extern crate conch_runtime;

use conch_runtime::io::{FileDesc, Permissions};
use conch_runtime::Fd;
use conch_runtime::env::{AsyncIoEnvironment, FileDescEnvironment, PlatformSpecificRead,
                         PlatformSpecificWriteAll, RedirectRestorer, RedirectEnvRestorer};
use conch_runtime::eval::RedirectAction;
use std::collections::HashMap;

#[derive(Debug, Clone, PartialEq, Eq)]
struct MockFileDescEnv<T> {
    fds: HashMap<Fd, (T, Permissions)>,
}

impl<T> MockFileDescEnv<T> {
    fn new() -> Self {
        MockFileDescEnv {
            fds: HashMap::new(),
        }
    }
}

impl<T> FileDescEnvironment for MockFileDescEnv<T> {
    type FileHandle = T;

    fn file_desc(&self, fd: Fd) -> Option<(&Self::FileHandle, Permissions)> {
        self.fds.get(&fd).map(|&(ref handle, perms)| (handle, perms))
    }

    fn set_file_desc(&mut self, fd: Fd, handle: Self::FileHandle, perms: Permissions) {
        self.fds.insert(fd, (handle, perms));
    }

    fn close_file_desc(&mut self, fd: Fd) {
        self.fds.remove(&fd);
    }
}

impl<T> AsyncIoEnvironment for MockFileDescEnv<T> {
    type Read = PlatformSpecificRead;
    type WriteAll = PlatformSpecificWriteAll;

    fn read_async(&mut self, _: FileDesc) -> Self::Read {
        unimplemented!()
    }

    fn write_all(&mut self, _: FileDesc, _: Vec<u8>) -> Self::WriteAll {
        unimplemented!()
    }

    fn write_all_best_effort(&mut self, _: FileDesc, _: Vec<u8>) {
        // Nothing to do
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct S(&'static str);

impl From<FileDesc> for S {
    fn from(_fdes: FileDesc) -> Self {
        S("FileDesc conversion")
    }
}

#[test]
fn smoke() {
    let mut env = MockFileDescEnv::new();
    env.set_file_desc(1, S("a"), Permissions::Read);
    env.set_file_desc(2, S("b"), Permissions::Write);
    env.set_file_desc(3, S("c"), Permissions::ReadWrite);
    env.close_file_desc(4);
    env.close_file_desc(5);

    let env_original = env.clone();

    let restorer: &mut RedirectEnvRestorer<_> = &mut RedirectRestorer::new();

    // Existing fd set to multiple other values
    restorer.apply_action(RedirectAction::Open(1, S("x"), Permissions::Read), &mut env).unwrap();
    restorer.apply_action(RedirectAction::Open(1, S("y"), Permissions::Write), &mut env).unwrap();
    restorer.apply_action(RedirectAction::HereDoc(1, vec!()), &mut env).unwrap();

    // Existing fd closed, then opened
    restorer.apply_action(RedirectAction::Close(2), &mut env).unwrap();
    restorer.apply_action(RedirectAction::Open(2, S("z"), Permissions::Write), &mut env).unwrap();

    // Existing fd changed, then closed
    restorer.apply_action(RedirectAction::Open(3, S("w"), Permissions::Write), &mut env).unwrap();
    restorer.apply_action(RedirectAction::Close(3), &mut env).unwrap();

    // Nonexistent fd set, then changed
    restorer.apply_action(RedirectAction::HereDoc(4, vec!()), &mut env).unwrap();
    restorer.apply_action(RedirectAction::Open(4, S("s"), Permissions::Write), &mut env).unwrap();

    // Nonexistent fd set, then closed
    restorer.apply_action(RedirectAction::Open(5, S("t"), Permissions::Read), &mut env).unwrap();
    restorer.apply_action(RedirectAction::Close(5), &mut env).unwrap();

    assert!(env_original != env);
    restorer.restore(&mut env);
    assert_eq!(env_original, env);
}