use ggez::event::EventHandler;
use ggez::graphics::{self, spritebatch::SpriteBatch, DrawParam, FilterMode, Image, WrapMode};
use ggez::input::mouse;
use ggez::mint::{Point2, Vector2};
use ggez::{Context, GameResult};
use std::time::Instant;

use crate::cell::{Cell, Occupant};
use crate::constants;
use crate::cosmonaut::Cosmonaut;

pub struct Game {
    selected: Option<(usize, usize)>,
    spritebatch: SpriteBatch,
    grid: Vec<Vec<Cell>>,
    background: Image,
    cosmonaut: Cosmonaut,
}

impl Game {
    pub fn new(context: &mut Context) -> GameResult<Game> {
        let mut background = Image::new(context, "/background.png")?;
        background.set_filter(FilterMode::Nearest);

        let mut image = Image::new(context, "/tileset.png")?;
        image.set_filter(FilterMode::Nearest);
        image.set_wrap(WrapMode::Mirror, WrapMode::Mirror);

        let mut grid = Vec::new();
        let mut y = 0.0;

        for _ in 0..constants::COLUMNS {
            let mut column = Vec::new();
            for j in 0..constants::ROWS {
                column.push(Cell::new(Point2 {
                    x: (j as f32)
                        * (constants::TILE_WIDTH * constants::TILE_SCALE + constants::BORDER_SIZE)
                        + constants::SHIFT_X,
                    y: y + constants::SHIFT_Y,
                }));
            }
            y += constants::TILE_HEIGHT * constants::TILE_SCALE + constants::BORDER_SIZE;
            grid.push(column);
        }

        Ok(Game {
            grid,
            selected: None,
            cosmonaut: Cosmonaut::new(context)?,
            spritebatch: SpriteBatch::new(image),
            background,
        })
    }

    fn update_explosions(&mut self) {
        let mut last = Occupant::None;
        let mut connected = Vec::new();
        for i in 0..constants::COLUMNS {
            let mut c = Vec::new();
            for j in 0..constants::ROWS {
                if self.grid[i][j].occupant == last && last != Occupant::None {
                    c.push((i, j));
                    c.push((i, j - 1));
                } else {
                    connected.push(c.clone());
                    c.clear();
                }
                last = self.grid[i][j].occupant;
            }
            connected.push(c);
            last = Occupant::None;
        }

        for c in connected.iter() {
            if c.len() > 3 {
                for (i, j) in c.iter() {
                    self.grid[*i][*j].occupant = Occupant::Explosion {
                        frame: 0,
                        timer: Instant::now(),
                    };
                }
            }
        }

        connected.clear();
        for i in 0..constants::COLUMNS {
            let mut c = Vec::new();
            for j in 0..constants::ROWS {
                if self.grid[j][i].occupant == last && last != Occupant::None {
                    c.push((j, i));
                    c.push((j - 1, i));
                } else {
                    connected.push(c.clone());
                    c.clear();
                }
                last = self.grid[j][i].occupant;
            }
            connected.push(c);
            last = Occupant::None;
        }

        for c in connected.iter() {
            if c.len() > 3 {
                for (j, i) in c.iter() {
                    self.grid[*j][*i].occupant = Occupant::Explosion {
                        frame: 0,
                        timer: Instant::now(),
                    };
                }
            }
        }
    }

    fn update_dropping(&mut self) {
        for i in 1..constants::COLUMNS {
            for j in 0..constants::ROWS {
                if self.grid[i][j].occupant == Occupant::None
                    && self.grid[i - 1][j].occupant != Occupant::None
                {
                    self.grid[i][j].occupant = self.grid[i - 1][j].occupant;
                    self.grid[i - 1][j].occupant = Occupant::None;
                }
            }
        }
    }

    fn update_feeding(&mut self) {
        for i in 0..constants::COLUMNS {
            if self.grid[0][i].occupant == Occupant::None {
                self.grid[0][i].occupant = rand::random();
            }
        }
    }

    fn update_frames(&mut self) {
        for row in self.grid.iter_mut() {
            for cell in row.iter_mut() {
                let mut done = false;
                if let Occupant::Explosion {
                    ref mut frame,
                    ref mut timer,
                } = cell.occupant
                {
                    if timer.elapsed().as_millis() > 500 {
                        if *frame < 4 {
                            *frame += 1;
                            *timer = Instant::now();
                        } else {
                            done = true;
                        }
                    }
                }
                if done {
                    cell.occupant = Occupant::None;
                }
            }
        }
    }
}

impl EventHandler for Game {
    fn update(&mut self, context: &mut Context) -> GameResult {
        for row in self.grid.iter_mut() {
            for cell in row.iter_mut() {
                cell.hover_off();
            }
        }

        let position = mouse::position(context);

        if self.cosmonaut.contains(position) {
            self.cosmonaut.start();
        }

        self.cosmonaut.update();

        for row in self.grid.iter_mut() {
            for cell in row.iter_mut() {
                if cell.contains(position) {
                    cell.hover_on();
                }
            }
        }

        self.update_explosions();
        self.update_frames();
        self.update_dropping();
        self.update_feeding();

        Ok(())
    }

    fn mouse_button_down_event(
        &mut self,
        _context: &mut Context,
        button: mouse::MouseButton,
        x: f32,
        y: f32,
    ) {
        if button == mouse::MouseButton::Left {
            let position = Point2 { x, y };
            for (i, row) in self.grid.iter_mut().enumerate() {
                for (j, cell) in row.iter_mut().enumerate() {
                    if cell.contains(position) && cell.moveable() {
                        self.selected = Some((i, j));
                        cell.clicked_on();
                    }
                }
            }
        }
    }

    fn mouse_button_up_event(
        &mut self,
        _context: &mut Context,
        button: mouse::MouseButton,
        x: f32,
        y: f32,
    ) {
        if button == mouse::MouseButton::Left {
            for row in self.grid.iter_mut() {
                for cell in row.iter_mut() {
                    cell.clicked_off();
                }
            }

            if let Some(selected) = self.selected {
                let position = Point2 { x, y };
                let mut swap = None;
                for (i, row) in self.grid.iter_mut().enumerate() {
                    for (j, cell) in row.iter_mut().enumerate() {
                        if cell.contains(position)
                            && cell.moveable()
                            && (((i + 1 == selected.0) && (j == selected.1))
                                || ((i.overflowing_sub(1).0 == selected.0) && (j == selected.1))
                                || ((i == selected.0) && (j + 1 == selected.1))
                                || ((i == selected.0) && (j.overflowing_sub(1)).0 == selected.1))
                        {
                            swap = Some((i, j));
                        }
                    }
                }
                if let Some((i, j)) = swap {
                    let clone = self.grid[i][j].occupant;
                    self.grid[i][j].occupant = self.grid[selected.0][selected.1].occupant;
                    self.grid[selected.0][selected.1].occupant = clone;
                    self.selected = None;
                }
            }
        }
    }

    fn draw(&mut self, context: &mut Context) -> GameResult {
        graphics::clear(context, [0.0, 0.0, 0.0, 1.0].into());
        graphics::draw(
            context,
            &self.background,
            DrawParam::default().scale(Vector2 { x: 3.35, y: 3.35 }),
        )?;
        self.cosmonaut.draw(context)?;

        for row in self.grid.iter() {
            for cell in row.iter() {
                cell.draw(context, &mut self.spritebatch)?;
            }
        }

        graphics::draw(context, &self.spritebatch, DrawParam::default())?;

        self.spritebatch.clear();

        graphics::present(context)?;
        Ok(())
    }
}