//! An agent's GitHub personal access token: an operator hands us the token, we
//! put it in the swarm's secret store.
//!
//! The agent end is `nix/agent-modules/github-token.nix`, which reads it under
//! the agent's own certificate into the `github-token` file its `gh` wrapper,
//! git credential helper and `hive-github-notify` read. No hive is in the path.

use axum::Json;
use axum::extract::State;
use axum::http::StatusCode;
use serde::Deserialize;
use swarm_secret_client::github;
use utoipa::ToSchema;

use super::linked_accounts::link;
use super::{AppState, error_problem, swarm_hive};

/// The token to store for one agent.
///
/// No `Debug` derive: this carries a token.
#[derive(Deserialize, ToSchema)]
pub struct PutGithubAccountRequest {
    /// The personal access token. Never logged, and never returned by this
    /// route.
    token: String,
}

/// Store an agent's GitHub token, unless it has one stored already.
#[utoipa::path(
    put,
    path = "/api/hives/{hive}/agents/{agent}/github-account",
    params(
        ("hive" = String, Path, description = "hive the agent runs on"),
        ("agent" = String, Path, description = "agent the token belongs to"),
    ),
    request_body = PutGithubAccountRequest,
    responses(
        (status = 204, description = "stored"),
        (status = 400, description = "the agent is not an identifier, the token is empty, or the hive is not in this swarm (problem+json)", body = String),
        (status = 409, description = "the agent has a token stored already; nothing was written (problem+json)", body = String),
        (status = 500, description = "the store could not be read or written (problem+json)", body = String),
    ),
    tag = "agents"
)]
pub async fn put_github_account(
    State(state): State<AppState>,
    axum::extract::Path((hive, agent)): axum::extract::Path<(String, String)>,
    Json(req): Json<PutGithubAccountRequest>,
) -> Result<StatusCode, problem_details::ProblemDetails> {
    let hive = swarm_hive(&state, &hive).map_err(|(s, d)| error_problem(s, &d))?;
    let agent = hive_types::Ident::parse(&agent)
        .map_err(|reason| error_problem(StatusCode::BAD_REQUEST, reason))?
        .into_string();
    let secret_path = github::account_path(&agent)
        .map_err(|e| error_problem(StatusCode::BAD_REQUEST, &e.to_string()))?;
    let credential = credential(&req).map_err(|e| error_problem(StatusCode::BAD_REQUEST, e))?;

    let store = crate::store::connect().await.map_err(|e| {
        tracing::warn!(error = %e, "connecting to the swarm secret store failed");
        error_problem(StatusCode::INTERNAL_SERVER_ERROR, &e.to_string())
    })?;
    link(&store, &secret_path, &credential).await.map_err(|e| {
        // The path names the agent; the value is not in it.
        tracing::warn!(path = %secret_path, error = ?e, "linking the github token failed");
        e.problem(&existing(&agent))
    })?;

    tracing::info!(%hive, %agent, "github token stored");
    Ok(StatusCode::NO_CONTENT)
}

/// The token a refused link names.
fn existing(agent: &str) -> String {
    format!("agent {agent} already has a github token")
}

/// The request as it is stored, or why it cannot be.
fn credential(req: &PutGithubAccountRequest) -> Result<github::Credential, &'static str> {
    let token = req.token.trim();
    if token.is_empty() {
        return Err("token is required");
    }
    Ok(github::Credential {
        value: token.to_owned(),
    })
}

#[cfg(test)]
mod tests {
    use super::{PutGithubAccountRequest, credential};

    fn request(token: &str) -> PutGithubAccountRequest {
        PutGithubAccountRequest {
            token: token.to_owned(),
        }
    }

    #[test]
    fn the_token_is_kept_without_surrounding_whitespace() {
        let c = credential(&request(" t0k3n\n")).expect("valid");
        assert_eq!(c.value, "t0k3n");
    }

    #[test]
    fn an_empty_token_is_refused() {
        assert!(credential(&request(" ")).is_err());
        assert!(credential(&request("")).is_err());
    }

    /// Bare-minimum `AppState`, as `forge_account`'s tests build it.
    fn state() -> super::super::AppState {
        super::super::AppState {
            hives: std::sync::Arc::new(vec![super::super::HiveEntry {
                name: "pr1ma".to_owned(),
                domain: "pr1ma.example".to_owned(),
            }]),
            links: std::sync::Arc::new(Vec::new()),
            status: None,
            wanted: None,
            agent_status: None,
            agent_icons: None,
            jobq: std::sync::Arc::new(std::sync::Mutex::new(hive_jobq::scheduler::Scheduler::new(
                hive_jobq::Graph::new(),
                hive_jobq::resources::ResourceTable::new(),
            ))),
            webhook_secret: None,
            config_prs: None,
            swarm_name: None,
            auth: None,
            forge: None,
            create_gate: std::sync::Arc::default(),
        }
    }

    async fn put(agent: &str, token: &str) -> problem_details::ProblemDetails {
        super::put_github_account(
            axum::extract::State(state()),
            axum::extract::Path(("pr1ma".to_owned(), agent.to_owned())),
            axum::Json(request(token)),
        )
        .await
        .expect_err("no store is configured in a test")
    }

    fn assert_store_unset() {
        for var in ["BAO_ADDR", "BAO_CLIENT_CERT", "BAO_CLIENT_KEY"] {
            assert!(
                std::env::var(var).is_err(),
                "{var} must be unset for this test to prove anything"
            );
        }
    }

    /// An agent name or an empty token is refused before the store: with
    /// `BAO_*` unset a store connect would answer 500.
    #[tokio::test]
    async fn a_bad_agent_or_an_empty_token_is_refused_before_the_store() {
        assert_store_unset();
        for (agent, token) in [("Atlas", "t0k3n"), ("../x", "t0k3n"), ("atlas", " ")] {
            let problem = put(agent, token).await;
            assert_eq!(
                problem.status,
                Some(axum::http::StatusCode::BAD_REQUEST),
                "{agent:?}: {problem:?}"
            );
        }
    }

    /// The control: a plain agent and a token reach the store connect.
    #[tokio::test]
    async fn a_plain_request_reaches_the_store() {
        assert_store_unset();
        let problem = put("atlas", "t0k3n").await;
        assert_eq!(
            problem.status,
            Some(axum::http::StatusCode::INTERNAL_SERVER_ERROR),
            "{problem:?}"
        );
    }

    #[tokio::test]
    async fn linking_a_second_token_is_a_409_and_the_first_stays() {
        use super::super::linked_accounts::{AccountStore, link, tests::FakeStore};
        use swarm_secret_client::github;

        let store = FakeStore::default();
        let path = github::account_path("atlas").expect("a valid path");
        let first = credential(&request("t0k3n-first")).expect("valid");
        let second = credential(&request("t0k3n-second")).expect("valid");

        link(&store, &path, &first)
            .await
            .expect("nothing is stored");
        let problem = link(&store, &path, &second)
            .await
            .expect_err("a token is stored")
            .problem(&super::existing("atlas"));

        assert_eq!(problem.status, Some(axum::http::StatusCode::CONFLICT));
        let detail = problem.detail.expect("a detail");
        assert!(
            detail.contains("agent atlas already has a github token"),
            "{detail}"
        );
        assert_eq!(store.written(), std::slice::from_ref(&path));
        let kept: github::Credential = store
            .read_optional(&path)
            .await
            .expect("store answers")
            .expect("still stored");
        assert_eq!(kept.value, "t0k3n-first");
    }
}