mine_client

SERVER_ID = 0

FUEL_COUNT = -1
FUEL_INDEX = -1
ACCEPTABLE_FUEL = {"minecraft:coal"}

BLOCK_COUNT = -1
BLOCK_INDEX = -1
BUILDING_BLOCKS = {"minecraft:cobblestone", "minecraft:dirt", "minecraft:andesite", "minecraft:granite", "minecraft:diorite", "minecraft:cobbled_deepslate", "minecraft:tuff"}

function arrHasValue(arr, val)
    for index, value in ipairs(arr) do
        if value == val then
            return true
        end
    end

    return false
end

function hasFuel()
    if FUEL_INDEX == -1 then
        for i=1, 16 do
            turtle.select(i)

            local slotData = turtle.getItemDetail()

            if slotData ~= nil then
                if arrHasValue(ACCEPTABLE_FUEL, slotData["name"]) == true then
                    FUEL_INDEX = i
                    FUEL_COUNT = slotData["count"]
                    break
                end
            end
        end
    end

    return FUEL_COUNT > 0
end

function shouldRefuel()
    return turtle.getFuelLevel() <= 0
end

function refuel()
    turtle.select(FUEL_INDEX)
    turtle.refuel(1)
    FUEL_COUNT = FUEL_COUNT - 1
end

function getBlockIndex()
    if BLOCK_COUNT == 0 then
        BLOCK_INDEX = -1
    end

    if BLOCK_INDEX == -1 then
        for i=1, 16 do
            turtle.select(i)

            local slotData = turtle.getItemDetail()

            if slotData ~= nil then
                if arrHasValue(BUILDING_BLOCKS, slotData["name"]) == true then
                    BLOCK_INDEX = i
                    BLOCK_COUNT = slotData["count"]
                    break
                end
            end
        end
    end

    return BLOCK_INDEX
end

function dumpDown()
    for i=1, 16 do
        turtle.select(i)
        local slotData = turtle.getItemDetail()

        if slotData ~= nil then
            if arrHasValue(ACCEPTABLE_FUEL, slotData["name"]) == false then
                turtle.dropDown(slotData["count"])
            end
        end
    end
end

-- +x -> east
-- -x -> west
-- -z -> north
-- +z -> south
function getFacingDirection(x, z, prevX, prevZ)
    if x < prevX then
        return "west"
    elseif x > prevX then
        return "east"
    end

    if z < prevZ then
        return "north"
    elseif z > prevZ then
        return "south"
    end
end

-- +x -> east = 0
-- -z -> north = 1
-- -x -> west = 2
-- +z -> south = 3
function rotateToFace(currentFacing, target)
    local turning = {
        east = 0,
        north = 1,
        west = 2,
        south = 3
    }

    if currentFacing == target then
        return
    end

    local currFacingVal = turning[currentFacing]
    local targFacingVal = turning[target]
    local offset = targFacingVal - currFacingVal

    if offset < 0 then
        offset = offset + 3
    end

    local moveFacing = currentFacing
    for i=0, offset do
        moveFacing = left(moveFacing)
    end
end

-- +x -> east
-- -x -> west
-- -z -> north
-- +z -> south
function incrementByFacing(facing, x, z, increment)
    if facing == "west" then
        return (x - increment), z
    elseif facing == "east" then
        return (x + increment), z
    elseif facing == "north" then
        return x, (z - increment)
    elseif facing == "south" then
        return x, (z + increment)
    end
end

function left(facing)
    turtle.turnLeft()
    if facing == "west" then
        return "south"
    elseif facing == "east" then
        return "north"
    elseif facing == "north" then
        return "west"
    elseif facing == "south" then
        return "east"
    end
end

function right(facing)
    turtle.turnRight()
    if facing == "west" then
        return "north"
    elseif facing == "east" then
        return "south"
    elseif facing == "north" then
        return "east"
    elseif facing == "south" then
        return "west"
    end
end

function moveToward(x, z, facing)
    local currX, currY, currZ = gps.locate()

    -- Change facing direction if we need to
    local newFacing = facing
    if currX < x then
        rotateToFace(facing, "east")
        newFacing = "east"
    elseif currX > x then
        rotateToFace(facing, "west")
        newFacing = "west"
    else
        if currZ < z then
            rotateToFace(facing, "south")
            newFacing = "south"
        elseif currZ > z then
            rotateToFace(facing, "north")
            newFacing = "north"
        end
    end

    -- Dig the block in front
    if turtle.detect() == true then
        turtle.dig()
    end

    -- Move forward
    turtle.forward()

    -- If there is no block below, place one if possible
    if turtle.detectDown() == false then
        local blockIndex = getBlockIndex()
        if blockIndex ~= -1 then
            turtle.select(blockIndex)
            turtle.placeDown()
        end
    end

    -- Dig the block above
    if turtle.detectUp() == true then
        turtle.digUp()
    end

    return newFacing
end

function moveBackTo(x, z, facing)
    local currX, currY, currZ = gps.locate()

    local newFacing = facing
    if currZ < z then
        rotateToFace(facing, "south")
        newFacing = "south"
    elseif currZ > z then
        rotateToFace(facing, "north")
        newFacing = "north"
    else
        if currX < x then
            rotateToFace(facing, "east")
            newFacing = "east"
        elseif currX > x then
            rotateToFace(facing, "west")
            newFacing = "west"
        end
    end

    local success = turtle.forward()
    if success == false then
        return ""
    end

    -- Pick up any blocks that may have dropped on the ground (e.g. gravel)
    turtle.suck()

    return newFacing
end

function reachedTarget(x, z, targetX, targetZ)
    return x == targetX and z == targetZ
end

function loop(targetX, targetZ, facing)
    if shouldRefuel() == true then
        if hasFuel() == true then
            refuel()
        else
            print("Not enough fuel!")
            rednet.send(SERVER_ID, "out_of_fuel", "minenettoserver")
            return ""
        end
    end

    return moveToward(targetX, targetZ, facing)
end

function returnTo(targetX, targetZ, facing)
    if shouldRefuel() == true then
        if hasFuel() == true then
            refuel()
        else
            print("Not enough fuel!")
            rednet.send(SERVER_ID, "out_of_fuel", "minenettoserver")
            return ""
        end
    end

    return moveBackTo(targetX, targetZ, facing)
end

function prepare()
    print("Connecting...")
    rednet.broadcast("turtle", "minenettoserver")

    local id, message = rednet.receive("minenettoclient")
    SERVER_ID = id

    print("Connected!")

    local id, distance = rednet.receive("minenettoclient")

    if shouldRefuel() == true then
        if hasFuel() == true then
            refuel()
        else
            print("Not enough fuel!")
            rednet.send(SERVER_ID, "out_of_fuel", "minenettoserver")
            return nil
        end
    end

    return distance
end

function main()
    rednet.open("left")
    if rednet.isOpen("left") ~= true then
        print("Failed to start modem!")
        return
    end

    local distance = prepare()

    if distance ~= nil then
        local currentX, currentY, currentZ = gps.locate()
        local startX, startZ = currentX, currentZ

        if turtle.detect() == true then
            turtle.dig()
        end

        turtle.forward()
        local nextX, nextY, nextZ = gps.locate()
        turtle.back()

        if turtle.detectUp() == true then
            turtle.digUp()
        end

        local facing = getFacingDirection(nextX, nextZ, currentX, currentZ)
        local targetX, targetZ = incrementByFacing(facing, currentX, currentZ, distance)

        print("Heading to target: " .. targetX .. ", " .. targetZ)

        while reachedTarget(currentX, currentZ, targetX, targetZ) ~= true do
            facing = loop(targetX, targetZ, facing)
            currentX, currentY, currentZ = gps.locate()

            if facing == "" then
                break
            end
        end

        rednet.send(SERVER_ID, "returning", "minenettoserver")

        while reachedTarget(currentX, currentZ, startX, startZ) ~= true do
            facing = returnTo(startX, startZ, facing)
            currentX, currentY, currentZ = gps.locate()

            if facing == "" then
                break
            end
        end

        rednet.send(SERVER_ID, "returned", "minenettoserver")

        while reachedTarget(currentX, currentZ, startX, startZ) ~= true do
            facing = returnTo(startX, startZ, facing)
            currentX, currentY, currentZ = gps.locate()

            if facing == "" then
                break
            end
        end

        dumpDown()
        left(facing)
        left(facing)
        rednet.send(SERVER_ID, "dumped", "minenettoserver")
    end

    rednet.close("left")
end

main()