import type {
  Board,
  Card,
  CardHistoryResponse,
  Column,
  Metrics,
  MetricsFilter,
  User,
} from "./types";

const BASE = "/api";

export class HTTPError extends Error {
  constructor(public status: number, message: string) {
    super(message);
  }
}

async function fetchJSON<T>(path: string, init?: RequestInit): Promise<T> {
  const res = await fetch(`${BASE}${path}`, {
    credentials: "include",
    ...init,
    headers: { "Content-Type": "application/json", ...(init?.headers || {}) },
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({ Message: res.statusText }));
    throw new HTTPError(res.status, err.Message || err.message || res.statusText);
  }
  if (res.status === 204) return undefined as T;
  return res.json();
}

export function getBoard(): Promise<Board> {
  return fetchJSON("/board");
}

export function createColumn(name: string): Promise<Column> {
  return fetchJSON("/columns", { method: "POST", body: JSON.stringify({ name }) });
}

export interface UpdateColumnInput {
  name?: string;
  position?: number;
  location?: "board" | "sidebar";
  width?: number;
  wip_limit?: number;
  is_done?: boolean;
}

export function updateColumn(id: string, patch: UpdateColumnInput): Promise<void> {
  return fetchJSON(`/columns/${id}`, {
    method: "PATCH",
    body: JSON.stringify(patch),
  });
}

export function deleteColumn(id: string): Promise<void> {
  return fetchJSON(`/columns/${id}`, { method: "DELETE" });
}

export function reorderColumns(ids: string[]): Promise<void> {
  return fetchJSON("/columns/reorder", { method: "POST", body: JSON.stringify({ ids }) });
}

export interface CreateCardInput {
  column_id: string;
  requester?: string;
  title: string;
  description?: string;
  assignee_id?: string | null;
}

export function createCard(input: CreateCardInput): Promise<Card> {
  return fetchJSON("/cards", { method: "POST", body: JSON.stringify(input) });
}

export interface UpdateCardInput {
  requester?: string;
  title?: string;
  description?: string;
  color?: string;
  locked?: boolean;
  assignee_id?: string | null;
}

export function updateCard(id: string, patch: UpdateCardInput): Promise<void> {
  return fetchJSON(`/cards/${id}`, { method: "PATCH", body: JSON.stringify(patch) });
}

export function deleteCard(id: string): Promise<void> {
  return fetchJSON(`/cards/${id}`, { method: "DELETE" });
}

export function listTrash(): Promise<Card[]> {
  return fetchJSON("/trash");
}

export function restoreCard(id: string): Promise<void> {
  return fetchJSON(`/cards/${id}/restore`, { method: "POST" });
}

export function purgeCard(id: string): Promise<void> {
  return fetchJSON(`/cards/${id}/purge`, { method: "DELETE" });
}

export function moveCard(id: string, column_id: string, ordered_ids: string[]): Promise<void> {
  return fetchJSON(`/cards/${id}/move`, {
    method: "POST",
    body: JSON.stringify({ column_id, ordered_ids }),
  });
}

export function cardHistory(id: string): Promise<CardHistoryResponse> {
  return fetchJSON(`/cards/${id}/history`);
}

export interface ChatMessage {
  role: "user" | "assistant";
  content: string;
}

export interface ChatToolCall {
  tool: string;
  ok: boolean;
  error?: string;
}

export interface ChatResponse {
  role: "assistant";
  content: string;
  board_changed: boolean;
  tool_calls?: ChatToolCall[];
}

export function sendChat(messages: ChatMessage[]): Promise<ChatResponse> {
  return fetchJSON("/chat", { method: "POST", body: JSON.stringify({ messages }) });
}

export function login(username: string, password: string): Promise<User> {
  return fetchJSON("/auth/login", {
    method: "POST",
    body: JSON.stringify({ username, password }),
  });
}

export function register(username: string, password: string, display_name?: string): Promise<User> {
  return fetchJSON("/auth/register", {
    method: "POST",
    body: JSON.stringify({ username, password, display_name }),
  });
}

export function logout(): Promise<void> {
  return fetchJSON("/auth/logout", { method: "POST" });
}

export function getMe(): Promise<User> {
  return fetchJSON("/me");
}

export function listUsers(): Promise<User[]> {
  return fetchJSON("/users");
}

export function getMetrics(f: MetricsFilter): Promise<Metrics> {
  const qs = new URLSearchParams();
  if (f.from) qs.set("from", f.from);
  if (f.to) qs.set("to", f.to);
  if (f.assignee_id) qs.set("assignee_id", f.assignee_id);
  if (f.requester) qs.set("requester", f.requester);
  const q = qs.toString();
  return fetchJSON(`/metrics${q ? `?${q}` : ""}`);
}