use math::*;
use ships::*;

use std::fmt;

use std::collections::HashSet;

#[derive(Clone, PartialEq, Eq, Debug, Serialize, Deserialize)]
pub enum Action {
    PlaceShips(Vec<ShipPlacement>),
    Shoot(Weapon, Point)
}

impl fmt::Display for Action {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            &Action::Shoot(w, p) => writeln!(f, "{},{},{}", w, p.x, p.y),
            &Action::PlaceShips(ref ships) => ships.iter().map(|ref ship| {
                writeln!(f, "{} {} {} {}", ship.ship_type, ship.point.x, ship.point.y, ship.direction)
            }).fold(Ok(()), |acc, next| acc.and(next))
        }
    }
}

#[derive(Clone, PartialEq, Eq, Debug, Serialize, Deserialize)]
pub struct ShipPlacement {
    ship_type: Ship,
    point: Point,
    direction: Direction
}

impl ShipPlacement {
    pub fn new(ship_type: Ship, point: Point, direction: Direction) -> ShipPlacement {
        ShipPlacement {
            ship_type: ship_type,
            point: point,
            direction: direction
        }
    }
        
    pub fn valid(&self, map_size: u16) -> bool {
        let start = self.point;
        let end = start.move_point(self.direction, self.ship_type.length() as i32, map_size);
        start.x < map_size && start.y < map_size && end.is_some()
    }
    pub fn valid_placements(placements: &Vec<ShipPlacement>, map_size: u16) -> bool {
        let mut occupied = HashSet::new();
        
        let individuals_valid = placements.iter().all(|p| p.valid(map_size));
        
        let mut no_overlaps = true;            
        for placement in placements {
            for i in 0..placement.ship_type.length() as i32 {
                match placement.point.move_point(placement.direction, i, map_size) {
                    Some(block) => {
                        no_overlaps = no_overlaps && !occupied.contains(&block);
                        occupied.insert(block);
                    },
                    None => {
                        //invalid case here is handled above
                    }
                }
            }

            //block out the area around the current ship to prevent adjacent ships
            for i in 0..placement.ship_type.length() as i32 {
                match placement.point.move_point(placement.direction, i, map_size) {
                    Some(current_block) => {
                        if let Some(p) = current_block.move_point(Direction::North, 1, map_size) {
                            occupied.insert(p);
                        }
                        if let Some(p) = current_block.move_point(Direction::South, 1, map_size) {
                            occupied.insert(p);
                        }
                        if let Some(p) = current_block.move_point(Direction::East, 1, map_size) {
                            occupied.insert(p);
                        }
                        if let Some(p) = current_block.move_point(Direction::West, 1, map_size) {
                            occupied.insert(p);
                        }
                    },
                    None => {
                        //invalid case here is handled above
                    }
                }
            }
        }
        individuals_valid && no_overlaps
    }
}