{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE RecordWildCards            #-}
{-# LANGUAGE OverloadedStrings          #-}

module Database.Bloodhound.Internal.Suggest where

import           Bloodhound.Import

import qualified Data.HashMap.Strict as HM

import           Database.Bloodhound.Internal.Newtypes
import           Database.Bloodhound.Internal.Query (Query, TemplateQueryKeyValuePairs)

data Suggest = Suggest
  { suggestText :: Text
  , suggestName :: Text
  , suggestType :: SuggestType
  } deriving (Eq, Show)

instance ToJSON Suggest where
  toJSON Suggest{..} =
    object [ "text" .= suggestText
           , suggestName .= suggestType
           ]

instance FromJSON Suggest where
  parseJSON (Object o) = do
    suggestText' <- o .: "text"
    let dropTextList =
            HM.toList
          $ HM.filterWithKey (\x _ -> x /= "text") o
    suggestName' <-
      case dropTextList of
        [(x, _)] -> return x
        _ -> fail "error parsing Suggest field name"
    suggestType' <- o .: suggestName'
    return $ Suggest suggestText' suggestName' suggestType'
  parseJSON x = typeMismatch "Suggest" x

data SuggestType =
  SuggestTypePhraseSuggester PhraseSuggester
  deriving (Eq, Show)

instance ToJSON SuggestType where
  toJSON (SuggestTypePhraseSuggester x) =
    object [ "phrase" .= x ]

instance FromJSON SuggestType where
  parseJSON = withObject "SuggestType" parse
    where parse o = phraseSuggester `taggedWith` "phrase"
           where taggedWith parser k = parser =<< o .: k
                 phraseSuggester = pure . SuggestTypePhraseSuggester

data PhraseSuggester = PhraseSuggester
  { phraseSuggesterField :: FieldName
  , phraseSuggesterGramSize :: Maybe Int
  , phraseSuggesterRealWordErrorLikelihood :: Maybe Int
  , phraseSuggesterConfidence :: Maybe Int
  , phraseSuggesterMaxErrors :: Maybe Int
  , phraseSuggesterSeparator :: Maybe Text
  , phraseSuggesterSize :: Maybe Size
  , phraseSuggesterAnalyzer :: Maybe Analyzer
  , phraseSuggesterShardSize :: Maybe Int
  , phraseSuggesterHighlight :: Maybe PhraseSuggesterHighlighter
  , phraseSuggesterCollate :: Maybe PhraseSuggesterCollate
  , phraseSuggesterCandidateGenerators :: [DirectGenerators]
  } deriving (Eq, Show)

instance ToJSON PhraseSuggester where
  toJSON PhraseSuggester{..} =
    omitNulls [ "field" .= phraseSuggesterField
              , "gram_size" .= phraseSuggesterGramSize
              , "real_word_error_likelihood" .=
                phraseSuggesterRealWordErrorLikelihood
              , "confidence" .= phraseSuggesterConfidence
              , "max_errors" .= phraseSuggesterMaxErrors
              , "separator" .= phraseSuggesterSeparator
              , "size" .= phraseSuggesterSize
              , "analyzer" .= phraseSuggesterAnalyzer
              , "shard_size" .= phraseSuggesterShardSize
              , "highlight" .= phraseSuggesterHighlight
              , "collate" .= phraseSuggesterCollate
              , "direct_generator" .=
                phraseSuggesterCandidateGenerators
              ]

instance FromJSON PhraseSuggester where
  parseJSON = withObject "PhraseSuggester" parse
    where parse o = PhraseSuggester
                      <$> o .: "field"
                      <*> o .:? "gram_size"
                      <*> o .:? "real_word_error_likelihood"
                      <*> o .:? "confidence"
                      <*> o .:? "max_errors"
                      <*> o .:? "separator"
                      <*> o .:? "size"
                      <*> o .:? "analyzer"
                      <*> o .:? "shard_size"
                      <*> o .:? "highlight"
                      <*> o .:? "collate"
                      <*> o .:? "direct_generator" .!= []

mkPhraseSuggester :: FieldName -> PhraseSuggester
mkPhraseSuggester fName =
  PhraseSuggester fName Nothing Nothing Nothing Nothing Nothing Nothing
    Nothing Nothing Nothing Nothing []

data PhraseSuggesterHighlighter =
  PhraseSuggesterHighlighter { phraseSuggesterHighlighterPreTag :: Text
                             , phraseSuggesterHighlighterPostTag :: Text
                             }
  deriving (Eq, Show)

instance ToJSON PhraseSuggesterHighlighter where
  toJSON PhraseSuggesterHighlighter{..} =
            object [ "pre_tag" .= phraseSuggesterHighlighterPreTag
                   , "post_tag" .= phraseSuggesterHighlighterPostTag
                   ]

instance FromJSON PhraseSuggesterHighlighter where
  parseJSON = withObject "PhraseSuggesterHighlighter" parse
    where parse o = PhraseSuggesterHighlighter
                      <$> o .: "pre_tag"
                      <*> o .: "post_tag"

data PhraseSuggesterCollate = PhraseSuggesterCollate
  { phraseSuggesterCollateTemplateQuery :: Query
  , phraseSuggesterCollateParams :: TemplateQueryKeyValuePairs
  , phraseSuggesterCollatePrune :: Bool
  } deriving (Eq, Show)

instance ToJSON PhraseSuggesterCollate where
  toJSON PhraseSuggesterCollate{..} =
    object [ "query" .= object
             [ "source" .= phraseSuggesterCollateTemplateQuery
             ]
           , "params" .= phraseSuggesterCollateParams
           , "prune" .= phraseSuggesterCollatePrune
           ]

instance FromJSON PhraseSuggesterCollate where
  parseJSON (Object o) = do
    query' <- o .: "query"
    inline' <- query' .: "source"
    params' <- o .: "params"
    prune' <- o .:? "prune" .!= False
    return $ PhraseSuggesterCollate inline' params' prune'
  parseJSON x = typeMismatch "PhraseSuggesterCollate" x

data SuggestOptions =
  SuggestOptions { suggestOptionsText :: Text
                 , suggestOptionsScore :: Double
                 , suggestOptionsFreq :: Maybe Int
                 , suggestOptionsHighlighted :: Maybe Text
                 }
  deriving (Eq, Read, Show)

instance FromJSON SuggestOptions where
  parseJSON = withObject "SuggestOptions" parse
    where
      parse o = SuggestOptions
            <$> o .: "text"
            <*> o .: "score"
            <*> o .:? "freq"
            <*> o .:? "highlighted"

data SuggestResponse =
  SuggestResponse { suggestResponseText :: Text
                  , suggestResponseOffset :: Int
                  , suggestResponseLength :: Int
                  , suggestResponseOptions :: [SuggestOptions]
                  }
  deriving (Eq, Read, Show)

instance FromJSON SuggestResponse where
  parseJSON = withObject "SuggestResponse" parse
    where parse o = SuggestResponse
                    <$> o .: "text"
                    <*> o .: "offset"
                    <*> o .: "length"
                    <*> o .: "options"

data NamedSuggestionResponse = NamedSuggestionResponse
  { nsrName :: Text
  , nsrResponses :: [SuggestResponse]
  } deriving (Eq, Read, Show)

instance FromJSON NamedSuggestionResponse where
  parseJSON (Object o) = do
    suggestionName' <- case HM.toList o of
                        [(x, _)] -> return x
                        _ -> fail "error parsing NamedSuggestionResponse name"
    suggestionResponses' <- o .: suggestionName'
    return $ NamedSuggestionResponse suggestionName' suggestionResponses'

  parseJSON x = typeMismatch "NamedSuggestionResponse" x

data DirectGeneratorSuggestModeTypes = DirectGeneratorSuggestModeMissing
                                | DirectGeneratorSuggestModePopular
                                | DirectGeneratorSuggestModeAlways
  deriving (Eq, Show)

instance ToJSON DirectGeneratorSuggestModeTypes where
  toJSON DirectGeneratorSuggestModeMissing = "missing"
  toJSON DirectGeneratorSuggestModePopular = "popular"
  toJSON DirectGeneratorSuggestModeAlways = "always"

instance FromJSON DirectGeneratorSuggestModeTypes where
  parseJSON = withText "DirectGeneratorSuggestModeTypes" parse
    where
      parse "missing" =
        pure DirectGeneratorSuggestModeMissing
      parse "popular" =
        pure DirectGeneratorSuggestModePopular
      parse "always" =
        pure DirectGeneratorSuggestModeAlways
      parse f =
        fail ("Unexpected DirectGeneratorSuggestModeTypes: " <> show f)

data DirectGenerators = DirectGenerators
  { directGeneratorsField :: FieldName
  , directGeneratorsSize :: Maybe Int
  , directGeneratorSuggestMode :: DirectGeneratorSuggestModeTypes
  , directGeneratorMaxEdits :: Maybe Double
  , directGeneratorPrefixLength :: Maybe Int
  , directGeneratorMinWordLength :: Maybe Int
  , directGeneratorMaxInspections :: Maybe Int
  , directGeneratorMinDocFreq :: Maybe Double
  , directGeneratorMaxTermFreq :: Maybe Double
  , directGeneratorPreFilter :: Maybe Text
  , directGeneratorPostFilter :: Maybe Text
  } deriving (Eq, Show)

instance ToJSON DirectGenerators where
  toJSON DirectGenerators{..} =
    omitNulls [ "field" .= directGeneratorsField
              , "size" .= directGeneratorsSize
              , "suggest_mode" .= directGeneratorSuggestMode
              , "max_edits" .= directGeneratorMaxEdits
              , "prefix_length" .= directGeneratorPrefixLength
              , "min_word_length" .= directGeneratorMinWordLength
              , "max_inspections" .= directGeneratorMaxInspections
              , "min_doc_freq" .= directGeneratorMinDocFreq
              , "max_term_freq" .= directGeneratorMaxTermFreq
              , "pre_filter" .= directGeneratorPreFilter
              , "post_filter" .= directGeneratorPostFilter
              ]

instance FromJSON DirectGenerators where
  parseJSON = withObject "DirectGenerators" parse
    where parse o = DirectGenerators
                      <$> o .: "field"
                      <*> o .:? "size"
                      <*> o .:  "suggest_mode"
                      <*> o .:? "max_edits"
                      <*> o .:? "prefix_length"
                      <*> o .:? "min_word_length"
                      <*> o .:? "max_inspections"
                      <*> o .:? "min_doc_freq"
                      <*> o .:? "max_term_freq"
                      <*> o .:? "pre_filter"
                      <*> o .:? "post_filter"

mkDirectGenerators :: FieldName -> DirectGenerators
mkDirectGenerators fn =
  DirectGenerators
  fn
  Nothing
  DirectGeneratorSuggestModeMissing
  Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing