/**
 * Component: Toast Notification System
 * Documentation: documentation/frontend/components.md
 */

'use client';

import { createContext, useContext, useState, useCallback, ReactNode } from 'react';

export type ToastType = 'success' | 'error' | 'info' | 'warning';

export interface Toast {
  id: string;
  message: string;
  type: ToastType;
  duration?: number;
}

interface ToastContextType {
  toasts: Toast[];
  addToast: (message: string, type: ToastType, duration?: number) => void;
  removeToast: (id: string) => void;
  success: (message: string, duration?: number) => void;
  error: (message: string, duration?: number) => void;
  info: (message: string, duration?: number) => void;
  warning: (message: string, duration?: number) => void;
}

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

export function ToastProvider({ children }: { children: ReactNode }) {
  const [toasts, setToasts] = useState<Toast[]>([]);

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

  const addToast = useCallback(
    (message: string, type: ToastType, duration: number = 5000) => {
      const id = `toast-${Date.now()}-${Math.random()}`;
      const newToast: Toast = { id, message, type, duration };

      setToasts((prev) => [...prev, newToast]);

      if (duration > 0) {
        setTimeout(() => {
          removeToast(id);
        }, duration);
      }
    },
    [removeToast]
  );

  const success = useCallback(
    (message: string, duration?: number) => addToast(message, 'success', duration),
    [addToast]
  );

  const error = useCallback(
    (message: string, duration?: number) => addToast(message, 'error', duration),
    [addToast]
  );

  const info = useCallback(
    (message: string, duration?: number) => addToast(message, 'info', duration),
    [addToast]
  );

  const warning = useCallback(
    (message: string, duration?: number) => addToast(message, 'warning', duration),
    [addToast]
  );

  return (
    <ToastContext.Provider
      value={{
        toasts,
        addToast,
        removeToast,
        success,
        error,
        info,
        warning,
      }}
    >
      {children}
      <ToastContainer toasts={toasts} onRemove={removeToast} />
    </ToastContext.Provider>
  );
}

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

function ToastContainer({
  toasts,
  onRemove,
}: {
  toasts: Toast[];
  onRemove: (id: string) => void;
}) {
  if (toasts.length === 0) return null;

  return (
    <div className="fixed top-4 right-4 z-50 space-y-2 pointer-events-none">
      {toasts.map((toast) => (
        <ToastItem key={toast.id} toast={toast} onRemove={onRemove} />
      ))}
    </div>
  );
}

function ToastItem({ toast, onRemove }: { toast: Toast; onRemove: (id: string) => void }) {
  const colors = {
    success: 'bg-green-50 dark:bg-green-900/30 border-green-200 dark:border-green-800 text-green-800 dark:text-green-200',
    error: 'bg-red-50 dark:bg-red-900/30 border-red-200 dark:border-red-800 text-red-800 dark:text-red-200',
    warning: 'bg-yellow-50 dark:bg-yellow-900/30 border-yellow-200 dark:border-yellow-800 text-yellow-800 dark:text-yellow-200',
    info: 'bg-blue-50 dark:bg-blue-900/30 border-blue-200 dark:border-blue-800 text-blue-800 dark:text-blue-200',
  };

  const icons = {
    success: (
      <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
        <path
          strokeLinecap="round"
          strokeLinejoin="round"
          strokeWidth={2}
          d="M9 12l2 2 4-4m6 2a9 9 0 11-18 0 9 9 0 0118 0z"
        />
      </svg>
    ),
    error: (
      <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
        <path
          strokeLinecap="round"
          strokeLinejoin="round"
          strokeWidth={2}
          d="M10 14l2-2m0 0l2-2m-2 2l-2-2m2 2l2 2m7-2a9 9 0 11-18 0 9 9 0 0118 0z"
        />
      </svg>
    ),
    warning: (
      <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
        <path
          strokeLinecap="round"
          strokeLinejoin="round"
          strokeWidth={2}
          d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"
        />
      </svg>
    ),
    info: (
      <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
        <path
          strokeLinecap="round"
          strokeLinejoin="round"
          strokeWidth={2}
          d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z"
        />
      </svg>
    ),
  };

  return (
    <div
      className={`flex items-start gap-3 px-4 py-3 rounded-lg border shadow-lg min-w-[300px] max-w-md pointer-events-auto animate-slide-in-right ${
        colors[toast.type]
      }`}
    >
      <div className="flex-shrink-0">{icons[toast.type]}</div>
      <div className="flex-1 text-sm font-medium">{toast.message}</div>
      <button
        onClick={() => onRemove(toast.id)}
        className="flex-shrink-0 hover:opacity-70 transition-opacity"
        aria-label="Close"
      >
        <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
          <path
            strokeLinecap="round"
            strokeLinejoin="round"
            strokeWidth={2}
            d="M6 18L18 6M6 6l12 12"
          />
        </svg>
      </button>
    </div>
  );
}