-- mining01.lua
-- 入っている燃料で行ける分だけ前に掘っていって、戻ってくるプログラム

-- ユーザ定義
PROGRAM_NAME = "mining"
FUEL_SLOT = 16
MINFUEL = 5
MAX_LEN = 100
MAX_RETRY = 15

-- for system
local ARGS = {...}

-- 関数

-- インベントリを調べて丸石捨てる
-- onlyOnece : bool 1スタック捨てたらそれでやめるか
-- return (true/false) 捨てるのに成功したかどうか
local function dropStones(onlyOnce)
    local droped = false --捨てるのに成功したかのフラグ
    for i=1,16 do
        turtle.select(i)
        local item = turtle.getItemDetail()
        if item ~= nil and item.name == "minecraft:cobblestone" then
            turtle.dropDown()
            droped = true
            if onlyOnce == true then
                turtle.select(1)
                return true
            end
        end
    end
    turtle.select(1)
    return droped
end

local function writeResumeFile()
    if not fs.exists("working") then
        return
    end
    local fh = fs.open("working/"..PROGRAM_NAME, "w")
    fh.writeLine(PROGRAM_NAME.." -r")
    fh.close()
end
local function delResumeFile()
    fs.delete("working/"..PROGRAM_NAME)
end

local function digHere()
    turtle.turnRight()
    turtle.dig()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.dig()
    turtle.turnRight()
    turtle.digUp()
    turtle.digDown()
end

local function writeCurrentData(data)
    if not fs.exists("memory") then
        return
    end
    local fh = fs.open("memory/"..PROGRAM_NAME, "w")
    local tempStr = textutils.serialise(data)
    fh.write(tempStr)
    fh.close()
end
local function delCurrentData()
    fs.delete("memory/"..PROGRAM_NAME)
end

-- init
local data = {state = "fwd", fwdCount = 0, backCount = 0}
local resumed = false
-- 復帰用ファイルの書き込み
writeResumeFile()

for i=1, table.maxn(ARGS) do
    local temp = ARGS[i]
    if temp == "-r" then
        resumed = true
        if fs.exists("memory/"..PROGRAM_NAME) then
            local fh = fs.open("memory/"..PROGRAM_NAME, "r")
            data = textutils.unserialise(fh.readAll())
            fh.close()
            if type(data.fwdCount) ~= "number" then
                data.fwdCount = 0
            end
            if type(data.backCount) ~= "number" then
                data.backCount = 0
            end
        end
    elseif temp == "--max-len" then
        MAX_LEN = tonumber(ARGS[i+1])
        i = i + 1
    end
end

if not resumed then
    turtle.select(FUEL_SLOT)
    turtle.refuel()
    if turtle.getFuelLevel() <= MINFUEL then
        print("can not refuel enogh fuel!")
        return
    end
    turtle.select(1)
end

-- 燃料がなくなるか最大の長さになるまで掘り進む
local retryCount = 0
while data.state == "fwd" and turtle.getFuelLevel() > data.fwdCount+MINFUEL and MAX_LEN > data.fwdCount do
    turtle.dig()
    if turtle.forward() then
        data.fwdCount = data.fwdCount + 1
        retryCount = 0
        writeCurrentData(data)
    else
        if retryCount >= MAX_RETRY then
            break
        end
        print("susumenai")
        turtle.dig()
        turtle.attack()
        retryCount = retryCount + 1
    end
    digHere()

    turtle.select(16)
    if turtle.getItemDetail() ~= nil then
        if not dropStones(true) then
            print("Go back. because of full inventory")
            break
        end
    end
    turtle.select(1)
end
-- 元の位置に戻る
if data.state == "fwd" then
    print("no enough fuel. I will go back start position.")
    turtle.turnRight()
    turtle.turnRight()
    data.state = "rtn"
end
retryCount = 0
while data.state == "rtn" and data.fwdCount > data.backCount do
    if turtle.forward() then
        data.backCount = data.backCount + 1
        retryCount = 0
        writeCurrentData(data)
    else
        if retryCount >= MAX_RETRY then
            data.state = "err"
            break
        end
        print("susumenai")
        turtle.dig()
        turtle.attack()
        retryCount = retryCount + 1
    end
end
if data.state == "rtn" then
    turtle.turnRight()
    turtle.turnRight()
    data.state = "done"
end

delResumeFile()
delCurrentData()
print("modotta!")