function bufferFromBase64(base64) {
    const binaryString = atob(base64);
    const length = binaryString.length;
    const bytes = new Uint8Array(length);

    for (let i = 0; i < length; i++) {
	bytes[i] = binaryString.charCodeAt(i);
    }

    return bytes;
}

function fromString(str, encoding = "utf8") {
    if (encoding === "utf8") {
	return new TextEncoder().encode(str);
    } else if (encoding === "base16") {
	if (str.length % 2 !== 0) {
	    throw new Error("Invalid hex string length.");
	}
	let bytes = new Uint8Array(str.length / 2);
	for (let i = 0; i < str.length; i += 2) {
	    bytes[i / 2] = parseInt(str.substring(i, i + 2), 16);
	}
	return bytes;
    } else if (encoding === "base64url") {
	str = str.replace(/-/g, "+").replace(/_/g, "/");
	while (str.length % 4) {
	    str += "=";
	}
	return new Uint8Array(bufferFromBase64(str));
    } else {
	throw new Error(`Unsupported encoding "${encoding}"`);
    }
}

/**
 * Convert a Uint8Array to a string with the given encoding.
 *
 * @param {Uint8Array} byteArray - The Uint8Array to convert.
 * @param {string} [encoding='utf8'] - The desired encoding ('utf8', 'base16', 'base64url').
 * @returns {string} - The encoded string.
 * @throws {Error} - Throws an error if the encoding is unsupported.
 */
function toString(byteArray, encoding = "utf8") {
    switch (encoding) {
    case "utf8":
	return decodeUTF8(byteArray);
    case "base16":
	return toBase16(byteArray);
    case "base64url":
	return toBase64Url(byteArray);
    default:
	throw new Error(`Unsupported encoding "${encoding}"`);
    }
}

/**
 * Decode a Uint8Array as a UTF-8 string.
 *
 * @param {Uint8Array} byteArray
 * @returns {string}
 */
function decodeUTF8(byteArray) {
    return new TextDecoder().decode(byteArray);
}

/**
 * Convert a Uint8Array to a base16 (hex) encoded string.
 *
 * @param {Uint8Array} byteArray
 * @returns {string}
 */
function toBase16(byteArray) {
    return Array.from(byteArray)
	.map((byte) => byte.toString(16).padStart(2, "0"))
	.join("");
}

/**
 * Convert a Uint8Array to a base64url encoded string.
 *
 * @param {Uint8Array} byteArray
 * @returns {string}
 */
function toBase64Url(byteArray) {
    let uint8Array = new Uint8Array(byteArray);
    let binaryString = "";
    for (let i = 0; i < uint8Array.length; i++) {
	binaryString += String.fromCharCode(uint8Array[i]);
    }

    // Encode to base64
    let base64 = btoa(binaryString);

    return base64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
}

const u8a = { toString, fromString };

function sha256(payload) {
    const data = typeof payload === "string" ? u8a.fromString(payload) : payload;
    return nobleHashes.sha256(data);
}

async function accessToken(identifier) {
    const did = identifier["did"];
    const privateKeyHex = identifier["keys"][0]["privateKeyHex"];

    const signer = await SimpleSigner(privateKeyHex);

    const nowEpoch = Math.floor(Date.now() / 1000);
    const endEpoch = nowEpoch + 60; // add one minute

    const tokenPayload = { exp: endEpoch, iat: nowEpoch, iss: did };
    const alg = undefined; // defaults to 'ES256K', more standardized but harder to verify vs ES256K-R
    const jwt = await createJWT(tokenPayload, {
	alg,
	issuer: did,
	signer,
    });
    console.error(jwt);
    return jwt;
}

async function createJWT(payload, options, header = {}) {
    const { issuer, signer, alg, expiresIn, canonicalize } = options;

    if (!signer)
	throw new Error(
	    "missing_signer: No Signer functionality has been configured",
	);
    if (!issuer)
	throw new Error("missing_issuer: No issuing DID has been configured");
    if (!header.typ) header.typ = "JWT";
    if (!header.alg) header.alg = alg;

    const timestamps = {
	iat: Math.floor(Date.now() / 1000),
	exp: undefined,
    };

    if (expiresIn) {
	if (typeof expiresIn === "number") {
	    timestamps.exp = (payload.nbf || timestamps.iat) + Math.floor(expiresIn);
	} else {
	    throw new Error("invalid_argument: JWT expiresIn is not a number");
	}
    }

    const fullPayload = { ...timestamps, ...payload, iss: issuer };
    return createJWS(fullPayload, signer, header, { canonicalize });
}

const defaultAlg = "ES256K";

async function createJWS(payload, signer, header = {}, options = {}) {
    if (!header.alg) header.alg = defaultAlg;
    const encodedPayload =
	  typeof payload === "string"
	  ? payload
	  : encodeSection(payload, options.canonicalize);
    const signingInput = [
	encodeSection(header, options.canonicalize),
	encodedPayload,
    ].join(".");

    const jwtSigner = ES256KSignerAlg(false);
    const signature = await jwtSigner(signingInput, signer);

    // JWS Compact Serialization
    // https://www.rfc-editor.org/rfc/rfc7515#section-7.1
    return [signingInput, signature].join(".");
}

function canonicalizeData(object) {
    if (typeof object === "number" && isNaN(object)) {
	throw new Error("NaN is not allowed");
    }

    if (typeof object === "number" && !isFinite(object)) {
	throw new Error("Infinity is not allowed");
    }

    if (object === null || typeof object !== "object") {
	return JSON.stringify(object);
    }

    if (object.toJSON instanceof Function) {
	return serialize(object.toJSON());
    }

    if (Array.isArray(object)) {
	const values = object.reduce((t, cv, ci) => {
	    const comma = ci === 0 ? "" : ",";
	    const value = cv === undefined || typeof cv === "symbol" ? null : cv;
	    return `${t}${comma}${serialize(value)}`;
	}, "");
	return `[${values}]`;
    }

    const values = Object.keys(object)
	  .sort()
	  .reduce((t, cv) => {
	      if (object[cv] === undefined || typeof object[cv] === "symbol") {
		  return t;
	      }
	      const comma = t.length === 0 ? "" : ",";
	      return `${t}${comma}${serialize(cv)}:${serialize(object[cv])}`;
	  }, "");
    return `{${values}}`;
}

function encodeSection(data, shouldCanonicalize = false) {
    if (shouldCanonicalize) {
	return encodeBase64url(canonicalizeData(data));
    } else {
	return encodeBase64url(JSON.stringify(data));
    }
}

function encodeBase64url(s) {
    return bytesToBase64url(u8a.fromString(s));
}

function instanceOfEcdsaSignature(object) {
    return typeof object === "object" && "r" in object && "s" in object;
}

function ES256KSignerAlg(recoverable) {
    return async function sign(payload, signer) {
	const signature = await signer(payload);
	if (instanceOfEcdsaSignature(signature)) {
	    return toJose(signature, recoverable);
	} else {
	    if (
		recoverable &&
		    typeof fromJose(signature).recoveryParam === "undefined"
	    ) {
		throw new Error(
		    `not_supported: ES256K-R not supported when signer doesn't provide a recovery param`,
		);
	    }
	    return signature;
	}
    };
}

function leftpad(data, size = 64) {
    if (data.length === size) return data;
    return "0".repeat(size - data.length) + data;
}

async function SimpleSigner(hexPrivateKey) {
    const signer = await ES256KSigner(hexToBytes(hexPrivateKey), true);
    return async (data) => {
	const signature = await signer(data);
	return fromJose(signature);
    };
}

function hexToBytes(s, minLength) {
    let input = s.startsWith("0x") ? s.substring(2) : s;

    if (input.length % 2 !== 0) {
	input = `0${input}`;
    }

    if (minLength) {
	const paddedLength = Math.max(input.length, minLength * 2);
	input = input.padStart(paddedLength, "00");
    }

    return u8a.fromString(input.toLowerCase(), "base16");
}

function ES256KSigner(privateKey, recoverable = false) {
    const privateKeyBytes = privateKey;
    if (privateKeyBytes.length !== 32) {
	throw new Error(
	    `bad_key: Invalid private key format. Expecting 32 bytes, but got ${privateKeyBytes.length}`,
	);
    }

    return async function (data) {
	const signature = nobleCurves.secp256k1.sign(sha256(data), privateKeyBytes);
	console.error(signature);
	return toJose(
	    {
		r: leftpad(signature.r.toString(16)),
		s: leftpad(signature.s.toString(16)),
		recoveryParam: signature.recovery,
	    },
	    recoverable,
	);
    };
}

function toJose(signature, recoverable) {
    const { r, s, recoveryParam } = signature;
    const jose = new Uint8Array(recoverable ? 65 : 64);
    jose.set(u8a.fromString(r, "base16"), 0);
    jose.set(u8a.fromString(s, "base16"), 32);

    if (recoverable) {
	if (typeof recoveryParam === "undefined") {
	    throw new Error("Signer did not return a recoveryParam");
	}
	jose[64] = recoveryParam;
    }
    return bytesToBase64url(jose);
}

function bytesToBase64url(b) {
    return u8a.toString(b, "base64url");
}

function base64ToBytes(s) {
    const inputBase64Url = s
	  .replace(/\+/g, "-")
	  .replace(/\//g, "_")
	  .replace(/=/g, "");
    return u8a.fromString(inputBase64Url, "base64url");
}

function bytesToHex(b) {
    return u8a.toString(b, "base16");
}

function fromJose(signature) {
    const signatureBytes = base64ToBytes(signature);
    if (signatureBytes.length < 64 || signatureBytes.length > 65) {
	throw new TypeError(
	    `Wrong size for signature. Expected 64 or 65 bytes, but got ${signatureBytes.length}`,
	);
    }
    const r = bytesToHex(signatureBytes.slice(0, 32));
    const s = bytesToHex(signatureBytes.slice(32, 64));
    const recoveryParam =
	  signatureBytes.length === 65 ? signatureBytes[64] : undefined;

    return { r, s, recoveryParam };
}

function validateBase64(s) {
    if (
	!/^(?:[A-Za-z0-9+\/]{2}[A-Za-z0-9+\/]{2})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/.test(
	    s,
	)
    ) {
	throw new TypeError("invalid encoding");
    }
}

function decodeBase64(s) {
    validateBase64(s);
    var i,
	d = atob(s),
	b = new Uint8Array(d.length);
    for (i = 0; i < d.length; i++) b[i] = d.charCodeAt(i);
    return b;
}

async function getSettingById(id) {
    return new Promise((resolve, reject) => {
	let openRequest = indexedDB.open("TimeSafari");

	openRequest.onupgradeneeded = (event) => {
	    // Handle database setup if necessary
	    let db = event.target.result;
	    if (!db.objectStoreNames.contains("settings")) {
		db.createObjectStore("settings", { keyPath: "id" });
	    }
	};

	openRequest.onsuccess = (event) => {
	    let db = event.target.result;
	    let transaction = db.transaction("settings", "readonly");
	    let objectStore = transaction.objectStore("settings");
	    let getRequest = objectStore.get(id);

	    getRequest.onsuccess = () => resolve(getRequest.result);
	    getRequest.onerror = () => reject(getRequest.error);
	};

	openRequest.onerror = () => reject(openRequest.error);
    });
}

async function setMostRecentNotified(id) {
    return new Promise((resolve, reject) => {

	const dbName = "TimeSafari";
	const storeName = "settings";
	const key = 1; 
	const propertyToUpdate = "lastNotifiedClaimId"; 
	const newValue = id; 

	let request = indexedDB.open(dbName);

	request.onerror = function(event) {
            console.error("Database error: " + event.target.errorCode);
	};

	request.onsuccess = function(event) {
	    let db = event.target.result;
	    let transaction = db.transaction(storeName, "readwrite");
	    let store = transaction.objectStore(storeName);

	    let getRequest = store.get(key);

	    getRequest.onsuccess = function(event) {
		let data = event.target.result;

		// Only update if the object exists
		if (data) {
		    // Update the specific property
		    data[propertyToUpdate] = newValue;

		    // Put the updated object back into the database
		    let putRequest = store.put(data);

		    putRequest.onsuccess = function() {
			console.error("Record updated successfully");
		    };

		    putRequest.onerror = function(event) {
			console.error("Error updating record: " + event.target.errorCode);
		    };
		} else {
		    console.error("Record not found");
		}
	    };

	    getRequest.onerror = function(event) {
		console.error("Error fetching record: " + event.target.errorCode);
	    };

	    transaction.oncomplete = function() {
		db.close();
	    };
	};

	request.onupgradeneeded = function(event) {
	    let db = event.target.result;
	    if (!db.objectStoreNames.contains(storeName)) {
		db.createObjectStore(storeName);
	    }
	};

	
    });
}


async function fetchAllAccounts() {
    return new Promise((resolve, reject) => {
	let openRequest = indexedDB.open("TimeSafariAccounts");

	openRequest.onupgradeneeded = function (event) {
	    let db = event.target.result;
	    if (!db.objectStoreNames.contains("accounts")) {
		db.createObjectStore("accounts", { keyPath: "id" });
	    }
	};

	openRequest.onsuccess = function (event) {
	    let db = event.target.result;
	    let transaction = db.transaction("accounts", "readonly");
	    let objectStore = transaction.objectStore("accounts");
	    let getAllRequest = objectStore.getAll();

	    getAllRequest.onsuccess = function () {
		resolve(getAllRequest.result);
	    };
	    getAllRequest.onerror = function () {
		reject(getAllRequest.error);
	    };
	};

	openRequest.onerror = function () {
	    reject(openRequest.error);
	};
    });
}

async function getNotificationCount() {
    let secret = null;
    let accounts = [];
    let result = null;
    if ("secret" in self) {
	secret = self.secret;
	const secretUint8Array = self.decodeBase64(secret);
	const settings = await getSettingById(1);
	const activeDid = settings["activeDid"];
	accounts = await fetchAllAccounts();
	let did = null;
	for (var i = 0; i < accounts.length; i++) {
	    let account = accounts[i];
	    let did = account["did"];
	    if (did == activeDid) {
		let publicKeyHex = account["publicKeyHex"];
		let identity = account["identity"];
		const messageWithNonceAsUint8Array = self.decodeBase64(identity);
		const nonce = messageWithNonceAsUint8Array.slice(0, 24);
		const message = messageWithNonceAsUint8Array.slice(24, identity.length);
		const decoder = new TextDecoder("utf-8");
		const decrypted = self.secretbox.open(message, nonce, secretUint8Array);

		const msg = decoder.decode(decrypted);
		const identifier = JSON.parse(JSON.parse(msg));

		console.log(identifier);

		const headers = {
		    "Content-Type": "application/json",
		};

		headers["Authorization"] = "Bearer " + (await accessToken(identifier));

		let response = await fetch(
		    "https://test-api.endorser.ch/api/v2/report/claims",
		    {
			method: "GET",
			headers: headers,
		    },
		);
		console.error(did, response.status);
		const claims = await response.json();
		// formulate a message back for notifications
		let lastNotifiedClaimId = null;
		if ('lastNotifiedClaimId' in settings) {
		    lastNotifiedClaimId = settings['lastNotifiedClaimId'];
		}
		let newClaims = 0;
		// search for id recent notified -- if it exists if not return everything count
		for (var i=0; i< response.json()['data'].length; i++) {
		    let claim = response.json()['data'];
		    if (claim['id'] == lastNotifiedClaimId) {
			break;
		    }
		    newClaims++;
		}
		// make the notification message here
		
		// first claim is the most recent (?)
		const most_recent_notified = claims[0]['id'];
		await setMostRecentNotified(most_recent_notified);


		break;
	    }
	}
	return result;
    }
}

self.getNotificationCount = getNotificationCount;
self.decodeBase64 = decodeBase64;