local FVector = import "Vector"
local Vector2D = require("Utils.Vector2D")
local Library = import "BusyGamePlayLibrary"
local GameplayStatics = import("GameplayStatics")

local SubSystem = {}

local function GetNearestBonfire(system, x, y)
    local selected_bonfire = nil
    local selected_distance = nil

    for _, bonfire in ipairs(system.bonfire_list) do
        local pos = bonfire:K2_GetActorLocation()
        local distance = (x - pos.X) ^ 2 + (y - pos.Y) ^ 2
        if selected_distance == nil or distance < selected_distance then
            selected_distance = distance
            selected_bonfire = bonfire
        end
    end
    return selected_bonfire
end

function SubSystem:ctor()
    self.current_role = nil
    self.bonfire_list = {}      -- 所有的篝火列表
end

function SubSystem:ReceiveSubSystemInitialize()
    self.current_role = nil
    self.bonfire_list = {}
end

function SubSystem:GetNearestBonfire()
    if self.current_role then
        local cur_pos = self.current_role:K2_GetActorLocation()
        return GetNearestBonfire(self, cur_pos.X, cur_pos.Y)
    end
    return nil
end

function SubSystem:SpawnBonfire(position)
    local pos = FVector()
    local world = self:K2_GetWorld()
    local cls = Library.GetGameClass("Bonfire")
    pos.X, pos.Y, pos.Z = position.X, position.Y, 20
    local bonfire = world:SpawnActor(cls, pos, nil, nil)
    table.insert(self.bonfire_list, bonfire)
    return bonfire
end

function SubSystem:SpawnRole(bonfire)
    local role_pos = FVector()
    local world = self:K2_GetWorld()
    local pos = bonfire:K2_GetActorLocation()
    local cls = Library.GetGameClass("BusyRole")
    role_pos.X, role_pos.Y, role_pos.Z = pos.X, pos.Y, pos.Z + 10
    self.current_role = world:SpawnActor(cls, role_pos, nil, nil)
    if self.current_role ~= nil then
        self.current_role:SetRole("Rabbit")
        return self.current_role
    else
        return nil
    end
end

function SubSystem:SpawnLevelItem(item_id)
    -- 随机在角色周围生成

    local distance = math.random(128, 500)
    local angle = (math.random(0, 360) / 360) * 2 * 3.14;

    local world = self:K2_GetWorld()
    local item_position = FVector()
    local center = self.current_role:K2_GetActorLocation()
    local cls = import("BusyLevelItem")

    item_position.Z = center.Z - 1
    item_position.X = center.X + math.cos(angle) * distance
    item_position.Y = center.Y + math.sin(angle) * distance

    local item = world:SpawnActor(cls, item_position, nil, nil)
    item:SetLevelItemID(item_id)
    return center
end

function SubSystem:SpawnLevelItemReward(level_item)
    assert(self.current_role ~= nil)

    local world = self:K2_GetWorld()
    local cls = Library.GetGameClass("LevelItemReward")

    local random_angle = (math.random() - 0.5) * (math.pi / 2)
    local direction = Vector2D.Normalize(self.current_role:GetMoveDirection())

    local sin, cos = math.sin(random_angle), math.cos(random_angle)

    -- 应用旋转矩阵
    direction.X = direction.X * cos - direction.Y * sin
    direction.Y = direction.X * sin + direction.Y * cos

    local item_location = level_item:K2_GetActorLocation()

    local reward_location = Vector2D.Add(item_location, Vector2D.Mul(direction, 200))

    local item = world:SpawnActor(cls,
        Vector2D.ToUnrealEngine3D(reward_location, item_location.Z),
        nil, nil
    )
    return item
end

return Class(nil, nil, SubSystem)