import { Service } from 'typedi';
import uniq from 'lodash/uniq';
import { createWriteStream } from 'fs';
import { mkdir } from 'fs/promises';
import path from 'path';

import type { ICredentialType, INodeTypeBaseDescription } from 'n8n-workflow';

import { GENERATED_STATIC_DIR } from '@/constants';
import { CredentialsOverwrites } from '@/CredentialsOverwrites';
import { CredentialTypes } from '@/CredentialTypes';
import { LoadNodesAndCredentials } from '@/LoadNodesAndCredentials';

@Service()
export class FrontendService {
	constructor(
		private readonly loadNodesAndCredentials: LoadNodesAndCredentials,
		private readonly credentialTypes: CredentialTypes,
		private readonly credentialsOverwrites: CredentialsOverwrites,
	) {}

	async generateTypes() {
		this.overwriteCredentialsProperties();

		// pre-render all the node and credential types as static json files
		await mkdir(path.join(GENERATED_STATIC_DIR, 'types'), { recursive: true });
		const { credentials, nodes } = this.loadNodesAndCredentials.types;
		this.writeStaticJSON('nodes', nodes);
		this.writeStaticJSON('credentials', credentials);
	}

	private writeStaticJSON(name: string, data: INodeTypeBaseDescription[] | ICredentialType[]) {
		const filePath = path.join(GENERATED_STATIC_DIR, `types/${name}.json`);
		const stream = createWriteStream(filePath, 'utf-8');
		stream.write('[\n');
		data.forEach((entry, index) => {
			stream.write(JSON.stringify(entry));
			if (index !== data.length - 1) stream.write(',');
			stream.write('\n');
		});
		stream.write(']\n');
		stream.end();
	}

	private overwriteCredentialsProperties() {
		const { credentials } = this.loadNodesAndCredentials.types;
		const credentialsOverwrites = this.credentialsOverwrites.getAll();
		for (const credential of credentials) {
			const overwrittenProperties = [];
			this.credentialTypes
				.getParentTypes(credential.name)
				.reverse()
				.map((name) => credentialsOverwrites[name])
				.forEach((overwrite) => {
					if (overwrite) overwrittenProperties.push(...Object.keys(overwrite));
				});

			if (credential.name in credentialsOverwrites) {
				overwrittenProperties.push(...Object.keys(credentialsOverwrites[credential.name]));
			}

			if (overwrittenProperties.length) {
				credential.__overwrittenProperties = uniq(overwrittenProperties);
			}
		}
	}
}