--[[******************************************************************************]]
--[[*  Project ib_win_core                                                       *]]
--[[*  Copyright 2023 Incredibuild Software Ltd.                                 *]]
--[[*  All rights reserved                                                       *]]
--[[******************************************************************************]]

local function binary_search(arr, target)
  local left, right = 1, #arr
  
  while left <= right do
    local mid = math.floor((left + right) / 2)
    local current = tonumber(arr[mid])
    if current == target then
      return mid
    elseif current < target then
      left = mid + 1
    else
      right = mid - 1
    end
  end
  
  return left
end

local function remove_inconsistent(inconsistent)
  local times = redis.call('KEYS', '*')
  table.sort(times)
  
  local unfixed = 0

  for _, item in ipairs(inconsistent)
  do
    local found = false
    local pos = binary_search(times, item.l)
    if (pos > 1)
    then
      for i = pos-1, 1, -1
      do
        local prev = times[i]
        if redis.call('HEXISTS', prev, item.u) == 1
        then
          redis.call('HDEL', prev, item.u)
          found = true
          break
        end
      end
      if not found
      then
        unfixed = unfixed + 1
      end
    end
  end

  if unfixed > 0
  then
    error(unfixed .. ' items inconsistency detected')
  end
end

local function update(items)
  local inconsistent = {};
  for i,str in ipairs(items)
  do
    local uuid,prev,last,size = loadstring('return '..str)()
    if redis.call('HDEL', prev, uuid) ~= 1
    then
      inconsistent[#inconsistent + 1] = { u = uuid, l = last }
    end
    redis.call('HSET', last, uuid, size)
  end
  if #inconsistent > 0
  then
    remove_inconsistent(inconsistent)
  end
  return 'OK'
end

local function main(usageDB, items)
  redis.call('SELECT', usageDB)
  return update(items)
end

local ok, result = pcall(main, KEYS[1], ARGV)
return result