100 REM BASIC Week 3: Under the Sea
 110 REM http://reddit.com/r/RetroBattlestations
 120 REM written by FozzTexx
 130 REM Apple II version by digarok

 200 REM Clear screen and setup variables
rem 210 ? CHR$(4)"PR #3" : HOME 
 210 home
 220 COLS = PEEK(33):ROWS = 24:REM Columns and Rows of screen
 230 GOSUB 2010:TU$ = SP$:TW = SC:TH = SR
 240 TE$ = SE$:GOSUB 2010:TD$ = SP$
 250 FOR EE = 1 TO 3:GOSUB 2010:EN$(EE) = SP$
 260 ER$(EE) = SE$:EW(EE) = SC:NEXT EE
 270 GOSUB 2010:GV$ = SP$:GW = SC:GH = SR
 280 AM = 10:WV$ = "-_."
 290 TY = 18:SF = 4:GOSUB 4100:PT = -10:GOSUB 4510

 300 REM Play game
 310 X = 1:Y = SF:GOSUB 1010
 320 FOR I = 1 TO COLS:PRINT MID$(WV$, INT(RND(1) * 3) + 1, 1);:NEXT I
 330 GOSUB 5140:GOSUB 6660:GOSUB 6140
 340 LY = TY
 350 FOR TX = 1 TO COLS - TW
 360 IF LY <> TY THEN GOSUB 3510
 370 GOSUB 5010:GOSUB 6510:GOSUB 6010
 380 SP$ = TU$:X = TX:Y = TY:GOSUB 1510
 390 LY = TY:GOSUB 2510
 400 IF KE$ = "A" OR KE$ = "a" THEN D = -1:GOSUB 3010
 410 IF KE$ = "Z" OR KE$ = "z" THEN D = 1: GOSUB 3010
 420 IF KE$ = "Q" OR KE$ = "q" THEN END
 430 IF TY = SF + 1 THEN GOTO 450
 440 IF TX = (COLS / 4) OR TX = (COLS / 4) * 3 THEN GOSUB 4010
 450 IF TY = SF + 1 AND AIR < AM THEN GOSUB 4100
 460 NEXT TX
 470 X = TX:SP$ = TE$:GOSUB 1510
 480 GOTO 310
 
1000 REM Position cursor at X,Y
1010 VTAB 1:PRINT:HTAB X : VTAB Y
1020 RETURN

1500 REM Draw sprite in SP$ at X,Y
1510 IF Y < 1 OR Y > ROWS OR X < 1 OR X > COLS THEN  RETURN 
1520 REM Set the left margin to the X position
1530 VTAB Y - 1:HTAB X:POKE 32,X - 1:PRINT:PRINT SP$;
1540 POKE 32,0
1550 RETURN

2000 REM Load a sprite from DATA into SP$
2010 SP$ = "":SE$ = "":SR = 0:SC = 0
2020 READ T$,S$:IF LEN(SP$) > 0 THEN SP$ = SP$ + CHR$(13)
2030 SP$ = SP$ + S$:SR = SR + 1:IF LEN(S$) > SC THEN SC = LEN(S$)
2040 BL$ = "":FOR I = 1 TO LEN(S$):BL$ = BL$ + " ":NEXT I
2050 IF LEN(SE$) > 0 THEN SE$ = SE$ + CHR$(13)
2060 SE$ = SE$ + BL$
2070 IF T$ <> "SE" THEN GOTO 2020
2080 RETURN

2500 REM Read the keyboard
2510 KE$ = "" : IF PEEK(49152) > 127 THEN GET KE$
2520 RETURN

3000 REM Player wants to move turtle up or down
3010 TY = TY + D
3020 IF TY <= SF THEN TY = SF + 1
3030 IF TY > ROWS - TH + 1 THEN TY = ROWS - TH + 1
3040 RETURN

3500 REM Turtle moved up or down, erase from previous line
3510 Y = LY:IF LY > TY THEN Y = Y + TH - 1
3520 X = TX:SP$ = TE$:GOSUB 1510
3530 RETURN

4000 REM Show remaining air
4010 AIR = AIR - 1:IF AIR < 0 THEN AIR = 0
4020 IF AIR > AM THEN AIR = AM
4030 X = COLS - 7 - AM:Y = 2:GOSUB 1010
4040 PRINT "Air: |";
4050 FOR I = 1 TO AIR:PRINT "#";:NEXT I
4060 IF AIR < AM THEN FOR I = AIR + 1 TO AM:PRINT " ";:NEXT I
4070 PRINT "|";
4080 IF AIR = 0 THEN GOTO 4110
4090 RETURN
4100 AIR = AM:GOTO 4030
4110 FOR I = TY to SF + 1 STEP -1
4120 X = TX:Y = I:SP$ = TD$:GOSUB 1510
4130 Y = Y + 1:SP$ = TE$:GOSUB 1510
4140 NEXT I
4150 X = (COLS - GW) / 2:Y = (ROWS - GH) / 2
4160 SP$ = GV$:GOSUB 1510
4170 X = 1:Y = ROWS - 2:GOSUB 1010
4180 END

4500 REM Display score
4510 PT = PT + 10:OX = X:OY = Y
4520 X = 3:Y = 2:GOSUB 1010:PRINT "Score: ";PT;
4540 X = OX:Y = OY:RETURN

5000 REM Take care of bubbles (NB = NumBubbles, BX/Y = BX/BY)
5010 FOR BB = 1 to NB
5020 IF INT(BY(BB)) <= SF THEN GOTO 5120
5030 NY = BY(BB) - (ROWS / COLS)
5040 X = BX(BB):Y = INT(BY(BB))
5050 GOSUB 5510:IF Hit = 0 THEN GOTO 5080
5060 AIR = AIR + 2:IF Bubble$(BB) = "O" THEN AIR = AIR + 1
5070 GOSUB 4010:NY = ROWS + COLS
5080 IF INT(NY) = Y THEN GOTO 5110
5090 SP$ = " ":GOSUB 1510:SP$ = Bubble$(BB):Y = INT(NY)
5100 IF Y > SF THEN GOSUB 1510
5110 BY(BB) = NY
5120 NEXT BB
5130 RETURN
5140 NB = INT(RND(1) * 3) + 1:FOR BB = 1 to NB
5150 BX(BB) = INT(RND(1) * COLS) + 1:BY(BB) = ROWS - INT(RND(1) * 3)
5160 Bubble$(BB) = CHR$(79 + INT(RND(1) * 2) * 32)
5170 NEXT BB:RETURN

5500 REM Hit detection
5510 Hit = 0
5520 IF X < TX + TW - 2 THEN RETURN
5530 IF X > TX + TW + 1 THEN RETURN
5540 IF Y < TY - 1 THEN RETURN
5550 IF Y > TY + 1 THEN RETURN
5560 Hit = 1:RETURN

6000 REM Take care of enemies (NE = NumEnemies, EnemyX/Y/Hit = EX/EY/EH,)
6010 FOR EE = 1 to NE
6020 IF INT(EY(EE)) <= SF THEN GOTO 6120
6030 NX = EX(EE) + XV(EE):NY = EY(EE) + YV(EE)
6040 X = INT(EX(EE)):Y = INT(EY(EE))
6050 IF EH(EE) = 1 THEN GOTO 6070
6060 GOSUB 5510:IF Hit = 1 THEN GOSUB 4010:EH(EE) = 1
6070 IF INT(NX) = X AND INT(NY) = Y THEN GOTO 6110
6080 SP$ = ER$(EC(EE)):GOSUB 1510
6090 SP$ = EN$(EC(EE)):X = INT(NX):Y = INT(NY)
6100 IF Y > SF THEN GOSUB 1510
6110 EX(EE) = NX:EY(EE) = NY
6120 NEXT EE
6130 RETURN
6140 FOR EE = 1 TO NE:SP$ = ER$(EC(EE))
6150 X = INT(EX(EE)):Y = INT(EY(EE)):GOSUB 1510:NEXT EE
6160 NE = INT(RND(1) * 3) + 1:FOR EE = 1 to NE
6170 EX(EE)=INT(RND(1)*COLS)+1:EY(EE)=ROWS-INT(RND(1)*(ROWS - SF))
6180 XV(EE) = RND(1):YV(EE) = RND(1) * ((ROWS - SF) / COLS)
6190 EC(EE) = INT(RND(1) * 3) + 1:EH(EE) = 0
6200 IF EX(EE) > COLS / 2 THEN XV(EE) = - XV(EE)
6210 IF EY(EE) > ROWS / 2 THEN YV(EE) = - YV(EE)
6220 NEXT EE:RETURN

6500 REM Take care of food (NF = NumFood, FoodX/Y = FX/FY)
6510 FOR FF = 1 to NF
6520 X = FX(FF):Y = INT(FY(FF)):GOSUB 5510
6530 IF Hit = 1 THEN GOSUB 4510:SP$ = " ":GOSUB 1510:FY(FF) = ROWS + COLS
6640 NEXT FF
6650 RETURN
6660 SP$=" ":FOR FF=1 TO NF:X = FX(FF):Y = FY(FF):GOSUB 1510:NEXT FF
6670 NF = INT(RND(1) * 3) + 1:FOR FF = 1 to NF
6680 FX(FF)=INT(RND(1) * COLS) + 1:FY(FF)=ROWS - INT(RND(1) * (ROWS - SF))
6690 FD$(FF) = CHR$(120 + INT(RND(1) * 2))
6700 X = FX(FF):Y = FY(FF):SP$ = FD$(FF):GOSUB 1510
6710 NEXT FF:RETURN

9000 DATA SP," _-%#%#}o"
9010 DATA SE,"       )"
9020 DATA SE,"  -OOOO}x"
9030 DATA SE,"^;;^"
9040 DATA SE,"<><"
9050 DATA SE,"$"
9060 DATA SP," _   _          __      _       __  _"
9070 DATA SP,"/ \ / \ |\  /| |       / \ | | |   | \"
9080 DATA SP,"| _ |_| | \/ | |--  *  | | \ / |-- |_/"
9090 DATA SE,"\_/ | | |    | |__     \_/  V  |__ | \"