import urls, { normalizeUrl } from '@cloudpss/env';
import * as defaultFetcher from '@cloudpss/fetch';

/** HTTP client 使用的 fetch 实现 */
export type HttpFetcher = Pick<typeof defaultFetcher, 'fetch' | 'Request' | 'Response' | 'Headers'>;

/** HTTP 选项 */
interface HttpClientOptionsBase {
    /** 使用的 token */
    token?: string;
    /** 使用的其他 token */
    altTokens: readonly string[];
    /** API 地址，eg: https://cloudpss.net/api */
    apiUrl: string;
    /** 使用 `X-Http-Method` `X-Http-Path` 进行访问 */
    apiTunnel?: boolean;
    /** GraphQL 地址，eg: https://cloudpss.net/graphql */
    gqlUrl: string;
    /** fetch 实现 */
    fetcher: HttpFetcher;
    /** WebSocket 实现 */
    webSocket: typeof WebSocket;
    /** 是否为开发环境 */
    dev: boolean;
}

/** HTTP 选项 */
export type HttpClientOptions = Partial<HttpClientOptionsBase>;
/** HTTP 配置 */
export type HttpClientConfig = Readonly<HttpClientOptionsBase>;

/** 检查 JWT */
function simpleCheckToken(token: string): void {
    if (!/^(?:[\w-]+\.){2}[\w-]+$/g.test(token)) {
        throw new Error(`Invalid JWT token.`);
    }
}

/** 获取 token */
function getToken(token?: string): string | undefined {
    if (token == null || token === '') return undefined;
    if (typeof token != 'string') throw new Error('token must be a string');
    simpleCheckToken(token);
    return token;
}

/** 获取 url */
function getUrl(url: string | undefined): string | undefined {
    if (!url) return undefined;
    return normalizeUrl(url);
}

/** 校验并生成完整配置 */
export function createConfig(options: HttpClientOptions = {}): HttpClientConfig {
    const token = getToken(options.token);
    const altTokens = Object.freeze(
        (options.altTokens ?? (options as { alterTokens?: string[] }).alterTokens ?? [])
            .map((t) => getToken(t))
            .filter((t): t is string => t != null),
    );
    const apiUrl = getUrl(options.apiUrl);
    const gqlUrl = getUrl(options.gqlUrl);
    return Object.freeze({
        token,
        altTokens,
        get apiUrl() {
            return apiUrl ?? urls.API_URL;
        },
        apiTunnel: !!options.apiTunnel,
        get gqlUrl() {
            return gqlUrl ?? urls.GQL_URL;
        },
        fetcher: options.fetcher ?? defaultFetcher,
        webSocket: options.webSocket ?? defaultFetcher.WebSocket,
        dev: !!options.dev,
    });
}