using System;
using S = System.String;
using System.Collections.Generic;
partial class M {
  Dictionary<S, S> d = new Dictionary<S, S>( );
  List<S> e = new List<S>( );
  int p = 9, m = 999, x, y, z, u, v, i, j;
  S a = "@", w = "#", f = ".", s = ">", c;
  Random r = new Random( );

  M( int k, int l, int h ) {
    //determine number of enemies
    u = m * l;
    
    //add enemies
    while ( i++ < u ) {
      e.Add( ( r.Next( m ) - 499 ) + a + ( r.Next( m ) - 499 ) );
      d[ e[ e.Count - 1 ] ] = "M";
    }

    //set player start
    d[ X ] = a;

    //k will be 0 if player presses Q or ESC
    while ( k > 0 ) {
      //store player co-ords
      u = x;
      v = y;
      
      //handle keyboard return code
      x = k > 2 && k < 20 ? x - 1 : k > 12 ? x + 1 : x;
      y = k % 2 > 0 && k % 10 != 0 ? y - 1 : k % 2 == 0 && k % 10 != 0 ? y + 1 : y;

      //get the string at the new location
      c = T( X );

      //if player is hitting an enemy
      if ( e.Contains( X ) ) {
        //kill the enemy
        e.Remove( X );
        d[ X ] = f;
      }

      //reset the cursor position
      R( );

      //if the player is standing on stairs
      if ( c == s ) {
        //reset the dungeon and enemies
        d.Clear( );
        e.Clear( );
        //new dungeon
        new M( 1, l + 1, h );
        //if we get here player has died, exit
        return;
      }

      //if the player tried to move onto something that isn't a floor, put them back where they were
      if ( c != f ) {
        x = u;
        y = v;
      }

      //set the last tile that the player was on to floor
      d[ u + a + v ] = f;
      //set the tile that the player is currently on to @
      d[ X ] = a;

      //iterate through the remaining enemies
      for ( z = 0; z < e.Count; z++ ) {
        //get the current enemy's location and store their X position in i and their Y position in j
        i = U( e[ z ], 0 );
        j = U( e[ z ], 1 );

        //move towards the player
        u = i < x ? i + 1 : i > x ? i - 1 : i;
        v = j < y ? j + 1 : j > y ? j - 1 : j;

        //get the dungeon tile at the new enemy coordinate
        c = T( u + a + v );

        //if the dungeon tile is floor, move the enemy onto the new coordinate
        if ( c == f ) {
          e[ z ] = u + a + v;
          d[ e[ z ] ] = d[ i + a + j ];
          d[ i + a + j ] = f;
        }

        //if the dungeon tile the enemy tried to move to contains the player, decrement the player's health
        if ( c == a ) h--;
      }

      //exit if player is dead
      if ( h < 1 ) return;

      //calculate the viewport size using p
      z = p * 2 - 1;

      //draw visible dungeon tiles to viewport
      for ( j = 0; j < z; j++ ) {
        for ( i = 0; i < z; i++ ) {
          //get tile at location X = i, Y = j
          c = T( ( i - p + x ) + a + ( j - p + y ) );
          //if it's a wall pass the level through to the IO call for the color, otherwise pass through 0 to use default color
          W( c, c == w ? l : 0 );
        }
        L( );
      }
      //show level and health
      L( l + f + h );
      //get keyboard input
      k = I;
    }
  }

  //return the player's coordinates as a string
  S X {
    get { return x + a + y; }
  }

  //get the dungeon tile at the passed in coordinate. If the tile doesn't exist create it
  S T( S c ) {
    return d.ContainsKey( c ) ? d[ c ] : d[ c ] = r.Next( m * p ) < 5 ? s : r.Next( 9 ) < 7 ? f : w;
  }

  //convert a string coordinate to an x or a y coordinate - if l is 0, return x, if l is 1 return y
  int U( S c, int l ) { return int.Parse( ( c.Split( '@' ) )[ l ] ); }

  //start a new game on level 1 with 9 health
  static void Main( ) { new M( 1, 1, 9 ); }
}