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+{-# LANGUAGE AllowAmbiguousTypes #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
+
+module Hsm.Log.Options
+ ( makeLoggerOptionParser
+ )
+where
+
+import Data.Proxy (Proxy (Proxy))
+import GHC.TypeLits (symbolVal)
+import Generic.Data.Function.Common.Generic.Meta (KnownSymbols, symbolVals)
+import Hsm.Log (LoggerOptionPrefix, Severity)
+import Language.Haskell.TH
+ ( Bang (Bang)
+ , Body (NormalB)
+ , Clause (Clause)
+ , Con (RecC)
+ , Dec (DataD, FunD, SigD)
+ , Exp (AppE, ConE, LitE, ParensE, UInfixE, VarE)
+ , Lit (StringL)
+ , Name
+ , Q
+ , SourceStrictness (NoSourceStrictness)
+ , SourceUnpackedness (NoSourceUnpackedness)
+ , Type (AppT, ConT)
+ , mkName
+ )
+import Options.Applicative (Parser, auto, help, long, metavar, option, showDefault, value)
+
+-- Generates an optparse-applicative parser for multiple logger severity levels
+--
+-- Creates a record type with configurable log levels and a corresponding parser
+-- that accepts command-line arguments like `--log-cam` and `--log-web`.
+--
+-- Example:
+--
+-- $(makeLoggerOptionParser @'[ "cam", "web"] "Options" "parser" 'Info)
+--
+-- Generates:
+-- - Record: `Options { logLevel_cam :: Severity, logLevel_web :: Severity }`
+-- - Parser: `parser :: Parser Options` with default values set to `Info`
+makeLoggerOptionParser
+ :: forall ls
+ . KnownSymbols ls
+ => String
+ -> String
+ -> Name
+ -> Q [Dec]
+makeLoggerOptionParser dataNameString parserNameString defaultSeverity =
+ return
+ [ DataD [] dataName [] Nothing [RecC dataName $ field <$> loggers] []
+ , SigD parserName $ ConT ''Parser `AppT` ConT dataName
+ , FunD parserName [Clause [] (NormalB $ foldl parserApply parserBase loggers) []]
+ ]
+ where
+ loggers = symbolVals @ls
+ -- Record
+ dataName = mkName dataNameString
+ fieldPrefix = symbolVal $ Proxy @LoggerOptionPrefix
+ fieldName logger = mkName $ fieldPrefix <> logger
+ fieldBang = Bang NoSourceUnpackedness NoSourceStrictness
+ fieldType = ConT ''Severity
+ field logger = (fieldName logger, fieldBang, fieldType)
+ -- Parser
+ parserName = mkName parserNameString
+ parserBase = VarE 'pure `AppE` ConE dataName
+ parserConfigApply expr = UInfixE expr $ VarE '(<>)
+ parserOptionLong logger = VarE 'long `AppE` LitE (StringL $ "log-" <> logger)
+ parserOptionHelp logger = VarE 'help `AppE` LitE (StringL $ "Sets log level for logger " <> logger)
+ parserOptionShowDefault = VarE 'showDefault
+ parserOptionValue = VarE 'value `AppE` ConE defaultSeverity
+ parserOptionMetavar = VarE 'metavar `AppE` LitE (StringL "LEVEL")
+ parserOptions logger = [parserOptionLong logger, parserOptionHelp logger, parserOptionShowDefault, parserOptionValue, parserOptionMetavar]
+ parserApply expr logger =
+ UInfixE expr (VarE '(<*>)) $
+ VarE 'option `AppE` VarE 'auto `AppE` ParensE (foldl1 parserConfigApply $ parserOptions logger)