import { getLogger } from './logger';
import { ensureUniqueId } from './utils';
import { UserError, ErrorCode } from './exceptions';
import { InterpreterClient } from './interpreter_client';
import type { PyProxyCallable } from 'pyodide';

const logger = getLogger('pyexec');

export async function pyExec(
    interpreter: InterpreterClient,
    pysrc: string,
    outElem: HTMLElement,
): Promise<{ result: any }> {
    ensureUniqueId(outElem);
    if (await interpreter._remote.pyscript_internal.uses_top_level_await(pysrc)) {
        const err = new UserError(
            ErrorCode.TOP_LEVEL_AWAIT,
            'The use of top-level "await", "async for", and ' +
                '"async with" has been removed.' +
                '\nPlease write a coroutine containing ' +
                'your code and schedule it using asyncio.ensure_future() or similar.' +
                '\nSee https://docs.pyscript.net/latest/guides/asyncio.html for more information.',
        );
        displayPyException(err, outElem);
        return { result: undefined };
    }

    try {
        return await interpreter.run(pysrc, outElem.id);
    } catch (e) {
        const err = e as Error;
        // XXX: currently we display exceptions in the same position as
        // the output. But we probably need a better way to do that,
        // e.g. allowing plugins to intercept exceptions and display them
        // in a configurable way.
        displayPyException(err, outElem);
        return { result: undefined };
    }
}

/**
 * Javascript API to call the python display() function
 *
 * Expected usage:
 *     pyDisplay(interpreter, obj);
 *     pyDisplay(interpreter, obj, { target: targetID });
 */
export async function pyDisplay(interpreter: InterpreterClient, obj: any, kwargs: { [k: string]: any } = {}) {
    const display = (await interpreter.globals.get('display')) as PyProxyCallable;
    try {
        await display.callKwargs(obj, kwargs);
    } finally {
        display.destroy();
    }
}

export function displayPyException(err: Error, errElem: HTMLElement) {
    const pre = document.createElement('pre');
    pre.className = 'py-error';

    if (err.name === 'PythonError') {
        // err.message contains the python-level traceback (i.e. a string
        // starting with: "Traceback (most recent call last) ..."
        logger.error('Python exception:\n' + err.message);
        pre.innerText = err.message;
    } else {
        // this is very likely a normal JS exception. The best we can do is to
        // display it as is.
        logger.error('Non-python exception:\n' + err.toString());
        pre.innerText = err.toString();
    }
    errElem.appendChild(pre);
}