-- platform_builder.lua
-- Improved version - builds platforms and returns for more blocks

local t = turtle

-- === Settings ===
local CHECK_FUEL = true        -- whether to check fuel
local REFUEL_LEVEL = 50        -- minimum fuel level

-- === State ===
local x, y = 0, 0              -- current position
local direction = 0             -- 0=east, 1=north, 2=west, 3=south

-- === Movement ===
local function turnLeft()
    t.turnLeft()
    direction = (direction + 1) % 4
end

local function turnRight()
    t.turnRight()
    direction = (direction + 3) % 4
end

local function face(targetDir)
    while direction ~= targetDir do
        if (direction - targetDir) % 4 == 1 then
            turnRight()
        else
            turnLeft()
        end
    end
end

local function forwardStep()
    -- Check fuel
    if CHECK_FUEL and t.getFuelLevel() < REFUEL_LEVEL then
        print("⛽ Low fuel! Trying to refuel...")
        for slot = 1, 16 do
            t.select(slot)
            if t.refuel(0) then  -- Check if item can be used as fuel
                t.refuel(1)      -- Refuel with one item
                print("✅ Refueled from slot " .. slot)
                break
            end
        end
    end
    
    -- Move forward
    local attempts = 0
    while attempts < 5 do  -- Max 5 attempts
        if t.forward() then
            -- Update coordinates
            if direction == 0 then x = x + 1
            elseif direction == 1 then y = y + 1
            elseif direction == 2 then x = x - 1
            else y = y - 1 end
            return true
        elseif t.detect() then
            t.dig()
        else
            sleep(0.5)
        end
        attempts = attempts + 1
    end
    print("❌ Cannot move forward!")
    return false
end

local function moveTo(targetX, targetY)
    -- First move along X, then along Y
    local dx = targetX - x
    local dy = targetY - y
    
    if dx > 0 then
        face(0)
        for i = 1, dx do forwardStep() end
    elseif dx < 0 then
        face(2)
        for i = 1, -dx do forwardStep() end
    end
    
    if dy > 0 then
        face(1)
        for i = 1, dy do forwardStep() end
    elseif dy < 0 then
        face(3)
        for i = 1, -dy do forwardStep() end
    end
end

local function goHome()
    print("🔄 Returning home...")
    moveTo(0, 0)
    face(0)  -- Face east by default
end

-- === Block management ===
local function countBlocks()
    local total = 0
    for slot = 1, 16 do
        total = total + t.getItemCount(slot)
    end
    return total
end

local function selectAnyBlock()
    for slot = 1, 16 do
        if t.getItemCount(slot) > 0 then
            t.select(slot)
            return true
        end
    end
    return false
end

local function waitForBlocks()
    print("📦 Blocks exhausted! Returning for resupply...")
    local savedX, savedY, savedDir = x, y, direction
    
    goHome()
    
    print("⏳ Waiting for blocks to be added...")
    while countBlocks() == 0 do
        print("📦 No blocks in inventory! Waiting...")
        sleep(3)
    end
    
    print("✅ Blocks available! Returning to work...")
    moveTo(savedX, savedY)
    face(savedDir)
end

local function placeBlockDown()
    if not t.detectDown() then
        if not selectAnyBlock() then
            waitForBlocks()
            selectAnyBlock()  -- Select block after resupply
        end
        
        if not t.placeDown() then
            print("❌ Cannot place block! Trying again...")
            sleep(0.5)
            return false
        end
    end
    return true
end

-- === Building functions ===
local function buildSquare(size, fill)
    print("🟦 Building square " .. size .. "x" .. size)
    local half = math.floor(size / 2)
    
    for row = -half, half - (size % 2 == 0 and 1 or 0) do
        moveTo(-half, row)
        face(0)  -- Face east
        
        for col = -half, half - (size % 2 == 0 and 1 or 0) do
            if fill or col == -half or col == half or row == -half or row == half then
                placeBlockDown()
            end
            
            if col < half - (size % 2 == 0 and 1 or 0) then
                forwardStep()
            end
        end
    end
    
    goHome()
end

local function buildRectangle(width, height, fill)
    print("🟦 Building rectangle " .. width .. "x" .. height)
    local halfW = math.floor(width / 2)
    local halfH = math.floor(height / 2)
    
    for row = -halfH, halfH - (height % 2 == 0 and 1 or 0) do
        moveTo(-halfW, row)
        face(0)
        
        for col = -halfW, halfW - (width % 2 == 0 and 1 or 0) do
            if fill or col == -halfW or col == halfW or row == -halfH or row == halfH then
                placeBlockDown()
            end
            
            if col < halfW - (width % 2 == 0 and 1 or 0) then
                forwardStep()
            end
        end
    end
    
    goHome()
end

local function buildCircle(radius, fill)
    print("🔵 Building circle with radius " .. radius)
    
    for row = -radius, radius do
        local width = math.floor(math.sqrt(radius * radius - row * row))
        if width > 0 then
            moveTo(-width, row)
            face(0)
            
            for col = -width, width do
                local distance = math.sqrt(col * col + row * row)
                if fill or (distance >= radius - 0.5 and distance <= radius + 0.5) then
                    placeBlockDown()
                end
                
                if col < width then
                    forwardStep()
                end
            end
        end
    end
    
    goHome()
end

-- === Simple interface ===
local function main()
    print("=== 🏗️ PLATFORM BUILDER ===")
    print("Available shapes:")
    print("1 - Square")
    print("2 - Rectangle")
    print("3 - Circle")
    print("========================")
    
    -- Shape selection
    local choice
    while true do
        print("Choose shape (1-3):")
        choice = tonumber(read())
        if choice and choice >= 1 and choice <= 3 then
            break
        end
        print("❌ Invalid choice! Try again.")
    end
    
    -- Fill option
    local fill = false
    print("Fill completely? (y/n):")
    local fillInput = read()
    if fillInput and string.lower(fillInput) == "y" then
        fill = true
    end
    
    -- Building parameters
    if choice == 1 then
        print("Square side size:")
        local size = tonumber(read())
        if size and size > 0 then
            buildSquare(size, fill)
        else
            print("❌ Invalid size!")
        end
        
    elseif choice == 2 then
        print("Rectangle width:")
        local width = tonumber(read())
        print("Rectangle height:")
        local height = tonumber(read())
        if width and height and width > 0 and height > 0 then
            buildRectangle(width, height, fill)
        else
            print("❌ Invalid dimensions!")
        end
        
    elseif choice == 3 then
        print("Circle radius:")
        local radius = tonumber(read())
        if radius and radius > 0 then
            buildCircle(radius, fill)
        else
            print("❌ Invalid radius!")
        end
    end
    
    print("✅ Construction completed!")
    print("📍 Turtle returned to start position")
end

-- Start program
main()