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#![allow(missing_docs)]
// Comes from https://github.com/inre/rust-mq/blob/master/netopt

use std::io::{self, Cursor, Read, Write};
use std::sync::{Arc, Mutex};

pub type MockCursor = Cursor<Vec<u8>>;

#[derive(Clone, Debug)]
pub struct MockStream {
    reader: Arc<Mutex<MockCursor>>,
    writer: Arc<Mutex<MockCursor>>,
}

impl Default for MockStream {
    fn default() -> Self {
        Self::new()
    }
}

impl MockStream {
    pub fn new() -> MockStream {
        MockStream {
            reader: Arc::new(Mutex::new(MockCursor::new(Vec::new()))),
            writer: Arc::new(Mutex::new(MockCursor::new(Vec::new()))),
        }
    }

    pub fn with_vec(vec: Vec<u8>) -> MockStream {
        MockStream {
            reader: Arc::new(Mutex::new(MockCursor::new(vec))),
            writer: Arc::new(Mutex::new(MockCursor::new(Vec::new()))),
        }
    }

    pub fn take_vec(&mut self) -> Vec<u8> {
        let mut cursor = self.writer.lock().unwrap();
        let vec = cursor.get_ref().to_vec();
        cursor.set_position(0);
        cursor.get_mut().clear();
        vec
    }

    pub fn next_vec(&mut self, vec: &[u8]) {
        let mut cursor = self.reader.lock().unwrap();
        cursor.set_position(0);
        cursor.get_mut().clear();
        cursor.get_mut().extend_from_slice(vec);
    }

    pub fn swap(&mut self) {
        let mut cur_write = self.writer.lock().unwrap();
        let mut cur_read = self.reader.lock().unwrap();
        let vec_write = cur_write.get_ref().to_vec();
        let vec_read = cur_read.get_ref().to_vec();
        cur_write.set_position(0);
        cur_read.set_position(0);
        cur_write.get_mut().clear();
        cur_read.get_mut().clear();
        // swap cursors
        cur_read.get_mut().extend_from_slice(vec_write.as_slice());
        cur_write.get_mut().extend_from_slice(vec_read.as_slice());
    }
}

impl Write for MockStream {
    fn write(&mut self, msg: &[u8]) -> io::Result<usize> {
        self.writer.lock().unwrap().write(msg)
    }

    fn flush(&mut self) -> io::Result<()> {
        self.writer.lock().unwrap().flush()
    }
}

impl Read for MockStream {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        self.reader.lock().unwrap().read(buf)
    }
}

#[cfg(test)]
mod test {
    use super::MockStream;
    use std::io::{Read, Write};

    #[test]
    fn write_take_test() {
        let mut mock = MockStream::new();
        // write to mock stream
        mock.write(&[1, 2, 3]).unwrap();
        assert_eq!(mock.take_vec(), vec![1, 2, 3]);
    }

    #[test]
    fn read_with_vec_test() {
        let mut mock = MockStream::with_vec(vec![4, 5]);
        let mut vec = Vec::new();
        mock.read_to_end(&mut vec).unwrap();
        assert_eq!(vec, vec![4, 5]);
    }

    #[test]
    fn clone_test() {
        let mut mock = MockStream::new();
        let mut cloned = mock.clone();
        mock.write(&[6, 7]).unwrap();
        assert_eq!(cloned.take_vec(), vec![6, 7]);
    }

    #[test]
    fn swap_test() {
        let mut mock = MockStream::new();
        let mut vec = Vec::new();
        mock.write(&[8, 9, 10]).unwrap();
        mock.swap();
        mock.read_to_end(&mut vec).unwrap();
        assert_eq!(vec, vec![8, 9, 10]);
    }
}