import { BROWSER_ID_STORAGE_KEY } from '@n8n/constants';
import { assert } from '@n8n/utils/assert';
import type { AxiosRequestConfig, Method, RawAxiosRequestHeaders } from 'axios';
import axios from 'axios';
import { ApplicationError, jsonParse } from 'n8n-workflow';
import type { GenericValue, IDataObject } from 'n8n-workflow';

import type { IRestApiContext } from './types';

const getBrowserId = () => {
	let browserId = localStorage.getItem(BROWSER_ID_STORAGE_KEY);
	if (!browserId) {
		browserId = crypto.randomUUID();
		localStorage.setItem(BROWSER_ID_STORAGE_KEY, browserId);
	}
	return browserId;
};

export const NO_NETWORK_ERROR_CODE = 999;
export const STREAM_SEPARATOR = '⧉⇋⇋➽⌑⧉§§\n';

export class MfaRequiredError extends ApplicationError {
	constructor() {
		super('MFA is required to access this resource. Please set up MFA in your user settings.');
		this.name = 'MfaRequiredError';
	}
}

export class ResponseError extends ApplicationError {
	// The HTTP status code of response
	httpStatusCode?: number;

	// The error code in the response
	errorCode?: number;

	// The stack trace of the server
	serverStackTrace?: string;

	// Additional metadata from the server (e.g., EULA URL)
	meta?: Record<string, unknown>;

	// Additional hint from the server
	hint?: string;

	/**
	 * Creates an instance of ResponseError.
	 * @param {string} message The error message
	 * @param {number} [errorCode] The error code which can be used by frontend to identify the actual error
	 * @param {number} [httpStatusCode] The HTTP status code the response should have
	 * @param {string} [stack] The stack trace
	 * @param {Record<string, unknown>} [meta] Additional metadata from the server
	 * @param {string} [hint] Additional hint from the server
	 */
	constructor(
		message: string,
		options: {
			errorCode?: number;
			httpStatusCode?: number;
			stack?: string;
			meta?: Record<string, unknown>;
			hint?: ResponseError['hint'];
		} = {},
	) {
		super(message);
		this.name = 'ResponseError';

		const { errorCode, httpStatusCode, stack, meta, hint } = options;
		if (errorCode) {
			this.errorCode = errorCode;
		}
		if (httpStatusCode) {
			this.httpStatusCode = httpStatusCode;
		}
		if (stack) {
			this.serverStackTrace = stack;
		}
		if (meta) {
			this.meta = meta;
		}
		if (hint) {
			this.hint = hint;
		}
	}
}

// eslint-disable-next-line @typescript-eslint/no-explicit-any
const legacyParamSerializer = (params: Record<string, any>) =>
	Object.keys(params)
		.filter((key) => params[key] !== undefined)
		.map((key) => {
			if (Array.isArray(params[key])) {
				return params[key].map((v: string) => `${key}[]=${encodeURIComponent(v)}`).join('&');
			}
			if (typeof params[key] === 'object') {
				params[key] = JSON.stringify(params[key]);
			}
			return `${key}=${encodeURIComponent(params[key])}`;
		})
		.join('&');

export async function request(config: {
	method: Method;
	baseURL: string;
	endpoint: string;
	headers?: RawAxiosRequestHeaders;
	data?: GenericValue | GenericValue[];
	withCredentials?: boolean;
}) {
	const { method, baseURL, endpoint, headers, data } = config;
	const options: AxiosRequestConfig = {
		method,
		url: endpoint,
		baseURL,
		headers: headers ?? {},
	};
	if (baseURL.startsWith('/')) {
		options.headers!['browser-id'] = getBrowserId();
	}
	if (
		import.meta.env.NODE_ENV !== 'production' &&
		!baseURL.includes('api.n8n.io') &&
		!baseURL.includes('n8n.cloud')
	) {
		options.withCredentials = options.withCredentials ?? true;
	}
	if (['POST', 'PATCH', 'PUT'].includes(method)) {
		options.data = data;
	} else if (data) {
		options.params = data;
		options.paramsSerializer = legacyParamSerializer;
	}

	try {
		const response = await axios.request(options);
		return response.data;
	} catch (error) {
		if (error.message === 'Network Error') {
			throw new ResponseError("Can't connect to n8n.", {
				errorCode: NO_NETWORK_ERROR_CODE,
			});
		}

		const errorResponseData = error.response?.data;
		if (errorResponseData?.mfaRequired === true) {
			throw new MfaRequiredError();
		}
		if (errorResponseData?.message !== undefined) {
			if (errorResponseData.name === 'NodeApiError') {
				errorResponseData.httpStatusCode = error.response.status;
				throw errorResponseData;
			}

			throw new ResponseError(errorResponseData.message, {
				errorCode: errorResponseData.code,
				httpStatusCode: error.response.status,
				stack: errorResponseData.stack,
				meta: errorResponseData.meta,
				hint: errorResponseData.hint,
			});
		}

		throw error;
	}
}

/**
 * Sends a request to the API and returns the response without extracting the data key.
 * @param context Rest API context
 * @param method HTTP method
 * @param endpoint relative path to the API endpoint
 * @param data request data
 * @returns data and total count
 */
export async function getFullApiResponse<T>(
	context: IRestApiContext,
	method: Method,
	endpoint: string,
	data?: GenericValue | GenericValue[],
) {
	const response = await request({
		method,
		baseURL: context.baseUrl,
		endpoint,
		headers: { 'push-ref': context.pushRef },
		data,
	});

	return response as { count: number; data: T };
}

export async function makeRestApiRequest<T>(
	context: IRestApiContext,
	method: Method,
	endpoint: string,
	data?: GenericValue | GenericValue[],
) {
	const response = await request({
		method,
		baseURL: context.baseUrl,
		endpoint,
		headers: { 'push-ref': context.pushRef },
		data,
	});

	// All cli rest api endpoints return data wrapped in `data` key
	return response.data as T;
}

export async function get(
	baseURL: string,
	endpoint: string,
	params?: IDataObject,
	headers?: RawAxiosRequestHeaders,
) {
	return await request({ method: 'GET', baseURL, endpoint, headers, data: params });
}

export async function post(
	baseURL: string,
	endpoint: string,
	params?: IDataObject,
	headers?: RawAxiosRequestHeaders,
) {
	return await request({ method: 'POST', baseURL, endpoint, headers, data: params });
}

export async function patch(
	baseURL: string,
	endpoint: string,
	params?: IDataObject,
	headers?: RawAxiosRequestHeaders,
) {
	return await request({ method: 'PATCH', baseURL, endpoint, headers, data: params });
}

export async function streamRequest<T extends object>(
	context: IRestApiContext,
	apiEndpoint: string,
	payload: object,
	onChunk?: (chunk: T) => void,
	onDone?: () => void,
	onError?: (e: Error) => void,
	separator = STREAM_SEPARATOR,
	abortSignal?: AbortSignal,
): Promise<void> {
	let onErrorOnce: ((e: Error) => void) | undefined = (e: Error) => {
		onErrorOnce = undefined;
		onError?.(e);
	};
	const headers: Record<string, string> = {
		'browser-id': getBrowserId(),
		'Content-Type': 'application/json',
	};
	const assistantRequest: RequestInit = {
		headers,
		method: 'POST',
		credentials: 'include',
		body: JSON.stringify(payload),
		signal: abortSignal,
	};
	try {
		const response = await fetch(`${context.baseUrl}${apiEndpoint}`, assistantRequest);

		if (response.body) {
			// Handle the streaming response
			const reader = response.body.getReader();
			const decoder = new TextDecoder('utf-8');

			let buffer = '';

			async function readStream() {
				const { done, value } = await reader.read();
				if (done) {
					if (response.ok) {
						onDone?.();
					} else {
						onErrorOnce?.(
							new ResponseError(response.statusText, {
								httpStatusCode: response.status,
							}),
						);
					}
					return;
				}
				const chunk = decoder.decode(value);
				buffer += chunk;

				const splitChunks = buffer.split(separator);

				buffer = '';
				for (const splitChunk of splitChunks) {
					if (splitChunk) {
						let data: T;
						try {
							data = jsonParse<T>(splitChunk, { errorMessage: 'Invalid json' });
						} catch (e) {
							// incomplete json. append to buffer to complete
							buffer += splitChunk;

							continue;
						}

						try {
							if (response.ok) {
								// Call chunk callback if request was successful
								onChunk?.(data);
							} else {
								// Otherwise, call error callback
								const message = 'message' in data ? data.message : response.statusText;
								onErrorOnce?.(
									new ResponseError(String(message), {
										httpStatusCode: response.status,
									}),
								);
							}
						} catch (e: unknown) {
							if (e instanceof Error) {
								onErrorOnce?.(e);
							}
						}
					}
				}
				await readStream();
			}

			// Start reading the stream
			await readStream();
		} else if (onErrorOnce) {
			onErrorOnce(new Error(response.statusText));
		}
	} catch (e: unknown) {
		assert(e instanceof Error);
		onErrorOnce?.(e);
	}
}