use crate::graphics::{BORDER_RADIUS, CELL_SIZE, COLOR_BACKGROUND};
use crate::random::RandomSystem;
use crate::tetromino::{MinoColor, Position, Tetromino, TetrominoType};
use crate::Renderable;
use sdl2::{pixels::Color, rect::Rect, render::Canvas, video::Window};
use std::collections::VecDeque;
use std::fmt;

pub const PLAYFIELD_HEIGHT: usize = 20;
pub const PLAYFIELD_WIDTH: usize = 10;

pub type Matrix = [[Option<MinoColor>; PLAYFIELD_WIDTH]; 2 * PLAYFIELD_HEIGHT];

enum Movement {
    Rotation,
    Gravity,
    Translation,
}

pub struct PlayField {
    can_swap_hold: bool,
    hold_piece: Option<TetrominoType>,
    field: Matrix,
    pub active_piece: Option<Tetromino>,
    bag: RandomSystem,
    next_pieces: VecDeque<TetrominoType>,
    last_movement: Movement,
}

impl fmt::Debug for PlayField {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.active_piece {
            Some(active_piece) => {
                writeln!(
                    f,
                    "current piece: {:?} @ {}, {}",
                    active_piece.piece_type, active_piece.position.x, active_piece.position.y
                )?;
            }
            None => (),
        }

        writeln!(f, "next pieces: {:?}", self.next_pieces)?;
        let occupied_spaces = self
            .active_piece
            .and_then(|t| Some(t.get_cur_occupied_spaces()))
            .unwrap_or_default();
        for y in PLAYFIELD_HEIGHT..self.field.len() {
            write!(
                f,
                "{} │",
                ('a' as usize - PLAYFIELD_HEIGHT + y) as u8 as char
            )?;
            for x in 0..PLAYFIELD_WIDTH {
                if occupied_spaces.contains(&Position::new(x as isize, y as isize)) {
                    write!(f, "#")?;
                } else {
                    match self.field[y][x] {
                        Some(t) => write!(f, "{:?}", t)?,
                        None => write!(f, " ")?,
                    }
                }
            }
            writeln!(f, "│")?;
        }
        writeln!(f, "  └{}┘", "─".repeat(PLAYFIELD_WIDTH))?;
        write!(
            f,
            "   {}",
            (0..PLAYFIELD_WIDTH)
                .map(|e| e.to_string())
                .collect::<Vec<_>>()
                .join("")
        )?;
        Ok(())
    }
}

impl PlayField {
    pub fn new() -> Self {
        let mut bag = RandomSystem::new();
        let active_piece = Tetromino::from(bag.get_tetromino());
        let mut next_pieces = VecDeque::with_capacity(3);
        for _ in 0..next_pieces.capacity() {
            next_pieces.push_back(bag.get_tetromino());
        }

        PlayField {
            can_swap_hold: true,
            hold_piece: None,
            field: [[None; PLAYFIELD_WIDTH]; 2 * PLAYFIELD_HEIGHT],
            active_piece: Some(active_piece),
            bag,
            next_pieces,
            last_movement: Movement::Gravity,
        }
    }

    pub fn move_offset(&mut self, x: isize, y: isize) -> bool {
        if self.can_move_offset(x, y) {
            match self.active_piece {
                Some(mut piece) => {
                    piece.position.x += x;
                    piece.position.y += y;
                    self.active_piece = Some(piece);
                    true
                }
                None => panic!("Active piece missing!"),
            }
        } else {
            false
        }
    }

    fn can_move_offset(&self, x: isize, y: isize) -> bool {
        match self.active_piece {
            Some(piece) => piece
                .get_occupied_spaces(piece.position.offset(x, y))
                .iter()
                .fold(true, |acc, pos| {
                    acc && (pos.y as usize) < self.field.len()
                        && (pos.x as usize) < PLAYFIELD_WIDTH
                        && self.field[pos.y as usize][pos.x as usize].is_none()
                }),
            None => false,
        }
    }

    pub fn spawn_tetromino(&mut self) {
        self.active_piece = Some(Tetromino::from(
            self.next_pieces
                .pop_front()
                .expect("visible queue to be populated"),
        ));
        self.next_pieces.push_back(self.bag.get_tetromino());
        self.can_swap_hold = true;
    }

    pub fn tick_gravity(&mut self) {
        match &self.active_piece {
            Some(mut active_piece) if self.can_active_piece_move_down() => {
                active_piece.position.y += 1;
                self.active_piece = Some(active_piece);
            }
            _ => (),
        }
    }

    pub fn can_active_piece_move_down(&self) -> bool {
        self.active_piece
            .and_then(|p| {
                Some(
                    p.get_falling_occupied_spaces()
                        .iter()
                        .fold(true, |acc, pos| {
                            acc && (pos.y as usize) < self.field.len()
                                && self.field[pos.y as usize][pos.x as usize].is_none()
                        }),
                )
            })
            .unwrap_or_else(|| false)
    }

    pub fn lock_active_piece(&mut self) -> Vec<Position> {
        match &self.active_piece {
            Some(active_piece) => {
                let active_color = active_piece.get_color();
                let new_pieces = active_piece.get_cur_occupied_spaces();
                for Position { x, y } in &new_pieces {
                    self.field[*y as usize][*x as usize] = Some(active_color);
                }

                self.active_piece = None;
                new_pieces
            }
            None => panic!("Tried to lock active piece while active piece doesn't exist!"),
        }
    }

    pub fn is_active_piece_in_valid_position(&self) -> bool {
        match self.active_piece {
            Some(active_piece) => {
                self.can_piece_be_at_position(&active_piece)
            },
            None => panic!("Tried checking if active piece is in a valid position but active piece doesn't exist")
        }
    }

    pub fn can_piece_be_at_position(&self, tetromino: &Tetromino) -> bool {
        tetromino
            .get_cur_occupied_spaces()
            .iter()
            .all(|Position { x, y }| {
                (*y as usize) < self.field.len()
                    && (*x as usize) < PLAYFIELD_WIDTH
                    && self.field[*y as usize][*x as usize].is_none()
            })
    }
}

impl Renderable for PlayField {
    fn render(&self, canvas: &mut Canvas<Window>) -> Result<(), String> {
        for y in 0..PLAYFIELD_HEIGHT {
            for x in 0..PLAYFIELD_WIDTH {
                canvas.set_draw_color(Color::RGB(0, 0, 0));
                canvas.fill_rect(Rect::new(
                    CELL_SIZE as i32 * x as i32,
                    CELL_SIZE as i32 * y as i32,
                    CELL_SIZE,
                    CELL_SIZE,
                ))?;

                match self.field[y + PLAYFIELD_HEIGHT][x] {
                    Some(mino) => canvas.set_draw_color(mino),
                    None => canvas.set_draw_color(COLOR_BACKGROUND),
                }
                canvas.fill_rect(Rect::new(
                    CELL_SIZE as i32 * x as i32 + BORDER_RADIUS as i32,
                    CELL_SIZE as i32 * y as i32 + BORDER_RADIUS as i32,
                    CELL_SIZE - 2 * BORDER_RADIUS,
                    CELL_SIZE - 2 * BORDER_RADIUS,
                ))?;
            }
        }

        match self.active_piece {
            Some(piece) => piece.render(canvas)?,
            None => (),
        }

        Ok(())
    }
}