-- convenience funcs for validation.
let Prelude =
      https://prelude.dhall-lang.org/v20.2.0/package.dhall
        sha256:a6036bc38d883450598d1de7c98ead113196fe2db02e9733855668b18096f07b

let NuConfig =
    -- | define a configuration schema.
      { Type =
          { Port : Natural
          , AppName : Text
          , LiveMode : Bool
          , DevelMode : Bool
          , LoginCookieName : Optional Text
          }
      , default =
        { Port = 3000
        , AppName = "pcmt"
        , LiveMode = False
        , DevelMode = False
        , LoginCookieName = None Text
        }
      }

let NuConfig/validate
    : NuConfig.Type -> Type
    =
      -- | define validation.
      \(c : NuConfig.Type) ->
        let expected = { validPort = True }

        let actual =
              { validPort =
                  -- | make sure port number belongs to the <1;65565> range.
                      Prelude.Natural.lessThanEqual 1 c.Port
                  &&  Prelude.Natural.lessThanEqual c.Port 65565
              }

        in  expected === actual

let nuconf = NuConfig::{ LiveMode = True, DevelMode = True }

let _ =
    -- | validate the configuration.
      assert : NuConfig/validate nuconf

let Config =
    -- | define configuration schema.
      { Host : Text
      , Port : Natural
      , AppName : Text
      , LiveMode : Bool
      , DevelMode : Bool
      , SessionCookieName : Text
      , SessionCookieSecret : Text
      }

let defconf
    -- | a full default configuration.
    -- | TODO: have this reside on the Internet and import it similar to how
    -- | the Dhall Prelude is imported.
    : Config
    = { Host = ""
      , Port = 3000
      , AppName = "pcmt"
      , LiveMode = False
      , DevelMode = False
      , SessionCookieName = "sessionz"
      , SessionCookieSecret = "secret"
      }

let conf
    : Config
    = defconf // { LiveMode = True, DevelMode = False }

let Config/validate
    : Config -> Type
    =
      -- | define validation.
      \(config : Config) ->
        let expected = { validPort = True }

        let actual =
              { validPort =
                  -- | make sure port number belongs to the <1;65565> range.
                      Prelude.Natural.lessThanEqual 1 config.Port
                  &&  Prelude.Natural.lessThanEqual config.Port 65565
              }

        in  expected === actual

let _ =
    -- | validate the configuration.
      assert : Config/validate conf

in  conf