// Shared helpers: API access, DOM building, formatting

import { accessToken, redirectToLogin, refresh } from './auth.js';

const API = '/api/v1';

/** What a training without a trainer is called */
export const SOLO = 'соло';

async function send(path, options, token) {
    const headers = { ...options.headers, Authorization: `Bearer ${token}` };
    return fetch(API + path, { ...options, headers });
}

/** JSON request to the API with the access token. Without a session the browser is sent to
 *  the login page; an expired token is refreshed and the request repeated once. */
export async function api(path, options = {}) {
    const token = await accessToken();
    if (!token) {
        return redirectToLogin();
    }
    let response = await send(path, options, token);
    if (response.status === 401) {
        if (!(await refresh())) {
            return redirectToLogin();
        }
        response = await send(path, options, await accessToken());
    }
    if (!response.ok) {
        const error = new Error(`HTTP ${response.status}`);
        error.status = response.status;
        throw error;
    }
    return response.json();
}

/** h('div', {class: 'x'}, 'text', childNode) -> element; strings become text nodes */
export function h(tag, attrs = {}, ...children) {
    const element = document.createElement(tag);
    for (const [name, value] of Object.entries(attrs)) {
        if (value !== null && value !== undefined && value !== false) {
            element.setAttribute(name, value === true ? '' : value);
        }
    }
    element.append(...children.filter((child) => child !== null && child !== undefined));
    return element;
}

export function alert(kind, ...children) {
    return h('div', { class: `alert alert-${kind}` }, ...children);
}

/** "2026-10-21" -> "21.10.2026" (no Date: a timezone must not shift the day) */
export function formatDate(iso) {
    const [year, month, day] = iso.split('-');
    return `${day}.${month}.${year}`;
}

/** "First Last" of a user, the email when the name is empty. Trainers in a list come with
 *  a ready `name`. */
export function userName(user) {
    return user.name || `${user.first_name} ${user.last_name}`.trim() || user.email;
}

/** "2026-10-23T17:27:00+00:00" -> "23.10.2026 17:27" in the viewer's timezone */
export function formatDateTime(iso) {
    return new Date(iso).toLocaleString('ru-RU', { dateStyle: 'short', timeStyle: 'short' }).replace(',', '');
}

/** Rounded to one decimal without trailing zeros: 22.5 -> "22.5", 20 -> "20" */
export function num(value) {
    return String(Math.round(value * 10) / 10);
}

/** Same with an explicit sign: "+12", "-3.5", "+0" */
export function signed(value) {
    const rounded = Math.round(value * 10) / 10;
    return (rounded > 0 ? '+' : '') + rounded;
}

/** Approaches as "weight × reps" chips */
export function approachChips(approaches) {
    return approaches.map((approach) =>
        h('span', { class: 'approach' },
            `${approach.weight ? num(approach.weight) + ' кг' : 'без веса'} × ${approach.reps}`)
    );
}

export function perArmBadge() {
    return h('span', { class: 'badge text-bg-light border', title: 'Вес указан на каждую руку (гантель)' }, 'на руку');
}

export function tip(text, hint) {
    return h('span', { class: 'has-tip', title: hint }, text);
}