Add system shop (buy from player)

SystemShop.lua

@@ -0,0 +1,76 @@
+require("libevent")
+require("util")
+local component = require("component")
+local sides = require("sides")
+
+-- System buy from player
+
+-- Auto configure
+local modem = proxy("modem")
+local trans = proxy("transposer")
+local redgate = proxy("redstone")
+
+-- Variables
+
+-- Functions
+
+local function init()
+    if(modem==nil or trans==nil or redgate==nil) then
+        error("Failed on checking devices.")
+    end
+
+    modem.open(10011)
+
+    redgate.setOutput(sides.east,0) -- open gate
+end
+
+local function uninit()
+    redgate.setOutput(sides.east,15) -- close gate on stop
+end
+
+local function main()
+    init()
+    while true do 
+        print("Item Price:")
+        print("Log (yuan mu) : $0.5")
+        print("Other : $0.1")
+
+        local e=WaitMultipleEvent("bioReader","modem_message","interrupted")
+        if(e.event=="bioReader") then
+            redgate.setOutput(sides.east,15) -- close gate
+            local sum=0
+            local x=trans.getAllStacks(sides.south) -- check item
+            while true do
+                local y=x()
+                if(y==nil) then 
+                    break
+                end
+                if(y.size~=nil) then
+                    if(y.name=="minecraft:log") then
+                        sum=sum+y.size*0.5
+                    else
+                        sum=sum+y.size*0.1
+                    end
+                end
+            end
+
+            print("Total Price: " .. sum)
+
+            -- Transfer item
+            print("Transfering items ... ")
+            while (trans.transferItem(sides.south,sides.down)) do 
+            end
+            print("Done")
+
+            redgate.setOutput(sides.east,0) -- open gate
+        else
+            print("Received ctrl+c signal.")
+            break
+        end
+    end
+    uninit()
+end
+
+print("SystemShop Start")
+main()
+print("SystemShop Stopped")