jelq

use axum::http::{HeaderName, StatusCode, header};

use serde_json::{Value, json};

use crate::link::{self, Link};

pub enum Payload {

    Empty,

    Json(Value),

    Raw(&'static str, Vec<u8>),

}

/// One way out of a 300, offered in the body and in `Link` alike.

pub struct Choice {

    pub(crate) href: String,

    pub(crate) method: &'static str,

    pub(crate) title: &'static str,

}

/// A successful result of a game action, before it becomes an HTTP response.

pub struct Outcome {

    status: StatusCode,

    payload: Payload,

    headers: Vec<(HeaderName, String)>,

}

impl Outcome {

    pub fn empty(status: StatusCode) -> Self {

        Self {

            status,

            payload: Payload::Empty,

            headers: Vec::new(),

        }

    }

    pub fn json(status: StatusCode, body: Value) -> Self {

        Self {

            payload: Payload::Json(body),

            ..Self::empty(status)

        }

    }

    pub fn raw(status: StatusCode, content_type: &'static str, body: impl Into<Vec<u8>>) -> Self {

        Self {

            payload: Payload::Raw(content_type, body.into()),

            ..Self::empty(status)

        }

    }

    pub fn choices(detail: &str, choices: &[Choice]) -> Self {

        let listed: Vec<Value> = choices

            .iter()

            .map(|c| json!({ "href": c.href, "method": c.method, "title": c.title }))

            .collect();

        let links = link::join(choices.iter().map(|c| {

            Link::registered(&c.href, "alternate")

                .title(c.title)

                .allow(c.method)

        }));

        Self::json(

            StatusCode::MULTIPLE_CHOICES,

            json!({ "detail": detail, "choices": listed }),

        )

        .header(header::LINK, links)

    }

    pub fn header(mut self, name: HeaderName, value: impl Into<String>) -> Self {

        self.headers.push((name, value.into()));

        self

    }

    pub fn status(&self) -> StatusCode {

        self.status

    }

    pub fn body(&self) -> Option<&Value> {

        match &self.payload {

            Payload::Json(body) => Some(body),

            _ => None,

        }

    }

    pub fn header_value(&self, name: &HeaderName) -> Option<&str> {

        self.headers

            .iter()

            .find(|(n, _)| n == name)

            .map(|(_, v)| v.as_str())

    }

    pub(super) fn retold(mut self, status: StatusCode, detail: &str) -> Self {

        self.status = status;

        if let Payload::Json(body) = &mut self.payload {

            body["detail"] = Value::from(detail);

        }

        self

    }

    pub fn into_parts(self) -> (StatusCode, Payload, Vec<(HeaderName, String)>) {

        (self.status, self.payload, self.headers)

    }

}