use std::str::FromStr;

use crate::domain;

use super::types::QueryParams;

#[derive(Debug, Default, Clone)]
pub struct Context {
    lang: Option<String>,
}

impl<'a> From<&QueryParams<'a>> for Context {
    fn from(params: &QueryParams<'a>) -> Self {
        params.iter().fold(Context::default(), |mut opts, p| {
            match p {
                ("lang", val) => opts.lang = Some(String::from(*val)),
                _ => {}
            };

            opts
        })
    }
}

impl From<Context> for domain::Context {
    fn from(rest: Context) -> Self {
        Self {
            lang: rest
                .lang
                .and_then(|l| domain::Lang::from_str(&l).ok())
                .unwrap_or_default(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn should_create_default_context() {
        let query_params = vec![];
        let rest_ctx = Context::from(&query_params);

        assert_eq!(rest_ctx.lang, None);
    }

    #[test]
    fn should_get_lang_from_query_params() {
        let query_params = vec![("lang", "rus")];
        let rest_ctx = Context::from(&query_params);

        assert_eq!(rest_ctx.lang, Some(String::from("rus")));
    }

    #[test]
    fn should_create_domain_context_from_rest() {
        let rest_ctx = Context {
            lang: Some(String::from("rus")),
        };
        let ctx = domain::Context::from(rest_ctx);

        assert_eq!(ctx.lang, domain::Lang::Rus);

        let rest_ctx = Context {
            lang: Some(String::from("eng")),
        };
        let ctx = domain::Context::from(rest_ctx);

        assert_eq!(ctx.lang, domain::Lang::Eng);
    }

    #[test]
    fn should_fallback_lang_to_default_if_lang_unsupported_or_missed() {
        let rest_ctx = Context::default();
        let ctx = domain::Context::from(rest_ctx);

        assert_eq!(ctx.lang, domain::Lang::Rus);

        let rest_ctx = Context {
            lang: Some(String::from("unsupported")),
        };
        let ctx = domain::Context::from(rest_ctx);

        assert_eq!(ctx.lang, domain::Lang::Rus);
    }
}