/******************************************************************************
*	@file		map.rs
*	@author		Joey Pollack
*	@date		2024/12/09 (y/m/d)
*	@modified	2024/12/09 (y/m/d)
*	@copyright	Joseph R Pollack
*	@brief		Represents the map and the guard on the map. 
******************************************************************************/

use nalgebra_glm::I32Vec2;

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum MapCell
{
	Space,
	Block,
	Guard,
	Visited,
}

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum Direction
{
	North,
	South,
	East,
	West,
}

#[derive(Clone, Debug)]
pub struct Map
{
	map: Vec<Vec<MapCell>>,
	guard_start_pos: I32Vec2,
	guard_direction: Direction,
	guard_pos: nalgebra_glm::I32Vec2,
}

impl Map
{
	pub fn new() -> Map
	{
		Map { map: vec![], guard_start_pos: I32Vec2::new(0, 0), guard_direction: Direction::North, guard_pos: I32Vec2::new(0, 0) }
	}

	pub fn parse(data: &str) -> Map
	{
		let mut split_pattern = "\n";
		if data.contains("\r\n")
		{
			split_pattern = "\r\n";
		}

		let rows = data.split(split_pattern);
		let height = rows.clone().count();

		let mut map: Vec<Vec<MapCell>> = vec![vec![]; height];
		let mut guard_pos = I32Vec2::new(0, 0);

		for (i, row) in rows.enumerate()
		{
			map[i] = vec![MapCell::Space; row.len()];
			for (j, c) in row.as_bytes().into_iter().enumerate()
			{
				match c
				{
					b'.' => map[i][j] = MapCell::Space,
					b'#' => map[i][j] = MapCell::Block,
					b'^' => { map[i][j] =  MapCell::Guard; guard_pos.x = i as i32; guard_pos.y = j as i32; }

					_ => panic!("Map ERROR: Failed to parse map data, Invalid map input: {}", c)
				}
			}
		}

		Map { map, guard_start_pos: guard_pos, guard_direction: Direction::North, guard_pos }
	}

	pub fn print(self: &Map)
	{
		print!("MAP:");
		for (i, row) in self.map.iter().enumerate()
		{
			print!("\n\t");
			for (j, c) in row.iter().enumerate()
			{

				if i as i32 == self.guard_pos.x && j as i32 == self.guard_pos.y
				{
					self.print_guard();
				}
				else
				{
					match *c
					{
						MapCell::Space => print!("."),	
						MapCell::Block => print!("#"),	
						MapCell::Visited => print!("X"),	
						MapCell::Guard => self.print_guard(),
					}
				}
				
			}
		}
		println!();
	}

	fn print_guard(self: &Map)
	{
		match self.guard_direction
		{
			Direction::North => print!("^"),
			Direction::South => print!("v"),
			Direction::East => print!(">"),
			Direction::West => print!("<"),
		}
	}

	pub fn width(self: &Map) -> i32
	{
		self.map[0].len() as i32
	}

	pub fn height(self: &Map) -> i32
	{
		self.map.len() as i32
	}

	pub fn add_blocker_at(self: &mut Map, at: &I32Vec2)
	{
		self.map[at.x as usize][at.y as usize] = MapCell::Block;
	}

	/// Step Rules:
	/// 
    /// If there is something directly in front of you, turn right 90 degrees.
    /// Otherwise, take a step forward.
	/// 
	/// Returns true if the guard is still on the map after the step.
	pub fn step_guard(self: &mut Map) -> bool
	{
		if !self.guard_is_on_map()
		{
			return false;
		}

		let next_guard_pos = self.guard_pos + self.guard_direction_vector();

		if !self.pos_is_on_map(&next_guard_pos)
		{
			self.map[self.guard_pos.x as usize][self.guard_pos.y as usize] = MapCell::Visited;
			self.guard_pos = next_guard_pos;
			return false;
		}

		if self.map[next_guard_pos.x as usize][next_guard_pos.y as usize] == MapCell::Block
		{
			self.rotate_guard_90();
			return true;
		}

		self.map[self.guard_pos.x as usize][self.guard_pos.y as usize] = MapCell::Visited;
		self.guard_pos = next_guard_pos;
		self.guard_is_on_map()
	}

	pub fn guard_is_on_map(self: &Map) -> bool
	{
		self.guard_pos.x >= 0 &&
		self.guard_pos.y >= 0 &&
		(self.guard_pos.x as usize) < self.map[0].len() &&
		(self.guard_pos.y as usize) < self.map.len()
	}

	fn pos_is_on_map(self: &Map, pos: &I32Vec2) -> bool
	{
		pos.x >= 0 &&
		pos.y >= 0 &&
		(pos.x as usize) < self.map.len() &&
		(pos.y as usize) < self.map[0].len()
	}

	pub fn guard_position(self: &Map) -> I32Vec2
	{
		self.guard_pos
	}

	pub fn guard_direction_vector(self: &Map) -> I32Vec2
	{
		match self.guard_direction
		{
			Direction::North => I32Vec2::new(-1,0),
			Direction::South => I32Vec2::new(1, 0),
			Direction::East => I32Vec2::new(0,1),
			Direction::West => I32Vec2::new(0, -1),
		}
	}

	// Rotate the guard clockwise 90 degrees
	fn rotate_guard_90(self: &mut Map)
	{
		match self.guard_direction
		{
			Direction::North => self.guard_direction = Direction::East,
			Direction::South => self.guard_direction = Direction::West,
			Direction::East => self.guard_direction = Direction::South,
			Direction::West => self.guard_direction = Direction::North,
		};
	}

	pub fn reset_guard(self: &mut Map)
	{
		self.guard_pos = self.guard_start_pos;
		self.guard_direction = Direction::North;
	}

	pub fn clear_visited(self: &mut Map)
	{
		for row in &mut self.map
		{
			for c in row
			{
				if *c == MapCell::Visited
				{
					*c = MapCell::Space;
				}
			}
		}
	}

}