee.lastName.charAt(0)}`.toUpperCase();
  };
  
  // Filter employees based on search query
  const filteredEmployees = employees.filter(employee => {
    const fullName = getFullName(employee).toLowerCase();
    const query = searchQuery.toLowerCase();
    
    return (
      fullName.includes(query) ||
      employee.email.toLowerCase().includes(query) ||
      employee.empCode.toLowerCase().includes(query)
    );
  });

  // Handle click outside to close dropdown
  useEffect(() => {
    function handleClickOutside(event: MouseEvent) {
      if (dropdownRef.current && !dropdownRef.current.contains(event.target as Node)) {
        setIsOpen(false);
      }
    }
    
    document.addEventListener("mousedown", handleClickOutside);
    return () => {
      document.removeEventListener("mousedown", handleClickOutside);
    };
  }, []);

  // Handle selecting an employee
  const handleSelectEmployee = (employeeId: string) => {
    onSelect(employeeId);
    setIsOpen(false);
    setSearchQuery("");
  };

  // Handle clearing selection
  const handleClearSelection = (e: React.MouseEvent) => {
    e.stopPropagation();
    onSelect("");
  };

  return (
    <div className={cn("relative w-full", className)} ref={dropdownRef}>
      <Button
        type="button"
        variant="outline"
        role="combobox"
        aria-expanded={isOpen}
        className={cn(
          "w-full justify-between font-normal",
          !selectedEmployeeId && "text-muted-foreground"
        )}
        onClick={() => setIsOpen(!isOpen)}
        disabled={disabled}
      >
        {selected ? (
          <div className="flex items-center gap-2">
            <Avatar className="h-6 w-6">
              <AvatarFallback>
                {getInitials(selected)}
              </AvatarFallback>
            </Avatar>
            <span>{getFullName(selected)}</span>
          </div>
        ) : (
          <span>{placeholder}</span>
        )}
        <div className="flex items-center">
          {selectedEmployeeId && (
            <Button
              variant="ghost"
              size="sm"
              className="h-4 w-4 p-0 mr-1 opacity-70 hover:opacity-100"
              onClick={handleClearSelection}
            >
              <X className="h-3 w-3" />
              <span className="sr-only">Clear selection</span>
            </Button>
          )}
          <ChevronsUpDown className="h-4 w-4 opacity-50" />
        </div>
      </Button>
      
      {isOpen && (
        <div className="absolute top-full z-[9999] mt-1 w-full rounded-md border border-input bg-popover shadow-md animate-in fade-in-0 zoom-in-95">
          <div className="flex items-center border-b px-3 py-2">
            <Search className="mr-2 h-4 w-4 shrink-0 opacity-50" />
            <Input
              placeholder="Search employees..."
              className="flex h-8 w-full rounded-md bg-transparent py-2 text-sm outline-none placeholder:text-muted-foreground disabled:cursor-not-allowed disabled:opacity-50 border-0 focus-visible:ring-0 focus-visible:ring-offset-0"
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              onClick={(e) => e.stopPropagation()}
            />
          </div>
          <div className="max-h-[15rem] overflow-y-auto py-1">
            {filteredEmployees.length === 0 ? (
              <div className="px-2 py-2 text-sm text-center text-muted-foreground">
                No employees found
              </div>
            ) : (
              filteredEmployees.map(employee => (
                <div
                  key={employee.id}
                  className={cn(
                    "flex items-center justify-between px-3 py-2 text-sm cursor-pointer hover:bg-accent",
                    employee.id.toString() === selectedEmployeeId && "bg-accent/50"
                  )}
                  onClick={() => handleSelectEmployee(employee.id.toString())}
                >
                  <div className="flex items-center gap-2">
                    <Avatar className="h-6 w-6">
                      <AvatarFallback>
                        {getInitials(employee)}
                      </AvatarFallback>
                    </Avatar>
                    <div>
                      <p className="font-medium">{getFullName(employee)}</p>
                      <p className="text-xs text-muted-foreground truncate max-w-[200px]">
                        {employee.email} • {employee.empCode}
                      </p>
                    </div>
                  </div>
                  {employee.id.toString() === selectedEmployeeId && (
                    <Check className="h-4 w-4 text-primary" />
                  )}
                </div>
              ))
            )}
          </div>
        </div>
      )}
    </div>
  );
};

export default EmployeeSelector;