use std;
use std::cell::RefCell;
use std::io;
use std::io::{BufWriter, Write};

use ropey::RopeSlice;
use termion;
use termion::color;
use termion::raw::{IntoRawMode, RawTerminal};
use termion::screen::AlternateScreen;
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;

use crate::utils::{grapheme_width, RopeGraphemes};

use super::smallstring::SmallString;

pub(crate) struct Screen {
    out: RefCell<AlternateScreen<RawTerminal<BufWriter<io::Stdout>>>>,
    buf: RefCell<Vec<Option<(Style, SmallString)>>>,
    w: usize,
    h: usize,
}

impl Screen {
    pub(crate) fn new() -> Self {
        let (w, h) = termion::terminal_size().unwrap();
        let buf = std::iter::repeat(Some((Style(Color::Black, Color::Black), " ".into())))
            .take(w as usize * h as usize)
            .collect();
        Screen {
            out: RefCell::new(AlternateScreen::from(
                BufWriter::with_capacity(1 << 14, io::stdout())
                    .into_raw_mode()
                    .unwrap(),
            )),
            buf: RefCell::new(buf),
            w: w as usize,
            h: h as usize,
        }
    }

    pub(crate) fn clear(&self, col: Color) {
        for cell in self.buf.borrow_mut().iter_mut() {
            match *cell {
                Some((ref mut style, ref mut text)) => {
                    *style = Style(col, col);
                    text.clear();
                    text.push_str(" ");
                }
                _ => {
                    *cell = Some((Style(col, col), " ".into()));
                }
            }
        }
    }

    pub(crate) fn resize(&mut self, w: usize, h: usize) {
        self.w = w;
        self.h = h;
        self.buf
            .borrow_mut()
            .resize(w * h, Some((Style(Color::Black, Color::Black), " ".into())));
    }

    pub(crate) fn present(&self) {
        let mut out = self.out.borrow_mut();
        let buf = self.buf.borrow();

        let mut last_style = Style(Color::Black, Color::Black);
        write!(out, "{}", last_style).unwrap();

        // Write everything to the tmp_string first.
        for y in 0..self.h {
            let mut x = 0;
            write!(out, "{}", termion::cursor::Goto(1, y as u16 + 1)).unwrap();
            while x < self.w {
                if let Some((style, ref text)) = buf[y * self.w + x] {
                    if style != last_style {
                        write!(out, "{}", style).unwrap();
                        last_style = style;
                    }
                    write!(out, "{}", text).unwrap();
                    x += 1;
                } else {
                    x += 1;
                }
            }
        }

        // Make sure everything is written out
        out.flush().unwrap();
    }

    pub(crate) fn draw(&self, x: usize, y: usize, text: &str, style: Style) {
        if y < self.h {
            let mut buf = self.buf.borrow_mut();
            let mut x = x;
            for g in UnicodeSegmentation::graphemes(text, true) {
                let width = UnicodeWidthStr::width(g);
                if width > 0 {
                    if x < self.w {
                        buf[y * self.w + x] = Some((style, g.into()));
                    }
                    x += 1;
                    for _ in 0..(width - 1) {
                        if x < self.w {
                            buf[y * self.w + x] = None;
                        }
                        x += 1;
                    }
                }
            }
        }
    }

    pub(crate) fn draw_rope_slice(&self, x: usize, y: usize, text: &RopeSlice, style: Style) {
        if y < self.h {
            let mut buf = self.buf.borrow_mut();
            let mut x = x;
            for g in RopeGraphemes::new(&text) {
                let width = grapheme_width(&g);
                if width > 0 {
                    if x < self.w {
                        buf[y * self.w + x] = Some((style, SmallString::from_rope_slice(&g)));
                    }
                    x += 1;
                    for _ in 0..(width - 1) {
                        if x < self.w {
                            buf[y * self.w + x] = None;
                        }
                        x += 1;
                    }
                }
            }
        }
    }

    pub(crate) fn hide_cursor(&self) {
        write!(self.out.borrow_mut(), "{}", termion::cursor::Hide).unwrap();
    }

    pub(crate) fn show_cursor(&self) {
        write!(self.out.borrow_mut(), "{}", termion::cursor::Show).unwrap();
    }
}

impl Drop for Screen {
    fn drop(&mut self) {
        write!(
            self.out.borrow_mut(),
            "{}{}{}",
            color::Fg(color::Reset),
            color::Bg(color::Reset),
            termion::clear::All,
        )
        .unwrap();
        self.show_cursor();
    }
}

#[derive(Debug, Copy, Clone, PartialEq)]
pub(crate) enum Color {
    Black,
    Blue,
    Cyan,
    Green,
    LightBlack,
    LightBlue,
    LightCyan,
    LightGreen,
    LightMagenta,
    LightRed,
    LightWhite,
    LightYellow,
    Magenta,
    Red,
    Rgb(u8, u8, u8),
    White,
    Yellow,
}

#[derive(Debug, Copy, Clone, PartialEq)]
pub(crate) struct Style(pub Color, pub Color); // Fg, Bg

impl std::fmt::Display for Style {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        match self.0 {
            Color::Black => write!(f, "{}", color::Fg(color::Black)),
            Color::Blue => write!(f, "{}", color::Fg(color::Blue)),
            Color::Cyan => write!(f, "{}", color::Fg(color::Cyan)),
            Color::Green => write!(f, "{}", color::Fg(color::Green)),
            Color::LightBlack => write!(f, "{}", color::Fg(color::LightBlack)),
            Color::LightBlue => write!(f, "{}", color::Fg(color::LightBlue)),
            Color::LightCyan => write!(f, "{}", color::Fg(color::LightCyan)),
            Color::LightGreen => write!(f, "{}", color::Fg(color::LightGreen)),
            Color::LightMagenta => write!(f, "{}", color::Fg(color::LightMagenta)),
            Color::LightRed => write!(f, "{}", color::Fg(color::LightRed)),
            Color::LightWhite => write!(f, "{}", color::Fg(color::LightWhite)),
            Color::LightYellow => write!(f, "{}", color::Fg(color::LightYellow)),
            Color::Magenta => write!(f, "{}", color::Fg(color::Magenta)),
            Color::Red => write!(f, "{}", color::Fg(color::Red)),
            Color::Rgb(r, g, b) => write!(f, "{}", color::Fg(color::Rgb(r, g, b))),
            Color::White => write!(f, "{}", color::Fg(color::White)),
            Color::Yellow => write!(f, "{}", color::Fg(color::Yellow)),
        }?;

        match self.1 {
            Color::Black => write!(f, "{}", color::Bg(color::Black)),
            Color::Blue => write!(f, "{}", color::Bg(color::Blue)),
            Color::Cyan => write!(f, "{}", color::Bg(color::Cyan)),
            Color::Green => write!(f, "{}", color::Bg(color::Green)),
            Color::LightBlack => write!(f, "{}", color::Bg(color::LightBlack)),
            Color::LightBlue => write!(f, "{}", color::Bg(color::LightBlue)),
            Color::LightCyan => write!(f, "{}", color::Bg(color::LightCyan)),
            Color::LightGreen => write!(f, "{}", color::Bg(color::LightGreen)),
            Color::LightMagenta => write!(f, "{}", color::Bg(color::LightMagenta)),
            Color::LightRed => write!(f, "{}", color::Bg(color::LightRed)),
            Color::LightWhite => write!(f, "{}", color::Bg(color::LightWhite)),
            Color::LightYellow => write!(f, "{}", color::Bg(color::LightYellow)),
            Color::Magenta => write!(f, "{}", color::Bg(color::Magenta)),
            Color::Red => write!(f, "{}", color::Bg(color::Red)),
            Color::Rgb(r, g, b) => write!(f, "{}", color::Bg(color::Rgb(r, g, b))),
            Color::White => write!(f, "{}", color::Bg(color::White)),
            Color::Yellow => write!(f, "{}", color::Bg(color::Yellow)),
        }
    }
}