import React, { createContext, useContext, useState, ReactNode } from 'react';
import Toast, { ToastType } from '../components/Toast';

interface ToastItem {
  id: string;
  type: ToastType;
  title?: string;
  message: string;
  duration?: number;
}

interface ToastContextType {
  showToast: (type: ToastType, message: string, title?: string, duration?: number) => void;
  showSuccess: (message: string, title?: string) => void;
  showError: (message: string, title?: string) => void;
  showWarning: (message: string, title?: string) => void;
  showInfo: (message: string, title?: string) => void;
}

const ToastContext = createContext<ToastContextType | undefined>(undefined);

export const useToast = () => {
  const context = useContext(ToastContext);
  if (!context) {
    throw new Error('useToast must be used within a ToastProvider');
  }
  return context;
};

interface ToastProviderProps {
  children: ReactNode;
}

export const ToastProvider: React.FC<ToastProviderProps> = ({ children }) => {
  const [toasts, setToasts] = useState<ToastItem[]>([]);

  const showToast = (type: ToastType, message: string, title?: string, duration?: number) => {
    const id = Date.now().toString();
    const newToast: ToastItem = { id, type, message, title, duration };

    setToasts(prev => {
      // 相同消息去重：如果已存在相同的消息（类型和内容相同），则先移除旧的
      const filtered = prev.filter(t => t.message !== message || t.type !== type);
      return [...filtered, newToast];
    });
  };

  const removeToast = (id: string) => {
    setToasts(prev => prev.filter(toast => toast.id !== id));
  };

  const showSuccess = (message: string, title?: string) => showToast('success', message, title);
  const showError = (message: string, title?: string) => showToast('error', message, title);
  const showWarning = (message: string, title?: string) => showToast('warning', message, title);
  const showInfo = (message: string, title?: string) => showToast('info', message, title);

  return (
    <ToastContext.Provider value={{ showToast, showSuccess, showError, showWarning, showInfo }}>
      {children}
      <div className="fixed bottom-0 right-0 z-[9999] p-4 space-y-3 pointer-events-none w-full max-w-sm flex flex-col items-end">
        {toasts.map((toast) => (
          <div
            key={toast.id}
            className="pointer-events-auto w-full"
          >
            <Toast
              type={toast.type}
              title={toast.title}
              message={toast.message}
              duration={toast.duration}
              onClose={() => removeToast(toast.id)}
            />
          </div>
        ))}
      </div>
    </ToastContext.Provider>
  );
};