local robot = require('robot')
local nav = require('nav')
local io = require('io')

local filename = ...

if not filename then
    print('Usage: build_circle <filename>')
    print('The robot starts in the center')
    return 1
end


local file = io.open(filename, 'r')

if not file then
    print('File not found')
    return 2
end

local radius = tonumber(file:read("*l"))

if not radius then
    print('Requires radius on the first line')
    return 3
end

local rings = {}

-- parse file:
for line in file:lines() do
    local ring = {}
    for c in string.gmatch(line, ".") do
        local n = tonumber(c)
        if c == 'X' then
            ring[#ring + 1] = c
        elseif n then
            ring[#ring + 1] = n
        else
            print('Invalid sequence: ' .. c)
            return 4
        end
    end
    rings[#rings + 1] = ring
end

file:close()

local inverted = false

robot.select(1)
local inventorySize = robot.inventorySize()

-- build:
nav.forward(radius)
robot.turnRight()
for _, ring in ipairs(rings) do
    for _ = 1, 4 do
        inverted = false
        for i, n in ipairs(ring) do
            if n == 'X' then
                robot.turnRight()
                inverted = true
            else
                -- place sequence
                for _ = 1, n do
                    robot.placeDown()
                    if robot.count() == 0 then
                        local current_slot = robot.select()
                        if current_slot == inventorySize then
                            print('Waiting for more materials')
                            local _ = io.read()
                            robot.select(1)
                        else
                            robot.select(current_slot + 1) -- select the next item slot
                            if robot.count() == 0 then
                                print('Waiting for more materials')
                                local _ = io.read()
                            end
                        end
                    end
                    nav.forward()
                end

                if i ~= #ring then
                    -- step level
                    if not inverted then
                        robot.turnRight()
                        nav.forward()
                        robot.turnLeft()
                    else
                        robot.turnLeft()
                        nav.forward()
                        robot.turnRight()
                    end
                end
            end
        end
    end
    robot.turnLeft()
    nav.forward()
    robot.turnRight()
end

robot.turnRight()
nav.forward(radius + #rings)
robot.turnAround()