Move

--[[
***********
 * prototype::move
 *
 * This is a prototype file for turtle's moving.
 *
 * generally, call this by dofile()
 * and use it in a basic object-based coding of lua.
 *
**********
]]



----------
-- a frame of the prototype
----------
Move = {}


----------
-- constructer
----------
function Move.new()
    -- create position file if it doesn't exists.
    if fs.exists("position") == false then
        local h = fs.open("position", "w")
        h.writeLine("position = {0,0,0,0}")

        h.flush()
        h.close()
    end

    -- get position data.
    dofile("position")

    local cords = {}
    cords[1] = position[1]  -- x
    cords[2] = position[2]  -- y
    cords[3] = position[3]  -- z
    cords[4] = position[4]  -- front. 1 is +z.

    local obj = {cords = cords}

    -- set metatable.
    return setmetatable(obj, {__index = Move})
end


----------
-- methods for moving.
----------
function Move:turnLeft()
    self.cords[4] = (self.cords[4] - 1) % 4
    self:save()

    if turtle.turnLeft() == false then
        self.cords[4] = (self.cords[4] + 1) % 4
        self:save()

        return false
    else
        return true
    end
end


function Move:turnRight()
    self.cords[4] = (self.cords[4] + 1) % 4
    self:save()

    if turtle.turnRight() == false then
        self.cords[4] = (self.cords[4] - 1) % 4
        self:save()

        return false
    else
        return true
    end
end


function Move:forward()
    if turtle.detect() == false then
        local sign, way = self:getFacingDir()

        local time = 1
        local flag = false
        while time < 11 do
            self.cords[way] = self.cords[way] + sign
            self:save()

            flag = turtle.forward()
            if flag == true then
                break
            elseif
                self.cords[way] = self.cords[way] - sign
                self:save()
            end
            time = time + 1
        end

        if flag == true then
            return true
        else
            return false
        end
    else
        return false
    end
end


-- always return true unless there are no mobs in facing direction
-- because turtle can't use detectBack().
-- so, be careful for using this method!
function Move:back()
    local sign, way = self:getFacingDir()

    local time = 1
    local flag = false
    while time < 11 do
        self.cords[way] = self.cords[way] - sign
        self:save()

        flag = turtle.back()
        if flag == true then
            break
        elseif
            self.cords[way] = self.cords[way] + sign
            self:save()
        end
        time = time + 1
    end

    if flag == true then
        return true
    else
        return false
    end
end


function Move:up()
    if turtle.detectUp() == false then
        local time = 1
        local flag = false

        while time < 11 do
            self.cords[2] = (self.cords[2] + 1)
            self:save()

            flag = turtle.up()
            if flag == true then
                break
            elseif
                self.cords[2] = (self.cords[2] - 1)
                self:save()
            end
            time = time + 1
        end

        if flag == true then
            return true
        else
            return false
        end
    else
        return false
    end
end


function Move:down()
    if turtle.detectDown() == false then
        local time = 1
        local flag = false

        while time < 11 do
            self.cords[2] = (self.cords[2] - 1)
            self:save()

            flag = turtle.down()
            if flag == true then
                break
            elseif
                self.cords[2] = (self.cords[2] + 1)
                self:save()
            end
            time = time + 1
        end

        if flag == true then
            return true
        else
            return false
        end
    else
        return false
    end
end


----------
-- method for saving positions
----------
function Move:getFacingDir()
    local sign = 1
    if self.cords[4] > 1
        sign = -1
    end

    local way = 1
    if self.cords[4] % 2 == 0
        way = 3
    end

    return sign, way
end


----------
-- method for rotation.
----------
function Move:rotate(direction)
    if (self.cords[4] - direction) ~= 1 then
        while self.cords[4] ~= direction do
            self:turnRight()
        end
    else
        while self.cords[4] ~= direction do
            self:turnLeft()
        end
    end
end


----------
-- method for saving positions
----------
function Move:save()
    local new_line = "position = {"..table.concat(self.cords, ",").."}"
    local new = fs.open("position", "w")
    new.writeLine(new_line)
    new.flush()
    new.close()
end


----------
-- method for getting distances.
----------
function Move:getDistances(x, y, z)
    local dist_x = x - self.cords[1]
    local dist_y = y - self.cords[2]
    local dist_z = z - self.cords[3]
    return dist_x, dist_y, dist_z
end



--[[
**********
 * end of the file
**********
]]