import { useState, useCallback } from 'react';

const BACKEND_URL = import.meta.env.VITE_BACKEND_URL || (import.meta.env.DEV ? 'http://localhost:8000' : '');

export default function useOperatorSSE() {
  const [toolCalls, setToolCalls] = useState([]);
  const [projectStatuses, setProjectStatuses] = useState({});
  const [briefText, setBriefText] = useState(null);
  const [isScanning, setIsScanning] = useState(false);
  const [isLive, setIsLive] = useState(false);

  const startScan = useCallback(() => {
    setToolCalls([]);
    setProjectStatuses({});
    setBriefText(null);
    setIsScanning(true);
    setIsLive(false);

    const source = new EventSource(`${BACKEND_URL}/api/run`);

    source.addEventListener('mode', (e) => {
      const data = JSON.parse(e.data);
      setIsLive(data.live);
    });

    source.addEventListener('tool_call', (e) => {
      const data = JSON.parse(e.data);
      setToolCalls(prev => [...prev, { tool: data.tool, project: data.project, status: 'running' }]);
    });

    source.addEventListener('tool_result', (e) => {
      const data = JSON.parse(e.data);
      setToolCalls(prev => {
        const updated = [...prev];
        const idx = updated.findLastIndex(t => t.tool === data.tool && t.project === data.project);
        if (idx >= 0) updated[idx] = { ...updated[idx], status: 'done' };
        return updated;
      });
    });

    source.addEventListener('initiative', (e) => {
      const data = JSON.parse(e.data);
      setProjectStatuses(prev => ({ ...prev, [data.project]: data }));
    });

    source.addEventListener('brief', (e) => {
      const data = JSON.parse(e.data);
      setBriefText(data.text);
      setIsScanning(false);
      source.close();
    });

    source.onerror = () => {
      setIsScanning(false);
      source.close();
    };
  }, []);

  const sendChat = useCallback(async (message) => {
    const res = await fetch(`${BACKEND_URL}/api/chat`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ message }),
    });

    const reader = res.body.getReader();
    const decoder = new TextDecoder();
    let replyText = '';
    let buffer = '';

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;
      buffer += decoder.decode(value, { stream: true });

      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        if (line.startsWith('data:') || line.startsWith('data: ')) {
          try {
            const data = JSON.parse(line.replace(/^data:\s*/, ''));
            if (data.type === 'chat_reply') {
              replyText = data.text;
            }
          } catch { /* skip */ }
        }
      }
    }

    return replyText;
  }, []);

  return { toolCalls, projectStatuses, briefText, isScanning, isLive, startScan, sendChat };
}