// 01 basic setup

// rogue at its simplest and most readable

// player can move around dungeon, bump into walls,
// pick up gold and items, kill monsters, and
// use the stairs

// random bits of level, monsters, gold, and items
// placed randomly in the dungeon

// help screen shows how to deal with fullscreen
// commands like inventory and discoveries

using System;

class Program
{
    static THING player = new THING();

    static bool found_amulet = false;

    static Random random = new Random();

    static void Main(string[] args)
    {
        Console.WindowWidth = Console.BufferWidth = 80;
        Console.WindowHeight = Console.BufferHeight = 25;
        Console.Title = "steelgolem rogue - 01 basic setup";

        CONSOLE.clear();

        dungeon_level = 1;
        new_level();

        update_status();

        while (true)
        {
            // put cursor under player to highlight
            CONSOLE.move_cursor(player.x, player.y);

            char key_ch = CONSOLE.read_key();

            switch(key_ch)
            {
                case '?': show_help(); break;

                case 'h': move_player(-1, 0); break;
                case 'j': move_player(0, +1); break;
                case 'k': move_player(0, -1); break;
                case 'l': move_player(+1, 0); break;
                case 'y': move_player(-1, -1); break;
                case 'u': move_player(+1, -1); break;
                case 'b': move_player(-1, +1); break;
                case 'n': move_player(+1, +1); break;

                case '>':
                    if (player.under_ch == '%')
                    {
                        if (found_amulet && dungeon_level == 1)
                            win_game();

                        if (found_amulet) dungeon_level--;
                        else dungeon_level++;

                        new_level();
                        update_status();
                    }
                    else
                    {
                        if (found_amulet) set_message("there is no way up");
                        else set_message("there is no way down");
                    }
                    break;

                case (char)18: // ^R
                    set_message(last_message);
                    break;

                case 'Q':
                    Environment.Exit(0);
                    break;
            }
        }
    }

    #region dungeon level

    static int dungeon_level;

    static void new_level()
    {
        CONSOLE.clear();

        // add some random level bits
        for (int c = 0; c < 80; c++)
        {
            int x = random.Next(80);
            int y = 1 + random.Next(23);
            char ch = "-|.+#"[random.Next(5)];
            CONSOLE.put_char(x, y, ch);
        }

        // add some gold
        for (int c = 0; c < 9; c++)
        {
            int x = random.Next(80);
            int y = 1 + random.Next(23);
            CONSOLE.put_char(x, y, '*');
        }

        // add some items
        for (int c = 0; c < 9; c++)
        {
            int x = random.Next(80);
            int y = 1 + random.Next(23);
            char ch = ":!?)]=/"[random.Next(7)];
            CONSOLE.put_char(x, y, ch);
        }

        // add some monsters
        for (int c = 0; c < 9; c++)
        {
            int x = random.Next(80);
            int y = 1 + random.Next(23);
            char ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[random.Next(26)];
            CONSOLE.put_char(x, y, ch);
        }

        // add the amulet
        if (dungeon_level >= 26)
        {
            int x = random.Next(80);
            int y = 1 + random.Next(23);
            CONSOLE.put_char(x, y, ',');
        }

        // add the stairs
        int stairs_x = random.Next(80);
        int stairs_y = 1 + random.Next(23);
        CONSOLE.put_char(stairs_x, stairs_y, '%');

        // place the player
        player.x = random.Next(80);
        player.y = 1 + random.Next(23);
        player.under_ch = ' ';
        player.draw();
    }

    #endregion // dungeon level

    #region commands

    static void show_help()
    {
        string[] help_text = new string[]
        {
            "?    show help",
            "h    move left",
            "j    move down",
            "k    move up",
            "l    move right",
            "y    move up & left",
            "u    move up & right",
            "b    move down & left",
            "n    move down & right",
            ">    use stairs",
            "^R   repeat last message",
            "Q    quit game",
        };

        CONSOLE.back_up_buffer();

        CONSOLE.clear();

        for (int h = 0; h < help_text.Length; h++)
            CONSOLE.write_string(0, h, help_text[h]);

        CONSOLE.write_string(0, 24, "[press any key]");

        CONSOLE.read_key();

        CONSOLE.restore_buffer();
    }

    static void move_player(int dx, int dy)
    {
        clear_message();

        int dest_x = player.x + dx;
        int dest_y = player.y + dy;
        char dest_ch = CONSOLE.get_char(dest_x, dest_y);

        // walls stop movement
        if (is_wall(dest_ch))
            return;

        // fight monster
        if (is_monster(dest_ch))
        {
            CONSOLE.put_char(dest_x, dest_y, ' ');

            set_message("defeated " + get_name(dest_ch));

            return;
        }

        player.erase();

        player.get_eraser(dest_x, dest_y);

        player.x = dest_x;
        player.y = dest_y;

        player.draw();

        // pick up gold
        if (dest_ch == '*')
        {
            player.under_ch = ' ';

            set_message("picked up gold");
        }

        // pick up item
        if (is_item(dest_ch))
        {
            player.under_ch = ' ';

            set_message("picked up " + get_name(dest_ch));

            if (dest_ch == ',')
                found_amulet = true;
        }
    }

    #endregion // commands

    #region helper functions

    static bool is_wall(char ch)
    {
        return "-|".Contains(ch.ToString());
    }

    static bool is_monster(char ch)
    {
        return char.IsLetter(ch);
    }

    static bool is_item(char ch)
    {
        return ":!?)]=/,".Contains(ch.ToString());
    }

    static string get_name(char dest_ch)
    {
        switch (dest_ch)
        {
            case 'A': return "giant ant";
            case 'B': return "bat";
            case 'C': return "centaur";
            case 'D': return "dragon";
            case 'E': return "floating eye";
            case 'F': return "violet fungi";
            case 'G': return "gnome";
            case 'H': return "hobgoblin";
            case 'I': return "invisible stalker";
            case 'J': return "jackal";
            case 'K': return "kobold";
            case 'L': return "leprechaun";
            case 'M': return "mimic";
            case 'N': return "nymph";
            case 'O': return "orc";
            case 'P': return "purple worm";
            case 'Q': return "quasit";
            case 'R': return "rust monster";
            case 'S': return "snake";
            case 'T': return "troll";
            case 'U': return "umber hulk";
            case 'V': return "vampire";
            case 'W': return "wraith";
            case 'X': return "xorn";
            case 'Y': return "yeti";
            case 'Z': return "zombie";

            case ':': return "food";
            case '!': return "potion";
            case '?': return "scroll";
            case ')': return "weapon";
            case ']': return "armor";
            case '=': return "ring";
            case '/': return "stick";
            case ',': return "the amulet of yendor";

            default: return null;
        }
    }

    static void update_status()
    {
        clear_status();

        CONSOLE.write_string(0, 24, "level: " + dungeon_level);
    }

    #endregion // helper functions

    #region messages

    static string last_message = "";

    static void set_message(string text)
    {
        CONSOLE.write_string(0, 0, text);
        last_message = text;
    }

    static void clear_message()
    {
        CONSOLE.cursor_off();
        CONSOLE.write_string(0, 0, "".PadRight(80));
        CONSOLE.cursor_on();
    }

    static void clear_status()
    {
        CONSOLE.write_string(0, 24, "".PadRight(79));
    }

    #endregion // messages

    #region game over

    static void win_game()
    {
        CONSOLE.clear();

        CONSOLE.write_string("you win");

        CONSOLE.read_key();

        Environment.Exit(0);
    }

    #endregion // game over
}

class THING
{
    public int x, y;
    public char under_ch;

    public void get_eraser(int x, int y)
    {
        this.under_ch = CONSOLE.get_char(x, y);
    }

    public void erase()
    {
        CONSOLE.put_char(this.x, this.y, this.under_ch);
    }

    public void draw()
    {
        CONSOLE.put_char(this.x, this.y, '@');
    }
}

class CONSOLE
{
    static char[,] buffer = new char[80, 25];

    static int cursor_x, cursor_y;
    
    public static char get_char(int x, int y)
    {
        return buffer[x, y];
    }

    public static void put_char(char ch)
    {
        buffer[cursor_x, cursor_y] = ch;
        cursor_x++;
        if (cursor_x == 80)
        {
            cursor_x = 0;
            cursor_y++;
        }

        Console.Write(ch);
    }

    public static void put_char(int x, int y, char ch)
    {
        move_cursor(x, y);
        put_char(ch);
    }

    public static void move_cursor(int x, int y)
    {
        cursor_x = x;
        cursor_y = y;

        Console.SetCursorPosition(x, y);
    }

    public static char read_key()
    {
        return Console.ReadKey(true).KeyChar;
    }

    public static void write_string(string text)
    {
        for (int c = 0; c < text.Length; c++)
            put_char(text[c]);
    }

    public static void write_string(int x, int y, string text)
    {
        move_cursor(x, y);
        write_string(text);
    }

    public static void cursor_on()
    {
        Console.CursorVisible = true;
    }

    public static void cursor_off()
    {
        Console.CursorVisible = false;
    }

    public static void clear()
    {
        for (int y = 0; y < 25; y++)
            for (int x = 0; x < 80; x++)
                buffer[x, y] = ' ';
        cursor_x = cursor_y = 0;

        Console.Clear();
    }

    static char[,] old_buffer = new char[80, 25];

    public static void back_up_buffer()
    {
        Array.Copy(CONSOLE.buffer, old_buffer, 80 * 25);
    }

    public static void restore_buffer()
    {
        Array.Copy(old_buffer, CONSOLE.buffer, 80 * 25);

        for (int y = 0; y < 25; y++)
            for (int x = 0; x < 80; x++)
                if (!(x == 79 && y == 24))
                    CONSOLE.put_char(x, y, CONSOLE.buffer[x, y]);
    }
}