import React, { useEffect, useRef } from 'react';

export interface Message {
  id: string;
  role: 'user' | 'assistant' | 'status';
  content: string;
  isError?: boolean;
  retryPayload?: Message;
}

interface ChatWorkspaceProps {
  messages: Message[];
  isLoading: boolean;
  onSendMessage: (message: string) => void;
  onRetry: (originalMessage: Message, errorStatusId: string) => void;
  composerValue: string;
  setComposerValue: (value: string) => void;
  composerRef: React.RefObject<HTMLTextAreaElement>;
}

const StarterPrompts = ({ onSelect }: { onSelect: (prompt: string) => void }) => {
  const prompts = [
    'Gi meg en kort status på det viktigste jeg bør følge opp.',
    'Hjelp meg å strukturere neste arbeidsøkt.',
    'Oppsummer risikoer og neste beslutninger.',
    'Lag et utkast til en konkret oppfølgingsplan.',
  ];

  return (
    <div className="empty-state">
      <div className="empty-state-mark">◇</div>
      <h1>Hva vil du få oversikt over i dag?</h1>
      <p>Emma hjelper deg å strukturere arbeid, analysere situasjoner og finne tydelige neste steg.</p>
      <div className="starter-prompts">
        {prompts.map((p) => (
          <button key={p} className="starter-prompt" onClick={() => onSelect(p)}>
            {p}
          </button>
        ))}
      </div>
    </div>
  );
};

const PromptComposer = ({ onSend, isLoading, value, setValue, composerRef }: {
  onSend: (val: string) => void;
  isLoading: boolean;
  value: string;
  setValue: (val: string) => void;
  composerRef: React.RefObject<HTMLTextAreaElement>;
}) => {
  useEffect(() => {
    if (composerRef.current) {
      composerRef.current.style.height = 'auto';
      composerRef.current.style.height = `${composerRef.current.scrollHeight}px`;
    }
  }, [value, composerRef]);

  const handleSend = () => {
    if (value.trim()) onSend(value.trim());
  };

  const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      handleSend();
    }
  };

  return (
    <div className="composer-container">
      <div className="composer-inner">
        <div className="composer">
          <textarea
            ref={composerRef}
            value={value}
            onChange={(e) => setValue(e.target.value)}
            onKeyDown={handleKeyDown}
            placeholder="Spør Emma om status, analyse eller neste steg …"
            disabled={isLoading}
            rows={1}
            aria-label="Chat message input"
          />
          <button onClick={handleSend} disabled={isLoading || !value.trim()} aria-label="Send message">
            ▲
          </button>
        </div>
      </div>
    </div>
  );
};

const ChatWorkspace: React.FC<ChatWorkspaceProps> = ({ messages, isLoading, onSendMessage, onRetry, composerValue, setComposerValue, composerRef }) => {
  const scrollRef = useRef<HTMLDivElement>(null);

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

  const handleStarterSelect = (prompt: string) => {
    setComposerValue(prompt);
    setTimeout(() => {
      if (composerRef.current) {
        composerRef.current.focus();
        composerRef.current.setSelectionRange(prompt.length, prompt.length);
      }
    }, 0);
  };

  return (
    <div className="chat-workspace">
      <div className="transcript" ref={scrollRef}>
        <div className="transcript-inner">
          {messages.length === 0 && !isLoading ? (
            <StarterPrompts onSelect={handleStarterSelect} />
          ) : (
            messages.map((msg) => {
              if (msg.role === 'status' && msg.isError) {
                return (
                  <div key={msg.id} className="message assistant">
                    <div className="error-message" role="alert">
                      <p>{msg.content}</p>
                      {msg.retryPayload && <button onClick={() => onRetry(msg.retryPayload!, msg.id)}>Prøv igjen</button>}
                    </div>
                  </div>
                );
              }
              return (
                <div key={msg.id} className={`message ${msg.role}`}>
                  <div className="message-content">
                    <div className="message-role" aria-hidden="true">{msg.role}</div>
                    <p>{msg.content}</p>
                  </div>
                </div>
              );
            })
          )}
          {isLoading && (
            <div className="message assistant">
              <div className="message-content">
                <div className="loading-indicator" aria-live="polite">Emma tenker …</div>
              </div>
            </div>
          )}
        </div>
      </div>
      <PromptComposer
        onSend={onSendMessage}
        isLoading={isLoading}
        value={composerValue}
        setValue={setComposerValue}
        composerRef={composerRef}
      />
    </div>
  );
};

export default ChatWorkspace;