gpsHost

--[[
--      Code by minecraft: montana_1
--      please send comments or questions to [email protected] with a subject I might read
--
--      Description of code:
--          This is a program written for use in minecraft with the mod "OpenComputers"
--          This is the server side or host code for a single computer or possible micro-controller to broadcast
--          a signal from a minimum of 4 (possibly more but not tested) access points containing there predetermined
--          co-ordinates which are entered into the program upon first run and saved in a file for later use.
--          The co-ordinates can then be determined by a client program from this information
--      Note:
--          Because the co-ordinates are calculated by the distance from each access point,
--          it is very important that all other access points within range are set to NOT REPEAT.
--          Which by default is ON. If you do not know how to change this, there is another program
--          on my pastebin account (montana_1) that will first find all access points on a network
--          and second set there range to zero and turn Repeating OFF. This is good practice with any programs
--          to turn the access points effectively off when not being immediately used to save power and
--          prevent errors.
--      Also Note:
--          The timings for this program are set so that there are no processors placed within the access points
]]--




function getAccessPoints()
    local component = require("component")
    local event = require("event")
    local t = component.list()
    local accessPoints = {}
    local i = 0
    for address,componentType in pairs(t) do
        if(componentType == "access_point") then
            accessPoints[i] = address
            i = i + 1
        end
    end
    return accessPoints
end

function turnOffRepeaters(accessPoints)
    local component = require("component")
    for i=0, #accessPoints do
        print(accessPoints[i])
        component.proxy(accessPoints[i]).setRepeater(false)
        component.proxy(accessPoints[i]).setStrength(0)
        print(component.proxy(accessPoints[i]).isRepeater())
    end
end

function split(inputstr, sep)
    if(inputstr == nil or inputstr == "") then
                return nil
        end
        if sep == nil then
                sep = ","
        end
        local t={} ; i=0
        for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
                t[i] = str
                i = i + 1
        end
        return t
end


local fileSystem = require("filesystem")
local accessPoints = getAccessPoints()
turnOffRepeaters(accessPoints)
local gps_port = 3665
local signal_strength = 400

if(#accessPoints+1 < 4) then
    print("Insuficient access_points, 4 are required you have (".. #accessPoints+1 ..")")
    error()
end

local term = require("term")
local shell = require("shell")
local component = require("component")
local hostCoordinates = {}

if(fileSystem.exists(shell.resolve("gpsHostData"))) then
    local file = io.open(shell.resolve("gpsHostData"), "r")
    local i = 0
    for line in io.lines(shell.resolve("gpsHostData")) do
        hostCoordinates[i] = split(line,",")
        i=i+1
    end
    file:close()
else
    local file = io.open(shell.resolve("gpsHostData"), "a")
    for i=0, #accessPoints do
        print("Enter coordinates (x,y,z) for access_point: " .. accessPoints[i])
        local tmp = term.read()
        hostCoordinates[i] = split(accessPoints[i]..","..tmp,",")
        file:write(accessPoints[i]..","..tmp)
    end
    file:close()
end

component.modem.open(gps_port)
while true do
    for i=0, #hostCoordinates do
        io.write(i..": "..hostCoordinates[i][0].." "..hostCoordinates[i][1]..","..hostCoordinates[i][2]..","..hostCoordinates[i][3])
        component.setPrimary("access_point",hostCoordinates[i][0])
        print("Primary set")
        component.proxy(hostCoordinates[i][0]).setStrength(signal_strength)
        component.modem.broadcast(gps_port, tonumber(hostCoordinates[i][1]),tonumber(hostCoordinates[i][2]),tonumber(hostCoordinates[i][3]))
        os.sleep(0.25)
        component.getPrimary("access_point").setStrength(0)
        os.sleep(1)
    end
end