use std::collections::HashSet;
use std::time;

pub trait ProgrammingLanguageInterface {
    type Config: Default;
    fn language_name() -> String;
    fn source_file_suffix() -> String;

    fn run_computation(&mut self, _request: ComputationRequest<Self::Config>) -> ComputationResponse;

    fn request_meta(&mut self, _request: LangMetaRequest) -> LangMetaResponse {
        LangMetaResponse::Custom {
            kind: "not-implemented".to_owned(),
            value: format!(""),
        }
    }
}

pub struct ComputationRequest<'a, T> {
    pub source: &'a str,
    pub config: T,
    pub debug_requests: HashSet<DebugAsk>,
}

pub struct ComputationResponse {
    pub main_output: Result<String, String>,
    pub global_output_stats: GlobalOutputStats,
    pub debug_responses: Vec<DebugResponse>,
}

#[derive(Default, Debug)]
pub struct GlobalOutputStats {
    pub total_duration: time::Duration,
    pub stage_durations: Vec<(String, time::Duration)>,
}

#[derive(Debug, Clone, Hash, Eq, PartialEq, Deserialize, Serialize)]
pub enum DebugAsk {
    Timing,
    ByStage {
        stage_name: String,
        token: Option<String>,
    },
}

pub struct DebugResponse {
    pub ask: DebugAsk,
    pub value: String,
}

pub enum LangMetaRequest {
    StageNames,
    Docs { source: String },
    Custom { kind: String, value: String },
    ImmediateDebug(DebugAsk),
}

pub enum LangMetaResponse {
    StageNames(Vec<String>),
    Docs { doc_string: String },
    Custom { kind: String, value: String },
    ImmediateDebug(DebugResponse),
}