/**
 * Functions/Methods that depend on the current runtime to function
 */
import process from 'node:process';
import Ansi from './ansi.ts';
import { IRuntime, ITerminalSize, ITestBase } from './types.ts';
import { noop } from './fns.ts';
import {
	defaultTerminalSize,
	SCROLL_LOG_FILE_PREFIX,
	SCROLL_LOG_FILE_SUFFIX,
} from './config.ts';

export type { IFileIO, IRuntime, ITerminal } from './types.ts';

/**
 * Which Typescript runtime is currently being used
 */
export enum RunTimeType {
	Bun = 'bun',
	Deno = 'deno',
	Tsx = 'tsx',
	Unknown = 'common',
}

/**
 * The label for type/severity of the log entry
 */
export enum LogLevel {
	Debug = 'Debug',
	Info = 'Info',
	Notice = 'Notice',
	Warning = 'Warning',
	Error = 'Error',
}

let scrollRuntime: IRuntime | null = null;

// ----------------------------------------------------------------------------
// Misc runtime functions
// ----------------------------------------------------------------------------

/**
 * Get the size of the terminal window via ANSI codes
 * @see https://viewsourcecode.org/snaptoken/kilo/03.rawInputAndOutput.html#window-size-the-hard-way
 */
async function _getTerminalSizeFromAnsi(): Promise<ITerminalSize> {
	const { term } = await getRuntime();

	// Tell the cursor to move to Row 999 and Column 999
	// Since this command specifically doesn't go off the screen
	// When we ask where the cursor is, we should get the size of the screen
	await term.writeStdout(
		Ansi.moveCursorForward(999) + Ansi.moveCursorDown(999),
	);

	// Ask where the cursor is
	await term.writeStdout(Ansi.GetCursorLocation);

	// Get the first chunk from stdin
	// The response is \x1b[(rows);(cols)R..
	const chunk = await term.readStdinRaw();
	if (chunk === null) {
		return defaultTerminalSize;
	}

	const rawCode = (new TextDecoder()).decode(chunk);
	const res = rawCode.trim().replace(/^.\[([0-9]+;[0-9]+)R$/, '$1');
	const [srows, scols] = res.split(';');
	const rows = parseInt(srows, 10) ?? 24;
	const cols = parseInt(scols, 10) ?? 80;

	// Clear the screen
	await term.writeStdout(Ansi.ClearScreen + Ansi.ResetCursor);

	return {
		rows,
		cols,
	};
}

/**
 * Basic logging -
 */
export function log(
	s: unknown,
	level: LogLevel = LogLevel.Notice,
	data?: any,
): void {
	getRuntime().then(({ file }) => {
		const rawS = JSON.stringify(s, null, 2);
		const rawData = JSON.stringify(data, null, 2);
		const output = (typeof data !== 'undefined')
			? `${rawS}\n${rawData}\n\n`
			: `${rawS}\n`;

		const outputFile =
			`${SCROLL_LOG_FILE_PREFIX}-${level.toLowerCase()}${SCROLL_LOG_FILE_SUFFIX}`;
		file.appendFile(outputFile, output).then(noop);
	});
}

export const logDebug = (s: unknown, data?: any) =>
	log(s, LogLevel.Debug, data);
export const logInfo = (s: unknown, data?: any) => log(s, LogLevel.Info, data);
export const logNotice = (s: unknown, data?: any) =>
	log(s, LogLevel.Notice, data);
export const logWarning = (s: unknown, data?: any) =>
	log(s, LogLevel.Warning, data);
export const logError = (s: unknown, data?: any) =>
	log(s, LogLevel.Warning, data);

/**
 * Kill program, displaying an error message
 * @param s
 */
export function die(s: string | Error): void {
	logError(s);
	process.stdin.setRawMode(false);
	console.error(s);
	getRuntime().then((r) => r.exit());
}

/**
 * Determine which Typescript runtime we are operating under
 */
export function runtimeType(): RunTimeType {
	let runtime = RunTimeType.Tsx;

	if ('Deno' in globalThis) {
		runtime = RunTimeType.Deno;
	}
	if ('Bun' in globalThis) {
		runtime = RunTimeType.Bun;
	}

	return runtime;
}

/**
 * Get the adapter object for the current Runtime
 */
export async function getRuntime(): Promise<IRuntime> {
	if (scrollRuntime === null) {
		const runtime = runtimeType();
		const path = `../${runtime}/mod.ts`;

		const pkg = await import(path);
		if ('default' in pkg) {
			scrollRuntime = pkg.default;
		}

		if (scrollRuntime !== null) {
			return Promise.resolve(scrollRuntime);
		}

		return Promise.reject('Missing default import');
	}

	return Promise.resolve(scrollRuntime);
}

/**
 * Get the common test interface object
 */
export async function getTestRunner(): Promise<ITestBase> {
	const runtime = runtimeType();
	const path = `../${runtime}/test_base.ts`;
	const pkg = await import(path);
	if ('default' in pkg) {
		return pkg.default;
	}

	return pkg;
}

/**
 * Import a runtime-specific module
 *
 * e.g. to load "src/bun/mod.ts", if the runtime is bun,
 * you can use like so `await importForRuntime('index')`;
 *
 * @param path - the path within the runtime module
 */
export const importForRuntime = async (path: string) => {
	const runtime = runtimeType();
	const suffix = '.ts';
	const base = `../${runtime}/`;

	const pathParts = path
		.split('/')
		.filter((part) => part !== '' && part !== '.' && part !== suffix)
		.map((part) => part.replace(suffix, ''));

	const cleanedPath = pathParts.join('/');
	const importPath = base + cleanedPath + suffix;

	const pkg = await import(importPath);
	if ('default' in pkg) {
		return pkg.default;
	}

	return pkg;
};