frontend/src/services/api.js

const API_BASE = import.meta.env.PROD ? '/api' : 'http://localhost:8001/api';

export async function uploadDocument(file) {
  const formData = new FormData();
  formData.append('file', file);

  const response = await fetch(`${API_BASE}/documents/upload`, {
    method: 'POST',
    body: formData,
  });

  if (!response.ok) {
    const error = await response.json();
    throw new Error(error.detail || 'Upload failed');
  }

  return response.json();
}

export async function listDocuments() {
  const response = await fetch(`${API_BASE}/documents/`);
  if (!response.ok) throw new Error('Failed to fetch documents');
  return response.json();
}

export async function deleteDocument(docId) {
  const response = await fetch(`${API_BASE}/documents/${docId}`, {
    method: 'DELETE',
  });
  if (!response.ok) throw new Error('Failed to delete document');
  return response.json();
}

export async function sendChatMessage(question, chatHistory, onChunk, onSources, onDone, onError) {
  try {
    const response = await fetch(`${API_BASE}/chat/`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        question,
        chat_history: chatHistory,
        stream: true,
      }),
    });

    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.detail || 'Chat request failed');
    }

    const reader = response.body.getReader();
    const decoder = new TextDecoder();
    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: ')) {
          const data = line.slice(6).trim();
          if (data === '[DONE]') {
            onDone?.();
            return;
          }
          try {
            const parsed = JSON.parse(data);
            if (parsed.type === 'content') {
              onChunk?.(parsed.content);
            } else if (parsed.type === 'sources') {
              onSources?.(parsed.sources);
            } else if (parsed.type === 'error') {
              onError?.(parsed.error);
            }
          } catch (e) {
            // Skip unparseable lines
          }
        }
      }
    }
    onDone?.();
  } catch (error) {
    onError?.(error.message);
  }
}