import { clearAuthState, fetchWithAuth } from '../../auth-session.js';

const DEFAULT_API_ERROR = 'Не удалось выполнить запрос';
const UNAUTHORIZED_ERROR = 'Требуется повторный вход в систему';

export class ApiRequestError extends Error {
    constructor(message, { data = null, status = 0 } = {}) {
        super(message);
        this.name = 'ApiRequestError';
        this.data = data;
        this.status = status;
    }
}

export async function requestJson(
    endpoint,
    { errorMessage = DEFAULT_API_ERROR, headers: initialHeaders, json, ...options } = {},
    {
        fetchImpl = fetchWithAuth,
        onUnauthorized = () => window.location.replace('/')
    } = {}
) {
    if (typeof endpoint !== 'string' || !endpoint.startsWith('/api/')) {
        throw new ApiRequestError('Разрешены только same-origin запросы к API');
    }

    const headers = new Headers(initialHeaders || {});
    headers.set('Accept', 'application/json');

    let body = options.body;
    if (json !== undefined) {
        headers.set('Content-Type', 'application/json');
        body = JSON.stringify(json);
    }

    const response = await fetchImpl(endpoint, {
        ...options,
        body,
        headers
    });
    const data = await readResponseData(response);

    if (response.status === 401) {
        clearAuthState();
        onUnauthorized();
        throw new ApiRequestError(UNAUTHORIZED_ERROR, { data, status: response.status });
    }

    if (!response.ok) {
        throw new ApiRequestError(errorMessage, { data, status: response.status });
    }

    return data;
}

export const apiClient = Object.freeze({
    delete: (endpoint, options = {}, dependencies) => requestJson(
        endpoint,
        { ...options, method: 'DELETE' },
        dependencies
    ),
    get: (endpoint, options = {}, dependencies) => requestJson(
        endpoint,
        { ...options, method: 'GET' },
        dependencies
    ),
    post: (endpoint, json, options = {}, dependencies) => requestJson(
        endpoint,
        { ...options, json, method: 'POST' },
        dependencies
    ),
    put: (endpoint, json, options = {}, dependencies) => requestJson(
        endpoint,
        { ...options, json, method: 'PUT' },
        dependencies
    )
});

async function readResponseData(response) {
    if (response.status === 204) {
        return null;
    }

    const text = await response.text();
    if (!text) {
        return null;
    }

    const contentType = response.headers.get('Content-Type') || '';
    if (!contentType.includes('application/json')) {
        return text;
    }

    try {
        return JSON.parse(text);
    } catch (error) {
        return null;
    }
}