-- OPTIONS
-- Dont set this to 0
-- Visibility will be reduce by this value each update
visibility_reduce_coefficient = 0.02

-- Visibility will start to reduce after this amount of updates
-- Each update is 200ms
visibility_reduce_tick_threshold = 6

-- Smoke field registry
smoke_fields = {}
function spawn_smoke_field(pos, radius, lifetime)
    local f = SmokeField(pos, radius, lifetime)
    smoke_fields[#smoke_fields + 1] = f
    return f
end
function update_smoke_fields()
    local tg = time_global()
    for i = #smoke_fields, 1, -1 do
        local f = smoke_fields[i]
        if tg > f:getEndTime() then
            table.remove(smoke_fields, i)
            printf("%s: SmokeField destroy", f.init_time)
        end
    end
end

-- Smoke field class
class "SmokeField"
function SmokeField:__init(pos, radius, lifetime)
    self.position = vector():set(pos)
    self.radius = radius
    self.lifetime = lifetime
    self.init_time = time_global()

    -- Adjust position by radius up
    self.position.y = self.position.y + 1

    printf("%s: SmokeField spawn", self.init_time)
end

function SmokeField:getEndTime()
    return self.init_time + self.lifetime * 1000
end

function bind(obj)
    obj:bind_object(smoke_grenade_binder(obj))
end

class "smoke_grenade_binder" (object_binder)

function smoke_grenade_binder:__init(obj) super(obj)
    self.sec = self.object:section()

    -- Flag of fused
    self.fused = false
    self.time_event_done = false

    -- Get fuse time
    self.fuse_time = SYS_GetParam(2, self.sec, "destroy_time", 0) / 1000

    -- Smoke params
    self.smoke_radius = SYS_GetParam(2, self.sec, "smoke_radius", 0)
    self.smoke_lifetime = SYS_GetParam(2, self.sec, "smoke_lifetime", 0)

    -- Fastcall to collision detection check
    self.object:set_fastcall(self.fastcall, self)
end

function smoke_grenade_binder:fastcall()
    local obj = self.object
    local id = obj:id()

    -- If object is in someone hands, dont check it
    if obj:parent() then
        if self.position then
            self.position = nil
        end
        self.fused = nil
        return
    end

    if self.fused == nil then
        printf("%s: check for fuse", obj:name())
        self.fused = not alife_object(obj:id())
    end

    if not self.fused then
        return
    end
    
    self.position = obj:position()
    if not self.time_event_done then
        self.time_event_done = true
        printf("%s: fused %s", obj:name(), self.fused)
        CreateTimeEvent(obj:name(), "spawn_smoke_field", self.fuse_time, function()
            printf("%s: spawn smoke field at %s", obj:name(), self.position)
            spawn_smoke_field(self.position, self.smoke_radius, self.smoke_lifetime)
            return true
        end)
    end
end

function actor_on_first_update()
    AddUniqueCall(update_smoke_fields)
end

function on_game_start()
    RegisterScriptCallback("actor_on_first_update", actor_on_first_update)
end

function get_npc_pos(npc)
    return utils_obj.safe_bone_pos(npc, "bip01_spine") or npc:position():add(vector():set(0, 0.4, 0))
end

if AddScriptCallback then
    AddScriptCallback("npc_behind_smoke")
end

function is_smoke_field_between_npcs(field, npc, who)
    -- Check if field is between npcs
    local npc_pos = get_npc_pos(npc)
    local who_pos = get_npc_pos(who)
    local field_to_npc = vector():set(field.position):sub(npc_pos)
    local field_to_who = vector():set(field.position):sub(who_pos)

    if field_to_npc:dotproduct(field_to_who) > 0 then
        -- Vectors are in the same direction, field is not in between
        -- printf("check %s against %s, field is not in between", npc:name(), who:name())
        return false
    end

    -- Construct invisibility cone
    local apex = npc_pos
    local pos = vector():set(who_pos):sub(apex):normalize()
    local axis_direction = vector():set(field_to_npc):normalize()
    local dot = pos:dotproduct(axis_direction)
    local cos_half_angle
    do
        local height = apex:distance_to(field.position)
        local half_angle = math.atan(field.radius / height)
        cos_half_angle = math.cos(half_angle)
    end

    -- Check if inside invisibility cone
    local res = dot >= cos_half_angle

    -- Visualize
    -- local function lerpVec(v1, v2, f)
    --     return vector():lerp(v1, v2, f)
    -- end
    -- local t = {}
    -- t[1] = vector_rotate_y(axis_direction, 90)
    -- t[2] = vector():set(t[1]):invert()
    -- t[3] = vector():crossproduct(axis_direction, t[1])
    -- t[4] = vector():set(t[3]):invert()
    -- t[5] = lerpVec(t[1], t[3], 0.5)
    -- t[6] = vector():set(t[5]):invert()
    -- t[7] = lerpVec(t[2], t[3], 0.5)
    -- t[8] = vector():set(t[7]):invert()
    -- for i, v in ipairs(t) do
    --     local v1 = vector():mad(field.position, v, field.radius)
    --     demonized_geometry_ray.VisualizeRay(
    --         npc_pos,
    --         vector():mad(npc_pos, vector():set(v1):sub(npc_pos):normalize(), vector():set(v1):sub(npc_pos):magnitude() + 10),
    --         nil,
    --         199
    --     )
    -- end
    -- if res then
        -- print_tip("check %s against %s, %s is in invisibility cone", npc:name(), who:name(), who:name())
    -- end
    
    return res
end

function IsValidMonster(o)
    local c = o:clsid()
    return c == clsid.burer
    or c == clsid.burer_s
    or c == clsid.controller
    or c == clsid.controller_s
end

local vis_decrease_ticks = {}
get_visible_value = visual_memory_manager.get_visible_value
visual_memory_manager.get_visible_value = function(npc,who,time_delta,time_quant,luminocity,velocity_factor,velocity,distance,object_distance,always_visible_distance)
    local res = get_visible_value(npc,who,time_delta,time_quant,luminocity,velocity_factor,velocity,distance,object_distance,always_visible_distance)
    if #smoke_fields > 0
    and npc
    and who
    and (IsStalker(npc) or IsValidMonster(npc))
    and (who:id() == AC_ID or IsStalker(who) or IsMonster(who))
    then
        local under_field = false
        for i = 1, #smoke_fields do
            local f = smoke_fields[i]
            if is_smoke_field_between_npcs(f, npc, who) then
                under_field = true

                -- Add an update threshold
                local npc_name = npc:name()
                local who_name = who:name()
                vis_decrease_ticks[npc_name] = vis_decrease_ticks[npc_name] or {}
                vis_decrease_ticks[npc_name][who_name] = (vis_decrease_ticks[npc_name][who_name] or 0) + 1
                if vis_decrease_ticks[npc_name][who_name] >= visibility_reduce_tick_threshold then
                    -- print_tip("check %s against %s, %s is in invisibility cone, start reducing visibility %s/%s", npc:name(), who:name(), who:name(), vis_decrease_ticks[npc_name][who_name], visibility_reduce_tick_threshold)
                    res = -visibility_reduce_coefficient
                else
                    -- print_tip("check %s against %s, %s is in invisibility cone, under threshold %s/%s", npc:name(), who:name(), who:name(), vis_decrease_ticks[npc_name][who_name], visibility_reduce_tick_threshold)
                end

                -- Send callback
                -- Npc is the one who tries to see enemy behind smoke
                -- Who is the enemy behind smoke
                if AddScriptCallback then 
                    SendScriptCallback("npc_behind_smoke", npc, who)
                end
            end
        end
        if not under_field then
            vis_decrease_ticks[npc:name()] = vis_decrease_ticks[npc:name()] or {}
            vis_decrease_ticks[npc:name()][who:name()] = 0
        end
    elseif npc and who then
        vis_decrease_ticks[npc:name()] = vis_decrease_ticks[npc:name()] or {}
        vis_decrease_ticks[npc:name()][who:name()] = 0
    end
    return res
end