[Feature] Add verdict library in lua

3 files changed, 199 insertions, 30 deletions

diff --git a/lualib/lua_bayes_learn.lua b/lualib/lua_bayes_learn.lua
index 066e86a4d..ae8d901f8 100644
--- a/lualib/lua_bayes_learn.lua
+++ b/lualib/lua_bayes_learn.lua
@@ -17,7 +17,7 @@ limitations under the License.
 -- This file contains functions to simplify bayes classifier auto-learning
 
 local lua_util = require "lua_util"
-
+local lua_verdict = require "lua_verdict"
 local N = "lua_bayes"
 
 local exports = {}
@@ -76,7 +76,7 @@ exports.autolearn = function(task, conf)
   end
 
   -- We have autolearn config so let's figure out what is requested
-  local verdict,score = lua_util.get_task_verdict(task)
+  local verdict,score = lua_verdict.get_specific_verdict("bayes", task)
   local learn_spam,learn_ham = false, false
 
   if verdict == 'passthrough' then
@@ -98,6 +98,12 @@ exports.autolearn = function(task, conf)
         learn_ham = true
       end
     end
+  elseif conf.learn_verdict then
+    if verdict == 'spam' or verdict == 'junk' then
+      learn_spam = true
+    elseif verdict == 'ham' then
+      learn_ham = true
+    end
   end
 
   if conf.check_balance then
diff --git a/lualib/lua_util.lua b/lualib/lua_util.lua
index 842f079b2..bda8b0c02 100644
--- a/lualib/lua_util.lua
+++ b/lualib/lua_util.lua
@@ -1026,35 +1026,9 @@ end
 -- * `uncertain`: all other cases
 --]]
 exports.get_task_verdict = function(task)
-  local result = task:get_metric_result()
+  local lua_verdict = require "lua_verdict"
 
-  if result then
-
-    if result.passthrough then
-      return 'passthrough',nil
-    end
-
-    local score = result.score
-
-    local action = result.action
-
-    if action == 'reject' and result.npositive > 1 then
-      return 'spam',score
-    elseif action == 'no action' then
-      if score < 0 or result.nnegative > 3 then
-        return 'ham',score
-      end
-    else
-      -- All colors of junk
-      if action == 'add header' or action == 'rewrite subject' then
-        if result.npositive > 2 then
-          return 'junk',score
-        end
-      end
-    end
-
-    return 'uncertain',score
-  end
+  return lua_verdict.get_default_verdict(task)
 end
 
 ---[[[
diff --git a/lualib/lua_verdict.lua b/lualib/lua_verdict.lua
new file mode 100644
index 000000000..d6a1634a7
--- /dev/null
+++ b/lualib/lua_verdict.lua
@@ -0,0 +1,189 @@
+--[[
+Copyright (c) 2019, 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 exports = {}
+
+---[[[
+-- @function lua_verdict.get_default_verdict(task)
+-- Returns verdict for a task + score if certain, must be called from idempotent filters only
+-- Returns string:
+-- * `spam`: if message have over reject threshold and has more than one positive rule
+-- * `junk`: if a message has between score between [add_header/rewrite subject] to reject thresholds and has more than two positive rules
+-- * `passthrough`: if a message has been passed through some short-circuit rule
+-- * `ham`: if a message has overall score below junk level **and** more than three negative rule, or negative total score
+-- * `uncertain`: all other cases
+--]]
+local function default_verdict_function(task)
+  local result = task:get_metric_result()
+
+  if result then
+
+    if result.passthrough then
+      return 'passthrough',nil
+    end
+
+    local score = result.score
+
+    local action = result.action
+
+    if action == 'reject' and result.npositive > 1 then
+      return 'spam',score
+    elseif action == 'no action' then
+      if score < 0 or result.nnegative > 3 then
+        return 'ham',score
+      end
+    else
+      -- All colors of junk
+      if action == 'add header' or action == 'rewrite subject' then
+        if result.npositive > 2 then
+          return 'junk',score
+        end
+      end
+    end
+
+    return 'uncertain',score
+  end
+end
+
+local default_possible_verdicts = {
+  passthrough = {
+    can_learn = false,
+    description = 'message has passthrough result',
+  },
+  spam = {
+    can_learn = 'spam',
+    description = 'message is likely spam',
+  },
+  junk = {
+    can_learn = 'spam',
+    description = 'message is likely possible spam',
+  },
+  ham = {
+    can_learn = 'ham',
+    description = 'message is likely ham',
+  },
+  uncertain = {
+    can_learn = false,
+    description = 'not certainity in verdict'
+  }
+}
+
+-- Verdict functions specific for modules
+local specific_verdicts = {
+  default = {
+    callback = default_verdict_function,
+    possible_verdicts = default_possible_verdicts
+  }
+}
+
+local default_verdict = specific_verdicts.default
+
+exports.get_default_verdict = default_verdict.callback
+exports.set_verdict_function = function(func, what)
+  assert(type(func) == 'function')
+  if not what then
+    -- Default verdict
+    local existing = specific_verdicts.default.callback
+    specific_verdicts.default.callback = func
+    exports.get_default_verdict = func
+
+    return existing
+  else
+    local existing = specific_verdicts[what]
+
+    if not existing then
+      specific_verdicts[what] = {
+        callback = func,
+        possible_verdicts = default_possible_verdicts
+      }
+    else
+      existing = existing.callback
+    end
+
+    specific_verdicts[what].callback = func
+    return existing
+  end
+end
+
+exports.set_verdict_table = function(verdict_tbl, what)
+  assert(type(verdict_tbl) == 'table' and
+    type(verdict_tbl.callback) == 'function' and
+    type(verdict_tbl.possible_verdicts) == 'table')
+
+  if not what then
+    -- Default verdict
+    local existing = specific_verdicts.default
+    specific_verdicts.default = verdict_tbl
+    exports.get_default_verdict = specific_verdicts.default.callback
+
+    return existing
+  else
+    local existing = specific_verdicts[what]
+    specific_verdicts[what] = verdict_tbl
+    return existing
+  end
+end
+
+exports.get_specific_verdict = function(what, task)
+  if specific_verdicts[what] then
+    return specific_verdicts[what].callback(task)
+  end
+
+  return exports.get_default_verdict(task)
+end
+
+exports.get_possible_verdicts = function(what)
+  local lua_util = require "lua_util"
+  if what then
+    if specific_verdicts[what] then
+      return lua_util.keys(specific_verdicts[what].possible_verdicts)
+    end
+  else
+    return lua_util.keys(specific_verdicts.default.possible_verdicts)
+  end
+
+  return nil
+end
+
+exports.can_learn = function(verdict, what)
+  if what then
+    if specific_verdicts[what] and specific_verdicts[what].possible_verdicts[verdict] then
+      return specific_verdicts[what].possible_verdicts[verdict].can_learn
+    end
+  else
+    if specific_verdicts.default.possible_verdicts[verdict] then
+      return specific_verdicts.default.possible_verdicts[verdict].can_learn
+    end
+  end
+
+  return nil -- To distinguish from `false` that could happen in can_learn
+end
+
+exports.describe = function(verdict, what)
+  if what then
+    if specific_verdicts[what] and specific_verdicts[what].possible_verdicts[verdict] then
+      return specific_verdicts[what].possible_verdicts[verdict].description
+    end
+  else
+    if specific_verdicts.default.possible_verdicts[verdict] then
+      return specific_verdicts.default.possible_verdicts[verdict].description
+    end
+  end
+
+  return nil
+end
+
+return exports
\ No newline at end of file