import { FaissStore } from '@langchain/community/vectorstores/faiss';
import { OpenAIEmbeddings } from '@langchain/openai';
import * as v from 'valibot';
import * as path from 'jsr:@std/path';
import { existsSync, readdirSync } from 'node:fs';
import { Document } from '@langchain/core/documents';
import { RecursiveCharacterTextSplitter } from '@langchain/textsplitters';
import { DirectoryLoader } from 'langchain/document_loaders/fs/directory';
import { JSONLoader, JSONLinesLoader } from 'langchain/document_loaders/fs/json';
import { TextLoader } from 'langchain/document_loaders/fs/text';
import { computeSha256FromText } from './crypto.ts';
import { PDFLoader } from '@langchain/community/document_loaders/fs/pdf';

export const embeddings = new OpenAIEmbeddings({
	model: 'text-embedding-3-large'
});

export const MetadataSchema = v.object({
	filesSha256: v.array(v.string())
});
export type Metadata = v.InferOutput<typeof MetadataSchema>;

export async function getDocsFromDirectory(directoryPath: string): Promise<Document[]> {
	const splitter = new RecursiveCharacterTextSplitter({
		chunkSize: 1000,
		chunkOverlap: 200
	});

	const loader = new DirectoryLoader(directoryPath, {
		'.json': (path) => new JSONLoader(path, '/texts'),
		'.jsonl': (path) => new JSONLinesLoader(path, '/html'),
		'.txt': (path) => new TextLoader(path),
		'.md': (path) => new TextLoader(path),
		'.mdx': (path) => new TextLoader(path)
	});
	const docs = await loader.load();
	const allSplits = await splitter.splitDocuments(docs);
	return allSplits;
}

export class Bucket {
	readonly bucketPath: string;
	readonly faissStorePath: string;
	readonly metadataPath: string;
	private _vectorStore: FaissStore | null = null;
	filesSha256: Set<string> = new Set();

	constructor(
		readonly bucketDir: string,
		readonly bucketName: string
	) {
		this.bucketPath = path.join(this.bucketDir, this.bucketName);
		this.faissStorePath = path.join(this.bucketPath, 'faiss-store');
		this.metadataPath = path.join(this.bucketPath, 'metadata.json');
	}

	async init() {
		if (!existsSync(this.bucketPath)) {
			Deno.mkdirSync(this.bucketPath, { recursive: true });
		}
		if (existsSync(this.metadataPath)) {
			const metadata = JSON.parse(Deno.readTextFileSync(this.metadataPath));
			const parsedMetadata = v.safeParse(MetadataSchema, metadata);
			if (parsedMetadata.success) {
				this.filesSha256 = new Set(parsedMetadata.output.filesSha256);
			} else {
				throw new Error('Invalid metadata');
			}
		}
		this.updateMetadata();
		this._vectorStore = await this.getVectorStore();
		// if (this._vectorStore) {
		//   await this._vectorStore.save(this.faissStorePath);
		// }
	}

	updateMetadata() {
		const metadata: Metadata = {
			filesSha256: Array.from(this.filesSha256)
		};
		Deno.writeTextFileSync(this.metadataPath, JSON.stringify(metadata));
	}

	async getVectorStore() {
		if (
			existsSync(this.faissStorePath) &&
			existsSync(path.join(this.faissStorePath, 'docstore.json'))
		) {
			const vectorStore = await FaissStore.load(this.faissStorePath, embeddings);
			return vectorStore;
		}
		// const vectorStore = await FaissStore.fromDocuments(docs, embeddings);
		const vectorStore = new FaissStore(embeddings, {});
		// await vectorStore.save(this.faissStorePath);
		return vectorStore;
	}

	get vectorStore() {
		if (this._vectorStore === null) {
			throw new Error('Vector store not initialized');
		}
		return this._vectorStore;
	}

	private async addDocuments(documents: Document[]) {
		await this.vectorStore.addDocuments(documents);
		// await this.vectorStore.save(this.faissStorePath);
	}

	private fillSha256(documents: Document[]) {
		for (const doc of documents) {
			const sha256 = computeSha256FromText(doc.pageContent);
			doc.metadata.sha256 = sha256;
		}
	}

	private getFilteredDocs(documents: Document[]) {
		return documents.filter((doc) => !this.filesSha256.has(doc.metadata.sha256));
	}

	private updateSha256(docs: Document[]) {
		for (const doc of docs) {
			this.filesSha256.add(doc.metadata.sha256 as string);
		}
		this.updateMetadata();
	}

	async addDirectory(directoryPath: string) {
		if (!existsSync(directoryPath)) {
			throw new Error('Directory does not exist');
		}
		// check if path is a directory or file
		const stats = Deno.statSync(directoryPath);
		if (stats.isFile) {
			throw new Error('Path is a file');
		}

		const docs = await getDocsFromDirectory(directoryPath);
		this.fillSha256(docs);
		const fileteredDocs = this.getFilteredDocs(docs);
		for (const doc of fileteredDocs) {
			this.filesSha256.add(doc.metadata.sha256 as string);
		}
		this.updateMetadata();
		const splitter = new RecursiveCharacterTextSplitter({
			chunkSize: 1000,
			chunkOverlap: 200
		});
		const allSplits = await splitter.splitDocuments(fileteredDocs);
		await this.addDocuments(allSplits);
	}

	async addTextFile(filePath: string) {
		const loader = new TextLoader(filePath);
		const docs = await loader.load();
		console.error('Loaded docs', docs.length);
		this.fillSha256(docs);
		const fileteredDocs = this.getFilteredDocs(docs);
		console.error('Filtered docs', fileteredDocs.length);
		this.updateSha256(docs);
		console.error('Updated sha256', this.filesSha256.size);
		// await this.addDocuments(fileteredDocs);
		return this.vectorStore.addDocuments(fileteredDocs).catch((err) => {
			console.error('Error adding documents', err);
		});
	}

	async save() {
		console.error('Save Bucket', this.vectorStore.docstore._docs.size);
		if (existsSync(this.faissStorePath) && readdirSync(this.faissStorePath).length === 0) {
			Deno.removeSync(this.bucketPath, { recursive: true });
		}
		if (this.vectorStore.docstore._docs.size === 0) {
			throw new Error('No documents to save');
		}
		await this.vectorStore.save(this.faissStorePath);
	}

	async addPDF(filePath: string) {
		const loader = new PDFLoader(filePath);
		const docs = await loader.load();
		this.fillSha256(docs);
		const fileteredDocs = this.getFilteredDocs(docs);
		this.updateSha256(docs);
		await this.addDocuments(fileteredDocs);
	}
}