import { Plugin } from '../plugin';
import { TargetedStdio, StdioMultiplexer } from '../stdio';
import { make_PyScript } from '../components/pyscript';
import { InterpreterClient } from '../interpreter_client';

type PyScriptTag = InstanceType<ReturnType<typeof make_PyScript>>;

/**
 * The StdioDirector plugin captures the output to Python's sys.stdio and
 * sys.stderr and writes it to a specific element in the DOM. It does this by
 * creating a new TargetedStdio manager and adding it to the global stdioMultiplexer's
 * list of listeners prior to executing the Python in a specific tag. Following
 * execution of the Python in that tag, it removes the TargetedStdio as a listener
 *
 */
export class StdioDirector extends Plugin {
    _stdioMultiplexer: StdioMultiplexer;

    constructor(stdio: StdioMultiplexer) {
        super();
        this._stdioMultiplexer = stdio;
    }

    /** Prior to a <py-script> tag being evaluated, if that tag itself has
     * an 'output' attribute, a new TargetedStdio object is created and added
     * to the stdioMultiplexer to route sys.stdout and sys.stdout to the DOM object
     * with that ID for the duration of the evaluation.
     *
     */
    beforePyScriptExec(options: { interpreter: InterpreterClient; src: string; pyScriptTag: PyScriptTag }): void {
        if (options.pyScriptTag.hasAttribute('output')) {
            const targeted_io = new TargetedStdio(options.pyScriptTag, 'output', true, true);
            options.pyScriptTag.stdout_manager = targeted_io;
            this._stdioMultiplexer.addListener(targeted_io);
        }
        if (options.pyScriptTag.hasAttribute('stderr')) {
            const targeted_io = new TargetedStdio(options.pyScriptTag, 'stderr', false, true);
            options.pyScriptTag.stderr_manager = targeted_io;
            this._stdioMultiplexer.addListener(targeted_io);
        }
    }

    /** After a <py-script> tag is evaluated, if that tag has a 'stdout_manager'
     *  (presumably TargetedStdio, or some other future IO handler), it is removed.
     */
    afterPyScriptExec(options: {
        interpreter: InterpreterClient;
        src: string;
        pyScriptTag: PyScriptTag;
        result: any; // eslint-disable-line @typescript-eslint/no-explicit-any
    }): void {
        if (options.pyScriptTag.stdout_manager != null) {
            this._stdioMultiplexer.removeListener(options.pyScriptTag.stdout_manager);
            options.pyScriptTag.stdout_manager = null;
        }
        if (options.pyScriptTag.stderr_manager != null) {
            this._stdioMultiplexer.removeListener(options.pyScriptTag.stderr_manager);
            options.pyScriptTag.stderr_manager = null;
        }
    }
}