// Settings:
set gTetris_start_speed 3 // Starting speed, as a delay of frames (lower numbers are faster).
set gTetris_lowest_speed 1 // Lowest (ie fastest) speed the game will reach as level advances.
set gTetris_max_flood 4 // Once the fastest speed has been reached, rows will begin to flood up to the maximum specified here.
set gTetris_level_length 25 // Length of each level, in number of blocks dropped.

// Characters used in display (changing these may result in unaligned rows):
set gTetris_empty "_" // Empty ("background").
set gTetris_block "0" // Block.
set gTetris_falling "*" // Falling block.
set gTetris_destroyed "o" // Destroyed line.
set gTetris_flood "u" // Flood block.
set gTetris_top "!!!!!!!!!!!!!!!!!" // Upper divider of display.
set gTetris_bottom "!!!!!!!!!!!!!!!!!" // Lower divider of display.

// Global initializations, do not change:
set gTetris_on 0
set gTetris_init 0
set gTetris_moving 0 // Positive for right, Negative for left.
set gTetris_rotating 0 // Positive for rotate right, Negative for rotate left.
set gTetris_dropping 0 // 1 for drop.

// Controls:
// Move left:
control-left
{
if gTetris_on == 1
  setglobal gTetris_moving - 1
  call "fTetris_show"
end if
}
// Move right:
control-right
{
if gTetris_on == 1
  setglobal gTetris_moving + 1
  call "fTetris_show"
end if
}
// Rotate left:
control-down
{
if gTetris_on == 1
  setglobal gTetris_rotating - 1
  call "fTetris_show"
end if
}
// Rotate right:
control-up
{
if gTetris_on == 1
  setglobal gTetris_rotating + 1
  call "fTetris_show"
end if
}
// Drop:
control-space
{
if gTetris_on == 1
  setglobal gTetris_dropping 1
  call "fTetris_show"
end if
}

// /tetris to start or pause/unpause.
"/tetris"
{
if gTetris_on == 1
  setglobal gTetris_on 0
else
  setglobal gTetris_on 1
  if gTetris_init == 0
    setglobal gTetris_init 1
    setglobal gTetris_speed gTetris_start_speed
    setglobal gTetris_level 1
    setglobal gTetris_timer 0
    setglobal gTetris_lines 0
    setglobal gTetris_flooded 0
    setglobal gTetris_state 0 // 0 - Block Landed. 1 - Block Falling. 2 - Line Destroyed.
    setglobal gTetris_score 0
    setglobal gTetris_rotate 0
    setglobal gTetris_posX 0
    setglobal gTetris_posY 0
    setglobal gTetris_block 0
    setglobal gTetris_show 1
    setglobal gTetris_temp 0
    label TETRISINITY
      if gTetris_temp < 10
        setglobal gTetris[gTetris_temp] "|"
        set tetris_X 0
        label TETRISINITX
          if tetris_X < 10
            setglobal gTetris[gTetris_temp] + gTetris_empty
            set tetris_X + 1
            goto "TETRISINITX"
          end if
        setglobal gTetris[gTetris_temp] + "|"
        setglobal gTetris_temp + 1
        goto "TETRISINITY"
      end if
  else
    setglobal gTetris_moving 0
    setglobal gTetris_rotating 0
    setglobal gTetris_dropping 0
  end if
  label TETRISGAME
    call "fTetris_input"
    if gTetris_state == 1 // Block Falling.
      setglobal gTetris_posY + 1
      call "fTetris_check"
      if tetris_ok == 0
        setglobal gTetris_posY - 1
        setglobal gTetris_state 0
        call "fTetris_solidify"  
      end if
    else if gTetris_state == 0 // Block Landed.
      call "fTetris_next"
      call "fTetris_check"
      setglobal gTetris_state 1
      if tetris_ok == 0
        // Game over.
        setglobal gTetris_on 0
        setglobal gTetris_init 0
      end if
    else // Line Destroyed.
      call "fTetris_destroy"
      setglobal gTetris_state 0
    end if
    call "fTetris_display"
    pause gTetris_speed
    if gTetris_on == 1
      goto "TETRISGAME"
    end if
end if
}

fTetris_show
{
if gTetris_show == 1
  call "fTetris_showing"
end if
}

fTetris_showing
{
set tetris_disp ""
set tetris_X gTetris_moving
if tetris_X != 0
  set tetris_disp "Move: "
  label TETRISSHOWM
    if tetris_X > 0
      set tetris_disp + "-> "
      set tetris_X - 1
      goto "TETRISSHOWM"
    else if tetris_X < 0
      set tetris_disp + "<- "
      set tetris_X + 1
      goto "TETRISSHOWM"
    end if
  set tetris_disp + "   "
end if
set tetris_X gTetris_rotating
if tetris_X != 0
  set tetris_disp + "Rotate: "
  label TETRISSHOWR
    if tetris_X > 0
      set tetris_disp + "=> "
      set tetris_X - 1
      goto "TETRISSHOWR"
    else if tetris_X < 0
      set tetris_disp + "<= "
      set tetris_X + 1
      goto "TETRISSHOWR"
    end if
  set tetris_disp + "   "
end if
if gTetris_dropping == 1
  set tetris_disp + "Drop!"
end if
if tetris_disp != ""
  message tetris_disp
end if
}

fTetris_input
{
if gTetris_state == 1
  label TETRISMOVE
    if gTetris_moving != 0
      if gTetris_moving > 0
        setglobal gTetris_posX + 1
        call "fTetris_check"
        if tetris_ok == 0
          setglobal gTetris_posX - 1
          setglobal gTetris_moving 0
        else
          setglobal gTetris_moving - 1
        end if
      else
        setglobal gTetris_posX - 1
        call "fTetris_check"
        if tetris_ok == 0
          setglobal gTetris_posX + 1
          setglobal gTetris_moving 0
        else
          setglobal gTetris_moving + 1
        end if
      end if
      goto "TETRISMOVE"
    end if
  label TETRISROTATE
    if gTetris_rotating != 0
      if gTetris_rotating > 0
        setglobal gTetris_rotate + 4
        if gTetris_rotate >= 16
          setglobal gTetris_rotate - 16
        else if gTetris_rotate < 0
          setglobal gTetris_rotate + 16
        end if
        call "fTetris_check"
        if tetris_ok == 0
          setglobal gTetris_rotate - 4
          if gTetris_rotate >= 16
            setglobal gTetris_rotate - 16
          else if gTetris_rotate < 0
            setglobal gTetris_rotate + 16
          end if
          setglobal gTetris_rotating 0
        else
          setglobal gTetris_rotating - 1
        end if
      else
        setglobal gTetris_rotate - 4
        if gTetris_rotate >= 16
          setglobal gTetris_rotate - 16
        else if gTetris_rotate < 0
          setglobal gTetris_rotate + 16
        end if
        call "fTetris_check"
        if tetris_ok == 0
          setglobal gTetris_rotate + 4
          if gTetris_rotate >= 16
            setglobal gTetris_rotate - 16
          else if gTetris_rotate < 0
            setglobal gTetris_rotate + 16
          end if
          setglobal gTetris_rotating 0
        else
          setglobal gTetris_rotating + 1
        end if
      end if          
      goto "TETRISROTATE"
    end if
  if gTetris_dropping == 1
    setglobal gTetris_dropping 0
    label TETRISDROP
      setglobal gTetris_posY + 1
      call "fTetris_check"
      if tetris_ok == 1
        setglobal gTetris_score + 1
        goto "TETRISDROP"
      else
        setglobal gTetris_posY - 1
      end if
  end if
else
  setglobal gTetris_moving 0
  setglobal gTetris_rotating 0
  setglobal gTetris_dropping 0
end if
}

fTetris_display
{
setglobal gTetris_show 0
set tetris_Y gTetris_posY
set tetris_Y + 4
set tetris_X gTetris_posX
set tetris_X + 4
set tetris_YY gTetris_rotate
if gTetris_posY < 0
  set tetris_YY - gTetris_posY
end if
setglobal gTetris_temp 0
message gTetris_top
label TETRISDISP
  if gTetris_temp < 10
    if gTetris_temp >= gTetris_posY
      if gTetris_temp == gTetris_posY
        set tetris_disp gTetris_temp
        call "fTetris_input"
        setglobal gTetris_temp tetris_disp
        set tetris_Y gTetris_posY
        set tetris_Y + 4
        set tetris_X gTetris_posX
        set tetris_X + 4
        set tetris_YY gTetris_rotate
        if gTetris_posY < 0
          set tetris_YY - gTetris_posY
        end if
        if gTetris_temp != gTetris_posY
          goto "TETRISDISP"
        end if
      end if
      if gTetris_temp < tetris_Y
        if gTetris_state == 1
          set tetris_disp 1
          set tetris_msg "|"
          set tetris_line gTetris[gTetris_temp]
          set tetris_block gTetris_block[tetris_YY]
          set tetris_XX 0
          if gTetris_posX < 1
            set tetris_XX - gTetris_posX
            set tetris_XX + 1
          end if
          label TETRISMSG
            if tetris_disp < 11
              if tetris_disp >= gTetris_posX
                if tetris_disp < tetris_X
                  set tetris_letter tetris_line.letter[tetris_disp]
                  if tetris_letter == gTetris_empty
                    if tetris_block.letter[tetris_XX] == "C"
                      set tetris_msg + gTetris_falling
                    else
                      set tetris_msg + gTetris_empty
                    end if
                  else
                    set tetris_msg + gTetris_block
                  end if
                  set tetris_XX + 1
                else
                  set tetris_msg + tetris_line.letter[tetris_disp]
                end if
              else
                set tetris_msg + tetris_line.letter[tetris_disp]
              end if
              set tetris_disp + 1
              goto "TETRISMSG"
            end if
          set tetris_msg + "|"
          message tetris_msg
          set tetris_YY + 1
        else
          message gTetris[gTetris_temp]
        end if
      else
        message gTetris[gTetris_temp]
      end if
    else
      message gTetris[gTetris_temp]
    end if
    setglobal gTetris_temp + 1
    goto "TETRISDISP"
  end if
message gTetris_bottom
message "Score:" gTetris_score "   Lines:" gTetris_lines "   Level:" gTetris_level
if gTetris_init == 0
  message "* GAME OVER!"
else
  call "fTetris_showing"
end if
setglobal gTetris_show 1
}

fTetris_destroy
{
set tetris_Y 0
set tetris_score 0
label TETRISDESTROY
  if tetris_Y < 10
    set tetris_line gTetris[tetris_Y]
    if tetris_line.letter[1] == gTetris_destroyed
      set tetris_score + 1
      setglobal gTetris_temp tetris_Y
      set tetris_YY tetris_Y
      label TETRISDESTROYY
        set tetris_YY - 1
        if gTetris_temp > 0
          setglobal gTetris[gTetris_temp] gTetris[tetris_YY]
          setglobal gTetris_temp - 1
          goto "TETRISDESTROYY"
        end if
      setglobal gTetris[0] "|"
      set tetris_X 0
      label TETRISINITXX
        if tetris_X < 10
          setglobal gTetris[0] + gTetris_empty
          set tetris_X + 1
          goto "TETRISINITXX"
        end if
      setglobal gTetris[0] + "|"
    end if
    set tetris_Y + 1
    goto "TETRISDESTROY"
  end if
setglobal gTetris_lines + tetris_score
set tetris_adj 5
set tetris_adj - gTetris_speed
if tetris_adj < 1
  set tetris_adj 1
end if
set tetris_adj + gTetris_flooded
if tetris_score == 1
  set tetris_score 30
else if tetris_score == 2
  set tetris_score 75
else if tetris_score == 3
  set tetris_score 150
else if tetris_score == 4
  set tetris_score 300
end if
set tetris_score * tetris_adj
setglobal gTetris_score + tetris_score
}

fTetris_solidify
{
set tetris_Y gTetris_posY // Y pos in main area.
set tetris_YY 0 // Y pos in block area.
if tetris_Y < 0
  set tetris_YY - tetris_Y
  set tetris_Y 0
end if
label TETRISSOLIDY
  if tetris_YY < 4
    if tetris_Y < 10
      set tetris_destroy 1
      set tetris_XX gTetris_posX
      set tetris_XX + 4 // Ending X pos of block.
      set tetris_line gTetris[tetris_Y]
      setglobal gTetris_temp tetris_YY
      setglobal gTetris_temp + gTetris_rotate
      set tetris_block gTetris_block[gTetris_temp]
      set tetris_disp "|"
      setglobal gTetris_temp 1
      label TETRISSOLIDX
      if gTetris_temp < 11
        if gTetris_temp >= gTetris_posX
          if gTetris_temp < tetris_XX  
            set tetris_X gTetris_temp
            set tetris_X - gTetris_posX
            if tetris_block.letter[tetris_X] == "C"
              set tetris_disp + gTetris_block
            else
              set tetris_disp + tetris_line.letter[gTetris_temp]
              if tetris_line.letter[gTetris_temp] != gTetris_block
                set tetris_destroy 0
              end if
            end if
          else
            set tetris_disp + tetris_line.letter[gTetris_temp]
            if tetris_line.letter[gTetris_temp] != gTetris_block
              set tetris_destroy 0
            end if
          end if
        else
          set tetris_disp + tetris_line.letter[gTetris_temp]
          if tetris_line.letter[gTetris_temp] != gTetris_block
            set tetris_destroy 0
          end if
        end if
        setglobal gTetris_temp + 1
        goto "TETRISSOLIDX"
      end if
      if tetris_destroy == 1
        set tetris_disp "|"
        set tetris_X 0
        label TETRISSOLIDD
          if tetris_X < 10
            set tetris_disp + gTetris_destroyed
            set tetris_X + 1
            goto "TETRISSOLIDD"
          end if
        setglobal gTetris_state 2
      end if
      set tetris_disp + "|"
      setglobal gTetris_temp tetris_Y
      setglobal gTetris[gTetris_temp] tetris_disp
      set tetris_Y + 1
      set tetris_YY + 1
      goto "TETRISSOLIDY"
    end if
  end if
if gTetris_speed > gTetris_lowest_speed
  setglobal gTetris_timer + 1
  if gTetris_timer >= gTetris_level_length
    setglobal gTetris_timer 0
    setglobal gTetris_level + 1
    setglobal gTetris_speed - 1
  end if
else if gTetris_flooded < gTetris_max_flood
  setglobal gTetris_timer + 1
  if gTetris_timer >= gTetris_level_length
    setglobal gTetris_timer 0
    setglobal gTetris_level + 1
    setglobal gTetris_flooded + 1
    call "fTetris_flood"
  end if
end if
}

fTetris_flood
{
setglobal gTetris_temp 0
set tetris_Y 1
label TETRISFLOODY
  if tetris_Y < 10
    setglobal gTetris[gTetris_temp] gTetris[tetris_Y]
    setglobal gTetris_temp + 1
    set tetris_Y + 1
    goto "TETRISFLOODY"
  end if
setglobal gTetris[9] "|"
set tetris_X 0
label TETRISFLOODX
  if tetris_X < 10
    setglobal gTetris[gTetris_temp] + gTetris_flood
    set tetris_X + 1
    goto "TETRISFLOODX"
  end if
setglobal gTetris[gTetris_temp] + "|"
}

fTetris_check
{
set tetris_ok 1
set tetris_Y gTetris_posY // Y pos in main area.
set tetris_YY 0 // Y pos in block area.
label TETRISCHECKY
  if tetris_YY < 4
    set tetris_XX 0 // X pos in block area.
    set tetris_X gTetris_posX // X pos in main area.
    if tetris_Y >= 0
      if tetris_Y < 10
        set tetris_line gTetris[tetris_Y]
      end if
    end if
    setglobal gTetris_temp tetris_YY
    setglobal gTetris_temp + gTetris_rotate
    set tetris_block gTetris_block[gTetris_temp]
    label TETRISCHECKX
      if tetris_XX < 4
        if tetris_block.letter[tetris_XX] == "C"
          if tetris_X < 1 // Not ok if off left edge.
            set tetris_ok 0
          else if tetris_X >= 11 // Not ok if off right edge.
            set tetris_ok 0
          else if tetris_Y >= 10 // Not ok if off bottom edge.
            set tetris_ok 0
          else if tetris_Y >= 0
            if tetris_line.letter[tetris_X] != gTetris_empty // Not ok if moving into block.
              set tetris_ok 0
            else
              set tetris_X + 1
              set tetris_XX + 1
              goto "TETRISCHECKX"
            end if
          else
            set tetris_X + 1
            set tetris_XX + 1
            goto "TETRISCHECKX"
          end if
        else
          set tetris_X + 1
          set tetris_XX + 1
          goto "TETRISCHECKX"
        end if
      else
        set tetris_YY + 1
        set tetris_Y + 1
        goto "TETRISCHECKY"
      end if
  end if
}

fTetris_next
{
setglobal gTetris_rotate 0
random
  // ####
  setglobal gTetris_posX 4
  setglobal gTetris_posY -2
  
  setglobal gTetris_block[0] "aaaa"
  setglobal gTetris_block[1] "aaaa"
  setglobal gTetris_block[2] "CCCC"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "aaCa"
  setglobal gTetris_block[5] "aaCa"
  setglobal gTetris_block[6] "aaCa"
  setglobal gTetris_block[7] "aaCa"
  
  setglobal gTetris_block[8] "aaaa"
  setglobal gTetris_block[9] "aaaa"
  setglobal gTetris_block[10] "CCCC"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aaCa"
  setglobal gTetris_block[13] "aaCa"
  setglobal gTetris_block[14] "aaCa"
  setglobal gTetris_block[15] "aaCa"
or // ###
   //   #
  setglobal gTetris_posX 4
  setglobal gTetris_posY -2
  
  setglobal gTetris_block[0] "aaaa"
  setglobal gTetris_block[1] "CCCa"
  setglobal gTetris_block[2] "aaCa"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "aCaa"
  setglobal gTetris_block[5] "aCaa"
  setglobal gTetris_block[6] "CCaa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "Caaa"
  setglobal gTetris_block[9] "CCCa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aCCa"
  setglobal gTetris_block[13] "aCaa"
  setglobal gTetris_block[14] "aCaa"
  setglobal gTetris_block[15] "aaaa"
or // ###
   // #
  setglobal gTetris_posX 4
  setglobal gTetris_posY -2
  
  setglobal gTetris_block[0] "aaaa"
  setglobal gTetris_block[1] "CCCa"
  setglobal gTetris_block[2] "Caaa"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "CCaa"
  setglobal gTetris_block[5] "aCaa"
  setglobal gTetris_block[6] "aCaa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "aaCa"
  setglobal gTetris_block[9] "CCCa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aCaa"
  setglobal gTetris_block[13] "aCaa"
  setglobal gTetris_block[14] "aCCa"
  setglobal gTetris_block[15] "aaaa"
or // ##
   //  ##
  setglobal gTetris_posX 5
  setglobal gTetris_posY -1
  setglobal gTetris_block[0] "CCaa"
  setglobal gTetris_block[1] "aCCa"
  setglobal gTetris_block[2] "aaaa"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "aaCa"
  setglobal gTetris_block[5] "aCCa"
  setglobal gTetris_block[6] "aCaa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "CCaa"
  setglobal gTetris_block[9] "aCCa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aaCa"
  setglobal gTetris_block[13] "aCCa"
  setglobal gTetris_block[14] "aCaa"
  setglobal gTetris_block[15] "aaaa"
or //  ##
   // ##
  setglobal gTetris_posX 5
  setglobal gTetris_posY -1
  
  setglobal gTetris_block[0] "aCCa"
  setglobal gTetris_block[1] "CCaa"
  setglobal gTetris_block[2] "aaaa"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "aCaa"
  setglobal gTetris_block[5] "aCCa"
  setglobal gTetris_block[6] "aaCa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "aCCa"
  setglobal gTetris_block[9] "CCaa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aCaa"
  setglobal gTetris_block[13] "aCCa"
  setglobal gTetris_block[14] "aaCa"
  setglobal gTetris_block[15] "aaaa"
or // ##
   // ##
  setglobal gTetris_posX 5
  setglobal gTetris_posY -1
  
  setglobal gTetris_block[0] "CCaa"
  setglobal gTetris_block[1] "CCaa"
  setglobal gTetris_block[2] "aaaa"
  setglobal gTetris_block[3] "aaaa"

  setglobal gTetris_block[4] "CCaa"
  setglobal gTetris_block[5] "CCaa"
  setglobal gTetris_block[6] "aaaa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "CCaa"
  setglobal gTetris_block[9] "CCaa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "CCaa"
  setglobal gTetris_block[13] "CCaa"
  setglobal gTetris_block[14] "aaaa"
  setglobal gTetris_block[15] "aaaa"
or // ###
   //  #
  setglobal gTetris_posX 4
  setglobal gTetris_posY -2
  
  setglobal gTetris_block[0] "aaaa"
  setglobal gTetris_block[1] "CCCa"
  setglobal gTetris_block[2] "aCaa"
  setglobal gTetris_block[3] "aaaa"
  
  setglobal gTetris_block[4] "aCaa"
  setglobal gTetris_block[5] "CCaa"
  setglobal gTetris_block[6] "aCaa"
  setglobal gTetris_block[7] "aaaa"
  
  setglobal gTetris_block[8] "aCaa"
  setglobal gTetris_block[9] "CCCa"
  setglobal gTetris_block[10] "aaaa"
  setglobal gTetris_block[11] "aaaa"
  
  setglobal gTetris_block[12] "aCaa"
  setglobal gTetris_block[13] "aCCa"
  setglobal gTetris_block[14] "aCaa"
  setglobal gTetris_block[15] "aaaa"
end random
}