// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

use super::io::ChildStderrResource;
use super::io::ChildStdinResource;
use super::io::ChildStdoutResource;
use super::io::StdFileResource;
use crate::permissions::Permissions;
use deno_core::error::AnyError;
use deno_core::op;

use deno_core::serde_json;
use deno_core::AsyncMutFuture;
use deno_core::AsyncRefCell;
use deno_core::Extension;
use deno_core::OpState;
use deno_core::RcRef;
use deno_core::Resource;
use deno_core::ResourceId;
use serde::Deserialize;
use serde::Serialize;
use std::borrow::Cow;
use std::cell::RefCell;
use std::rc::Rc;
use tokio::process::Command;

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

pub fn init() -> Extension {
    Extension::builder()
        .ops(vec![op_run::decl(), op_run_status::decl(), op_kill::decl()])
        .build()
}

#[derive(Copy, Clone, PartialEq, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum Stdio {
    Inherit,
    Piped,
    Null,
}

impl Stdio {
    pub fn as_stdio(&self) -> std::process::Stdio {
        match &self {
            Stdio::Inherit => std::process::Stdio::inherit(),
            Stdio::Piped => std::process::Stdio::piped(),
            Stdio::Null => std::process::Stdio::null(),
        }
    }
}

#[derive(Copy, Clone, PartialEq)]
pub enum StdioOrRid {
    Stdio(Stdio),
    Rid(ResourceId),
}

impl<'de> Deserialize<'de> for StdioOrRid {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        use serde_json::Value;
        let value = Value::deserialize(deserializer)?;
        match value {
            Value::String(val) => match val.as_str() {
                "inherit" => Ok(StdioOrRid::Stdio(Stdio::Inherit)),
                "piped" => Ok(StdioOrRid::Stdio(Stdio::Piped)),
                "null" => Ok(StdioOrRid::Stdio(Stdio::Null)),
                val => Err(serde::de::Error::unknown_variant(
                    val,
                    &["inherit", "piped", "null"],
                )),
            },
            Value::Number(val) => match val.as_u64() {
                Some(val) if val <= ResourceId::MAX as u64 => {
                    Ok(StdioOrRid::Rid(val as ResourceId))
                }
                _ => Err(serde::de::Error::custom("Expected a positive integer")),
            },
            _ => Err(serde::de::Error::custom(
                r#"Expected a resource id, "inherit", "piped", or "null""#,
            )),
        }
    }
}

impl StdioOrRid {
    pub fn as_stdio(&self, state: &mut OpState) -> Result<std::process::Stdio, AnyError> {
        match &self {
            StdioOrRid::Stdio(val) => Ok(val.as_stdio()),
            StdioOrRid::Rid(rid) => StdFileResource::as_stdio(state, *rid),
        }
    }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct RunArgs {
    cmd: Vec<String>,
    cwd: Option<String>,
    clear_env: bool,
    env: Vec<(String, String)>,
    #[cfg(unix)]
    gid: Option<u32>,
    #[cfg(unix)]
    uid: Option<u32>,
    stdin: StdioOrRid,
    stdout: StdioOrRid,
    stderr: StdioOrRid,
}

struct ChildResource {
    child: AsyncRefCell<tokio::process::Child>,
}

impl Resource for ChildResource {
    fn name(&self) -> Cow<str> {
        "child".into()
    }
}

impl ChildResource {
    fn borrow_mut(self: Rc<Self>) -> AsyncMutFuture<tokio::process::Child> {
        RcRef::map(self, |r| &r.child).borrow_mut()
    }
}

#[derive(Serialize)]
#[serde(rename_all = "camelCase")]
// TODO(@AaronO): maybe find a more descriptive name or a convention for return structs
struct RunInfo {
    rid: ResourceId,
    pid: Option<u32>,
    stdin_rid: Option<ResourceId>,
    stdout_rid: Option<ResourceId>,
    stderr_rid: Option<ResourceId>,
}

#[op]
fn op_run(state: &mut OpState, run_args: RunArgs) -> Result<RunInfo, AnyError> {
    let args = run_args.cmd;
    state.borrow_mut::<Permissions>().run.check(&args[0])?;
    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));

    if run_args.clear_env {
        super::check_unstable(state, "Deno.run.clearEnv");
        c.env_clear();
    }
    for (key, value) in &env {
        c.env(key, value);
    }

    #[cfg(unix)]
    if let Some(gid) = run_args.gid {
        super::check_unstable(state, "Deno.run.gid");
        c.gid(gid);
    }
    #[cfg(unix)]
    if let Some(uid) = run_args.uid {
        super::check_unstable(state, "Deno.run.uid");
        c.uid(uid);
    }
    #[cfg(unix)]
    // TODO(bartlomieju):
    #[allow(clippy::undocumented_unsafe_blocks)]
    unsafe {
        c.pre_exec(|| {
            libc::setgroups(0, std::ptr::null());
            Ok(())
        });
    }

    // TODO: make this work with other resources, eg. sockets
    c.stdin(run_args.stdin.as_stdio(state)?);
    c.stdout(
        match run_args.stdout {
            StdioOrRid::Stdio(Stdio::Inherit) => StdioOrRid::Rid(1),
            value => value,
        }
        .as_stdio(state)?,
    );
    c.stderr(
        match run_args.stderr {
            StdioOrRid::Stdio(Stdio::Inherit) => StdioOrRid::Rid(2),
            value => value,
        }
        .as_stdio(state)?,
    );

    // 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
                .add(ChildStdinResource::from(child_stdin));
            Some(rid)
        }
        None => None,
    };

    let stdout_rid = match child.stdout.take() {
        Some(child_stdout) => {
            let rid = state
                .resource_table
                .add(ChildStdoutResource::from(child_stdout));
            Some(rid)
        }
        None => None,
    };

    let stderr_rid = match child.stderr.take() {
        Some(child_stderr) => {
            let rid = state
                .resource_table
                .add(ChildStderrResource::from(child_stderr));
            Some(rid)
        }
        None => None,
    };

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

    Ok(RunInfo {
        rid: child_rid,
        pid,
        stdin_rid,
        stdout_rid,
        stderr_rid,
    })
}

#[derive(Serialize)]
#[serde(rename_all = "camelCase")]
struct ProcessStatus {
    got_signal: bool,
    exit_code: i32,
    exit_signal: i32,
}

#[op]
async fn op_run_status(
    state: Rc<RefCell<OpState>>,
    rid: ResourceId,
) -> Result<ProcessStatus, AnyError> {
    let resource = state
        .borrow_mut()
        .resource_table
        .get::<ChildResource>(rid)?;
    let mut child = resource.borrow_mut().await;
    let run_status = child.wait().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(ProcessStatus {
        got_signal,
        exit_code: code.unwrap_or(-1),
        exit_signal: signal.unwrap_or(-1),
    })
}

#[cfg(unix)]
pub fn kill(pid: i32, signal: &str) -> Result<(), AnyError> {
    let signo = super::signal::signal_str_to_int(signal)?;
    use nix::sys::signal::{kill as unix_kill, Signal};
    use nix::unistd::Pid;
    let sig = Signal::try_from(signo)?;
    unix_kill(Pid::from_raw(pid), Option::Some(sig)).map_err(AnyError::from)
}

#[cfg(not(unix))]
pub fn kill(pid: i32, signal: &str) -> Result<(), AnyError> {
    use deno_core::error::type_error;
    use std::io::Error;
    use std::io::ErrorKind::NotFound;
    use winapi::shared::minwindef::DWORD;
    use winapi::shared::minwindef::FALSE;
    use winapi::shared::minwindef::TRUE;
    use winapi::shared::winerror::ERROR_INVALID_PARAMETER;
    use winapi::um::errhandlingapi::GetLastError;
    use winapi::um::handleapi::CloseHandle;
    use winapi::um::processthreadsapi::OpenProcess;
    use winapi::um::processthreadsapi::TerminateProcess;
    use winapi::um::winnt::PROCESS_TERMINATE;

    if !matches!(signal, "SIGKILL" | "SIGTERM") {
        Err(type_error(format!("Invalid signal: {}", signal)))
    } else if pid <= 0 {
        Err(type_error("Invalid pid"))
    } else {
        // SAFETY: winapi call
        let handle = unsafe { OpenProcess(PROCESS_TERMINATE, FALSE, pid as DWORD) };

        if handle.is_null() {
            // SAFETY: winapi call
            let err = match unsafe { GetLastError() } {
                ERROR_INVALID_PARAMETER => Error::from(NotFound), // Invalid `pid`.
                errno => Error::from_raw_os_error(errno as i32),
            };
            Err(err.into())
        } else {
            // SAFETY: winapi calls
            unsafe {
                let is_terminated = TerminateProcess(handle, 1);
                CloseHandle(handle);
                match is_terminated {
                    FALSE => Err(Error::last_os_error().into()),
                    TRUE => Ok(()),
                    _ => unreachable!(),
                }
            }
        }
    }
}

#[op]
fn op_kill(state: &mut OpState, pid: i32, signal: String) -> Result<(), AnyError> {
    state.borrow_mut::<Permissions>().run.check_all()?;
    kill(pid, &signal)?;
    Ok(())
}