import gleam/dynamic/decode.{type Decoder}
import gleam/json.{type Json}

pub type ActivityLevel {
  Weak
  Growing
  Strong
  Restricted
}

pub fn parse(value: String) -> Result(ActivityLevel, Nil) {
  case value {
    "WEAK" -> Ok(Weak)
    "GROWING" -> Ok(Growing)
    "STRONG" -> Ok(Strong)
    "RESTRICTED" -> Ok(Restricted)
    _ -> Error(Nil)
  }
}

pub fn decoder() -> Decoder(ActivityLevel) {
  use value <- decode.then(decode.string)
  case parse(value) {
    Ok(activity_level) -> decode.success(activity_level)
    Error(Nil) -> decode.failure(Weak, "ActivityLevel")
  }
}

pub fn to_string(activity_level: ActivityLevel) -> String {
  case activity_level {
    Weak -> "WEAK"
    Growing -> "GROWING"
    Strong -> "STRONG"
    Restricted -> "RESTRICTED"
  }
}

pub fn encode(activity_level: ActivityLevel) -> Json {
  json.string(to_string(activity_level))
}