disknet

--disknet api by KingofGamesYami
local files = { }
local oldFiles = {}

function open( sSide, sFile, sLabel )
    if type( sSide ) ~= "string" or type( sFile ) ~= "string" then
        error( "Expected string, string, got " .. type( sSide) .. ", " .. type( sFile ) .. ", " .. type( sLabel ), 2 )
    end
    if disk.isPresent( sSide ) then
        if disk.hasData( sSide ) then
            files[ #files + 1 ] = { side = sSide, file = sFile, label = sLabel }
            return #files
        else
            error( "No data on disk in drive " .. sSide, 2 )
        end
    else
        error( "No connected drive on the " .. sSide, 2 )
    end
end

function close( id )
    if not files[ id ] then
        error( "Invalid disknet ID", 2 )
    end
    files[ id ] = nil
end

function send( sMessage, id )
    if type( sMessage ) ~= "string" then
        error( "Expected string, number, got "..type( sMessage ) .. ", " .. type( id ), 2 )
    elseif #files == 0 then
        error( "No open disknet", 2 )
    elseif not files[ id ] then
        error( "Invalid disknet id", 2 )
    else
        disk.setLabel( files[ id ].side, files[ id ].label )
        local filePath = fs.combine( disk.getMountPath( files[ id ].side ), files[ id ].file )
        local tbl
        if fs.exists( filePath ) then
            local file = fs.open( filePath, "r" )
            tbl = textutils.unserialize( file.readAll() )
            file.close()
        else
            tbl = {}
        end
        tbl[ #tbl + 1 ] = { messsage = sMessage, sender = os.getComputerLabel() or os.getComputerID() }
        local file = fs.open( filePath, "w" )
        file.write( textutils.serialize( tbl ) )
        file.close()
    end
end

function broadcast( sMessage )
    if type( sMessage ) ~= "string" then
        error( "Expected string, got " .. type( sMessage), 2 )
    end
    for id, _ in pairs( files ) do
        send( sMessage, id )
    end
end

function receive( pFilter, nTimeout, _side, _sender )
    local id
    if nTimeout and type( nTimeout ) ~= "number" then
        error( "Expected string, number[, string], got " .. type( pFilter ) .. ", " .. type( nTimeout ) .. "," .. type( _side ), 2 )
    elseif pFilter and type( pFilter ) ~= "string" then
        error( "Expected string, number[, string], got " .. type( pFilter ) .. ", " .. type( nTimeout ) .. "," .. type( _side ), 2 )
    elseif _side and type( _side ) ~= "string" then
        error( "Expected string, number[, string], got " .. type( pFilter ) .. ", " .. type( nTimeout ) .. "," .. type( _side ), 2 )
    end
    if nTimeout then
        id = os.startTimer( nTimeout )
    end
    while true do
        local event = { os.pullEvent() }
        if event[ 1 ] == "disknet_message" then
            if event[ 2 ] == _side or not _side then
                if event[ 3 ] == pFilter or not pFilter then
                    return unpack( event )
                end
            end
        elseif event[ 1 ] == "timer" and event[ 2 ] == id then
            return nil
        end
    end
end

function isOpen( side, file ) --attempts to find an open "port"
    for k, v in pairs( files ) do
        if v.side == side and v.file == file then
            return k
        end
    end
    return false
end

local function checkFile()  --checks the files for new data once per tick
    while true do
        for id, tbl in pairs( files ) do
            disk.setLabel( tbl.side, tbl.label )
            local filePath = fs.combine( disk.getMountPath( tbl.side ), tbl.file )
            if fs.getFreeSpace( disk.getMountPath( tbl.side ) ) < 100 then
                local file = fs.open( filePath, "w" )
                file.write( textutils.serialize( {} ) )
                file.close()
            end
            if fs.exists( filePath ) then
                local file = fs.open( filePath, "r" )
                local data = textutils.unserialize( file.readAll() )
                file.close()
                local toSend = {}
                if not oldFiles[ id ] then
                    oldFiles[ id ] = {}
                end
                for k, v in ipairs( data ) do
                    if oldFiles[ id ][ k ] ~= v then
                        toSend[ #toSend + 1 ] = v
                    end
                end
                for k, v in pairs( toSend ) do
                    os.queueEvent( "disknet_message", tbl.side, tbl.file, v.sender, v.message )
                    os.pullEvent()
                    oldFiles[ id ] = data
                end
            end
        end
        sleep( 0.1 )
    end
end

function redRepeat( side, file ) --sends/recieves disknet/rednet messages back and forth.
    while true do
        local event = { os.pullEvent() }
        if event[ 1 ] == "disknet_message" and event[ 2 ] == side and event[ 3 ] == file then
            rednet.send( event[ 3 ], file )
        elseif event[ 1 ] == "rednet_message" then
            disknet.broadcast( event[ 3 ] )
        end
    end
end

local cocheck = coroutine.create( checkFile )

function os.pullEventRaw( sFilter )
    while true do
        local event = { coroutine.yield() }
        if coroutine.status( cocheck ) == "suspended" then
            coroutine.resume( cocheck, unpack( event ) )
        end
        if event[ 1 ] == sFilter or not sFilter then
            return unpack( event )
        end
    end
end