--[[
Copyright (c) 2017, Vsevolod Stakhov <vsevolod@highsecure.ru>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
]]--

local logger = require "rspamd_logger"
local lutil = require "lua_util"

local exports = {}

local E = {}

-- This function parses redis server definition using either
-- specific server string for this module or global
-- redis section
local function rspamd_parse_redis_server(module_name, module_opts, no_fallback)

  local result = {}
  local default_port = 6379
  local default_timeout = 1.0
  local default_expand_keys = false
  local upstream_list = require "rspamd_upstream_list"

  local function try_load_redis_servers(options)
    -- Try to get read servers:
    local upstreams_read, upstreams_write

    if options['read_servers'] then
      upstreams_read = upstream_list.create(rspamd_config,
        options['read_servers'], default_port)
    elseif options['servers'] then
      upstreams_read = upstream_list.create(rspamd_config,
        options['servers'], default_port)
    elseif options['server'] then
      upstreams_read = upstream_list.create(rspamd_config,
        options['server'], default_port)
    end

    if upstreams_read then
      if options['write_servers'] then
        upstreams_write = upstream_list.create(rspamd_config,
          options['write_servers'], default_port)
      else
        upstreams_write = upstreams_read
      end
    end

    -- Store options
    if not result['timeout'] and not result['timeout'] == default_timeout then
      if options['timeout'] then
        result['timeout'] = tonumber(options['timeout'])
      else
        result['timeout'] = default_timeout
      end
    end

    if options['prefix'] and not result['prefix'] then
      result['prefix'] = options['prefix']
    end

    if type(options['expand_keys']) == 'boolean' then
      result['expand_keys'] = options['expand_keys']
    else
      result['expand_keys'] = default_expand_keys
    end

    if not result['db'] then
      if options['db'] then
        result['db'] = tostring(options['db'])
      elseif options['dbname'] then
        result['db'] = tostring(options['dbname'])
      end
    end
    if options['password'] and not result['password'] then
      result['password'] = options['password']
    end

    if upstreams_write and upstreams_read then
      result.read_servers = upstreams_read
      result.write_servers = upstreams_write

      return true
    end

    return false
  end

  -- Try local options
  local opts
  if not module_opts then
    opts = rspamd_config:get_all_opt(module_name)
  else
    opts = module_opts
  end
  local ret = false

  if opts then
    ret = try_load_redis_servers(opts, result)
  end

  if ret then
    return result
  end

  if no_fallback then return nil end

  -- Try global options
  opts = rspamd_config:get_all_opt('redis')

  if opts then
    if opts[module_name] then
      ret = try_load_redis_servers(opts[module_name], result)
      if ret then
        return result
      end
    else
      ret = try_load_redis_servers(opts, result)

      -- Exclude disabled
      if opts['disabled_modules'] then
        for _,v in ipairs(opts['disabled_modules']) do
          if v == module_name then
            logger.infox(rspamd_config, "NOT using default redis server for module %s: it is disabled",
              module_name)

              return nil
          end
        end
      end

      if ret then
        logger.infox(rspamd_config, "using default redis server for module %s",
          module_name)
      end
    end
  end

  if result.read_servers then
    return result
  else
    return nil
  end
end

exports.rspamd_parse_redis_server = rspamd_parse_redis_server
exports.parse_redis_server = rspamd_parse_redis_server

local process_cmd = {
  bitop = function(args)
    local idx_l = {}
    for i = 2, #args do
      table.insert(idx_l, i)
    end
    return idx_l
  end,
  blpop = function(args)
    local idx_l = {}
    for i = 1, #args -1 do
      table.insert(idx_l, i)
    end
    return idx_l
  end,
  eval = function(args)
    local idx_l = {}
    local numkeys = args[2]
    if numkeys >= 1 then
      for i = 3, numkeys + 2 do
        table.insert(idx_l, i)
      end
    end
    return idx_l
  end,
  set = function(args)
    return {1}
  end,
  mget = function(args)
    local idx_l = {}
    for i = 1, #args do
      table.insert(idx_l, i)
    end
    return idx_l
  end,
  mset = function(args)
    local idx_l = {}
    for i = 1, #args, 2 do
      table.insert(idx_l, i)
    end
    return idx_l
  end,
  sdiffstore = function(args)
    local idx_l = {}
    for i = 2, #args do
      table.insert(idx_l, i)
    end
    return idx_l
  end,
  smove = function(args)
    return {1, 2}
  end,
  script = function() end
}
process_cmd.append = process_cmd.set
process_cmd.auth = process_cmd.script
process_cmd.bgrewriteaof = process_cmd.script
process_cmd.bgsave = process_cmd.script
process_cmd.bitcount = process_cmd.set
process_cmd.bitfield = process_cmd.set
process_cmd.bitpos = process_cmd.set
process_cmd.brpop = process_cmd.blpop
process_cmd.brpoplpush = process_cmd.blpop
process_cmd.client = process_cmd.script
process_cmd.cluster = process_cmd.script
process_cmd.command = process_cmd.script
process_cmd.config = process_cmd.script
process_cmd.dbsize = process_cmd.script
process_cmd.debug = process_cmd.script
process_cmd.decr = process_cmd.set
process_cmd.decrby = process_cmd.set
process_cmd.del = process_cmd.mget
process_cmd.discard = process_cmd.script
process_cmd.dump = process_cmd.set
process_cmd.echo = process_cmd.script
process_cmd.evalsha = process_cmd.eval
process_cmd.exec = process_cmd.script
process_cmd.exists = process_cmd.mget
process_cmd.expire = process_cmd.set
process_cmd.expireat = process_cmd.set
process_cmd.flushall = process_cmd.script
process_cmd.flushdb = process_cmd.script
process_cmd.geoadd = process_cmd.set
process_cmd.geohash = process_cmd.set
process_cmd.geopos = process_cmd.set
process_cmd.geodist = process_cmd.set
process_cmd.georadius = process_cmd.set
process_cmd.georadiusbymember = process_cmd.set
process_cmd.get = process_cmd.set
process_cmd.getbit = process_cmd.set
process_cmd.getrange = process_cmd.set
process_cmd.getset = process_cmd.set
process_cmd.hdel = process_cmd.set
process_cmd.hexists = process_cmd.set
process_cmd.hget = process_cmd.set
process_cmd.hgetall = process_cmd.set
process_cmd.hincrby = process_cmd.set
process_cmd.hincrbyfloat = process_cmd.set
process_cmd.hkeys = process_cmd.set
process_cmd.hlen = process_cmd.set
process_cmd.hmget = process_cmd.set
process_cmd.hscan = process_cmd.set
process_cmd.hset = process_cmd.set
process_cmd.hsetnx = process_cmd.set
process_cmd.hstrlen = process_cmd.set
process_cmd.hvals = process_cmd.set
process_cmd.incr = process_cmd.set
process_cmd.incrby = process_cmd.set
process_cmd.incrbyfloat = process_cmd.set
process_cmd.info = process_cmd.script
process_cmd.keys = process_cmd.script
process_cmd.lastsave = process_cmd.script
process_cmd.lindex = process_cmd.set
process_cmd.linsert = process_cmd.set
process_cmd.llen = process_cmd.set
process_cmd.lpop = process_cmd.set
process_cmd.lpush = process_cmd.set
process_cmd.lpushx = process_cmd.set
process_cmd.lrange = process_cmd.set
process_cmd.lrem = process_cmd.set
process_cmd.lset = process_cmd.set
process_cmd.ltrim = process_cmd.set
process_cmd.migrate = process_cmd.script
process_cmd.monitor = process_cmd.script
process_cmd.move = process_cmd.set
process_cmd.msetnx = process_cmd.mset
process_cmd.multi = process_cmd.script
process_cmd.object = process_cmd.script
process_cmd.persist = process_cmd.set
process_cmd.pexpire = process_cmd.set
process_cmd.pexpireat = process_cmd.set
process_cmd.pfadd = process_cmd.set
process_cmd.pfcount = process_cmd.set
process_cmd.pfmerge = process_cmd.mget
process_cmd.ping = process_cmd.script
process_cmd.psetex = process_cmd.set
process_cmd.psubscribe = process_cmd.script
process_cmd.pubsub = process_cmd.script
process_cmd.pttl = process_cmd.set
process_cmd.publish = process_cmd.script
process_cmd.punsubscribe = process_cmd.script
process_cmd.quit = process_cmd.script
process_cmd.randomkey = process_cmd.script
process_cmd.readonly = process_cmd.script
process_cmd.readwrite = process_cmd.script
process_cmd.rename = process_cmd.mget
process_cmd.renamenx = process_cmd.mget
process_cmd.restore = process_cmd.set
process_cmd.role = process_cmd.script
process_cmd.rpop = process_cmd.set
process_cmd.rpoplpush = process_cmd.mget
process_cmd.rpush = process_cmd.set
process_cmd.rpushx = process_cmd.set
process_cmd.sadd = process_cmd.set
process_cmd.save = process_cmd.script
process_cmd.scard = process_cmd.set
process_cmd.sdiff = process_cmd.mget
process_cmd.select = process_cmd.script
process_cmd.setbit = process_cmd.set
process_cmd.setex = process_cmd.set
process_cmd.setnx = process_cmd.set
process_cmd.sinterstore = process_cmd.sdiff
process_cmd.sismember = process_cmd.set
process_cmd.slaveof = process_cmd.script
process_cmd.slowlog = process_cmd.script
process_cmd.smembers = process_cmd.script
process_cmd.sort = process_cmd.set
process_cmd.spop = process_cmd.set
process_cmd.srandmember = process_cmd.set
process_cmd.srem = process_cmd.set
process_cmd.strlen = process_cmd.set
process_cmd.subscribe = process_cmd.script
process_cmd.sunion = process_cmd.mget
process_cmd.sunionstore = process_cmd.mget
process_cmd.swapdb = process_cmd.script
process_cmd.sync = process_cmd.script
process_cmd.time = process_cmd.script
process_cmd.touch = process_cmd.mget
process_cmd.ttl = process_cmd.set
process_cmd.type = process_cmd.set
process_cmd.unsubscribe = process_cmd.script
process_cmd.unlink = process_cmd.mget
process_cmd.unwatch = process_cmd.script
process_cmd.wait = process_cmd.script
process_cmd.watch = process_cmd.mget
process_cmd.zadd = process_cmd.set
process_cmd.zcard = process_cmd.set
process_cmd.zcount = process_cmd.set
process_cmd.zincrby = process_cmd.set
process_cmd.zinterstore = process_cmd.eval
process_cmd.zlexcount = process_cmd.set
process_cmd.zrange = process_cmd.set
process_cmd.zrangebylex = process_cmd.set
process_cmd.zrank = process_cmd.set
process_cmd.zrem = process_cmd.set
process_cmd.zrembylex = process_cmd.set
process_cmd.zrembyrank = process_cmd.set
process_cmd.zrembyscore = process_cmd.set
process_cmd.zrevrange = process_cmd.set
process_cmd.zrevrangebyscore = process_cmd.set
process_cmd.zrevrank = process_cmd.set
process_cmd.zscore = process_cmd.set
process_cmd.zunionstore = process_cmd.eval
process_cmd.scan = process_cmd.script
process_cmd.sscan = process_cmd.set
process_cmd.hscan = process_cmd.set
process_cmd.zscan = process_cmd.set

local function get_key_indexes(cmd, args)
  local idx_l = {}
  cmd = string.lower(cmd)
  if process_cmd[cmd] then
    idx_l = process_cmd[cmd](args)
  else
    logger.warnx(rspamd_config, "Don't know how to extract keys for %s Redis command", cmd)
  end
  return idx_l
end

local function get_key_expansion_metadata(task)

  local gen_meta = {
    principal_recipient = function()
      local a = (task:get_principal_recipient() or E)['addr']
      if a and string.len(a) == 0 then
        a = '<>'
      end
      return a
    end,
    principal_recipient_domain = function()
      return (task:get_principal_recipient() or E)['domain']
    end,
    ip = function()
      local i = task:get_ip()
      if i and i:is_valid() then return i:to_string() end
    end,
    from = function()
      return task:get_from('smtp')
    end,
    from_domain = function()
      return (task:get_from('smtp') or E)['domain']
    end,
  }

  local md_mt = {
    __index = function(self, k)
      k = string.lower(k)
      local v = rawget(self, k)
      if v then
        return v
      end
      if gen_meta[k] then
        v = gen_meta[k]()
        rawset(self, k, v)
      end
      return v
    end,
  }

  local lazy_meta = {}
  setmetatable(lazy_meta, md_mt)
  return lazy_meta

end

-- Performs async call to redis hiding all complexity inside function
-- task - rspamd_task
-- redis_params - valid params returned by rspamd_parse_redis_server
-- key - key to select upstream or nil to select round-robin/master-slave
-- is_write - true if need to write to redis server
-- callback - function to be called upon request is completed
-- command - redis command
-- args - table of arguments
local function rspamd_redis_make_request(task, redis_params, key, is_write, callback, command, args)
  local addr
  local function rspamd_redis_make_request_cb(err, data)
    if err then
      addr:fail()
    else
      addr:ok()
    end
    callback(err, data, addr)
  end
  if not task or not redis_params or not callback or not command then
    return false,nil,nil
  end

  local rspamd_redis = require "rspamd_redis"

  if key then
    if is_write then
      addr = redis_params['write_servers']:get_upstream_by_hash(key)
    else
      addr = redis_params['read_servers']:get_upstream_by_hash(key)
    end
  else
    if is_write then
      addr = redis_params['write_servers']:get_upstream_master_slave(key)
    else
      addr = redis_params['read_servers']:get_upstream_round_robin(key)
    end
  end

  if not addr then
    logger.errx(task, 'cannot select server to make redis request')
  end

  if redis_params['expand_keys'] then
    local m = get_key_expansion_metadata(task)
    local indexes = get_key_indexes(command, args)
    for _, i in ipairs(indexes) do
      args[i] = lutil.template(args[i], m)
    end
  end

  local options = {
    task = task,
    callback = rspamd_redis_make_request_cb,
    host = addr:get_addr(),
    timeout = redis_params['timeout'],
    cmd = command,
    args = args
  }

  if redis_params['password'] then
    options['password'] = redis_params['password']
  end

  if redis_params['db'] then
    options['dbname'] = redis_params['db']
  end

  local ret,conn = rspamd_redis.make_request(options)
  return ret,conn,addr
end

exports.rspamd_redis_make_request = rspamd_redis_make_request
exports.redis_make_request = rspamd_redis_make_request

local function redis_make_request_taskless(ev_base, cfg, redis_params, key, is_write, callback, command, args)
  if not ev_base or not redis_params or not callback or not command then
    return false,nil,nil
  end

  local addr
  local rspamd_redis = require "rspamd_redis"

  if key then
    if is_write then
      addr = redis_params['write_servers']:get_upstream_by_hash(key)
    else
      addr = redis_params['read_servers']:get_upstream_by_hash(key)
    end
  else
    if is_write then
      addr = redis_params['write_servers']:get_upstream_master_slave(key)
    else
      addr = redis_params['read_servers']:get_upstream_round_robin(key)
    end
  end

  if not addr then
    logger.errx(cfg, 'cannot select server to make redis request')
  end

  local options = {
    ev_base = ev_base,
    config = cfg,
    callback = callback,
    host = addr:get_addr(),
    timeout = redis_params['timeout'],
    cmd = command,
    args = args
  }

  if redis_params['password'] then
    options['password'] = redis_params['password']
  end

  if redis_params['db'] then
    options['dbname'] = redis_params['db']
  end

  local ret,conn = rspamd_redis.make_request(options)
  if not ret then
    logger.errx('cannot execute redis request')
  end
  return ret,conn,addr
end

exports.rspamd_redis_make_request_taskless = redis_make_request_taskless
exports.redis_make_request_taskless = redis_make_request_taskless

return exports