//! This module provides one place to work with the screen.
//!
//!   In Rust we can call `stdout()` to get a handle to the current default console handle.
//!   When working with UNIX or Windows10 systems you could print some text to the screen by doing the following:
//!
//!   ```
//!   write!(std::io::stdout(), "{}", "some text").
//!   ```
//!
//!   But things change when we are in alternate screen modes.
//!   We can not simply use `stdout()` to get a handle to the 'alternate screen', since this call returns the current default console handle (main screen).
//!
//!   To get the handle to the `alternate screen` we first need to store this handle so that we are able to call it later on.
//!   Through this stored handle, crossterm can write to or execute commands at the current screen whether it be an alternate screen or main screen.
//!
//!   For UNIX and Windows10 systems, we store the handle gotten from `stdout()`. For Windows systems who are not supporting ANSI escape codes, we can call `CONOUT$` to get the current screen `HANDLE`.

use super::*;

use std::default::Default;
use std::io::Write;

/// Struct that is a handle to a terminal screen.
/// This handle could be used to write to the current screen
///
/// For UNIX and Windows 10 `stdout()` will be used as handle. And for Windows systems, not supporting ANSI escape codes, will use WinApi's `HANDLE` as handle.
pub struct TerminalOutput {
    stdout: Box<IStdout + Send + Sync>,
    pub is_in_raw_mode: bool,
}

impl TerminalOutput {
    /// Create a new screen write instance whereon screen related actions can be performed.
    pub fn new(raw_mode: bool) -> Self {
        #[cfg(target_os = "windows")]
        let stdout: Box<IStdout + Send + Sync> =
            functions::get_module::<Box<IStdout + Send + Sync>>(
                Box::from(WinApiOutput::new()),
                Box::from(AnsiOutput::new()),
            )
            .unwrap();

        #[cfg(not(target_os = "windows"))]
        let stdout = Box::from(AnsiOutput::new()) as Box<IStdout + Send + Sync>;

        TerminalOutput {
            stdout,
            is_in_raw_mode: raw_mode,
        }
    }

    /// Write String to the current screen.
    pub fn write_string(&self, string: String) -> io::Result<usize> {
        self.stdout.write_str(string.as_str())
    }

    /// Flush the current screen.
    pub fn flush(&self) -> io::Result<()> {
        self.stdout.flush()
    }

    /// Write &str to the current screen.
    pub fn write_str(&self, string: &str) -> io::Result<usize> {
        self.stdout.write_str(string)
    }

    /// Write buffer to the screen
    pub fn write_buf(&self, buf: &[u8]) -> io::Result<usize> {
        self.stdout.write(buf)
    }
}

impl Write for TerminalOutput {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        self.write_buf(buf)
    }

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

impl Default for TerminalOutput {
    /// Get the default handle to the current screen.
    fn default() -> Self {
        #[cfg(target_os = "windows")]
        let stdout = functions::get_module::<Box<IStdout + Send + Sync>>(
            Box::from(WinApiOutput::new()),
            Box::from(AnsiOutput::new()),
        )
        .unwrap();

        #[cfg(not(target_os = "windows"))]
        let stdout = Box::from(AnsiOutput::new()) as Box<IStdout + Send + Sync>;

        TerminalOutput {
            stdout,
            is_in_raw_mode: false,
        }
    }
}