import { formatBytes } from "@oh-my-pi/pi-utils";
import chalk from "chalk";
import {
	DEFAULT_TINY_TITLE_MODEL_KEY,
	getTinyTitleModelSpec,
	isTinyTitleLocalModelKey,
	TINY_TITLE_LOCAL_MODELS,
	type TinyTitleLocalModelKey,
} from "../tiny/models";
import { shutdownTinyTitleClient, tinyTitleClient } from "../tiny/title-client";
import type { TinyTitleProgressEvent } from "../tiny/title-protocol";

export type TinyModelsAction = "download" | "list";

export interface TinyModelsCommandArgs {
	action: TinyModelsAction;
	model?: string;
	flags: {
		json?: boolean;
	};
}

interface ProgressReporter {
	onProgress(event: TinyTitleProgressEvent): void;
	finish(ok: boolean): void;
}

interface DownloadResult {
	model: TinyTitleLocalModelKey;
	ok: boolean;
}

function writeLine(text = ""): void {
	process.stdout.write(`${text}\n`);
}

function resolveModels(model: string | undefined): TinyTitleLocalModelKey[] {
	if (!model) return [DEFAULT_TINY_TITLE_MODEL_KEY];
	if (model === "all") return TINY_TITLE_LOCAL_MODELS.map(spec => spec.key);
	if (!isTinyTitleLocalModelKey(model)) {
		const values = TINY_TITLE_LOCAL_MODELS.map(spec => spec.key).join(", ");
		throw new Error(`Unknown tiny title model: ${model}. Expected one of: ${values}, all`);
	}
	return [model];
}

function listModels(json: boolean | undefined): void {
	if (json) {
		writeLine(JSON.stringify({ models: TINY_TITLE_LOCAL_MODELS }));
		return;
	}
	writeLine(chalk.bold("Tiny title models"));
	for (const spec of TINY_TITLE_LOCAL_MODELS) {
		const defaultMark = spec.key === DEFAULT_TINY_TITLE_MODEL_KEY ? chalk.cyan(" default") : "";
		writeLine(`${chalk.cyan(spec.key)}${defaultMark}`);
		writeLine(`  ${spec.label} — ${spec.description}`);
	}
}

function makeProgressReporter(modelKey: TinyTitleLocalModelKey, json: boolean | undefined): ProgressReporter {
	if (json || !process.stdout.isTTY) {
		return { onProgress: () => undefined, finish: () => undefined };
	}
	const spec = getTinyTitleModelSpec(modelKey);
	let lastWidth = 0;
	let lastProgress = -1;
	const render = (event: TinyTitleProgressEvent): void => {
		const progress = event.progress ?? lastProgress;
		if (progress >= 0 && progress < lastProgress + 1 && event.status !== "ready") return;
		if (progress >= 0) lastProgress = progress;
		const ratio = progress >= 0 ? Math.max(0, Math.min(1, progress / 100)) : 0;
		const barWidth = 30;
		const filled = Math.round(ratio * barWidth);
		const bar = `${"█".repeat(filled)}${"░".repeat(barWidth - filled)}`;
		const pct = progress >= 0 ? `${Math.floor(progress).toString().padStart(3, " ")}%` : " --%";
		const bytes = event.loaded && event.total ? ` ${formatBytes(event.loaded)}/${formatBytes(event.total)}` : "";
		const file = event.file ? ` ${event.file.split("/").at(-1) ?? event.file}` : "";
		const label = event.status === "ready" ? "Ready" : "Downloading";
		const line = `${chalk.cyan(label)} ${spec.label} [${bar}] ${pct}${bytes}${file}`;
		process.stdout.write(`\r${line.padEnd(lastWidth)}`);
		lastWidth = line.length;
	};
	return {
		onProgress(event) {
			if (event.modelKey !== modelKey) return;
			render(event);
		},
		finish(ok) {
			const suffix = ok ? chalk.green("done") : chalk.red("failed");
			process.stdout.write(`\r${`${spec.label}: ${suffix}`.padEnd(lastWidth)}\n`);
		},
	};
}

async function downloadOne(modelKey: TinyTitleLocalModelKey, json: boolean | undefined): Promise<DownloadResult> {
	const spec = getTinyTitleModelSpec(modelKey);
	if (!json && !process.stdout.isTTY) writeLine(`Downloading ${spec.label} (${modelKey})...`);
	const progress = makeProgressReporter(modelKey, json);
	const ok = await tinyTitleClient.downloadModel(modelKey, { onProgress: progress.onProgress });
	progress.finish(ok);
	if (!json && !process.stdout.isTTY)
		writeLine(ok ? `Downloaded ${spec.label}.` : `Failed to download ${spec.label}.`);
	return { model: modelKey, ok };
}

export async function runTinyModelsCommand(command: TinyModelsCommandArgs): Promise<void> {
	if (command.action === "list") {
		listModels(command.flags.json);
		return;
	}

	const models = resolveModels(command.model);
	const results: DownloadResult[] = [];
	try {
		for (const model of models) {
			results.push(await downloadOne(model, command.flags.json));
		}
	} finally {
		await shutdownTinyTitleClient();
	}

	if (command.flags.json) {
		writeLine(JSON.stringify({ results }));
	}
	if (results.some(result => !result.ok)) {
		throw new Error("One or more tiny title models failed to download");
	}
}