Dapper Map Scanner

if not turtle and not commands then
    error("The map scanner must be run with a turtle or command computer.", 0)
end

local args = {...}
if #args ~= 2 and #args ~= 3 then
    print("Usage: mapscan <y-limit> <radius> <fill>")
    print("Y-Limit should be the maximum Y coordinate (1 - 256) that the turtle scans from. This should be just a bit above the height of the landscape.")
    print("Radius is the horizontal distance from the start position the turtle will scan.")
    print("Fill should be 'fill' if you only want it to scan missing blocks.")
    return
end
local yLimit = tonumber(args[1])
if not yLimit or yLimit <= 1 or yLimit > 256 then
    print("Y-Limit should be the maximum Y coordinate (1 - 256) that the turtle scans from. This should be just a bit above the height of the landscape.")
    return
end
local radius = tonumber(args[2])
if not radius or radius < 1 then
    print("Radius is the horizontal distance from the start position the turtle will scan.")
    return
end
local isFill = args[3] == "fill"
if isFill then
    print("Scanning only missing blocks...")
end

local DAPPER_SCAN_DATA_CHANNEL = 4263
local DAPPER_SCAN_ACKNOWLEDGE_CHANNEL = 4264
local DAPPER_SCAN_NEXT_REQUEST_CHANNEL = 4265
local DAPPER_SCAN_NEXT_REPLY_CHANNEL = 4266

print("Dapper Mapper Scanner by oeed")
local modem = peripheral.find("modem")
if not modem or not modem.isWireless() then
    error("Please connect a wireless modem and re-run the program.", 0)
end
modem.open(DAPPER_SCAN_DATA_CHANNEL)
modem.open(DAPPER_SCAN_ACKNOWLEDGE_CHANNEL)
modem.open(DAPPER_SCAN_NEXT_REQUEST_CHANNEL)
modem.open(DAPPER_SCAN_NEXT_REPLY_CHANNEL)

os.setComputerLabel("Dapper Mapper Scanner")
if turtle then
    print("WARNING: This program will use a TON of fuel. You should fill the ENTIRE turtle inventory with fuel if possible.")
    print("Press any key once fuel is loaded.")
    os.pullEvent("key")
end

local function location()
    local x, y, z = gps.locate(2)
    if not x or not y or not z then
        print("Unable to locate self using GPS... trying again in 5 seconds...")
        sleep(5)
        return location()
    end
    return x, y, z
end

local function checkFuel(amount)
    amount = amount or 1
    if turtle.getFuelLevel() < amount then
        local slot = 1
        repeat
            turtle.select(slot)
            slot = slot + 1
        until turtle.refuel(1) or slot > 16
        if turtle.getFuelLevel() < amount then
            print("Turtle is out of fuel, enter more and press any key.")
            os.pullEvent("key")
            return checkFuel()
        end
    end
end

local function toY(destY)
    local currX, currY, currZ = location()
    local diffY = destY - currY
    if diffY >= 1 then
        -- We need to go up
        checkFuel(diffY)
        for i = 1, diffY do
            turtle.up()
        end
    elseif diffY <= -1 then
        -- We need to go down
        checkFuel(math.abs(diffY))
        for i = -1, diffY, -1 do
            turtle.down()
        end
    end
end

local directions = {
    X_POS = 1,
    X_NEG = 2,
    Z_POS = 3,
    Z_NEG = 4,
}
local currentDirection

local function toAxis(axis)
    if axis == "x" then
        if currentDirection == directions.X_POS then
            return 1
        elseif currentDirection == directions.X_NEG then
            return -1
        elseif currentDirection == directions.Z_NEG then
            turtle.turnRight()
            currentDirection = directions.X_POS
            return 1
        elseif currentDirection == directions.Z_POS then
            turtle.turnLeft()
            currentDirection = directions.X_POS
            return 1
        end
    elseif axis == "z" then
        if currentDirection == directions.Z_POS then
            return 1
        elseif currentDirection == directions.Z_NEG then
            return -1
        elseif currentDirection == directions.X_NEG then
            turtle.turnLeft()
            currentDirection = directions.Z_POS
            return 1
        elseif currentDirection == directions.X_POS then
            turtle.turnRight()
            currentDirection = directions.Z_POS
            return 1
        end
    end
end

local function toX(destX)
    local currX, currY, currZ = location()
    local diffX = (destX - currX) * toAxis("x")
    if diffX >= 1 then
        -- We need to go up
        checkFuel(diffX)
        for i = 1, diffX do
            turtle.forward()
        end
    elseif diffX <= -1 then
        -- We need to go down
        checkFuel(math.abs(diffX))
        for i = -1, diffX, -1 do
            turtle.back()
        end
    end
end

local function toZ(destZ)
    local currX, currY, currZ = location()
    local diffZ = (destZ - currZ) * toAxis("z")
    if diffZ >= 1 then
        -- We need to go up
        checkFuel(diffZ)
        for i = 1, diffZ do
            turtle.forward()
        end
    elseif diffZ <= -1 then
        -- We need to go down
        checkFuel(math.abs(diffZ))
        for i = -1, diffZ, -1 do
            turtle.back()
        end
    end
end

local unsentScans = {}

local function sendScans()
    print("Sending " .. #unsentScans .. " scans...")
    modem.transmit(DAPPER_SCAN_DATA_CHANNEL, DAPPER_SCAN_ACKNOWLEDGE_CHANNEL, unsentScans)
    parallel.waitForAny(function()
        while #unsentScans > 0 do
            local event, side, senderChannel, replyChannel, message, distance = os.pullEvent("modem_message")
            if senderChannel == DAPPER_SCAN_ACKNOWLEDGE_CHANNEL and type(message) == "table" then
                for _, messageScan in ipairs(message) do
                    -- loop through all our unsent scans and remove any with the same coordinates
                    for i, scan in ipairs(unsentScans) do
                        if messageScan.x == scan.x and messageScan.z == scan.z then
                            unsentScans[i] = nil
                        end
                    end
                end
            end
        end
    end, function()
        sleep(1)
    end)
end

local function scanDown()
    local hit, block
    repeat
        checkFuel()
        turtle.down()
        hit, block = turtle.inspectDown()
    until hit
    local x, y, z = location()
    print("Found the block: " .. x .. ", " .. y .. ", " .. z)
    block.y = y
    table.insert(unsentScans, {x = x, z = z, block = block})
    sendScans()
end

local homeX, homeY, homeZ = location()
if turtle then
    print("Determining direction...")
    checkFuel()
    turtle.forward()
    local newX, newY, newZ = location()
    print(newX, newY, newZ)
    print(homeX, homeY, homeZ )
    turtle.back()
    if newX > homeX then
        currentDirection = directions.X_POS
    elseif newX < homeX then
        currentDirection = directions.X_NEG
    elseif newZ > homeZ then
        currentDirection = directions.Z_POS
    elseif newZ < homeZ then
        currentDirection = directions.Z_NEG
    else
        error("Failed to determine turtle direction (it probably couldn't move forward).", 0)
    end
end


local xStart, xStop = homeX - radius, homeX + radius
local zStart, zStop = homeZ - radius, homeZ + radius
if turtle then
    toY(yLimit)
    if not isFill then
        for x = xStart, xStop, 1 do
            toX(x)
            for z = zStart, zStop, 1 do
                toZ(z)
                scanDown()
                toY(yLimit)
            end
        end
    else
        local nextX, nextZ
        repeat
            print("Requesting next block...")
            modem.transmit(DAPPER_SCAN_NEXT_REQUEST_CHANNEL, DAPPER_SCAN_NEXT_REPLY_CHANNEL, {
                xStart = xStart,
                xStop = xStop,
                zStart = zStart,
                zStop = zStop,
            })
            parallel.waitForAny(function()
                while true do
                    local event, side, senderChannel, replyChannel, message, distance = os.pullEvent("modem_message")
                    if senderChannel == DAPPER_SCAN_NEXT_REPLY_CHANNEL and type(message) == "table" then
                        nextX = message.x
                        nextZ = message.z
                        break
                    end
                end
            end, function()
                sleep(5)
                print("Timeout, going home.")
                nextX, nextZ = nil, nil
            end)
            if nextX and nextZ then
                toX(nextX)
                toZ(nextZ)
                scanDown()
                toY(yLimit)
            end
        until not nextX or not nextZ
    end

    print("Scan complete, returning home.")
    toX(homeX)
    toZ(homeZ)
    toY(homeY)
else
    print("Scanning blocks...")
    local BLOCK_COUNT_LIMIT = 4096
    local xBlockCount, zBlockCount, yBlockCount = xStop - xStart + 1, zStop - zStart + 1, yLimit
    print("B count: " .. xBlockCount)
    local minSegmentCount = math.ceil((xBlockCount * zBlockCount * yBlockCount) / BLOCK_COUNT_LIMIT)
    local xSegmentSize = math.ceil(xBlockCount / math.sqrt(minSegmentCount))
    local xSegmentCount = math.ceil(xBlockCount / xSegmentSize)
    local zSegmentSize = math.floor(zBlockCount / math.ceil((minSegmentCount / xSegmentCount)))
    local zSegmentCount = math.ceil(zBlockCount / zSegmentSize)
    local totalSegmentCount = xSegmentCount * zSegmentCount
    local currentSegment = 1
    for xSegment = 0, xSegmentCount - 1 do
        local xSegmentStart = xStart + xSegment * xSegmentSize
        local xSegmentStop = math.min(xSegmentStart + xSegmentSize, xStop) - 1
        for zSegment = 0, zSegmentCount - 1 do
            local zSegmentStart = zStart + zSegment * zSegmentSize
            local zSegmentStop = math.min(zSegmentStart + zSegmentSize, zStop) - 1
            print("Scanning (" .. math.floor(100 * (currentSegment / totalSegmentCount) + 0.5) .. "%): X: " .. xSegmentStart .. ", Z: " .. zSegmentStart .. " - X:" .. xSegmentStop .. ", Z: " .. zSegmentStop)
            local xSize, zSize, ySize = xSegmentStop - xSegmentStart + 1, zSegmentStop - zSegmentStart + 1, yLimit
            local segmentBlocks = commands.getBlockInfos(xSegmentStart, 1, zSegmentStart, xSegmentStop, yLimit, zSegmentStop)
            for x = 1, xSize do
                for z = 0, zSize - 1 do
                    for y = yLimit - 1, 0, -1 do
                        local block = segmentBlocks[x + z * xSize + y * xSize * zSize]
                        if block.name ~= "minecraft:air" then
                            table.insert(unsentScans, {x = x + xSegmentStart - 1, z = z + zSegmentStart, block = block})
                            break
                        end
                    end
                end
            end
            currentSegment = currentSegment + 1
        end
    end
    print("Scan complete, sending scans...")
    sendScans()
    print("Complete!")
end