import { exec as shell_exec, spawn as shell_spawn } from 'child_process';

const MAX_BUFFER = 10 * Math.pow(2, 20);

export function exec(
  command: string,
  stdout?: ((...args) => void) | NodeJS.WriteStream,
  stderr?: ((...args) => void) | NodeJS.WriteStream,
  stdin?: NodeJS.ReadableStream | string
) {
  return new Promise<string>((resolve, reject) => {
    try {
      let stdoutbuf = '';
      let stderrbuf = '';

      // EXEC CHILD PROCESS
      const p = shell_exec(command, { maxBuffer: MAX_BUFFER }, (err, out) => {
        if (stdoutbuf.length > 0 && typeof stdout === 'function') stdout(stdoutbuf);
        if (stderrbuf.length > 0 && typeof stderr === 'function') stderr(stderrbuf);

        if (err) return reject(err);

        resolve(out);
      });

      // PIPE STDIN (?)
      if (typeof stdin === 'string') {
        p.stdin.setDefaultEncoding('utf-8');
        if (!stdin.endsWith('\n')) stdin += '\n';
        p.stdin.write(stdin);
        p.stdin.end();
      } else if (typeof stdin !== 'undefined') {
        stdin.pipe(p.stdin);
      }

      // PIPE STDOUT
      if (typeof stdout === 'function') {
        p.stdout.on('data', (chunk) => {
          stdoutbuf += chunk;
          let i = -1;
          while ((i = stdoutbuf.indexOf('\n')) >= 0) {
            const line = stdoutbuf.substring(0, i);
            stdoutbuf = stdoutbuf.substring(i + 1);
            if (typeof stdout === 'function') {
              stdout(line);
            }
          }
        });
      } else if (typeof stdout !== 'undefined') {
        p.stdout.pipe(stdout);
      }

      // PIPE STDERR
      if (typeof stderr === 'function') {
        p.stderr.on('data', (chunk) => {
          stderrbuf += chunk;
          let i = -1;
          while ((i = stderrbuf.indexOf('\n')) >= 0) {
            const line = stderrbuf.substring(0, i);
            stderrbuf = stderrbuf.substring(i + 1);
            if (typeof stderr === 'function') {
              stderr(line);
            }
          }
        });
      } else if (typeof stderr !== 'undefined') {
        p.stderr.pipe(stderr);
      }
    } catch (err) {
      reject(err);
    }
  });
}

export function spawn(
  command: string,
  args: string[],
  stdout?: ((...args) => void) | NodeJS.WriteStream,
  stderr?: ((...args) => void) | NodeJS.WriteStream,
  stdin?: NodeJS.ReadableStream | string
) {
  return new Promise<void>((resolve, reject) => {
    try {
      let stdoutbuf = '';
      let stderrbuf = '';

      const p = shell_spawn(command, args);

      // PIPE STDIN (?)
      if (typeof stdin === 'string') {
        p.stdin.setDefaultEncoding('utf-8');
        if (!stdin.endsWith('\n')) stdin += '\n';
        p.stdin.write(stdin);
        p.stdin.end();
      } else if (typeof stdin !== 'undefined') {
        stdin.pipe(p.stdin);
      }

      // PIPE STDOUT
      if (typeof stdout === 'function') {
        p.stdout.on('data', (chunk) => {
          stdoutbuf += chunk;
          let i = -1;
          while ((i = stdoutbuf.indexOf('\n')) >= 0) {
            const line = stdoutbuf.substring(0, i);
            stdoutbuf = stdoutbuf.substring(i + 1);
            if (typeof stdout === 'function') {
              stdout(line);
            }
          }
        });
      } else if (typeof stdout !== 'undefined') {
        p.stdout.pipe(stdout);
      }

      // PIPE STDERR
      if (typeof stderr === 'function') {
        p.stderr.on('data', (chunk) => {
          stderrbuf += chunk;
          let i = -1;
          while ((i = stderrbuf.indexOf('\n')) >= 0) {
            const line = stderrbuf.substring(0, i);
            stderrbuf = stderrbuf.substring(i + 1);
            if (typeof stderr === 'function') {
              stderr(line);
            }
          }
        });
      } else if (typeof stderr !== 'undefined') {
        p.stderr.pipe(stderr);
      }

      p.on('close', (code, sig) => {
        if (!code) resolve();
        else reject();
      });
      p.on('error', reject);
      p.on('exit', (code, sig) => {
        if (!code) resolve();
        else reject();
      });
    } catch (err) {
      reject(err);
    }
  });
}