export type ChatSummary = {
  id: string;
  title: string | null;
  createdAt: string;
  updatedAt: string;
};

export type Message = {
  id: string;
  createdAt: string;
  role: "system" | "user" | "assistant" | "tool";
  content: string;
  name: string | null;
};

export type ChatDetail = {
  id: string;
  title: string | null;
  createdAt: string;
  updatedAt: string;
  messages: Message[];
};

export type CompletionRequestMessage = {
  role: "system" | "user" | "assistant" | "tool";
  content: string;
  name?: string;
};

type CompletionResponse = {
  chatId: string | null;
  message: {
    role: "assistant";
    content: string;
  };
};

const API_BASE_URL = import.meta.env.VITE_API_BASE_URL ?? "http://localhost:8787";
const ENV_ADMIN_TOKEN = (import.meta.env.VITE_ADMIN_TOKEN as string | undefined)?.trim() || null;
let authToken: string | null = ENV_ADMIN_TOKEN;

export function getConfiguredToken() {
  return ENV_ADMIN_TOKEN;
}

export function setAuthToken(token: string | null) {
  authToken = token?.trim() || null;
}

async function api<T>(path: string, init?: RequestInit): Promise<T> {
  const headers = new Headers(init?.headers ?? {});
  headers.set("Content-Type", "application/json");
  if (authToken) {
    headers.set("Authorization", `Bearer ${authToken}`);
  }

  const response = await fetch(`${API_BASE_URL}${path}`, {
    ...init,
    headers,
  });

  if (!response.ok) {
    const fallback = `${response.status} ${response.statusText}`;
    let message = fallback;
    try {
      const body = (await response.json()) as { message?: string };
      if (body.message) message = body.message;
    } catch {
      // keep fallback message
    }
    throw new Error(message);
  }

  return (await response.json()) as T;
}

export async function listChats() {
  const data = await api<{ chats: ChatSummary[] }>("/v1/chats");
  return data.chats;
}

export async function verifySession() {
  return api<{ authenticated: true; mode: "open" | "token" }>("/v1/auth/session");
}

export async function createChat(title?: string) {
  const data = await api<{ chat: ChatSummary }>("/v1/chats", {
    method: "POST",
    body: JSON.stringify({ title }),
  });
  return data.chat;
}

export async function getChat(chatId: string) {
  const data = await api<{ chat: ChatDetail }>(`/v1/chats/${chatId}`);
  return data.chat;
}

export async function runCompletion(body: {
  chatId: string;
  provider: "openai" | "anthropic" | "xai";
  model: string;
  messages: CompletionRequestMessage[];
}) {
  return api<CompletionResponse>("/v1/chat-completions", {
    method: "POST",
    body: JSON.stringify(body),
  });
}