Aegisub Lua 自动化脚本「还原卡拉 OK 特效」，用于将字幕恢复到应用卡拉 OK 模板前的状态。

revert-karaoke.lua

script_name = '还原卡拉 OK 特效'
script_description = '将字幕恢复到应用卡拉 OK 模板前的状态。'
script_author = 'ipid君 <https://github.com/ipid>'
script_version = '1.0'

--[[ 判断 text 是否以 suffix 为结尾 ]]
local function endsWith(text, suffix)
    return text:sub(-#suffix) == suffix
end

--[[ 解析所有的 Style: 行 ]]
local function parseStyles(subs)
    local styles = {}

    for i = 1, #subs do
        local sub = subs[i]
        if sub.class == 'style' then
            styles[sub.name] = i
        elseif sub.class == 'dialogue' then
            return styles
        end
    end

    return styles
end

--[[ 对于特定的一行字幕，返回是否应该保留 ]]
local function shouldDelete(sub, styles)
    local isFx = (sub.class == 'dialogue' and sub.effect == 'fx' and not sub.comment)
    if isFx then
        return true
    end

    local isFurigana = (sub.class == 'style' and endsWith(sub.name, '-furigana') and styles[sub.name:sub(1, -10)] ~= nil)
    return isFurigana
end

--[[ 如果遇到被设为 karaoke 的普通轴，就删掉 karaoke 这个特效值，然后把注释改回正常状态 ]]
local function processFunc(sub)
    if sub.class == 'dialogue' and sub.effect == 'karaoke' then
        sub.effect = ''
        sub.comment = false
        return sub
    end

    return nil
end

local function revertKaraokeFx(subs)
    local styles = parseStyles(subs)
    local deleteIndexes = {}

    aegisub.set_undo_point('还原卡拉 OK 特效')

    for i = 1, #subs do
        local sub = subs[i]

        if shouldDelete(sub, styles) then
            table.insert(deleteIndexes, i)
        else
            local newSub = processFunc(sub)
            if newSub ~= nil then
                subs[i] = newSub
            end
        end
    end

    subs.delete(deleteIndexes)
end

aegisub.register_macro(script_name, script_description, revertKaraokeFx)