【后端接口】任务对话分支：前置条件校验与选项跳转的接口

local DIALOG = {
    { text = "接取屠夫委托", cond = { { "level", 25 }, { "item", "野牛肉", 0 } }, next = 101 },
    { text = "打听野人线索", cond = { { "level", 25 } }, next = 102 },
    { text = "兑换战利品",   cond = { { "item", "野牛肉", 10 } }, next = 103 },
}
local function checkCond(actor, cond)
    local player = class(actor)
    for _, c in ipairs(cond) do
        if c[1] == "level" and getbaseinfo(actor, 6) < c[2] then
            return false
        end
        if c[1] == "item" and c[3] > 0 and player:checkitemw(c[2], c[3]) == false then
            return false
        end
    end
    return true
end

function onPickOption(actor, idx)
    local opt = DIALOG[idx]
    if opt == nil or not checkCond(actor, opt.cond) then
        sendmsg(actor, 0, "暂时无法选择该项")
        return
    end
    local c = opt.cond[2]
    if c ~= nil and c[1] == "item" and c[3] > 0 then
        class(actor):takeitem(c[2], c[3])
    end
    setplayvar(actor, "HUMAN", "QUEST_NODE", opt.next, 1)
    sendmsg(actor, 0, "任务推进到节点" .. opt.next)
end