package script

const (
	ScriptHashMapIUDName = "hash_map_iud"

	// ScriptHashMapIUD
	// Hash Map IUD
	ScriptHashMapIUD = `
local function batch_hmset(key, data)
	return redis.call('HMSET', key, unpack(data))
end

local function arrayToTable(arr)
    local tbl = {}
    for i = 1, #arr, 2 do
        tbl[arr[i]] = arr[i + 1]
    end
    return tbl
end

local function updateHash(key, args)
	local fv = arrayToTable(args)
	
	-- 删除不再使用的字段
	local cursor = '0'
	local count = 100 -- 每次扫描返回的数量
	local matchPattern = '*'
	
	repeat
	    local scan_result = redis.call('HSCAN', key, cursor, 'MATCH', matchPattern, 'COUNT', count)
	    cursor = scan_result[1]
	    local fields = scan_result[2]
	
		if fields and #fields > 0 then
		    for _, field in ipairs(fields) do
				--检查字段是否存在于 m 中
				if not fv[field] then
					redis.call('HDEL', key, field)
				end
			end
		end
	until cursor == '0'

	-- 更新或添加字段
	batch_hmset(key, args)

	-- 返回元素数量
	return #fv
end

return updateHash(KEYS[1], ARGV)
`
)