【后端接口】暗器系统：投掷道具与弹药消耗

---投掷暗器：弹药校验与伤害结算
function Throwing.attack(actor, targetId)
    local player = class(actor)
    if not player then return false end
    local ammo = tonumber(getplayvar(actor, 2, "Ammo")) or 0
    if ammo <= 0 then
        sendmsg(actor, 1, "飞刀已用尽，请补充弹药")
        return false
    end
    -- 距离校验：飞刀射程 7 格
    if not Throwing.inRange(actor, targetId, 7) then
        sendmsg(actor, 1, "目标超出射程")
        return false
    end
    setplayvar(actor, "HUMAN", "Ammo", ammo - 1, 0)
    local dmg = math.floor(Throwing.base(actor) *
        (0.8 + math.random() * 0.4))
    throwitem(actor, targetId, dmg)
    -- 30% 概率淬毒：附加 5 秒毒伤
    if math.random(1, 100) <= 30 then
        makeposion(targetId, 1, 5, 20, 0)
    end
    return true
end

---弹药的购买与容量
function Throwing.buyAmmo(actor, count)
    local player = class(actor)
    if not player then return false end
    local ammo = tonumber(getplayvar(actor, 2, "Ammo")) or 0
    if ammo + count > 999 then
        sendmsg(actor, 1, "携带上限 999 把")
        return false
    end
    local cost = count * 50
    if not checkitemw(actor, "金币", cost) then
        sendmsg(actor, 1, "金币不足，需 " .. cost)
        return false
    end
    takeitem(actor, "金币", cost, 0, "购买飞刀")
    setplayvar(actor, "HUMAN", "Ammo", ammo + count, 1)
    sendmsg(actor, 1, "购入飞刀 x" .. count)
    return true
end