Object.defineProperty(exports, '__esModule', { value: true });

const getStreamContents = async (stream, {init, convertChunk, getSize, truncateChunk, addChunk, getFinalChunk, finalize}, {maxBuffer = Number.POSITIVE_INFINITY} = {}) => {
	if (!isAsyncIterable(stream)) {
		throw new Error('The first argument must be a Readable, a ReadableStream, or an async iterable.');
	}

	const state = init();
	state.length = 0;

	try {
		for await (const chunk of stream) {
			const chunkType = getChunkType(chunk);
			const convertedChunk = convertChunk[chunkType](chunk, state);
			appendChunk({convertedChunk, state, getSize, truncateChunk, addChunk, maxBuffer});
		}

		appendFinalChunk({state, convertChunk, getSize, truncateChunk, addChunk, getFinalChunk, maxBuffer});
		return finalize(state);
	} catch (error) {
		error.bufferedData = finalize(state);
		throw error;
	}
};

const appendFinalChunk = ({state, getSize, truncateChunk, addChunk, getFinalChunk, maxBuffer}) => {
	const convertedChunk = getFinalChunk(state);
	if (convertedChunk !== undefined) {
		appendChunk({convertedChunk, state, getSize, truncateChunk, addChunk, maxBuffer});
	}
};

const appendChunk = ({convertedChunk, state, getSize, truncateChunk, addChunk, maxBuffer}) => {
	const chunkSize = getSize(convertedChunk);
	const newLength = state.length + chunkSize;

	if (newLength <= maxBuffer) {
		addNewChunk(convertedChunk, state, addChunk, newLength);
		return;
	}

	const truncatedChunk = truncateChunk(convertedChunk, maxBuffer - state.length);

	if (truncatedChunk !== undefined) {
		addNewChunk(truncatedChunk, state, addChunk, maxBuffer);
	}

	throw new MaxBufferError();
};

const addNewChunk = (convertedChunk, state, addChunk, newLength) => {
	state.contents = addChunk(convertedChunk, state, newLength);
	state.length = newLength;
};

const isAsyncIterable = stream => typeof stream === 'object' && stream !== null && typeof stream[Symbol.asyncIterator] === 'function';

const getChunkType = chunk => {
	const typeOfChunk = typeof chunk;

	if (typeOfChunk === 'string') {
		return 'string';
	}

	if (typeOfChunk !== 'object' || chunk === null) {
		return 'others';
	}

	// eslint-disable-next-line n/prefer-global/buffer
	if (globalThis.Buffer?.isBuffer(chunk)) {
		return 'buffer';
	}

	const prototypeName = objectToString.call(chunk);

	if (prototypeName === '[object ArrayBuffer]') {
		return 'arrayBuffer';
	}

	if (prototypeName === '[object DataView]') {
		return 'dataView';
	}

	if (
		Number.isInteger(chunk.byteLength)
		&& Number.isInteger(chunk.byteOffset)
		&& objectToString.call(chunk.buffer) === '[object ArrayBuffer]'
	) {
		return 'typedArray';
	}

	return 'others';
};

const {toString: objectToString} = Object.prototype;

class MaxBufferError extends Error {
	name = 'MaxBufferError';

	constructor() {
		super('maxBuffer exceeded');
	}
}

const identity = value => value;

const noop = () => undefined;

const getContentsProp = ({contents}) => contents;

const throwObjectStream = chunk => {
	throw new Error(`Streams in object mode are not supported: ${String(chunk)}`);
};

const getLengthProp = convertedChunk => convertedChunk.length;

async function getStreamAsArray(stream, options) {
	return getStreamContents(stream, arrayMethods, options);
}

const initArray = () => ({contents: []});

const increment = () => 1;

const addArrayChunk = (convertedChunk, {contents}) => {
	contents.push(convertedChunk);
	return contents;
};

const arrayMethods = {
	init: initArray,
	convertChunk: {
		string: identity,
		buffer: identity,
		arrayBuffer: identity,
		dataView: identity,
		typedArray: identity,
		others: identity,
	},
	getSize: increment,
	truncateChunk: noop,
	addChunk: addArrayChunk,
	getFinalChunk: noop,
	finalize: getContentsProp,
};

async function getStreamAsArrayBuffer(stream, options) {
	return getStreamContents(stream, arrayBufferMethods, options);
}

const initArrayBuffer = () => ({contents: new ArrayBuffer(0)});

const useTextEncoder = chunk => textEncoder.encode(chunk);
const textEncoder = new TextEncoder();

const useUint8Array = chunk => new Uint8Array(chunk);

const useUint8ArrayWithOffset = chunk => new Uint8Array(chunk.buffer, chunk.byteOffset, chunk.byteLength);

const truncateArrayBufferChunk = (convertedChunk, chunkSize) => convertedChunk.slice(0, chunkSize);

// `contents` is an increasingly growing `Uint8Array`.
const addArrayBufferChunk = (convertedChunk, {contents, length: previousLength}, length) => {
	const newContents = hasArrayBufferResize() ? resizeArrayBuffer(contents, length) : resizeArrayBufferSlow(contents, length);
	new Uint8Array(newContents).set(convertedChunk, previousLength);
	return newContents;
};

// Without `ArrayBuffer.resize()`, `contents` size is always a power of 2.
// This means its last bytes are zeroes (not stream data), which need to be
// trimmed at the end with `ArrayBuffer.slice()`.
const resizeArrayBufferSlow = (contents, length) => {
	if (length <= contents.byteLength) {
		return contents;
	}

	const arrayBuffer = new ArrayBuffer(getNewContentsLength(length));
	new Uint8Array(arrayBuffer).set(new Uint8Array(contents), 0);
	return arrayBuffer;
};

// With `ArrayBuffer.resize()`, `contents` size matches exactly the size of
// the stream data. It does not include extraneous zeroes to trim at the end.
// The underlying `ArrayBuffer` does allocate a number of bytes that is a power
// of 2, but those bytes are only visible after calling `ArrayBuffer.resize()`.
const resizeArrayBuffer = (contents, length) => {
	if (length <= contents.maxByteLength) {
		contents.resize(length);
		return contents;
	}

	const arrayBuffer = new ArrayBuffer(length, {maxByteLength: getNewContentsLength(length)});
	new Uint8Array(arrayBuffer).set(new Uint8Array(contents), 0);
	return arrayBuffer;
};

// Retrieve the closest `length` that is both >= and a power of 2
const getNewContentsLength = length => SCALE_FACTOR ** Math.ceil(Math.log(length) / Math.log(SCALE_FACTOR));

const SCALE_FACTOR = 2;

const finalizeArrayBuffer = ({contents, length}) => hasArrayBufferResize() ? contents : contents.slice(0, length);

// `ArrayBuffer.slice()` is slow. When `ArrayBuffer.resize()` is available
// (Node >=20.0.0, Safari >=16.4 and Chrome), we can use it instead.
// eslint-disable-next-line no-warning-comments
// TODO: remove after dropping support for Node 20.
// eslint-disable-next-line no-warning-comments
// TODO: use `ArrayBuffer.transferToFixedLength()` instead once it is available
const hasArrayBufferResize = () => 'resize' in ArrayBuffer.prototype;

const arrayBufferMethods = {
	init: initArrayBuffer,
	convertChunk: {
		string: useTextEncoder,
		buffer: useUint8Array,
		arrayBuffer: useUint8Array,
		dataView: useUint8ArrayWithOffset,
		typedArray: useUint8ArrayWithOffset,
		others: throwObjectStream,
	},
	getSize: getLengthProp,
	truncateChunk: truncateArrayBufferChunk,
	addChunk: addArrayBufferChunk,
	getFinalChunk: noop,
	finalize: finalizeArrayBuffer,
};

async function getStreamAsBuffer(stream, options) {
	if (!('Buffer' in globalThis)) {
		throw new Error('getStreamAsBuffer() is only supported in Node.js');
	}

	try {
		return arrayBufferToNodeBuffer(await getStreamAsArrayBuffer(stream, options));
	} catch (error) {
		if (error.bufferedData !== undefined) {
			error.bufferedData = arrayBufferToNodeBuffer(error.bufferedData);
		}

		throw error;
	}
}

// eslint-disable-next-line n/prefer-global/buffer
const arrayBufferToNodeBuffer = arrayBuffer => globalThis.Buffer.from(arrayBuffer);

async function getStreamAsString(stream, options) {
	return getStreamContents(stream, stringMethods, options);
}

const initString = () => ({contents: '', textDecoder: new TextDecoder()});

const useTextDecoder = (chunk, {textDecoder}) => textDecoder.decode(chunk, {stream: true});

const addStringChunk = (convertedChunk, {contents}) => contents + convertedChunk;

const truncateStringChunk = (convertedChunk, chunkSize) => convertedChunk.slice(0, chunkSize);

const getFinalStringChunk = ({textDecoder}) => {
	const finalChunk = textDecoder.decode();
	return finalChunk === '' ? undefined : finalChunk;
};

const stringMethods = {
	init: initString,
	convertChunk: {
		string: identity,
		buffer: useTextDecoder,
		arrayBuffer: useTextDecoder,
		dataView: useTextDecoder,
		typedArray: useTextDecoder,
		others: throwObjectStream,
	},
	getSize: getLengthProp,
	truncateChunk: truncateStringChunk,
	addChunk: addStringChunk,
	getFinalChunk: getFinalStringChunk,
	finalize: getContentsProp,
};

exports.MaxBufferError = MaxBufferError;
exports.default = getStreamAsString;
exports.getStreamAsArray = getStreamAsArray;
exports.getStreamAsArrayBuffer = getStreamAsArrayBuffer;
exports.getStreamAsBuffer = getStreamAsBuffer;