import {JSONAttemptParse} from '@ztimson/utils';
import {AbortablePromise, Ai} from './ai.ts';
import {Anthropic} from './antrhopic.ts';
import {Ollama} from './ollama.ts';
import {OpenAi} from './open-ai.ts';
import {LLMProvider} from './provider.ts';
import {AiTool} from './tools.ts';
import {Worker} from 'worker_threads';
import {fileURLToPath} from 'url';
import {dirname, join} from 'path';

export type LLMMessage = {
	/** Message originator */
	role: 'assistant' | 'system' | 'user';
	/** Message content */
	content: string | any;
	/** Timestamp */
	timestamp?: number;
} | {
	/** Tool call */
	role: 'tool';
	/** Unique ID for call */
	id: string;
	/** Tool that was run */
	name: string;
	/** Tool arguments */
	args: any;
	/** Tool result */
	content: undefined | string;
	/** Tool error */
	error: undefined | string;
	/** Timestamp */
	timestamp?: number;
}

export type LLMOptions = {
	/** Anthropic settings */
	anthropic?: {
		/** API Token */
		token: string;
		/** Default model */
		model: string;
	},
	/** Ollama settings */
	ollama?: {
		/** connection URL */
		host: string;
		/** Default model */
		model: string;
	},
	/** Open AI settings */
	openAi?: {
		/** API Token */
		token: string;
		/** Default model */
		model: string;
	},
	/** Default provider & model */
	model: string | [string, string];
} & Omit<LLMRequest, 'model'>;

export type LLMRequest = {
	/** System prompt */
	system?: string;
	/** Message history */
	history?: LLMMessage[];
	/** Max tokens for request */
	max_tokens?: number;
	/** 0 = Rigid Logic, 1 = Balanced, 2 = Hyper Creative **/
	temperature?: number;
	/** Available tools */
	tools?: AiTool[];
	/** LLM  model */
	model?: string | [string, string];
	/** Stream response */
	stream?: (chunk: {text?: string, tool?: string, done?: true}) => any;
	/** Compress old messages in the chat to free up context */
	compress?: {
		/** Trigger chat compression once context exceeds the token count */
		max: number;
		/** Compress chat until context size smaller than */
		min: number
	}
}

export class LLM {
	private embedWorker: Worker | null = null;
	private embedQueue = new Map<number, { resolve: (value: number[]) => void; reject: (error: any) => void }>();
	private embedId = 0;
	private providers: {[key: string]: LLMProvider} = {};


	constructor(public readonly ai: Ai) {
		this.embedWorker = new Worker(join(dirname(fileURLToPath(import.meta.url)), 'embedder.js'));
		this.embedWorker.on('message', ({ id, embedding }) => {
			const pending = this.embedQueue.get(id);
			if (pending) {
				pending.resolve(embedding);
				this.embedQueue.delete(id);
			}
		});

		if(ai.options.anthropic?.token) this.providers.anthropic = new Anthropic(this.ai, ai.options.anthropic.token, ai.options.anthropic.model);
		if(ai.options.ollama?.host) this.providers.ollama = new Ollama(this.ai, ai.options.ollama.host, ai.options.ollama.model);
		if(ai.options.openAi?.token) this.providers.openAi = new OpenAi(this.ai, ai.options.openAi.token, ai.options.openAi.model);
	}

	/**
	 * Chat with LLM
	 * @param {string} message Question
	 * @param {LLMRequest} options Configuration options and chat history
	 * @returns {{abort: () => void, response: Promise<LLMMessage[]>}} Function to abort response and chat history
	 */
	ask(message: string, options: LLMRequest = {}): AbortablePromise<LLMMessage[]> {
		let model: any = [null, null];
		if(options.model) {
			if(typeof options.model == 'object') model = options.model;
			else model = [options.model, (<any>this.ai.options)[options.model]?.model];
		}
		if(!options.model || model[1] == null) {
			if(typeof this.ai.options.model == 'object') model = this.ai.options.model;
			else model = [this.ai.options.model, (<any>this.ai.options)[this.ai.options.model]?.model];
		}
		if(!model[0] || !model[1]) throw new Error(`Unknown LLM provider or model: ${model[0]} / ${model[1]}`);
		return this.providers[model[0]].ask(message, {...options, model: model[1]});
	}

	/**
	 * Compress chat history to reduce context size
	 * @param {LLMMessage[]} history Chatlog that will be compressed
	 * @param max Trigger compression once context is larger than max
	 * @param min Summarize until context size is less than min
	 * @param {LLMRequest} options LLM options
	 * @returns {Promise<LLMMessage[]>} New chat history will summary at index 0
	 */
	async compressHistory(history: LLMMessage[], max: number, min: number, options?: LLMRequest): Promise<LLMMessage[]> {
		if(this.estimateTokens(history) < max) return history;
		let keep = 0, tokens = 0;
		for(let m of history.toReversed()) {
			tokens += this.estimateTokens(m.content);
			if(tokens < min) keep++;
			else break;
		}
		if(history.length <= keep) return history;
		const recent = keep == 0 ? [] : history.slice(-keep),
			process = (keep == 0 ? history : history.slice(0, -keep)).filter(h => h.role === 'assistant' || h.role === 'user');
		const summary = await this.summarize(process.map(m => `${m.role}: ${m.content}`).join('\n\n'), 250, options);
		return [{role: 'assistant', content: `Conversation Summary: ${summary}`, timestamp: Date.now()}, ...recent];
	}

	cosineSimilarity(v1: number[], v2: number[]): number {
		if (v1.length !== v2.length) throw new Error('Vectors must be same length');
		let dotProduct = 0, normA = 0, normB = 0;
		for (let i = 0; i < v1.length; i++) {
			dotProduct += v1[i] * v2[i];
			normA += v1[i] * v1[i];
			normB += v2[i] * v2[i];
		}
		const denominator = Math.sqrt(normA) * Math.sqrt(normB);
		return denominator === 0 ? 0 : dotProduct / denominator;
	}

	chunk(target: object | string, maxTokens = 500, overlapTokens = 50): string[] {
		const objString = (obj: any, path = ''): string[] => {
			if(!obj) return [];
			return Object.entries(obj).flatMap(([key, value]) => {
				const p = path ? `${path}${isNaN(+key) ? `.${key}` : `[${key}]`}` : key;
				if(typeof value === 'object' && !Array.isArray(value)) return objString(value, p);
				return `${p}: ${Array.isArray(value) ? value.join(', ') : value}`;
			});
		};

		const lines = typeof target === 'object' ? objString(target) : target.split('\n');
		const tokens = lines.flatMap(l => [...l.split(/\s+/).filter(Boolean), '\n']);
		const chunks: string[] = [];
		for(let i = 0; i < tokens.length;) {
			let text = '', j = i;
			while(j < tokens.length) {
				const next = text + (text ? ' ' : '') + tokens[j];
				if(this.estimateTokens(next.replace(/\s*\n\s*/g, '\n')) > maxTokens && text) break;
				text = next;
				j++;
			}
			const clean = text.replace(/\s*\n\s*/g, '\n').trim();
			if(clean) chunks.push(clean);
			i = Math.max(j - overlapTokens, j === i ? i + 1 : j);
		}
		return chunks;
	}

	embedding(target: object | string, maxTokens = 500, overlapTokens = 50) {
		const embed = (text: string): Promise<number[]> => {
			return new Promise((resolve, reject) => {
				const id = this.embedId++;
				this.embedQueue.set(id, { resolve, reject });
				this.embedWorker?.postMessage({ id, text });
			});
		};

		const chunks = this.chunk(target, maxTokens, overlapTokens);
		return Promise.all(chunks.map(async (text, index) => ({
			index,
			embedding: await embed(text),
			text,
			tokens: this.estimateTokens(text),
		})));
	}

	/**
	 * Estimate variable as tokens
	 * @param history Object to size
	 * @returns {number} Rough token count
	 */
	estimateTokens(history: any): number {
		const text = JSON.stringify(history);
		return Math.ceil((text.length / 4) * 1.2);
	}

	/**
	 * Compare the difference between two strings using tensor math
	 * @param target Text that will checked
	 * @param {string} searchTerms Multiple search terms to check against target
	 * @returns {{avg: number, max: number, similarities: number[]}} Similarity values 0-1: 0 = unique, 1 = identical
	 */
	fuzzyMatch(target: string, ...searchTerms: string[]) {
		if(searchTerms.length < 2) throw new Error('Requires at least 2 strings to compare');
		const vector = (text: string, dimensions: number = 10): number[] => {
			return text.toLowerCase().split('').map((char, index) =>
				(char.charCodeAt(0) * (index + 1)) % dimensions / dimensions).slice(0, dimensions);
		}
		const v = vector(target);
		const similarities = searchTerms.map(t => vector(t)).map(refVector => this.cosineSimilarity(v, refVector))
		return {avg: similarities.reduce((acc, s) => acc + s, 0) / similarities.length, max: Math.max(...similarities), similarities}
	}

	/**
	 * Ask a question with JSON response
	 * @param {string} message Question
	 * @param {LLMRequest} options Configuration options and chat history
	 * @returns {Promise<{} | {} | RegExpExecArray | null>}
	 */
	async json(message: string, options?: LLMRequest) {
		let resp = await this.ask(message, {
			system: 'Respond using a JSON blob',
			...options
		});
		if(!resp?.[0]?.content) return {};
		return JSONAttemptParse(new RegExp('\{[\s\S]*\}').exec(resp[0].content), {});
	}

	/**
	 * Create a summary of some text
	 * @param {string} text Text to summarize
	 * @param {number} tokens Max number of tokens
	 * @param options LLM request options
	 * @returns {Promise<string>} Summary
	 */
	summarize(text: string, tokens: number, options?: LLMRequest): Promise<string | null> {
		return this.ask(text, {system: `Generate a brief summary <= ${tokens} tokens. Output nothing else`, temperature: 0.3, ...options})
			.then(history => <string>history.pop()?.content || null);
	}
}