import * as config from "./config";
import fetch, { Response as FetchResponse } from "node-fetch";

export interface TokenPair {
	access_token: string;
	refresh_token: string;
}

// Refresh the API token. Returns true on success and false on failure.
async function refreshApiToken(tokens: TokenPair): Promise<boolean> {
	return fetch("https://id.twitch.tv/oauth2/token", {
		method: 'POST',
		body: new URLSearchParams({
			client_id: config.twitchClientId,
			client_secret: config.twitchSecret,
			grant_type: "refresh_token",
			refresh_token: tokens.refresh_token
		})
	}).then(async (res: FetchResponse) => {
		if (res.status == 200) {
			var data = await (res.json() as Promise<TokenPair>);
			tokens.access_token = data.access_token;
			tokens.refresh_token = data.refresh_token;
			return true;
		} else {
			return false;
		}
	})
}

// Send an API request. On success, return the specified data. On failure,
// attempt to refresh the API token and retry
export async function apiRequest(tokens: TokenPair, endpoint: string): Promise <any> {
	var headers = {
		"Authorization": "Bearer " + tokens.access_token,
		"Client-ID": config.twitchClientId
	};
	return fetch("https://api.twitch.tv/helix" + endpoint, { headers: headers })
		.then((res: FetchResponse) => {
			if (res.status == 200) {
				return res.json();
			} else {
				if (refreshApiToken(tokens)) {
					return fetch("https://api.twitch.tv/helix" + endpoint, { headers: headers })
						.then(async (res: FetchResponse) => {
							if (res.status == 200) {
								return res.json();
							} else {
								console.log("Failed API request:");
								console.log("Request URL: https://api.twitch.tv/helix" + endpoint);
								console.log("Headers: ");
								console.log(headers);
								console.log("Response: ");
								console.log(await res.json());
								return false;
							}
					})
				} else {
					return false;
				}
			}
		})
}

// Check if API token is valid. Checks Twitch's OAuth validation endpoint. If
// success, return true. If failure, return the result of attempting to refresh
// the API token.
export async function isApiTokenValid(tokens: TokenPair) {
	return fetch("https://id.twitch.tv/oauth2/validate", {
		headers: {'Authorization': `OAuth ${tokens.access_token}`}
	}).then((res: FetchResponse) => {
		if (res.status == 200) {
			return true;
		} else {
			return refreshApiToken(tokens);
		}
	})
}