function steampunk_blimp.testDamage(self, velocity, position)
    if self._last_accell == nil then return end
    local p = position --self.object:get_pos()
    local collision = false
    local low_node_pos = -2.5
    if self._last_vel == nil then return end
    --lets calculate the vertical speed, to avoid the bug on colliding on floor with hard lag
    if math.abs(velocity.y - self._last_vel.y) > 2 then
		local noded = airutils.nodeatpos(airutils.pos_shift(p,{y=low_node_pos}))
	    if (noded and noded.drawtype ~= 'airlike') then
		    collision = true
	    else
            self.object:set_velocity(self._last_vel)
            --self.object:set_acceleration(self._last_accell)
            self.object:set_velocity(vector.add(velocity, vector.multiply(self._last_accell, self.dtime/8)))
        end
    end
    local impact = math.abs(steampunk_blimp.get_hipotenuse_value(velocity, self._last_vel))
    if impact > 2 then
        if self.colinfo then
            collision = self.colinfo.collides
            --minetest.chat_send_all(impact)
        end
    end

    if collision then
        --self.object:set_velocity({x=0,y=0,z=0})
        local damage = impact -- / 2
        minetest.sound_play("steampunk_blimp_collision", {
            --to_player = self.driver_name,
            object = self.object,
            max_hear_distance = 15,
            gain = 1.0,
            fade = 0.0,
            pitch = 1.0,
        }, true)
        if damage > 5 then
            self._power_lever = 0
        end

        if self.driver_name then
            local player_name = self.driver_name

            local player = minetest.get_player_by_name(player_name)
            if player then
		        if player:get_hp() > 0 then
			        player:set_hp(player:get_hp()-(damage/2))
		        end
            end
            if self._passenger ~= nil then
                local passenger = minetest.get_player_by_name(self._passenger)
                if passenger then
		            if passenger:get_hp() > 0 then
			            passenger:set_hp(passenger:get_hp()-(damage/2))
		            end
                end
            end
        end

    end
end

local function do_attach(self, player, slot)
    if slot == 0 then return end
    if self._passengers[slot] == nil then
        local name = player:get_player_name()
        --minetest.chat_send_all(self.driver_name)
        self._passengers[slot] = name
        player:set_attach(self._passengers_base[slot], "", {x = 0, y = 0, z = 0}, {x = 0, y = 0, z = 0})
        player_api.player_attached[name] = true
    end
end

function steampunk_blimp.check_passenger_is_attached(self, name)
    local is_attached = false
    if is_attached == false then
        for i = 5,1,-1 
        do 
            if self._passengers[i] == name then
                is_attached = true
                break
            end
        end
    end
    return is_attached
end

--this method checks each 1 second for a disconected player who comes back
function steampunk_blimp.rescueConnectionFailedPassengers(self)
    self._disconnection_check_time = self._disconnection_check_time + self.dtime
    if self._disconnection_check_time > 1 then
        --minetest.chat_send_all(dump(self._passengers))
        self._disconnection_check_time = 0
        for i = 5,1,-1 
        do 
            if self._passengers[i] then
                local player = minetest.get_player_by_name(self._passengers[i])
                if player then --we have a player!
                    if player_api.player_attached[self._passengers[i]] == nil then --but isn't attached?
                        --minetest.chat_send_all("okay")
		                if player:get_hp() > 0 then
                            self._passengers[i] = nil --clear the slot first
                            do_attach(self, player, i) --attach
                        else
                            --steampunk_blimp.dettachPlayer(self, player)
		                end
                    end
                end
            end
        end
    end
end

-- attach passenger
function steampunk_blimp.attach_pax(self, player, slot)
    slot = slot or 0

    --verify if is locked to non-owners
    if self._passengers_locked == true then
        local name = player:get_player_name()
        local can_bypass = minetest.check_player_privs(player, {protection_bypass=true})
        local is_shared = false
        if name == self.owner or can_bypass then is_shared = true end
        for k, v in pairs(self._shared_owners) do
            if v == name then
                is_shared = true
                break
            end
        end
        if is_shared == false then
            minetest.chat_send_player(name,core.colorize('#ff0000', " >>> This blimp is currently locked for non-owners"))
            return
        end
    end


    if slot > 0 then
        do_attach(self, player, slot)
        return
    end
    --minetest.chat_send_all(dump(self._passengers))

    --now yes, lets attach the player
    --randomize the seat
    local t = {1,2,3,4,5}
    for i = 1, #t*2 do
        local a = math.random(#t)
        local b = math.random(#t)
        t[a],t[b] = t[b],t[a]
    end

    --minetest.chat_send_all(dump(t))

    local i=0
    for k,v in ipairs(t) do
        i = t[k]
        if self._passengers[i] == nil then
            do_attach(self, player, i)
            break
        end
    end
end

function steampunk_blimp.dettach_pax(self, player, side)
    side = side or "r"
    if player then
        local name = player:get_player_name() --self._passenger
        steampunk_blimp.remove_hud(player)

        -- passenger clicked the object => driver gets off the vehicle
        for i = 5,1,-1 
        do 
            if self._passengers[i] == name then
                self._passengers[i] = nil
                self._passengers_base_pos[i] = steampunk_blimp.copy_vector(steampunk_blimp.passenger_pos[i])
                --break
            end
        end

        -- detach the player
        player:set_detach()
        player_api.player_attached[name] = nil
        player_api.set_animation(player, "stand")

        -- move player down
        minetest.after(0.1, function(pos)
            local rotation = self.object:get_rotation()
            local direction = rotation.y

            if side == "l" then
                direction = direction - math.rad(180)
            end

            local move = 5
            pos.x = pos.x + move * math.cos(direction)
            pos.z = pos.z + move * math.sin(direction)
            if self.isinliquid then
                pos.y = pos.y + 1
            else
                pos.y = pos.y - 2.5
            end
            player:set_pos(pos)
        end, player:get_pos())
    end
end

function steampunk_blimp.textures_copy()
    local tablecopy = {}
    for k, v in pairs(steampunk_blimp.textures) do
      tablecopy[k] = v
    end
    return tablecopy
end

local function paint(self)
    local l_textures = steampunk_blimp.textures_copy()
    for _, texture in ipairs(l_textures) do
        local indx = texture:find('wool_blue.png')
        if indx then
            l_textures[_] = "wool_".. self.color..".png"
        end
        indx = texture:find('wool_yellow.png')
        if indx then
            l_textures[_] = "wool_".. self.color2..".png"
        end
        indx = texture:find('steampunk_blimp_alpha_logo.png')
        if indx then
            l_textures[_] = self.logo
        end
    end
    self.object:set_properties({textures=l_textures})
end

function steampunk_blimp.set_logo(self, texture_name)
    if texture_name == "" or texture_name == nil then
        self.logo = "steampunk_blimp_alpha_logo.png"
    elseif texture_name then
        self.logo = texture_name
    end
    paint(self)
end

--painting
function steampunk_blimp.paint(self, colstr)
    if colstr then
        self.color = colstr
        paint(self)
    end
end
function steampunk_blimp.paint2(self, colstr)
    if colstr then
        self.color2 = colstr
        paint(self)
    end
end

-- destroy the boat
function steampunk_blimp.destroy(self, overload)
    if self.sound_handle then
        minetest.sound_stop(self.sound_handle)
        self.sound_handle = nil
    end

    local pos = self.object:get_pos()
    if self.fire then self.fire:remove() end
    if self._passengers_base[1] then self._passengers_base[1]:remove() end
    if self._passengers_base[2] then self._passengers_base[2]:remove() end
    if self._passengers_base[3] then self._passengers_base[3]:remove() end
    if self._passengers_base[4] then self._passengers_base[4]:remove() end
    if self._passengers_base[5] then self._passengers_base[5]:remove() end

    airutils.destroy_inventory(self)
    self.object:remove()

    pos.y=pos.y+2
    --[[for i=1,7 do
        minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'default:steel_ingot')
    end

    for i=1,7 do
        minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'default:mese_crystal')
    end]]--

    --minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'steampunk_blimp:boat')
    --minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'default:diamond')

    --[[local total_biofuel = math.floor(self._energy) - 1
    for i=0,total_biofuel do
        minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'biofuel:biofuel')
    end]]--
    if overload then
        local stack = ItemStack(self.item)
        local item_def = stack:get_definition()
        
        if item_def.overload_drop then
            for _,item in pairs(item_def.overload_drop) do
                minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},item)
            end
            return
        end
    end
    local stack = ItemStack(self.item)
    local item_def = stack:get_definition()
    if self.hull_integrity then
        local boat_wear = math.floor(65535*(1-(self.hull_integrity/item_def.hull_integrity)))
        stack:set_wear(boat_wear)
    end
    minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5}, stack)
end

--returns 0 for old, 1 for new
function steampunk_blimp.detect_player_api(player)
    local player_proterties = player:get_properties()
    local mesh = "character.b3d"
    if player_proterties.mesh == mesh then
        local models = player_api.registered_models
        local character = models[mesh]
        if character then
            if character.animations.sit.eye_height then
                return 1
            else
                return 0
            end
        end
    end

    return 0
end

function steampunk_blimp.checkAttach(self, player)
    local retVal = false
    if player then
        local player_attach = player:get_attach()
        if player_attach then
            for i = 5,1,-1 
            do 
                if player_attach == self._passengers_base[i] then
                    retVal = true
                    break
                end
            end
        end
    end
    return retVal
end

function steampunk_blimp.clamp(value, min, max)
    local retVal = value
    if value < min then retVal = min end
    if value > max then retVal = max end
    --minetest.chat_send_all(value .. " - " ..retVal)
    return retVal
end

function steampunk_blimp.reclamp(value, min, max)
    local retVal = value
    local mid = (max/min)/2
    if value > min and value <= mid then retVal = min end
    if value < max and value > mid then retVal = max end
    --minetest.chat_send_all(value .. " - " ..retVal)
    return retVal
end

function steampunk_blimp.engineSoundPlay(self)
    --sound
    if self.sound_handle then minetest.sound_stop(self.sound_handle) end
    if self.sound_handle_pistons then minetest.sound_stop(self.sound_handle_pistons) end
    if self.object then
        self.sound_handle = minetest.sound_play({name = "default_furnace_active"},
            {object = self.object, gain = 0.2,
                max_hear_distance = 5,
                loop = true,})

        self.sound_handle_pistons = minetest.sound_play({name = "default_cool_lava"},--"default_item_smoke"},
            {object = self.object, gain = 0.05,
                pitch = 0.4+((math.abs(self._power_lever)/100)/2),
                max_hear_distance = 32,
                loop = true,})
    end
end

function steampunk_blimp.engine_set_sound_and_animation(self)
    if self._last_applied_power ~= self._power_lever then
        --minetest.chat_send_all('test2')
        self._last_applied_power = self._power_lever
        self.object:set_animation_frame_speed(steampunk_blimp.iddle_rotation + (self._power_lever))
        if self._last_sound_update == nil then self._last_sound_update = self._power_lever end
        if math.abs(self._last_sound_update - self._power_lever) > 5 then
            self._last_sound_update = self._power_lever
            steampunk_blimp.engineSoundPlay(self)
        end
    end
    if self._engine_running == false then
        if self.sound_handle then
            minetest.sound_stop(self.sound_handle)
            self.sound_handle = nil
            --self.object:set_animation_frame_speed(0)
        end
    end
end


function steampunk_blimp.start_furnace(self)
    if self._engine_running then
	    self._engine_running = false
        -- sound and animation
        if self.sound_handle then
            minetest.sound_stop(self.sound_handle)
            self.sound_handle = nil
        end
    elseif self._engine_running == false and self._energy > 0 then
	    self._engine_running = true
        -- sound
        if self.sound_handle then minetest.sound_stop(self.sound_handle) end
        if self.object then
            self.sound_handle = minetest.sound_play({name = "default_furnace_active"},
                {object = self.object, gain = 0.2,
                    max_hear_distance = 5,
                    loop = true,})
        end
    end
end

function steampunk_blimp.boat_upper_deck_map(pos, dpos)
    local orig_pos = steampunk_blimp.copy_vector(pos)
    local position = steampunk_blimp.copy_vector(dpos)
    local new_pos = steampunk_blimp.copy_vector(dpos)
    
    new_pos.z = steampunk_blimp.clamp(new_pos.z, -47, -16)

    if position.z >= -49 and position.z < -32 then --limit 10
        new_pos.y = 20.821
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -8, 8)
        return new_pos
    end
    if position.z >= -32 and position.z < -14 then --limit 11
        new_pos.y = 20.821
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -11, 11)
        if position.z >= -28 then --timao
            if orig_pos.x <= -4 or orig_pos.x >= 4 then
                new_pos.x = steampunk_blimp.reclamp(new_pos.x, -4, 4)
            else
                new_pos.z = steampunk_blimp.reclamp(new_pos.z, -28, -20)
            end
        end
        if position.z > -24 then --escada
            if orig_pos.x <= 4 then
                new_pos.z = steampunk_blimp.reclamp(new_pos.z, -24, -12)
            end
        end
        return new_pos
    end
    return new_pos
end

function steampunk_blimp.boat_lower_deck_map(pos, dpos)
    local orig_pos = steampunk_blimp.copy_vector(pos)
    local position = steampunk_blimp.copy_vector(dpos)
    local new_pos = steampunk_blimp.copy_vector(dpos)
    new_pos.z = steampunk_blimp.clamp(new_pos.z, -29, 45)
    if position.z > -31 and position.z < -14 then --limit 10
        new_pos.y = 0
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -10, 10)
        return new_pos
    end
    if position.z >= -14 and position.z < -4 then --limit 11
        new_pos.y = 0
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -12, 12)
        if position.z > -9 then
            if orig_pos.x <= -6 or orig_pos.x >= 6 then
                new_pos.x = steampunk_blimp.reclamp(new_pos.x, -6, 6)
            else
                new_pos.z = steampunk_blimp.reclamp(new_pos.z, -9, -4)
            end
        end
        return new_pos
    end
    if position.z >= -4 and position.z <= 4 then --limit 14
        new_pos.y = 0
        new_pos.x = steampunk_blimp.clamp(position.x, -14, 14)
        if orig_pos.x <= -6 or orig_pos.x >= 6 then new_pos.x = steampunk_blimp.reclamp(new_pos.x, -6, 6) end
        return new_pos
    end
    if position.z > 4 and position.z <= 19 then --limit 11
        new_pos.y = 0
        new_pos.x = steampunk_blimp.clamp(position.x, -12, 12)
        if position.z < 14 then
            if orig_pos.x <= -6 or orig_pos.x >= 6 then
                new_pos.x = steampunk_blimp.reclamp(new_pos.x, -6, 6)
            else
                new_pos.z = steampunk_blimp.reclamp(new_pos.z, 4, 14)
            end
        end
        return new_pos
    end
    if position.z > 19 and position.z <= 22 then --limit 10
        new_pos.y = 4.4
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -10, 10)
        return new_pos
    end
    if position.z > 22 and position.z <= 30 then --limit 7
        new_pos.y = 8.5
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -7, 7)
        return new_pos
    end
    if position.z > 30 and position.z <= 36 then --limit 5
        new_pos.y = 8.5
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -5, 5)
        return new_pos
    end
    if position.z > 36 and position.z < 47 then --limit 1
        new_pos.y = 8.5
        new_pos.x = steampunk_blimp.clamp(new_pos.x, -2, 2)
        return new_pos
    end
    return new_pos
end

function steampunk_blimp.ladder_map(pos, dpos)
    local orig_pos = steampunk_blimp.copy_vector(pos)
    local position = steampunk_blimp.copy_vector(dpos)
    local new_pos = steampunk_blimp.copy_vector(dpos)
    new_pos.z = steampunk_blimp.clamp(new_pos.z, -18, -12)
    if position.z > -20 and position.z < -10 then --limit 10
        new_pos.x = steampunk_blimp.clamp(new_pos.x, 4, 12)
    end
    return new_pos
end

local function is_ladder_zone(pos)
    local ladder_zone = false
    if pos.z <= -12 and pos.z >= -18 and pos.x > 4 and pos.x < 12 then ladder_zone = true end
    return ladder_zone
end

function steampunk_blimp.play_rope_sound(self)
    minetest.sound_play({name = "steampunk_blimp_rope"},
                {object = self.object, gain = 1,
                    max_hear_distance = 5,
                    ephemeral = true,})
end

--note: index variable just for the walk
local function get_result_pos(self, player, index)
    local pos = nil
    if player then
        local direction = player:get_look_horizontal()
        local rotation = self.object:get_rotation()
        direction = direction - rotation.y
        local y_rot = -math.deg(direction)
        local ctrl = player:get_player_control()
        pos = vector.new()
        pos.y = y_rot --okay, this is strange to keep here, but as I dont use it anyway...
        if ctrl.up or ctrl.down or ctrl.left or ctrl.right then
            player_api.set_animation(player, "walk", 30)
            local dir = 0
            if ctrl.up then dir = -1 end
            if ctrl.down then dir = 1 end
            if ctrl.left then
                direction = direction - math.rad(90)
                dir = 1
            end
            if ctrl.right then
                direction = direction + math.rad(90)
                dir = 1
            end
            local time_correction = (self.dtime/steampunk_blimp.ideal_step)
            local move = 0.3 * dir * time_correction
            pos.x = move * math.cos(-direction)
            pos.z = move * math.sin(-direction)

            --lets fake walk sound
            if self._passengers_base_pos[index].dist_moved == nil then self._passengers_base_pos[index].dist_moved = 0 end
            self._passengers_base_pos[index].dist_moved = self._passengers_base_pos[index].dist_moved + move;
            if math.abs(self._passengers_base_pos[index].dist_moved) > 5 then
                self._passengers_base_pos[index].dist_moved = 0
                minetest.sound_play({name = "default_wood_footstep"},
                    {object = self._passengers_base_pos[index].object, gain = 0.1,
                        max_hear_distance = 5,
                        ephemeral = true,})
            end

            --[[
            sin(theta) = opposite/hypotenuse
            cos(theta) = adjacent/hypotenuse
            For X "Distance * COS ( Angle )"
            For Y "Distance * SIN ( Angle )"
            ]]--
        else
            player_api.set_animation(player, "stand")
        end
    end
    return pos
end

function steampunk_blimp.navigate_deck(pos, dpos, player)
    local pos_d = dpos
    local ladder_zone = is_ladder_zone(pos)
    local upper_deck_y = 20.821
    if player then
        if pos.y == upper_deck_y then
            pos_d = steampunk_blimp.boat_upper_deck_map(pos, dpos)
        elseif pos.y <= 8.5 and pos.y >= 0 then
            if ladder_zone == false then
                pos_d = steampunk_blimp.boat_lower_deck_map(pos, dpos)
            end
        elseif pos.y > 8.5 and pos.y < upper_deck_y then
            pos_d = steampunk_blimp.ladder_map(pos, dpos)
        end

        local ctrl = player:get_player_control()
        if ctrl.jump or ctrl.sneak then --ladder
            if ladder_zone then
                --minetest.chat_send_all(dump(pos))
                if ctrl.jump then
                    pos_d.y = pos_d.y + 0.9
                    if pos_d.y > upper_deck_y then pos_d.y = upper_deck_y end
                end
                if ctrl.sneak then
                    pos_d.y = pos_d.y - 0.9
                    if pos_d.y < 0 then pos_d.y = 0 end
                end
            end
        end
    end

    return pos_d
end

function steampunk_blimp.move_persons(self)
    --self._passenger = nil
    if self.object == nil then return end
    for i = 5,1,-1 
    do
        local player = nil
        if self._passengers[i] then player = minetest.get_player_by_name(self._passengers[i]) end

        if self.driver_name and self._passengers[i] == self.driver_name then
            --clean driver if it's nil
            if player == nil then
                self._passengers[i] = nil
                self.driver_name = nil
            end
        else
            if self._passengers[i] ~= nil then
                --minetest.chat_send_all("pass: "..dump(self._passengers[i]))
                --the rest of the passengers
                if player then
                    local result_pos = get_result_pos(self, player, i)
                    local y_rot = 0
                    if result_pos then
                        y_rot = result_pos.y -- the only field that returns a rotation
                        local new_pos = steampunk_blimp.copy_vector(self._passengers_base_pos[i])
                        new_pos.x = new_pos.x - result_pos.z
                        new_pos.z = new_pos.z - result_pos.x
                        --minetest.chat_send_all(dump(new_pos))
                        --local pos_d = steampunk_blimp.boat_lower_deck_map(self._passengers_base_pos[i], new_pos)
                        local pos_d = steampunk_blimp.navigate_deck(self._passengers_base_pos[i], new_pos, player)
                        --minetest.chat_send_all(dump(height))
                        self._passengers_base_pos[i] = steampunk_blimp.copy_vector(pos_d)
                        self._passengers_base[i]:set_attach(self.object,'',self._passengers_base_pos[i],{x=0,y=0,z=0})
                    end
                    --minetest.chat_send_all(dump(self._passengers_base_pos[i]))
                    player:set_attach(self._passengers_base[i], "", {x = 0, y = 0, z = 0}, {x = 0, y = y_rot, z = 0})
                else
                    --self._passengers[i] = nil
                end
            end
        end
    end
end

function steampunk_blimp.copy_vector(original_vector)
    local tablecopy = {}
    for k, v in pairs(original_vector) do
      tablecopy[k] = v
    end
    return tablecopy
end