"use client";

import { useState, useRef, useEffect } from "react";
import { useChat } from "ai/react";
import { XMarkIcon } from "@heroicons/react/24/outline";

type MessageWithLoading = {
  content: string;
  role: string;
  isStreaming?: boolean;
};

// Define theme CSS variables
const themeStyles = {
  light: {
    '--bg-primary': '#ffffff',
    '--bg-secondary': 'rgba(243, 244, 246, 0.7)',
    '--text-primary': '#111827',
    '--text-secondary': '#6B7280',
    '--border-color': 'rgba(229, 231, 235, 0.5)',
    '--shadow-color': 'rgba(0, 0, 0, 0.1)',
    '--message-bg': 'rgba(243, 244, 246, 0.7)',
    '--input-bg': 'rgba(255, 255, 255, 0.9)',
  },
  dark: {
    '--bg-primary': '#1F2937',
    '--bg-secondary': 'rgba(31, 41, 55, 0.7)',
    '--text-primary': '#F9FAFB',
    '--text-secondary': '#D1D5DB',
    '--border-color': 'rgba(75, 85, 99, 0.5)',
    '--shadow-color': 'rgba(0, 0, 0, 0.3)',
    '--message-bg': 'rgba(55, 65, 81, 0.7)',
    '--input-bg': 'rgba(31, 41, 55, 0.9)',
  },
} as const;

// Inject required styles into iframe
const injectStyles = `
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  }

  .playgo-chat {
    background-color: var(--bg-primary);
    color: var(--text-primary);
  }

  .playgo-chat-header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
  }

  .playgo-chat-messages {
    background-color: var(--bg-primary);
  }

  .playgo-chat-input {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
  }

  .playgo-chat-input-field {
    background-color: var(--input-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 0.75rem 3rem 0.75rem 0.75rem;
    width: 100%;
    transition: all 0.2s;
  }

  .playgo-chat-input-field:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(var(--primary-rgb), 0.2);
  }

  .playgo-chat-input-field::placeholder {
    color: var(--text-secondary);
  }

  .playgo-message-bubble {
    box-shadow: 0 1px 2px var(--shadow-color);
    max-width: 80%;
    padding: 0.75rem;
    border-radius: 0.75rem;
  }

  .playgo-message-assistant {
    background-color: var(--message-bg);
    color: var(--text-primary);
    margin-right: 1rem;
  }

  .playgo-message-user {
    background-color: var(--primary-color);
    color: white;
    margin-left: 1rem;
  }

  @media (prefers-color-scheme: dark) {
    .playgo-chat[data-theme="system"] {
      --bg-primary: #1F2937;
      --bg-secondary: rgba(31, 41, 55, 0.7);
      --text-primary: #F9FAFB;
      --text-secondary: #D1D5DB;
      --border-color: rgba(75, 85, 99, 0.5);
      --shadow-color: rgba(0, 0, 0, 0.3);
      --message-bg: rgba(55, 65, 81, 0.7);
      --input-bg: rgba(31, 41, 55, 0.9);
    }
  }
`;

interface EmbeddableChatBotConfig {
  apiUrl?: string;
  height?: string | number;
  width?: string | number;
  theme?: 'light' | 'dark' | 'system';
  primaryColor?: string;
  placeholder?: string;
  buttonText?: string;
}

// First, let's fix the CSS type error by declaring the CSS custom properties
declare module 'react' {
  interface CSSProperties {
    '--primary-color'?: string;
    '--primary-rgb'?: string;
    '--bg-primary'?: string;
    '--bg-secondary'?: string;
    '--text-primary'?: string;
    '--text-secondary'?: string;
    '--border-color'?: string;
    '--shadow-color'?: string;
    '--message-bg'?: string;
    '--input-bg'?: string;
  }
}

export default function EmbeddableChatBot({
  apiUrl = "/api/landing_page_chat",
  theme = 'system',
  primaryColor = "#FF6B6B",
  placeholder = "請問任何關於學習的問題...",
  buttonText = "需要協助嗎？",
}: EmbeddableChatBotConfig) {
  const chatContainerRef = useRef<HTMLDivElement>(null);
  const [isOpen, setIsOpen] = useState(false);
  const [messages, setMessages] = useState<MessageWithLoading[]>([]);
  const [currentTheme, setCurrentTheme] = useState(theme);

  // Convert hex color to RGB for CSS variables
  const hexToRgb = (hex: string) => {
    const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    return result ?
      `${parseInt(result[1], 16)}, ${parseInt(result[2], 16)}, ${parseInt(result[3], 16)}`
      : '255, 107, 107'; // fallback RGB for #FF6B6B
  };

  const {
    input,
    handleInputChange,
    handleSubmit,
    isLoading,
  } = useChat({
    api: apiUrl,
    onError: (error) => {
      console.error("Chat error:", error);
    },
    onFinish: () => {
      setMessages((prev) =>
        prev.map((msg) => ({ ...msg, isStreaming: false }))
      );
    },
  });

  // Handle system theme changes
  useEffect(() => {
    if (theme === 'system') {
      const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
      const handleChange = (e: MediaQueryListEvent) => {
        setCurrentTheme(e.matches ? 'dark' : 'light');
      };

      mediaQuery.addEventListener('change', handleChange);
      setCurrentTheme(mediaQuery.matches ? 'dark' : 'light');

      return () => mediaQuery.removeEventListener('change', handleChange);
    } else {
      setCurrentTheme(theme);
    }
  }, [theme]);

  useEffect(() => {
    if (chatContainerRef.current) {
      chatContainerRef.current.scrollTop = chatContainerRef.current.scrollHeight;
    }
  }, [messages]);

  // Inject styles when component mounts
  useEffect(() => {
    if (isOpen && chatContainerRef.current) {
      const styleSheet = document.createElement('style');
      styleSheet.textContent = injectStyles;
      chatContainerRef.current.appendChild(styleSheet);
    }
  }, [isOpen]);

  const containerStyle = {
    ...(themeStyles[currentTheme === 'system' ? 'light' : currentTheme]),
    '--primary-color': primaryColor,
    '--primary-rgb': hexToRgb(primaryColor),
  } as React.CSSProperties;

  // Send message to parent when chat state changes
  useEffect(() => {
    if (typeof window !== 'undefined') {
      window.parent.postMessage({
        type: isOpen ? 'chatOpen' : 'chatClose'
      }, '*');
    }
  }, [isOpen]);

  if (!isOpen) {
    return (
      <div className="w-full h-full flex items-center justify-end">
        <button
          onClick={() => setIsOpen(true)}
          className="bg-primary text-white rounded-full p-4
                   transition-colors duration-200
                   inline-flex items-center"
          style={{ backgroundColor: primaryColor }}
        >
          <span className="flex items-center gap-2">
            <svg
              xmlns="http://www.w3.org/2000/svg"
              fill="none"
              viewBox="0 0 24 24"
              strokeWidth={1.5}
              stroke="currentColor"
              className="w-6 h-6"
            >
              <path
                strokeLinecap="round"
                strokeLinejoin="round"
                d="M7.5 8.25h9m-9 3H12m-9.75 1.51c0 1.6 1.123 2.994 2.707 3.227 1.129.166 2.27.293 3.423.379.35.026.67.21.865.501L12 21l2.755-4.133a1.14 1.14 0 01.865-.501 48.172 48.172 0 003.423-.379c1.584-.233 2.707-1.626 2.707-3.228V6.741c0-1.602-1.123-2.995-2.707-3.228A48.394 48.394 0 0012 3c-2.392 0-4.744.175-7.043.513C3.373 3.746 2.25 5.14 2.25 6.741v6.018z"
              />
            </svg>
            {buttonText}
          </span>
        </button>
      </div>
    );
  }

  return (
    <div
      ref={chatContainerRef}
      className="w-full h-full rounded-2xl"
      style={{
        ...containerStyle,
        overflow: 'hidden',
      }}
      data-theme={theme}
    >
      <div 
        className="playgo-chat-container rounded-2xl bg-background-primary w-full h-full"
        style={{ 
          position: 'absolute',
          top: 0,
          left: 0,
          right: 0,
          bottom: 0,
          overflow: 'hidden'
        }}
      >
        <div className="flex flex-col h-full absolute inset-0">
          <div className="playgo-chat-header p-4 flex justify-between items-center flex-shrink-0">
            <h2 className="text-xl font-bold">
              <span className="text-[#FF6B6B]">P</span>
              <span className="text-[#4ECDC4]">l</span>
              <span className="text-[#45B7D1]">a</span>
              <span className="text-[#FDCB6E]">y</span>
              <span className="text-[#FF6B6B]">G</span>
              <span className="text-[#4ECDC4]">o</span>
              <span className="ml-2 text-[#45B7D1]">A</span>
              <span className="text-[#FDCB6E]">I</span>
            </h2>
            <button 
              onClick={() => setIsOpen(false)}
              className="p-1 hover:bg-background-secondary/50 rounded-full transition-colors"
            >
              <XMarkIcon className="w-6 h-6 text-text-secondary" />
            </button>
          </div>

          <div className="flex-1 relative">
            <div 
              className="playgo-chat-messages absolute inset-0 overflow-y-auto p-4 space-y-4"
              style={{ 
                overscrollBehavior: 'contain',
                WebkitOverflowScrolling: 'touch'
              }}
            >
              {messages.map((message, index) => (
                <div
                  key={index}
                  className={`flex ${
                    message.role === "user" ? "justify-end" : "justify-start"
                  }`}
                >
                  <div
                    className={`playgo-message-bubble ${
                      message.role === "user" 
                        ? "playgo-message-user" 
                        : "playgo-message-assistant"
                    }`}
                  >
                    {message.content}
                    {message.isStreaming && (
                      <span className="ml-1 animate-pulse">...</span>
                    )}
                  </div>
                </div>
              ))}
            </div>
          </div>

          <form
            onSubmit={handleSubmit}
            className="playgo-chat-input p-4 flex-shrink-0"
          >
            <div className="relative">
              <input
                type="text"
                value={input}
                onChange={handleInputChange}
                placeholder={placeholder}
                className="playgo-chat-input-field"
              />
              <button
                type="submit"
                disabled={isLoading || !input.trim()}
                className="absolute right-2 top-1/2 -translate-y-1/2 p-2
                         text-primary hover:text-primary/80 disabled:opacity-50
                         transition-colors duration-200"
                style={{ color: primaryColor }}
              >
                <svg
                  xmlns="http://www.w3.org/2000/svg"
                  fill="none"
                  viewBox="0 0 24 24"
                  strokeWidth={1.5}
                  stroke="currentColor"
                  className="w-6 h-6"
                >
                  <path
                    strokeLinecap="round"
                    strokeLinejoin="round"
                    d="M6 12L3.269 3.126A59.768 59.768 0 0121.485 12 59.77 59.77 0 013.27 20.876L5.999 12zm0 0h7.5"
                  />
                </svg>
              </button>
            </div>
          </form>
        </div>
      </div>
    </div>
  );
}