【Lua实战】权重轮盘：动态权重的原地缩减抽取

local WHEEL = {
    { name = "金币50000",    w = 300, gold = 50000 },
    { name = "强化石",       w = 250, item = "强化石",   cnt = 2 },
    { name = "祝福油",       w = 200, item = "祝福油",   cnt = 1 },
    { name = "裁决之杖碎片", w = 40,  item = "裁决之杖碎片", cnt = 1 },
}
local function draw()
    local sum = 0
    for _, s in ipairs(WHEEL) do sum = sum + s.w end
    local r = math.random(1, sum)
    for _, s in ipairs(WHEEL) do
        r = r - s.w
        if r <= 0 then return s end
    end
    return WHEEL[1]
end

local function shift()
    for _, s in ipairs(WHEEL) do
        if s.item == "裁决之杖碎片" then
            s.w = math.min(500, s.w + 30)
        elseif s.w > 50 then
            s.w = s.w - 10
        end
    end
end
function spin(actor)
    if not checkitemw(actor, "金盒钥匙", 1) then
        sendmsg(actor, 0, "需要金盒钥匙一把")
        return
    end
    takeitem(actor, "金盒钥匙", 1)
    local cnt = tonumber(getplayvar(actor, "HUMAN", "SPIN_CNT") or "0") + 1
    local s = draw()
    if cnt >= 60 then
        for _, x in ipairs(WHEEL) do
            if x.item == "裁决之杖碎片" then s = x end
        end
        cnt = 0
    end
    setplayvar(actor, "HUMAN", "SPIN_CNT", cnt, 1)
    if s.gold then giveitem(actor, "金币", s.gold) end
    if s.item then giveitem(actor, s.item, s.cnt or 1) end
    shift()
    sendmsg(actor, 0, "抽中：" .. s.name .. "，距保底还剩 " .. (60 - cnt) .. " 次")
end