import {
    Either,
    IEither,
    type ITraceable,
    LogLevel,
    LogMetricTraceSupplier,
    Metric,
    TraceUtil,
} from '@emprespresso/pengueno';
import { promisify } from 'node:util';
import { exec as execCallback } from 'node:child_process';
const exec = promisify(execCallback);

export type Command = string[] | string;
export type StdStreams = { stdout: string; stderr: string };

export const CmdMetric = Metric.fromName('Exec').asResult();
export const getStdout = (
    c: ITraceable<Command, LogMetricTraceSupplier>,
    options: { env?: Record<string, string>; clearEnv?: boolean } = {},
): Promise<IEither<Error, string>> =>
    c
        .flatMap(TraceUtil.withFunctionTrace(getStdout))
        .flatMap((tCmd) => tCmd.traceScope(() => `Command = ${tCmd.get()}`))
        .map((tCmd) => {
            const cmd = tCmd.get();
            const _exec = typeof cmd === 'string' ? cmd : cmd.join(' ');
            const env = options.clearEnv ? options.env : { ...process.env, ...options.env };
            return Either.fromFailableAsync<Error, StdStreams>(exec(_exec, { env }));
        })
        .map(
            TraceUtil.promiseify((tEitherStdStreams) =>
                tEitherStdStreams.get().mapRight(({ stderr, stdout }) => {
                    if (stderr) tEitherStdStreams.trace.traceScope(LogLevel.DEBUG).trace(`StdErr = ${stderr}`);
                    return stdout;
                }),
            ),
        )
        .peek(TraceUtil.promiseify(TraceUtil.traceResultingEither(CmdMetric)))
        .get();