// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

use super::io::{std_file_resource, StreamResource, StreamResourceHolder};
use crate::signal::kill;
use crate::state::State;
use deno_core::BufVec;
use deno_core::ErrBox;
use deno_core::OpRegistry;
use deno_core::ZeroCopyBuf;
use futures::future::poll_fn;
use futures::future::FutureExt;
use serde_derive::Deserialize;
use serde_json::Value;
use std::rc::Rc;
use tokio::process::Command;

#[cfg(unix)]
use std::os::unix::process::ExitStatusExt;

pub fn init(s: &Rc<State>) {
  s.register_op_json_sync("op_run", op_run);
  s.register_op_json_async("op_run_status", op_run_status);
  s.register_op_json_sync("op_kill", op_kill);
}

fn clone_file(state: &State, rid: u32) -> Result<std::fs::File, ErrBox> {
  std_file_resource(state, rid, move |r| match r {
    Ok(std_file) => std_file.try_clone().map_err(ErrBox::from),
    Err(_) => Err(ErrBox::bad_resource_id()),
  })
}

fn subprocess_stdio_map(s: &str) -> Result<std::process::Stdio, ErrBox> {
  match s {
    "inherit" => Ok(std::process::Stdio::inherit()),
    "piped" => Ok(std::process::Stdio::piped()),
    "null" => Ok(std::process::Stdio::null()),
    _ => Err(ErrBox::type_error("Invalid resource for stdio")),
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct RunArgs {
  cmd: Vec<String>,
  cwd: Option<String>,
  env: Vec<(String, String)>,
  stdin: String,
  stdout: String,
  stderr: String,
  stdin_rid: u32,
  stdout_rid: u32,
  stderr_rid: u32,
}

struct ChildResource {
  child: tokio::process::Child,
}

fn op_run(
  state: &State,
  args: Value,
  _zero_copy: &mut [ZeroCopyBuf],
) -> Result<Value, ErrBox> {
  let run_args: RunArgs = serde_json::from_value(args)?;

  state.check_run()?;

  let args = run_args.cmd;
  let env = run_args.env;
  let cwd = run_args.cwd;

  let mut c = Command::new(args.get(0).unwrap());
  (1..args.len()).for_each(|i| {
    let arg = args.get(i).unwrap();
    c.arg(arg);
  });
  cwd.map(|d| c.current_dir(d));
  for (key, value) in &env {
    c.env(key, value);
  }

  // TODO: make this work with other resources, eg. sockets
  if run_args.stdin != "" {
    c.stdin(subprocess_stdio_map(run_args.stdin.as_ref())?);
  } else {
    let file = clone_file(state, run_args.stdin_rid)?;
    c.stdin(file);
  }

  if run_args.stdout != "" {
    c.stdout(subprocess_stdio_map(run_args.stdout.as_ref())?);
  } else {
    let file = clone_file(state, run_args.stdout_rid)?;
    c.stdout(file);
  }

  if run_args.stderr != "" {
    c.stderr(subprocess_stdio_map(run_args.stderr.as_ref())?);
  } else {
    let file = clone_file(state, run_args.stderr_rid)?;
    c.stderr(file);
  }

  // We want to kill child when it's closed
  c.kill_on_drop(true);

  // Spawn the command.
  let mut child = c.spawn()?;
  let pid = child.id();

  let stdin_rid = match child.stdin.take() {
    Some(child_stdin) => {
      let rid = state.resource_table.borrow_mut().add(
        "childStdin",
        Box::new(StreamResourceHolder::new(StreamResource::ChildStdin(
          child_stdin,
        ))),
      );
      Some(rid)
    }
    None => None,
  };

  let stdout_rid = match child.stdout.take() {
    Some(child_stdout) => {
      let rid = state.resource_table.borrow_mut().add(
        "childStdout",
        Box::new(StreamResourceHolder::new(StreamResource::ChildStdout(
          child_stdout,
        ))),
      );
      Some(rid)
    }
    None => None,
  };

  let stderr_rid = match child.stderr.take() {
    Some(child_stderr) => {
      let rid = state.resource_table.borrow_mut().add(
        "childStderr",
        Box::new(StreamResourceHolder::new(StreamResource::ChildStderr(
          child_stderr,
        ))),
      );
      Some(rid)
    }
    None => None,
  };

  let child_resource = ChildResource { child };
  let child_rid = state
    .resource_table
    .borrow_mut()
    .add("child", Box::new(child_resource));

  Ok(json!({
    "rid": child_rid,
    "pid": pid,
    "stdinRid": stdin_rid,
    "stdoutRid": stdout_rid,
    "stderrRid": stderr_rid,
  }))
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct RunStatusArgs {
  rid: i32,
}

async fn op_run_status(
  state: Rc<State>,
  args: Value,
  _zero_copy: BufVec,
) -> Result<Value, ErrBox> {
  let args: RunStatusArgs = serde_json::from_value(args)?;
  let rid = args.rid as u32;

  state.check_run()?;

  let run_status = poll_fn(|cx| {
    let mut resource_table = state.resource_table.borrow_mut();
    let child_resource = resource_table
      .get_mut::<ChildResource>(rid)
      .ok_or_else(ErrBox::bad_resource_id)?;
    let child = &mut child_resource.child;
    child.poll_unpin(cx).map_err(ErrBox::from)
  })
  .await?;

  let code = run_status.code();

  #[cfg(unix)]
  let signal = run_status.signal();
  #[cfg(not(unix))]
  let signal = None;

  code
    .or(signal)
    .expect("Should have either an exit code or a signal.");
  let got_signal = signal.is_some();

  Ok(json!({
     "gotSignal": got_signal,
     "exitCode": code.unwrap_or(-1),
     "exitSignal": signal.unwrap_or(-1),
  }))
}

#[derive(Deserialize)]
struct KillArgs {
  pid: i32,
  signo: i32,
}

fn op_kill(
  state: &State,
  args: Value,
  _zero_copy: &mut [ZeroCopyBuf],
) -> Result<Value, ErrBox> {
  state.check_unstable("Deno.kill");
  state.check_run()?;

  let args: KillArgs = serde_json::from_value(args)?;
  kill(args.pid, args.signo)?;
  Ok(json!({}))
}