local net = require('libs/net')
local utils = require('libs/utils')
local inferium = require('config/inferium')

local DEFAULT_HARVESTER_NAME = 'harvester'
local VERSION = "2.0.1"
local INFERIUM_SERVER = 'inferium.com'

local PERSISTED_CONFIGS = '/data/inferium-configs'
local UPGRADE_SCRIPT = '/upgrade.lua'

local defaultConfig = inferium.defaultConfig or error('no default config provided in config', 0)

-- Persistance utils

local savePersistedConfigs = function(configs)
  local file = fs.open(PERSISTED_CONFIGS, 'w')

  if not file then
    error('savePersistedConfigs: cannot open ' .. PERSISTED_CONFIGS .. ' file!')
  end

  file.write(textutils.serialize(configs))
  file.close()
end

local readPersistedConfigs = function()
  local file = fs.open(PERSISTED_CONFIGS, 'r')

  if not file then
    local initialConfig = {}
    savePersistedConfigs(initialConfig)
    return initialConfig
  end

  local serializedConfigs = file.readAll()
  file.close()

  return textutils.unserialize(serializedConfigs)
end

-- State
local LOCAL_CONFIGS = readPersistedConfigs()

local function getConfigForComputer(computerId)
  return LOCAL_CONFIGS[tostring(computerId)]
end

local function saveConfigForComputer(computerId, config)
  LOCAL_CONFIGS[tostring(computerId)] = config
  savePersistedConfigs(LOCAL_CONFIGS)
end

-- Utils

local function getConfigWithLength(config)
  local configWithLength = utils.shallowClone(config)
  configWithLength.length = utils.sizeof(config.plan)

  return configWithLength
end

local function isValidConfig(config)
  if not config or type(config.plan) ~= 'table' then
    return false
  end

  if config.firstCropZ == nil or config.firstCropZ < 1 then
    return false
  end

  if config.fertilizedBoost == nil then
    return false
  end
end

-- Routes

local function getConfig(message, computerId)
  if not computerId == nil then
    print('get-config error: no computerId found')
    return nil
  end

  local givenHarvesterId = message and message.payload and message.payload.id

  local id = givenHarvesterId or computerId
  local config = getConfigForComputer(id)

  if not givenHarvesterId and not config then
    print('new harvester detected: ' .. tostring(computerId))
    saveConfigForComputer(computerId, defaultConfig)
    config = defaultConfig
  end

  return {
    type = "get-config/response",
    payload = getConfigWithLength(config)
  }
end

local function setConfig(message)
  local payload = message and message.payload
  local harvesterId = payload and payload.id
  local config = payload and payload.config

  if not isValidConfig(config) or not harvesterId then
    return false
  end

  saveConfigForComputer(harvesterId, config)
  return true
end

local function deleteConfig(message)
  local payload = message and message.payload
  local harvesterId = payload and payload.id

  if not harvesterId then
    return false
  end

  if LOCAL_CONFIGS[harvesterId] then
    saveConfigForComputer(harvesterId, nil)
    return true
  end

  return false
end

-- return a table of harvesters { id: string, name: string }[]
local function listHarvesters()
  local result = {}

  for k, v in pairs(LOCAL_CONFIGS) do
    table.insert(result, { id = k, name = v.name or DEFAULT_HARVESTER_NAME })
  end

  return result
end

local function exitServer(_, _, stopServer)
  stopServer();
  return true
end

local function upgradeServer()
  shell.execute(UPGRADE_SCRIPT)
  return true
end

local ROUTES = {
  ['get-config'] = getConfig,
  ['set-config'] = setConfig,
  ['delete-config'] = deleteConfig,
  ['list-harvesters'] = listHarvesters,
  ['exit-server'] = exitServer,
  ['upgrade-server'] = upgradeServer,
}

net.openRednet()
print('> inferium server v' .. VERSION .. ' started')

net.listenQuery(INFERIUM_SERVER, function(message, computerId, stopServer)
  if type(message) ~= 'table' then
    print('error: malformed message received', textutils.serialize(message))
    return {}
  end

  local router = ROUTES[message.type]

  if not router then
    print('warning: unknown type of message received', message.type)
    return {}
  end

  return router(message, computerId, stopServer)
end)
print('> server stopped')

net.closeRednet()
print('> rednet closed')