export async function GetBlueskyDID(PDS, Handle) {
	let request = fetch(PDS + "/xrpc/com.atproto.identity.resolveDid?handle=" + Handle, { method: "GET"})
	.then((response) => response.json());
	return request;
}

// Component 1/4
export async function GetPDSWellKnown() {
	let Data = await fetch("https://bsky.social/.well-known/oauth-authorization-server", {method: "GET"})
	.then((response) => response.json());
	return Data;
}

// Component 2/4
// Many thanks to https://github.com/tonyxu-io/pkce-generator. It was the base for this code.
export async function CreatePKCECodeVerifier() {
	// Generate some Numbers
	let Numbers = new Uint8Array(32);
	crypto.getRandomValues(Numbers);
	// Generate a random string of characters.
	let CodeVerifier = "";
	for (let i in Numbers) {
		CodeVerifier += String.fromCharCode(Numbers[i]);
	}
	// Put this random string into Base64URL format.
	CodeVerifier = btoa(CodeVerifier).replace(/=/g, '').replace(/\+/g, '-').replace(/\//g, '_');
	return CodeVerifier;
}

export async function CreatePKCECodeChallenge(CodeVerifier) {
	// Generate a code challenge with the code verifier.
	// This is done by first SHA256 encrypting the CodeVerifier, then putting the outputted string into Base64URL format.
	let CodeChallenge = btoa(await sha256(CodeVerifier)).replace(/=/g, '').replace(/\+/g, '-').replace(/\//g, '_');
	return CodeChallenge;
}

// Component 3/4
export async function PARrequest(PAREndpoint, State, ChallengeCode) {
	return fetch(PAREndpoint, {method: "POST", body: new URLSearchParams({ response_type: "code", code_challenge_method: "S256", scope: "atproto transition:generic", client_id: "https://fedi.crowdedgames.group/oauth/client-metadata.json", redirect_uri: "https://fedi.crowdedgames.group/HTML/setting.html", code_challenge: ChallengeCode, state: State, login_hint: "crowdedgames.group" }), headers: {"Content-Type": "application/x-www-form-urlencoded"}});
}

export async function AuthRequest(TokenEndpoint, ChallengeVerifier, code, DPoP) {
	return fetch(TokenEndpoint, {method: "POST", body: new URLSearchParams({ grant_type: "authorization_code", code: code, client_id: "https://fedi.crowdedgames.group/oauth/client-metadata.json", redirect_uri: "https://fedi.crowdedgames.group/HTML/setting.html", code_verifier: ChallengeVerifier}), headers: { "DPoP": DPoP, "Content-Type": "application/x-www-form-urlencoded"}});
}

// Component 4/4
export async function ClientDPoP(POSTorGET, RequestURL, DPoPNonce) {	
	let KeyPair = await crypto.subtle.generateKey({name: "ECDSA", namedCurve: "P-256"}, true, ["sign", "verify"]);
	
	// Header
	var Header = {alg: "ES256", typ: "dpop+jwt", jwk: await crypto.subtle.exportKey("jwk", KeyPair.publicKey).then(function(response) {return response})};
	// Payload
	var Payload = {};
	Payload.jti = GenerateToken(64);
	Payload.htm = POSTorGET;
	Payload.htu = RequestURL;
	Payload.iat = Math.floor(new Date(Date.now()).getTime() / 1000);
	Payload.iss = "https://fedi.crowdedgames.group/oauth/client-metadata.json";
	Payload.nonce = DPoPNonce;

	var sHeader = JSON.stringify(Header);
	var sPayload = JSON.stringify(Payload);
	var JWT = KJUR.jws.JWS.sign("ES256", sHeader, sPayload, await crypto.subtle.exportKey("jwk", KeyPair.privateKey).then(function(response) {return response}));
	console.log(JWT);
	return JWT;
}

// So far does nothing? Don't touch :3
export async function AssertionJWT() {
	let KeyPair = await crypto.subtle.generateKey({name: "ECDSA", namedCurve: "P-256"}, true, ["sign", "verify"]);
	
	// Header
	var Header = {alg: "HS256", kid: await crypto.subtle.exportKey("jwk", KeyPair.publicKey).then(function(response) {return response})};
	// Payload
	var Payload = {};
	
	Payload.iss = "https://fedi.crowdedgames.group/oauth/client-metadata.json";
	Payload.sub = "https://fedi.crowdedgames.group/oauth/client-metadata.json";
	// Payload.aud
	Payload.jti = GenerateToken(64);
	Payload.iat = Math.floor(new Date(Date.now()).getTime() / 1000);

	var sHeader = JSON.stringify(Header);
	var sPayload = JSON.stringify(Payload);
	var JWT = KJUR.jws.JWS.sign("HS256", sHeader, sPayload, "838383");
}

export async function HandleAuthorization(BlueskyPKCEverifer, BlueskyPKCEchallenge, BlueskyNonce) {
	// Declare Variables
	let KeyPair = await crypto.subtle.generateKey({name: "ECDSA", namedCurve: "P-256"}, true, ["sign", "verify"]);
	
	let WellKnown = await GetPDSWellKnown();
	let PAREndpoint = WellKnown.pushed_authorization_request_endpoint;
	
	let State = GenerateToken(64);
	
	let PKCEverifier = await CreatePKCECodeVerifier();
	let PKCEchallenge = await CreatePKCECodeChallenge(PKCEverifier);
	// PAR request (beginning)
	let PAR = PARrequest(WellKnown.pushed_authorization_request_endpoint, State, PKCEchallenge);
	let body = await PAR.then((response) => response.json());
	let nonce = await PAR.then((response) => response.headers.get("dpop-nonce"));
	
	let ExportedKey1 = await crypto.subtle.exportKey("raw", KeyPair.publicKey);
	// Save these things.
	document.cookie = BlueskyPKCEverifer + "=" + PKCEverifier + ";samesite=strict;path=/;expires=Fri, 31 Dec 9999 23:59:59 GMT;";
	document.cookie = BlueskyPKCEchallenge + "=" + PKCEchallenge + ";samesite=strict;path=/;expires=Fri, 31 Dec 9999 23:59:59 GMT;";
	document.cookie = BlueskyNonce + "=" + nonce + ";samesite=strict;path=/;expires=Fri, 31 Dec 9999 23:59:59 GMT;";
	// Don't remove the keys. They are important.
	// if (document.cookie.split("; ").find((row) => row.startsWith(BlueskyPublicKey + "="))?.split("=").length == 1 || document.cookie.split("; ").find((row) => row.startsWith(BlueskyPrivateKey + "="))?.split("=").length == 1) {
	//	document.cookie = BlueskyPublicKey + "=" + ExportedKey1 + ";samesite=strict;path=/;expires=Fri, 31 Dec 9999 23:59:59 GMT;";
	// }
	// Now we need to authenticate. Make sure the State stays the same throughout this whole process :]
	document.location.href = "https://bsky.social/oauth/authorize?client_id=https://fedi.crowdedgames.group/oauth/client-metadata.json&request_uri=" + body.request_uri;
}

export async function GainTokens(PKCEcodeName, NonceName) {
	if ((document.location.href.split("state=").length > 1 && document.location.href.split("iss=").length > 1 && document.location.href.split("code=").length > 1) && document.cookie.split("; ").find((row) => row.startsWith(PKCEcodeName + "="))?.split("=").length > 1) {
		let DPoP = ClientDPoP("POST", "https://bsky.social/oauth/token", document.cookie.split("; ").find((row) => row.startsWith(NonceName + "="))?.split("=")[1]);
		let PKCE = document.cookie.split("; ").find((row) => row.startsWith(PKCEcodeName + "="))?.split("=")[1];
		let code = document.location.href.split("code=")[1];
		console.log(code);
		let Auth = AuthRequest("https://bsky.social/oauth/token", PKCE, code, DPoP);
		console.log(AuthRequest);
	}
}

// Stolen from elsewhere.
// Firefox snippet; Slightly edited.
async function sha256(message) {
	// encode as UTF-8
	const MessageBuffer = new TextEncoder().encode(message);                    
	
	// hash the message
	const HashBuffer = await crypto.subtle.digest('SHA-256', MessageBuffer);
	
	// convert ArrayBuffer to Array
	const HashArray = Array.from(new Uint8Array(HashBuffer));
	
	// convert this hashArray to a string
	let string = "";
	for (let i in HashArray) {
		string += String.fromCharCode(HashArray[i]);
	}
	
	return string;
}

// Stolen from Search
// TODO: implement my own function.
export function GenerateToken(length) {
    var chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    var token = '';
    for(var i = 0; i < length; i++) {
        token += chars[Math.floor(Math.random() * chars.length)];
    }
    return token;
}