//! Options contains everything related to engine options. The idea behind this is to take as much
//! advantage of the typechecker as possible. As a result, engine option names are constant static strings,
//! and EngineOption tries to be flexible so it can be reused for each option, which also maintaining some
//! of the nicer parts of typechecking.

use std::collections::HashMap;
use commands;

pub mod constants {

  /// Represents the hash option
  pub const HASH: &'static str = "Hash";

  /// Represents the Nalimov Path option
  pub const NALIMOVPATH: &'static str = "NalimovPath";

  /// Represents the Nalimov Cache option
  pub const NALIMOVCACHE: &'static str = "NalimovCache";

  /// Represents the ponder option
  pub const PONDER: &'static str = "Ponder";

  /// Represents the OwnBook option
  pub const OWNBOOK: &'static str = "OwnBook";

  /// Represents the MultiPV option
  pub const MULTIPV: &'static str = "MultiPV";

  /// Represents the UCI_ShowCurrLine option
  pub const UCISHOWCURRLINE: &'static str = "UCI_ShowCurrLine";

  /// Represents the UCI_Refutations option
  pub const UCISHOWREFUTATIONS: &'static str = "UCI_ShowRefutations";

  /// Represents the UCI_LimitStrength option
  pub const UCILIMITSTRENGTH: &'static str = "UCI_LimitStrength";

  /// Represents the UCI_Elo option
  pub const UCIELO: &'static str = "UCI_Elo";

  /// Represents the UCI_AnalysisMode option
  pub const UCIANALYSISMODE: &'static str = "UCI_AnalysisMode";

  /// Represents the UCI_Opponent option
  pub const UCIOPPONENT: &'static str = "UCI_Opponent";

}

/// The `EngineOptionType` type used to indicate what type of option the GUI should display
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum EngineOptionType {
  Check,
  Spin,
  Combo,
  Button,
  TypeString,     // `String` is a reserved word so `TypeString` is substituted
}

#[derive(Clone, Debug, PartialEq, PartialOrd)]
/// The `EngineOptionData` makes the data type generic so one `EngineOption` can represent everything
/// This would be set to the type of the engine option (ex. i32)
pub enum EngineOptionData {
  Int(i32),
  Float(f64),
  Text(String),
}

#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
/// The `EngineOptionDataType` type used to indicate the type of the `EngineOption` setting
pub enum EngineOptionDataType {
  DefaultVal,    // `Default` is reserved so `DefaultVal` is used
  Min,
  Max,
  Var,
}

#[derive(Debug, PartialEq)]
/// The `EngineOption` type is the overarching type representing a single configurable engine option
pub struct EngineOption {
  pub name: &'static str,
  pub option_type: EngineOptionType,
  pub option_data: HashMap<EngineOptionDataType, EngineOptionData>,
}

impl EngineOption {

  /// Constructs a new EngineOption of type T
  pub fn new(name: &'static str, option_type: EngineOptionType,
             option_data: HashMap<EngineOptionDataType, EngineOptionData>) -> EngineOption {
    EngineOption { name, option_type, option_data, }
  }

  fn engine_option_data_type_string(&t: EngineOptionDataType) -> String {
    match t {
      EngineOptionDataType::DefaultVal => String::new("default"),
      EngineOptionDataType::Min => String::new("min"),
      EngineOptionDataType::Max => String::new("max"),
      EngineOptionDataType::Var => String::new("var"),
    }
  }

  fn engine_option_data_string(&d: EngineOptionData) -> String {
    match eod {
      EngineOptionData::Int(v) => v.to_string(),
      EngineOptionData::Float(v) => v.to_string(),
      EngineOptionData::Text(ref v) => v.clone(),
    }
  }

  pub fn option_string(&self) -> String {
    let mut option_data_string: String = String::new();

    // FIXME: Hash maps are iterated out of order (obviously). In order to guarantee order in the response it'll be
    //        Easier to test if the key exists (since there are only 3 of them ever), if it does, get the value with
    //        HashMap::Get, which returns a reference.
    //
    //        Test for the key with HashMap::contains_key. You'll have to match for each instance using the private
    //        functions above. You will _still_ need to build a string like you did before.
    for (dt, eod) in self.option_data.iter() {
      let _: (&EngineOptionDataType, &EngineOptionData) = (dt, eod);


      option_data_string.push_str(&format!("{} {} ", dts, res));
    }

    let ots = match self.option_type {
      EngineOptionType::Check => "check",
      EngineOptionType::Spin => "spin",
      EngineOptionType::Combo => "combo",
      EngineOptionType::Button => "button",
      EngineOptionType::TypeString => "string",
    };

    format!("{} {} {} {} {} {}\n", commands::OPTION, commands::OPTIONNAME, self.name,
            commands::TYPE, ots, option_data_string)
  }
}