--[[
Station 2/3 Schedule Program
]]
require("util")
local sides = require("sides")
local event = require("event")

-- Config your update functions here (Do not change function name)
local redin1 = proxy("redstone", "")
local redin2 = proxy("redstone", "")
local redout1 = proxy("redstone", "")
local redout2 = proxy("redstone", "")

--[[
Redstone Signals
Direction_[Type][Info]: number
]]
local ab_st, ab_sr, ab_lin, ab_lout
local ba_st, ba_sr, ba_lin, ba_lout

local function updateRedstoneInput()
    ab_st = redin1.getInput(sides.north)
    ab_sr = redin1.getInput(sides.east)
    ba_st = redin1.getInput(sides.south)
    ba_sr = redin1.getInput(sides.west)
    ab_lin = redin2.getInput(sides.north)
    ab_lout = redin2.getInput(sides.east)
    ba_lin = redin2.getInput(sides.south)
    ba_lout = redin2.getInput(sides.west)
end

-- Internal Schedule Status (Notice: Program must start without any trains in station)
local mid_direction
local ab_station_time = 0
local ba_station_time = 0
local mid_time = 0
local ab_exit_time = 0
local ba_exit_time = 0
local midab_exit_time=0 -- Mid needs cool
local midba_exit_time=0

-- NOOP print function (for release use)
local function noop_print(...)

end

-- Debug Output
local dprint = print

local function debugOutputInfo()
    dprint("ab_st",ab_st,"ab_sr",ab_sr,"ba_st",ba_st,"ba_sr",ba_sr,"ab_lin",ab_lin,"ab_lout",ab_lout,"ba_lin",ba_lin,"ba_lout",ba_lout)
    dprint("mid_direction",mid_direction,"ab_station_time",ab_station_time,"ba_station_time",ba_station_time,"mid_time",mid_time,"ab_exit_time",ab_exit_time,"ba_exit_time",ba_exit_time,"midab_exit_time",midab_exit_time,"midba_exit_time",midba_exit_time)
end

--[[
    Internal Functions
]]

local function enabledevice(Name)
local d,s=getRawFromName(Name)
if(d~=nil and s~=nil) then d.setOutput(s,15) end
end

local function disabledevice(Name)
local d,s=getRawFromName(Name)
if(d~=nil and s~=nil) then d.setOutput(s,15) end
end

-- Notice: RedTick=0.1s GameTick=0.05s
local function delay(loop)
if(loop<0.2) then loop=0.2 end -- Less than 0.1s is useless
os.sleep(loop*0.5)
end

local running=true

local function clearRedstoneOutput()
disabledevice("ab_ko")
disabledevice("ab_m")
disabledevice("ab_ks")
disabledevice("ba_ko")
disabledevice("ba_m")
disabledevice("ba_ks")
disabledevice("mid_ka")
disabledevice("mid_kb")
end

local function doInit()
    -- Flash output to zero.
    clearRedstoneOutput()
    AddEventListener("interrupted",
    function()
    running=false
    print("Interrupt Signal Received.")
    return false --Unregister event listener itself
    end)
    
    running=true
end

-- Main Program
local function TCSMain()
    doCheck() --TODO
    doInit()
    while running do
        -- Flush input
        updateRedstoneInput()
        
        -- Update status
        if (ab_station_time > 0) then
            ab_station_time = ab_station_time + 1
        end
        if (ba_station_time > 0) then
            ba_station_time = ba_station_time + 1
        end
        if (mid_time > 0) then
            mid_time = mid_time + 1
        end
        if (ab_exit_time > 0) then
            ab_exit_time = ab_exit_time + 1
            if (ab_exit_time > 10) then -- Exit will reset in 10 loops (5seconds)
                ab_exit_time = 0
            end
        end
        if (ba_exit_time > 0) then
            ba_exit_time = ba_exit_time + 1
            if (ba_exit_time > 10) then -- Exit will reset in 10 loops (5seconds)
                ba_exit_time = 0
            end
        end
        if(midab_exit_time>0) then
        midab_exit_time=midab_exit_time+1
        if(midab_exit_time>8) then -- MidAB will cool in 8 loops (4seconds)
        midab_exit_time=0
        end
        end
        if(midba_exit_time>0) then
        midba_exit_time=midba_exit_time+1
        if(midba_exit_time>8) then -- MidBA will cool in 8 loops (4seconds)
        midba_exit_time=0
        end
        end
        

        -- Judge Incoming bus.
        if (ab_st > 0) then -- New incoming bus from A to B
            if (ab_sr > 0) then -- This bus want to stop
                if (ab_station_time == 0) then -- If AB Station is free
                    dprint("A-->B Train In")
                    disabledevice("ab_ks") -- disabe to let it stop
                    disabledevice("ab_m") -- disable to allow incoming to station
                    enabledevice("ab_ko") -- enable to allow incoming
                    delay(0.5) -- delay 50% loop time
                    disabledevice("ab_ko") -- disable to block another train
                    ab_station_time = 1 -- Start Time Counter
                else -- AB Station is not free
                    -- This train should wait outside the station
                    dprint("A-->B Train Pending")
                end
            else -- This bus want to pass by
                if (mid_time == 0 and midba_exit_time==0) then -- Mid is free and MidBA is cool
                    dprint("A-->Mid Train In")
                    enabledevice("ab_m") -- enable motor to let it pass.
                    enabledevice("mid_ka") -- enable switch from A
                    disabledevice("mid_kb") -- disable switch to B
                    mid_direction = "ab"
                    enabledevice("ab_ko") -- enable to allow incoming
                    delay(0.5)
                    disabledevice("ab_ko") -- disable to block another train
                    mid_time = 1 -- Start time counter
                else -- Mid is busy
                    dprint("A-->Mid Train Pending")
                    -- This train should wait outside the station
                end
            end
        end

        if (ba_st > 0) then -- New incoming bus from B to A
            if (ba_sr > 0) then -- This bus want to stop
                if (ba_station_time == 0) then -- If BA Station is free
                    dprint("B-->A Train In")
                    disabledevice("ba_ks") -- disable to let it stop
                    disabledevice("ba_m") -- disable to allow incoming to station
                    enabledevice("ba_ko") -- enable to allow incoming
                    delay(0.5)
                    disabledevice("ba_ko") -- disable to block another train
                    ba_station_time = 1 -- Start Time Counter
                else -- BA Station is not free
                    -- This train should wait outside the station
                    dprint("B-->A Train Pending")
                end
            else -- This bus want to pass by
                if (mid_time == 0 and midab_exit_time==0) then -- Mid is free and MidAB is free
                    dprint("B-->Mid Train In")
                    enabledevice("ba_m")-- enable motor to let it pass.
                    disabledevice("mid_ka")
                    enabledevice("mid_kb")
                    enabledevice("ba_ko") -- enable to allow incoming
                    delay(0.5)
                    disabledevice("ba_ko") -- disable to block another train
                    mid_direction = "ba"
                    mid_time = 1
                else -- Mid is busy
                    dprint("B-->Mid Train Pending")
                    -- This train should wait outside the station
                end
            end
        end

        if (ab_lout > 0 and ab_exit_time == 0) then -- AB next free
            -- Judge which train should pass.
            if (ab_station_time > 16 and (mid_time > 0 and mid_direction == "ab")) then -- Two Trains
                if (ab_station_time > mid_time) then -- StationTrain wait longer.
                    dprint("A-->B Train Out")
                    ab_station_time = 0 -- Stop counter
                    enabledevice("ab_ks") -- enable swith to let it go
                    ab_exit_time = 1 -- Start Exit Counter
                else -- MidTrain wait longer
                    dprint("Mid-->B Train out")
                    mid_time = 0 -- Stop Counter
                    enabledevice("mid_kb") -- enable switch
                    ab_exit_time = 1 -- Start Exit Counter
                    midab_exit_time = 1 -- Start mid exit counter
                end
            elseif (ab_station_time > 16) then --Only Station Train
                dprint("A-->B Train Out")
                ab_station_time = 0 -- Stop Counter
                enabledevice("ab_ks")
                ab_exit_time = 1 -- Start exit counter
            elseif (mid_time > 0 and mid_direction == "ab") then -- Only Mid Train
                dprint("Mid-->B Train Out")
                mid_time = 0 -- Stop counter
                enabledevice("mid_kb")
                ab_exit_time = 1 -- Start exit counter
            end -- No train, do nothing
        end -- End of AB judge

        if (ba_lout > 0 and ba_exit_time == 0) then -- BA next free
            -- Judge which train should pass.
            if (ba_station_time > 16 and (mid_time > 0 and mid_direction == "ba")) then -- Two Trains
                if (ba_station_time > mid_time) then -- StationTrain wait longer.
                    dprint("B-->A Train Out")
                    ba_station_time = 0 -- Stop counter
                    enabledevice("ba_ks") -- enable swith to let it go
                    ba_exit_time = 1 -- Start exit counter
                else -- MidTrain wait longer
                    dprint("Mid-->A Train Out")
                    mid_time = 0 -- Stop Counter
                    enabledevice("mid_ka")
                    ba_exit_time = 1 -- Start Counter
                end
            elseif (ba_station_time > 16) then --Only Station Train
                dprint("B-->A Train Out")
                ba_station_time = 0 -- Stop counter
                enabledevice("ba_ks") -- enable swith to let it go
                ba_exit_time = 1 -- Start exit counter
            elseif (mid_time > 0 and mid_direction == "ba") then -- Only Mid Train
                dprint("Mid-->A Train Out")
                mid_time = 0 -- Stop Counter
                enabledevice("mid_ka")
                ba_exit_time = 1 -- Start Counter
            end -- No train, do nothing
        end -- End of BA judge

        debugValueInfo()

        -- Sleep for next loop
        dprint("==========")
        delay(1)
    end -- End of while loop
    -- Block All Trains on terminate.
    clearRedstoneOutput()
end

print("Train Control System Start!")
TCSMain()
print("Train Control System Stop!")