-- resumable signed-volume miner with start offset, slow start, return+dump
local ST="mine_state.txt"
local t=turtle

-- input: numbers or "quit"/"resume"
local function rd(p)
  io.write(p..": "); local s=read() or ""
  s=s:lower()
  if s=="quit" then error() end
  if s=="resume" then return "resume" end
  local n=tonumber(s); if not n then return rd(p) end
  return n
end

local function save(S) local h=fs.open(ST,"w"); h.write(textutils.serialize(S)); h.close() end
local function load() if not fs.exists(ST) then return nil end local h=fs.open(ST,"r");local s=h.readAll();h.close();return textutils.unserialize(s) end

-- dig helpers
local function digf() while t.detect() do t.dig() end end
local function dgu() while t.detectUp() do t.digUp() end end
local function dgd() while t.detectDown() do t.digDown() end end

-- state
local S=load()
if not S then
  local X=rd("X (signed fwd/back)"); if X=="resume" then S=load() end
  if not S then
    local Y=rd("Y (signed up/down)")
    local Z=rd("Z (signed right/left)")
    local OX=rd("OffX (signed fwd/back; stand beside first mined)")
    local OY=rd("OffY (signed up/down)")
    local OZ=rd("OffZ (signed right/left)")
    S={
      xlen=math.abs(X), ylen=math.abs(Y), zlen=math.abs(Z),
      xneg=X<0, yneg=Y<0, zneg=Z<0,
      x=1, y=1, z=1, dir=0,
      ox=OX, oy=OY, oz=OZ, at_off=false,
      slow=10,
      px=0,py=0,pz=0, h=0, sh=0   -- pos/orient rel to start
    }
    save(S)
  end
end

-- turns and facing
local function TL() t.turnLeft();  S.h=(S.h+3)%4 end
local function TR() t.turnRight(); S.h=(S.h+1)%4 end
local function T2() TL(); TL() end
local function face(d) while S.h~=d do if (d-S.h)%4==1 then TR() else TL() end end end

-- slow-start pause on first 10 moves
local function tick() if S.slow and S.slow>0 then sleep(5); S.slow=S.slow-1; save(S) end end

-- moves that track pos
local function F()
  local n=0
  while not t.forward() do t.attack(); digf(); n=n+1; if n>50 then return end end
  if S.h==0 then S.px=S.px+1 elseif S.h==1 then S.pz=S.pz+1 elseif S.h==2 then S.px=S.px-1 else S.pz=S.pz-1 end
  tick(); save(S)
end
local function U()
  local n=0
  while not t.up() do t.attackUp(); dgu(); n=n+1; if n>50 then return end end
  S.py=S.py+1; tick(); save(S)
end
local function D()
  local n=0
  while not t.down() do t.attackDown(); dgd(); n=n+1; if n>50 then return end end
  S.py=S.py-1; tick(); save(S)
end

-- go to start offset once (stand in adjacent space, NOT on first mined block)
local function go_off()
  if S.at_off then return end
  if S.oy>0 then for i=1,S.oy do dgu(); U() end elseif S.oy<0 then for i=1,-S.oy do dgd(); D() end end
  if S.oz>0 then TR(); for i=1,S.oz do digf(); F() end; TL()
  elseif S.oz<0 then TL(); for i=1,-S.oz do digf(); F() end; TR() end
  if S.ox>0 then for i=1,S.ox do digf(); F() end
  elseif S.ox<0 then T2(); for i=1,-S.ox do digf(); F() end; T2() end
  S.at_off=true; save(S)
end

-- Manhattan goto (vertical, then X, then Z) in mined space
local function goto_rel(x,y,z)
  while S.py<y do dgu(); U() end
  while S.py>y do dgd(); D() end
  if S.px<x then face(0); for i=1,x-S.px do digf(); F() end
  elseif S.px>x then face(2); for i=1,S.px-x do digf(); F() end end
  if S.pz<z then face(1); for i=1,z-S.pz do digf(); F() end
  elseif S.pz>z then face(3); for i=1,S.pz-z do digf(); F() end end
end

-- dump: at home (0,0,0). below is chest A for [cobble,dirt,gravel,sand]. chest B is one lower.
local function dump_home()
  -- pass 1: drop selected down into chest A
  local ok = {["minecraft:cobblestone"]=1,["minecraft:dirt"]=1,["minecraft:gravel"]=1,["minecraft:sand"]=1}
  for s=1,16 do
    local d=t.getItemDetail(s)
    if d and ok[d.name] then t.select(s); t.dropDown() end
  end
  -- pass 2: side-drop everything else into chest B (y=-2)
  -- carve a tiny service to chest B side and drop forward
  face(0); digf(); F()        -- (1,0,0)
  dgd(); D() ; dgd(); D()     -- (1,-2,0)
  face(2)                     -- face -X (toward chests)
  for s=1,16 do
    local d=t.getItemDetail(s)
    if d and not ok[d.name] then t.select(s); t.drop() end
  end
  face(0); F()                -- (1,-2,1) -> step out to avoid re-picking? optional
  face(2); F()                -- back to (1,-2,0)
  face(0);                    -- reorient
  -- return to home (0,0,0)
  face(2); F()                -- (0,-2,0)
  U(); U();                   -- (0,0,0)
end

-- === run ===
go_off()
if S.xneg then T2() end

while S.y<=S.ylen do
  if S.dir==1 then T2() end
  for i=S.x,S.xlen do
    dgu(); dgd()
    local last=(i==S.xlen) and (S.z==S.zlen) and (S.y==S.ylen)
    if not last and i<S.xlen then digf(); F() end
    S.x=i+1; save(S)
  end
  S.x=1
  if S.z<S.zlen then
    if not S.zneg then TR(); digf(); F(); TR() else TL(); digf(); F(); TL() end
    S.z=S.z+1; S.dir=1-S.dir; save(S)
  else
    if S.y<S.ylen then
      if not S.yneg then dgu(); U() else dgd(); D() end
      if (S.z%2)==1 then T2(); for i=1,S.xlen-1 do digf(); F() end; T2() end
      S.y=S.y+1; S.z=1; S.dir=0; save(S)
    else break end
  end
end

-- return to start, dump, restore facing
goto_rel(0,0,0)
dump_home()
goto_rel(0,0,0)
face(S.sh)
if fs.exists(ST) then fs.delete(ST) end
print("done")