// Единое место для всех HTTP-запросов к бэкенду.
// Порт web/api_client.py. Базовый путь /api проксируется nginx (прод) или Vite (dev) на api:8000.

const BASE = "/api";

// ---------------------------------------------------------------------------
// Типы
// ---------------------------------------------------------------------------
export interface Me {
  id: string;
  first_name?: string;
  last_name?: string;
  group_id?: string | null;
  organization_id?: string | null;
}

export interface Organization {
  id: string;
  name_organization: string;
  group_id?: string | null;
}

export interface Group {
  id: string;
  name_group: string;
}

export interface Choice {
  id: string;
  text: string;
}

export interface Question {
  id: string;
  text: string;
  choices: Choice[];
}

export interface Poll {
  id: string;
  title: string;
  description?: string | null;
  questions?: Question[];
}

export interface Answer {
  question_id: string;
  choice_id: string;
  text?: string | null;
}

export interface ResponseDetail {
  id: string;
  poll_id: string;
  submitted_at: string;
  answers: Answer[];
}

export interface UserResponse {
  id: string;
  poll_id: string;
  submitted_at: string;
}

export interface RadarResult {
  image_url?: string | null;
  [k: string]: unknown;
}

export type Result<T> = { data: T | null; error: string | null };

// ---------------------------------------------------------------------------
// Низкоуровневые помощники
// ---------------------------------------------------------------------------
function authHeaders(token?: string | null): Record<string, string> {
  return token ? { Authorization: `Bearer ${token}` } : {};
}

async function safeJson(resp: Response): Promise<any> {
  try {
    return await resp.json();
  } catch {
    return null;
  }
}

// GET, возвращает распарсенный JSON или null при любой ошибке (как в api_client.py)
async function getJson<T>(path: string, token?: string | null): Promise<T | null> {
  try {
    const resp = await fetch(BASE + path, { headers: authHeaders(token) });
    if (resp.ok) return (await resp.json()) as T;
  } catch {
    /* network error -> null */
  }
  return null;
}

// ---------------------------------------------------------------------------
// Auth
// ---------------------------------------------------------------------------
export async function login(username: string, password: string): Promise<Result<string>> {
  try {
    const body = new URLSearchParams({ username, password });
    const resp = await fetch(BASE + "/auth/login", {
      method: "POST",
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body,
    });
    if (resp.ok) {
      const json = await resp.json();
      return { data: json.access_token, error: null };
    }
    if (resp.status === 401) return { data: null, error: "Неверный логин или пароль" };
    return { data: null, error: `Ошибка сервера: ${resp.status}` };
  } catch {
    return { data: null, error: "Не удалось подключиться к серверу" };
  }
}

export async function logout(token: string): Promise<void> {
  try {
    await fetch(BASE + "/auth/logout", { method: "POST", headers: authHeaders(token) });
  } catch {
    /* локальный logout произойдёт в любом случае */
  }
}

export async function getMe(token: string): Promise<Me | null> {
  return getJson<Me>("/users/me", token);
}

const FIELD_NAMES: Record<string, string> = { password: "Пароль", username: "Логин" };
const MSG_MAP: Record<string, string> = {
  "Password must be at least 8 characters": "Пароль должен быть не менее 8 символов",
  "Username must be at least 3 characters": "Логин должен быть не менее 3 символов",
};

export interface RegisterPayload {
  username: string;
  password: string;
  first_name: string;
  last_name: string;
  group_id?: string | null;
  organization_id?: string | null;
}

// Возвращает строку с ошибкой или null при успехе (как register в api_client.py)
export async function register(p: RegisterPayload): Promise<string | null> {
  const payload: Record<string, unknown> = {
    username: p.username,
    password: p.password,
    first_name: p.first_name,
    last_name: p.last_name,
  };
  if (p.group_id) payload.group_id = p.group_id;
  if (p.organization_id) payload.organization_id = p.organization_id;

  try {
    const resp = await fetch(BASE + "/auth/register", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (resp.status === 201) return null;
    const json = await safeJson(resp);
    if (resp.status === 400) return json?.detail ?? "Ошибка регистрации";
    if (resp.status === 422) {
      const errors: any[] = json?.detail ?? [];
      for (const err of errors) {
        const raw = err?.ctx?.error || err?.msg || "";
        if (raw in MSG_MAP) return MSG_MAP[raw];
        const loc: any[] = err?.loc ?? [];
        const field = FIELD_NAMES[loc[loc.length - 1]] ?? "";
        const msg = (err?.msg ?? "Ошибка валидации").replace(/^Value error, /, "");
        return `${field}: ${msg}`.replace(/^: |:?\s*$/g, "").trim() || "Проверьте правильность введённых данных";
      }
      return "Проверьте правильность введённых данных";
    }
    return `Ошибка сервера: ${resp.status}`;
  } catch {
    return "Не удалось подключиться к серверу";
  }
}

// ---------------------------------------------------------------------------
// Organizations & Groups
// ---------------------------------------------------------------------------
export async function getOrganizations(): Promise<Organization[]> {
  return (await getJson<Organization[]>("/organizations/")) ?? [];
}

export async function getGroups(): Promise<Group[]> {
  return (await getJson<Group[]>("/groups/")) ?? [];
}

// ---------------------------------------------------------------------------
// Polls
// ---------------------------------------------------------------------------
export async function getPolls(): Promise<Poll[]> {
  return (await getJson<Poll[]>("/polls/")) ?? [];
}

export async function getPoll(pollId: string): Promise<Poll | null> {
  return getJson<Poll>(`/polls/${pollId}`);
}

export async function getResponse(responseId: string): Promise<ResponseDetail | null> {
  return getJson<ResponseDetail>(`/polls/responses/${responseId}`);
}

export async function getRadarResult(responseId: string): Promise<RadarResult | null> {
  return getJson<RadarResult>(`/responses/${responseId}/radar`);
}

// URL SVG-диаграммы — браузер тянет напрямую с того же origin (через nginx-прокси).
export function radarImageUrl(responseId: string): string {
  return `${BASE}/responses/${responseId}/radar/image`;
}

export interface SubmitPayload {
  user_id?: string | null;
  group_id?: string | null;
  organization_id?: string | null;
}

export async function submitResponse(
  pollId: string,
  answers: Answer[],
  extra: SubmitPayload = {},
): Promise<Result<string>> {
  const payload: Record<string, unknown> = { answers };
  if (extra.user_id) payload.user_id = extra.user_id;
  if (extra.group_id) payload.group_id = extra.group_id;
  if (extra.organization_id) payload.organization_id = extra.organization_id;
  try {
    const resp = await fetch(BASE + `/polls/${pollId}/responses`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (resp.status === 201) {
      const json = await resp.json();
      return { data: json.id, error: null };
    }
    return { data: null, error: `Ошибка сервера: ${resp.status}` };
  } catch {
    return { data: null, error: "Не удалось подключиться к серверу" };
  }
}

export async function getUserResponses(userId: string): Promise<UserResponse[]> {
  return (await getJson<UserResponse[]>(`/polls/users/${userId}/responses`)) ?? [];
}

export interface UpdateUserPayload {
  first_name?: string | null;
  last_name?: string | null;
  group_id?: string | null;
  organization_id?: string | null;
}

export async function updateUser(
  userId: string,
  token: string,
  payload: UpdateUserPayload,
): Promise<Result<Me>> {
  const body: Record<string, unknown> = {};
  if (payload.first_name !== undefined) body.first_name = payload.first_name;
  if (payload.last_name !== undefined) body.last_name = payload.last_name;
  if (payload.group_id !== undefined) body.group_id = payload.group_id;
  if (payload.organization_id !== undefined) body.organization_id = payload.organization_id;
  try {
    const resp = await fetch(BASE + `/users/${userId}`, {
      method: "PUT",
      headers: { "Content-Type": "application/json", ...authHeaders(token) },
      body: JSON.stringify(body),
    });
    if (resp.ok) return { data: await resp.json(), error: null };
    return { data: null, error: `Ошибка сервера: ${resp.status}` };
  } catch {
    return { data: null, error: "Не удалось подключиться к серверу" };
  }
}