[DarkBASIC] Making an Instant Messenger

[ReidE96]

Spinny cubes are fun and all, but of limited practical value. So here's an Instant Messenger, coded in DarkBASIC. The comments (REM or ` for each comment line, REMSTART for the beginning of a block of comments (no REM needed in the block) and REMEND for the end of a block), should help you understand how it all works.

REMSTART
Project: Simplechat
Rem Created: 05/05/2006 17:09:03

***** Main Source File *****
REMEND

` Set the resolution to 800 by 600, 32 bit
SET DISPLAY MODE 800, 600, 32

` Set the screen refresh rate to 30 Hz
SYNC ON
SYNC RATE 30

` Keep track of what was said and who said it (declaring a few arrays)
DIM ChatText$(32)
DIM PlayersName$(1)
DIM NumberOfPlayers(1)
DIM LastNumberOfPlayers(1)

` Find the TCP/IP connection number with a function we'll write later
TcpIpNumber = FindTCPIPConnectionNumber()

` Print the text in the "" to the screen, then a blank line
PRINT "Welcome to SimpleChat! Press the Escape key to exit."
PRINT

` Make the screen reload
SYNC

` Create a GOTO point in case they don't enter a name
:name

` Get the user's name and store it in the MyName variable
INPUT "Please enter your name. ", MyName$

` Refresh the screen a couple of times
SYNC
SYNC

` Check they entered a name
If MyName$ = ""
   ` If they didn't, tell them they need to
   PRINT "You need to enter a name!"

   ` Wait for the user to press a key
   WAIT KEY

   ` Get them to enter a name again
   GOTO name

` Close our IF
ENDIF

` Store the name in the array
PlayersName$(1) = MyName$

` Find out whether they're the host or client

` Throw in a blank line
PRINT

` Ask ze question
PRINT "Are you the host or client? (Press 1 or 2 to choose)"

` Display the possible answers
PRINT "(1) I'm the Host"
PRINT "(2) I'm the Client"

` Refresh the screen a couple of times
SYNC
SYNC

` Set a variable for what key they press
A$ = ""

` Set a variable to get their answer
Answer = 0

` Get their answer

` Loop till they choose something
WHILE Answer = 0
   ` Make the key variable whatever key they press
   A$ = INKEY$()

   ` If they press 1, set the answer to 1   
   IF A$ = "1" THEN Answer = 1

   ` If they press 2, set the answer to 2
   IF A$ = "2" THEN Answer = 2

` Close the loop
ENDWHILE

` Show a new line
PRINT

` Tell them how to exit
PRINT "Press the Escape key to quit."

` If they're the host, do the hosty stuff
IF Answer = 1

   ` Tell them we're setting up the session
   PRINT "Creating chat session. Please wait"

   ` Refresh the screen
   SYNC

   ` Wait 0.2 seconds
   SLEEP 200

   ` Create a new connection on the port we picked up earlier
   SET NET CONNECTION TcpIpNumber, " "

   ` Create a net "game", as DarkBASIC calls it (t is made for games, after all). We're calling the game "Chat" and their player name will be the name they chose earlier. We're allowing 16 people to be in the room at once, and the flag is 1, making this peer-to-peer (P2P)
   CREATE NET GAME "Chat", MyName$, 16, 1

` Close our If statement
ENDIF

` If they're the client, do the clienty stuff
IF Answer = 2
   ` Create a GOTO point, just in case they screw up
   :client

   ` Ask for an IP to connect to and store it in the AddressData variable
   INPUT "Please enter the host's IP address. ", AddressData$

   ` Tell them we're connecting
   PRINT "Connecting to chat session. Please wait"

   ` Update the screen
   SYNC

   ` Create a net connection using the number we picked up earlier to the IP they just provided
   SET NET CONNECTION TcpIpNumber, AddressData$

   ` Ask the host how many "games" it has open
   PERFORM CHECKLIST FOR NET SESSIONS

   ` Store the number of games in a variable
   NumberOfGames = CHECKLIST QUANTITY()

   ` If there's no "games"
   IF NumberOfGames = 0

      ` Tell the user there's no games
      PRINT "No chat session found at that address"

      ` Update the screen
      SYNC

      ` Wait for the user to press a key
      WAIT KEY

      ` Go to the :client GOTO point
      GOTO client

   ` Close our IF
   ENDIF

   ` If we got past the IF, we've found a game, so connect to it. There's only ever going to be 1 instance of this on the host, so it's game number will be 1. Our player name will be the one they chose earlier
   JOIN NET GAME 1, MyName$

   ` Tell them we've connected
   PRINT "Connected to session!"

   ` Update the screen
   SYNC

` Close our IF
ENDIF

` The prep is complete, so we'll run our main chat client, which is a function. Yay!
ChatClient()

` End the program (because the chat client function will keep going until they leave)
END

` This function will determine which NET CONNECTION number is TCP/IP
FUNCTION FindTCPIPConnectionNumber()
   ` Create a variable to hold the number
   Flag = 0

   ` Clear the screen
   CLS

   ` Get a list of current net connections
   PERFORM CHECKLIST FOR NET CONNECTIONS

   ` Start a FOR loop for every item in the checklist
   FOR x = 1 TO CHECKLIST QUANTITY()

      ` Get the name of the current item in the checklist
      Service$ = CHECKLIST STRING$(x)

      ` See if the first 15 letters of the name are "Internet TCP/IP"
      IF LEFT$(Service$,15) = "Internet TCP/IP"
         ` If they are, set the flag to the current number
         Flag = x

      ` End the IF
      ENDIF

   ` Move on to the next item in the checklist
   NEXT x

` This ends the function, and returns the value of flag
ENDFUNCTION Flag

`This function has all the chat functionality
FUNCTION ChatClient()

   ` Clear the chat text from the array (another function!)
   ClearChatText()

   ` Display the initial chatters in the room
   
   ` Get a list of people in the "game"
   PERFORM CHECKLIST FOR NET PLAYERS

   ` Store the number of players in a variable
   NumberOfPlayers(1) = CHECKLIST QUANTITY()

   ` Start a FOR loop for every entry on the checklist
   FOR x = 1 TO NumberOfPlayers(1)
      ` Use ANOTHER function to show a list of who is here, for each entry on the list
      AddUserMessage(CHECKLIST STRING$(x))

   ` Move onto the next person in the list
   NEXT x

   `Send an entry message

   ` Set the variable C to their name and "has joined"
   C$ = PlayersName$(1)+" has joined."

   ` Send the message to the entire room (0 means everyone, a number would mean an individual in the room)
   SEND NET MESSAGE STRING 0,C$

   ` Displays the chat text with yet ANOTHER function
   DisplayChatText()

   ` Set the buffers for text entry
   A$ = ""
   B$ = ""
   C$ = ""

   ` Clear whatever key was last pressed from the buffer so it's ready
   CLEAR ENTRY BUFFER

   ` Capture Text Input and process it accordingly

   ` Start a WHILE loop that runs until Esc is pressed
   WHILE ESCAPEKEY() = 0
      ` Do the CheckIncomingMessages function
      CheckIncomingMessages()

      ` Set variable A to the key pressed
      A$ = INKEY$()

      ` If the ASCII value of the key pressed is 8 (the backspace key)
      IF ASC(A$) = 8
         ` Set the C variable to whatever it currently is and whatever is in the ENTRY buffer
         C$ = C$ + ENTRY$()

         ` Take the left x letter of C, x being one less than the current length of C
         C$ = LEFT$(C$,LEN(C$)-1)

         ` Clear the entry buffer
         CLEAR ENTRY BUFFER

         ` Clear the screen (to remove any traces of the backspaced letter)
         CLS

         ` Show the current chat text (yup, it's a function :D)
         DisplayChatText()

      ` Close our IF statement
      ENDIF

      ` Set the B variable to the C variable, plus whatever's currently in the ENTRY buffer
      B$ = C$ + ENTRY$()

      ` Show whatever's in B at x coordinate 10, y coordinate 460
      TEXT 10,460,B$

      ` If enter is pressed and the B variable isn't empty
      IF RETURNKEY()=1 AND B$ <> ""

         ` Wait for 0.25 seconds
         SLEEP 250

         ` Send the message

         ` Set variable D to the current user's name, a :, a space, and whatever's in B
         D$ = PlayersName$(1) + ": " + B$

         ` Send D to everyone in the room
         SEND NET MESSAGE STRING 0,D$

         ` Add the message to our own screen with ANOTHER FUNCTION!
         AddStringToChat(D$)

         ` Clear the D, B and C variables, along with the ENTRY buffer
         D$ = ""
         B$ = ""
         C$ = ""
         CLEAR ENTRY BUFFER

         ` Show the current chat text
         DisplayChatText()

      ` Close our IF
      ENDIF

      ` Update the screen
      SYNC

   ` Close the while
   ENDWHILE

`End the function, not returning a variable
ENDFUNCTION

` This function scans the incoming packets for strings of text and displays them
FUNCTION CheckIncomingMessages()
   ` This command gets the oldest message from the incoming message queue (any messages DarkBASIC sends are stored in a queue) and makes it the current message
   GET NET MESSAGE

   ` If there's no incoming packets, end the function
   IF NET MESSAGE EXISTS() = 0 THEN EXITFUNCTION

   ` While there IS a message
   WHILE NET MESSAGE EXISTS() <> 0
      ` Store the type of message (integer, float, string, memblock, image, bitmap, sound, or mesh) in the MsgType variable
      MsgType = NET MESSAGE TYPE()

      ` If the message is of type 3 (a string)
      IF MsgType = 3
         ` Set the Msg variable to the text from the message
         Msg$ = NET MESSAGE STRING$()

         ` Use the AddStringToChat function to add Msg to the chat
         AddStringToChat(Msg$)

         ` Run the DisplayChatText function
         DisplayChatText()

      ` End the IF
      ENDIF

      ` Check for a new net message (once processed, net messages are automagically deleted)
      GET NET MESSAGE

   ` End the WHILE loop
   ENDWHILE

` End the function, returning no variable
ENDFUNCTION

` This function displays messages saying who's in the room when you join, taking the Name variable from when it's called
FUNCTION AddUserMessage(Name$)
   ` Set the NewString variable to the Name variable and the phrase "is here"
   NewString$ = Name$ + " is here."

   ` Use the AddStringToChat function to add NewString to the chat
   AddStringToChat(NewString$)

` End the function
ENDFUNCTION

` This function adds a string to the chat, taking the variable a when it is called
FUNCTION AddStringToChat(a$)
   ` Start a FOR loop going from 1 to 32
   FOR x = 1 TO 32
      ` If the ChatText array at value x is blank
      IF ChatText$(x) = ""
         ` Set the text of the ChatText array at value x to a
         ChatText$(x) = a$
         ` Exit the function
         EXITFUNCTION

      ` End the IF statement
      ENDIF

   ` End the FOR loop
   NEXT x

   ` Start a FOR loop running from 32 to 2
   FOR x = 32 TO 2
      ` Set the variable y to 1 less then the current value of x
      y = x-1

      ` Set the value of the ChatText array at y to the value of the ChatText array at x (has the effect of moving everything up a line and scrolling the top line off the screen)
      ChatText$(y) = ChatText$(x)

   ` End the FOR loop
   NEXT x

   ` Set the 32nd value of the ChatText array to a (if we got to here, the ChatText array was full as the first function would have noticed a blank line and exited the function)
   ChatText$(32) = a$

` This marks the end of the function
ENDFUNCTION

` This function clears the ChatText$ array
FUNCTION ClearChatText()
   ` Starts a FOR loop from 1 to 32
   FOR x = 1 TO 32
      ` Clear the value of the ChatText array at the value of x
      ChatText$(x) = ""

   ` End the FOR loop
   NEXT x

` This marks the end of the funciton
ENDFUNCTION

` This function displays the chat text on the screen
FUNCTION DisplayChatText()
   ` Clear the screen
   CLS

   ` Sets the bitmap we're sending the text to to bitmap 0 (the screen)
   SET CURRENT BITMAP 0

   ` Centres the text "SimpleChat - Copyright(c) Euan Reid, 2006" at x coordinate 400 and y coordinate 10. This is from when I released it in 2006, you can change it if you want. This entire thing is just the source code from an app I made, with added comments to make things REALLY clear
   CENTER TEXT 400, 10, "SimpleChat - Copyright(c) Euan Reid, 2006"

   ` Starts a FOR loop from 1 to 32
   FOR x = 1 TO 32
      ` Show the value of ChatText at the value of x at x coordinate 10 and y coordinate 10 plus the current value of x times 15
      TEXT 10, 10+(x*15), ChatText$(x)

   ` Ends the FOR loop
   NEXT x

` This marks the end of the function
ENDFUNCTION

With any luck, this will help you learn some DarkBASIC. I coded this using DarkBASIC Professional v1.0, and it worked then. It also works in DarkBASIC Professional v1.03, as I just tested it. I don't know if it will work in DarkBASIC v1.x (the not-professional version) as it is far more limited as regards networking commands.

Happy coding!

[warsheep]

So.. This is like a client for a instant messenger?
Gotta download DarkBasic to test it out.

Edit:
Read through the well commented code... It looks great! Installing DarkBasic now, this sounds like something I'll have to check out!

[Kissy]

you might wanna check line 32

:name