/**
 * API client for the LLM Council backend.
 */

const API_BASE = 'http://localhost:8001';

export const api = {
  /**
   * List all conversations.
   */
  async listConversations() {
    const response = await fetch(`${API_BASE}/api/conversations`);
    if (!response.ok) {
      throw new Error('Failed to list conversations');
    }
    return response.json();
  },

  /**
   * Create a new conversation.
   */
  async createConversation() {
    const response = await fetch(`${API_BASE}/api/conversations`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({}),
    });
    if (!response.ok) {
      throw new Error('Failed to create conversation');
    }
    return response.json();
  },

  /**
   * Get a specific conversation.
   */
  async getConversation(conversationId) {
    const response = await fetch(
      `${API_BASE}/api/conversations/${conversationId}`
    );
    if (!response.ok) {
      throw new Error('Failed to get conversation');
    }
    return response.json();
  },

  /**
   * Send a message in a conversation.
   */
  async sendMessage(conversationId, content) {
    const response = await fetch(
      `${API_BASE}/api/conversations/${conversationId}/message`,
      {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ content }),
      }
    );
    if (!response.ok) {
      throw new Error('Failed to send message');
    }
    return response.json();
  },

  /**
   * Send a message and receive streaming updates.
   * @param {string} conversationId - The conversation ID
   * @param {string} content - The message content
   * @param {function} onEvent - Callback function for each event: (eventType, data) => void
   * @returns {Promise<void>}
   */
  async sendMessageStream(conversationId, content, onEvent, signal) {
    const response = await fetch(
      `${API_BASE}/api/conversations/${conversationId}/message/stream`,
      {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ content }),
        signal,
      }
    );

    if (!response.ok) {
      throw new Error('Failed to send message');
    }

    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 });

      // Split on double newline (SSE event boundary)
      const parts = buffer.split('\n\n');
      // Last part may be incomplete — keep it in buffer
      buffer = parts.pop();

      for (const part of parts) {
        const lines = part.split('\n');
        for (const line of lines) {
          if (line.startsWith('data: ')) {
            const data = line.slice(6);
            try {
              const event = JSON.parse(data);
              onEvent(event.type, event);
            } catch (e) {
              console.error('Failed to parse SSE event:', e);
            }
          }
        }
      }
    }
  },
};