import React, { useState, useEffect, useRef } from 'react';
import { CurrentView } from '../types';
import { NAVIGABLE_VIEWS } from '../constants';
import { ArrowUpIcon } from './icons';
import { STRAPI_URL } from '../strapiService';

const PLACEHOLDERS = [
  "Создайте мне сайт для моего бизнеса",
  "Какие у вас есть вакансии?",
  "Расскажите о ваших услугах для бизнеса",
  "Мне нужно мобильное приложение",
  "Что такое ваш ИИ-акселератор?",
  "Я хочу научиться ИИ",
  "Покажите ваши последние исследования"
];

interface ChatInputProps {
  setCurrentView: (view: CurrentView) => void;
  isSticky?: boolean;
  autoFocusOnMount?: boolean;
}

const ChatInput: React.FC<ChatInputProps> = ({ setCurrentView, isSticky = false, autoFocusOnMount = false }) => {
  const [prompt, setPrompt] = useState('');
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [currentPlaceholderIndex, setCurrentPlaceholderIndex] = useState(0);
  const textareaRef = useRef<HTMLTextAreaElement>(null);

  useEffect(() => {
    const interval = setInterval(() => {
      setCurrentPlaceholderIndex((prevIndex) => (prevIndex + 1) % PLACEHOLDERS.length);
    }, 5000); // Change placeholder every 5 seconds
    return () => clearInterval(interval);
  }, []);

  useEffect(() => {
    if (textareaRef.current) {
      textareaRef.current.style.height = 'auto';
      textareaRef.current.style.height = `${textareaRef.current.scrollHeight}px`;
    }
  }, [prompt]);
  
  useEffect(() => {
    if (autoFocusOnMount && textareaRef.current) {
      // Small timeout to ensure the element is fully visible and transitions are complete before focusing
      const timer = setTimeout(() => {
          textareaRef.current?.focus();
      }, 100); 
      return () => clearTimeout(timer);
    }
  }, [autoFocusOnMount]);

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!prompt.trim() || isLoading) return;

    setIsLoading(true);
    setError(null);

    const validViewsString = NAVIGABLE_VIEWS.join(', ');
    const systemInstruction = `You are an expert navigation assistant for a website. Your task is to analyze the user's query and determine which section of the website they want to visit. Respond ONLY with a JSON object containing a single key "view". The possible values for "view" are: ${validViewsString}.

    Here are some examples of user queries and your expected JSON response:
    - "I want to see your work" -> {"view": "storiesAll"}
    - "Do you have any jobs?" -> {"view": "careers"}
    - "What services do you offer for businesses?" -> {"view": "businessServices"}
    - "I need a website" or "I need a program" -> {"view": "businessServices"}
    - "Tell me about your company" -> {"view": "about"}
    - "How can I contact you?" -> {"view": "main"}
    - "What AI research do you do?" -> {"view": "researchAll"}
    - "I want to learn AI" -> {"view": "educationStudents"}
    - "I have an idea" or "I have a project" -> {"view": "acceleratorAbout"}
    - "Do you have an accelerator?" -> {"view": "acceleratorAbout"}

    If the user's query is about having an idea or a project they want to develop, direct them to the accelerator. If they explicitly want to order a service like a website or an app, direct them to business services.

    If the user's query is unclear or doesn't map to a specific view, respond with {"view": "main"}.
    Your entire response must be only the JSON object, with no other text, explanation, or markdown formatting.`;

    try {
      // Запрос через прокси Strapi (/api/ollama/chat) — один origin с фронтом, нет CORS и работает из любой сети
      const response = await fetch(`${STRAPI_URL}/api/ollama/chat`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          model: 'gemma3n:e4b',
          messages: [
            { role: 'system', content: systemInstruction },
            { role: 'user', content: prompt }
          ],
          stream: false,
        }),
      });

      if (!response.ok) {
        throw new Error(`Ошибка сети: ${response.status} ${response.statusText}. Убедитесь, что бэкенд и Ollama доступны.`);
      }

      const data = await response.json();
      
      if (data.error) {
        throw new Error(`Сервер ИИ вернул ошибку: ${typeof data.error === 'string' ? data.error : data.error.message || 'неизвестная ошибка'}`);
      }

      // Ответ Ollama в /api/chat (без стриминга):
      // { message: { role: 'assistant', content: '...' }, ... }
      const responseJsonString = data.message?.content;
      if (!responseJsonString) {
        throw new Error("Сервер ИИ вернул пустой ответ.");
      }

      // More robust JSON extraction
      let parsedData = null;
      const jsonMatch = responseJsonString.match(/\{[\s\S]*\}/);
      if (jsonMatch) {
        try {
          parsedData = JSON.parse(jsonMatch[0]);
        } catch (e) {
          // JSON might be invalid, fall through to error
          console.error("Failed to parse JSON from response:", e);
        }
      }
      
      if (parsedData && parsedData.view && NAVIGABLE_VIEWS.includes(parsedData.view as any)) {
        setCurrentView(parsedData.view);
      } else {
        setError("К сожалению, я не смог понять ваш запрос. Попробуйте переформулировать.");
      }
    } catch (err: any) {
      console.error("Ошибка при обращении к серверу ИИ (Ollama):", err);
      setError(err.message || "Произошла ошибка. Убедитесь, что бэкенд и сервер Ollama доступны. Пожалуйста, попробуйте еще раз.");
    } finally {
      setIsLoading(false);
    }
  };
  
  const wrapperClasses = isSticky ? "" : "relative z-10 mx-auto w-full max-w-3xl";

  const baseLabelClasses = "relative flex w-full cursor-text flex-col overflow-hidden rounded-3xl py-3 pl-4 pr-14 transition-all duration-300";
  
  const nonStickyLabelClasses = "border border-slate-200 bg-white shadow-sm focus-within:shadow-md";
  const stickyLabelClasses = "border border-slate-300 bg-white/80 shadow-lg backdrop-blur-xl focus-within:shadow-xl";

  const labelClasses = `${baseLabelClasses} ${isSticky ? stickyLabelClasses : nonStickyLabelClasses}`;


  return (
    <div className={wrapperClasses}>
      <form onSubmit={handleSubmit} className="relative">
        <label className={labelClasses}>
          <div className={`text-slate-400 min-h-[24px] pointer-events-none absolute left-0 top-0 w-full select-none px-4 pt-[18px] text-base transition-opacity duration-200 ${prompt ? 'opacity-0' : 'opacity-100'}`} aria-hidden={!!prompt}>
            <div className="transition-transform ease-in-out duration-300" style={{ transform: `translateY(-${currentPlaceholderIndex * 1.5}rem)` }}>
              {PLACEHOLDERS.map((text, index) => (
                <div key={index} className={`overflow-hidden text-ellipsis whitespace-nowrap transition-opacity duration-300 ${currentPlaceholderIndex === index ? 'opacity-100' : 'opacity-0'}`}>
                  {text}
                </div>
              ))}
            </div>
          </div>
          <textarea
            ref={textareaRef}
            value={prompt}
            onChange={(e) => setPrompt(e.target.value)}
            onKeyDown={(e) => { if (e.key === 'Enter' && !e.shiftKey) handleSubmit(e); }}
            className="w-full resize-none bg-transparent text-base focus:outline-none text-slate-800"
            rows={1}
            style={{ minHeight: '24px' }}
            aria-label="Задайте ваш вопрос"
          />
        </label>
        <div className="absolute bottom-2 right-2 mt-auto flex justify-end">
          <button
            className="bg-slate-800 text-white disabled:bg-slate-200 disabled:text-slate-400 relative h-10 w-10 rounded-full p-0 transition-colors hover:bg-black disabled:hover:bg-slate-200 flex items-center justify-center"
            type="submit"
            disabled={!prompt.trim() || isLoading}
            aria-label="Отправить запрос"
          >
            {isLoading ? (
              <svg className="animate-spin h-5 w-5 text-white" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
                <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4"></circle>
                <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
              </svg>
            ) : (
              <ArrowUpIcon className="w-5 h-5" />
            )}
          </button>
        </div>
      </form>
      {error && <p className="mt-2 text-center text-sm text-red-600">{error}</p>}
    </div>
  );
};

export default ChatInput;